EPA/ 600/2-88^003
                                          January 1988
                                                    - 16-037*
                CONTROL TECHNOLOGY OVERVIEW REPORT:

                     CFC EMISSIONS FROM RIGID

                        FOAM MANUFACTURING
                               by:

             K.P. Wert, T.P. Nelson, and J.D. Quass
                       Radian Corporation
                     Austin,  Texas  78720
                   EPA Contract No. 68-02-3994
                       Work Assignment 66
                      EPA Project Officer:

                          N. Dean Smith
         Air and Energy Engineering Research Laboratory
Office of Environmental Engineering and Technology Demonstration
                Research Triangle Park. NC  27711
          AIR AND ENERGY ENGINEERING RESEARCH LABORATORY
                OFFICE OF RESEARCH AND DEVELOPMENT
               U.S. ENVIRONMENTAL PROTECTION AGENCY
                 RESEARCH TRIANGLE PARK, NC 27711

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                                TECHNICAL REPORT DATA
                          (Please read Instructions on the reverie before completing)
 i. REPORT NO
 EPA/600/2-88/003
                           2.
               ECIPIENT'S ACCESSION-NO.... _ „-.__
               PBS 8   1608797AS
4. TITLE AND SUBTITLE
 Control Technology Overview Report: CFC Emis-
  sions from Rigid Foam Manufacturing
            5. REPORT DATE
              January 1988
            6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
 K. P. Wert,  T. P. Nelson,  and J. D.  Quass
                                                       B. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
                                                       10. PROGRAM ELEMENT NO.
 Radian Corporation
 P.O. Box 9948
 Austin, Texas 78720
            11. CONTRACT/GRANT NO.

             68-02-3994, Task 66
 12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 Air and Energy Engineering Research Laboratory
 Research Triangle Park, NC  27711
            13. TYPE OF REPORT AND PERIOD COVERED
             Task Final; 3/86 - 11/86
            14. SPONSORING AGENCY CODE
              EPA/600/13
 is. SUPPLEMENTARY NOTES  AEERL project officer is N. Dean Smith. Mail Drop 62B.  919 /
 541-2708.
 is. ABSTRACT
              repOrt estimates total chlorofluorocarbon (CFC) emissions from the
 various rigid foam manufacturing processes and from the foam products themselves.
 and examines potential methods for reducing these emissions. Options studied in-
 clude replacement of CFC- blown products with alternative products not requiring
 CFCs, replacement of ozone- depleting CFCs with other chemicals  less likely to des-
 troy stratospheric ozone,  and recovery/recycle of CFCs released during manufac-
 turing processes. In the production of rigid cellular foams,  CFCs are used as physi-
 cal blowing agents to reduce foam density and impart thermal insulating properties.
 Such rigid foams include polyurethane, polyisocyanurate.  polystyrene,  polyethylene,
 polypropylene, polyvinyl chloride, and phenolic foams.  Uses of these foams include
 building insulation, packaging materials,  and single- service dinner-ware. Depletion
 of stratospheric ozone through action of halocarbons,  particularly CFCs^ has been
 the subject of extensive, study and wide debate. Although many uncertainties remain,
 current scientific evidence strongly suggests that anthropogenic CFCs could contri-
 bute to depletion of the stratospheric  ozone layer as was first postulated in 1974.
17.
                             KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Croup
 Pollution
 Foam Rubber
 Manufacturing
 Halohydrocarbons
 Ozone
Pollution Control
Stationary Sources
Rigid Foams
Chlorofluorocarbons
Stratospheric Ozone
13B
UJ
05C
07 C
07B
18. DISTRIBUTION STATEMENT
 Release to Public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
     199
20. SECURITY CLASS (Ttiispagt)
Unclassified
22. PRICE
EPA Perm 2220-1 (t-73)

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                      NOTICE

This document has been reviewed in accordance with
U.S. Environmental Protection Agency policy and
approved for publication.  Mention of trade names
or commercial products does not constitute endorse-
ment or recommendation for use.
                       11

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                                   ABSTRACT

     Over the past decade, depletion of stratospheric ozone through the action
of fully-halogenated hydrocarbons  (halocarbons) has been the subject of
extensive study and wide debate.  Current evidence suggests that such man-made
halocarbons could contribute to depletion of the stratospheric ozone layer,
although many scientific uncertainties remain.  A family of halocarbons known
as chlorofluorocarbons  (CFCs) are the primary suspects in ozone depletion
theory.

     In the production  of rigid polymer foams, CFCs are used as physical
blowing agents.  Rigid  plastic foams include polyurethane, polystyrene,
polyethylene, polypropylene, polyvinyl chloride, and phenolic foams.

     This report estimates the total CFC emissions from various types of rigid
foams, with emphasis on polyurethane and polystyrene foams, and suggests
methods for reducing these emissions.  A potential method for reducing CFC
emissions would be substitution of CFC-blown rigid foams with non-CFC
containing products.  A second method involves replacing ozone depleting CFC
blowing agents with low ozone depleting blowing agents.  A final alternative
would be to capture CFCs emitted during the manufacturing process.  The
effectiveness of each of these alternatives is discussed.
                                       iii

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                                   CONTENTS

Section
1.    Project Description 	      1
          Background 	  ......      1
          Project Objectives 	      4

2.    Summary of Results	      6
          Rigid Polyurethane and Polyisocyanurate Foams	      6
          Nonpolyurethane Foams  	     14
          Controls Likely to be Adopted by Industry	     23

3.    Industry and Emission Profile 	     39
          Overview of Rigid Foam Manufacture	     39
          Rigid Foam Industry Profile	     45
          CFC Emissions Characteristics  	     64
          Characterization of World CFC Emissions from Rigid Foams .  .     72

4i    Description of Current Process Technology 	     74
          Rigid Polyurethane Foam Production	     74
          Rigid Polystyrene Foam Production  . .	     82

5.    Control/Recycle Technologies for CFC-12 in Polystyrene Foam Sheet
     Manufacturing 	     87
          Carbon Adsorption and Steam Desorption Systems .	     87
          Incineration of Plant Exhaust  	    110

6.    Hydrocarbons as Polystyrene Foam Sheet Blowing Agents 	    112
          Plant Equipment and Operation Modifications	    113
          Control Effectiveness  	    114
          Cost of Control	    115
          Health and Safety Factors  	    121
          Current Status 	    121
          Economic Factors	    123
          Barriers to Implementation 	    124

7.    Alternative CFC Blowing Agents	    126
          Rigid Polyurethane Foam Blowing Agents	    127
          Polystyrene Foam Blowing Agents	    136
          Polyolefin and Phenolic Foam Blowing Agents	    145

8.    Substitutes for Current Rigid Foam Products 	    153
          Alternatives to CFC Blown Rigid Polyurethane Foam Products  .    153
          Alternatives to CFC Blown Polystyrene Foam Products  ....    172
          Alternatives to Other CFC Blown Foam Products	    180
               Preceding page blank

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                              CONTENTS  (Continued)

Section                                                                 Page

9.   Additional CFC Control Methods	   182
          Recovery of  CFC-11  Upon Product Disposal 	   182
          Use of Non-CFC, Non-Hydrocarbon Blowing Agents for
          Nonpolyurethane Foams  .....  	   184

REFERENCES	   186
                                    FIGURES

Number                                                                  Page

4-1  Laminated foam boardstock	    75

4—2  Foam injection operation	    77

4—3  Sprayed-foam operations 	    79

4-4  Rigid polyur ethane bun stock foam line	    81

4-5  Flow diagram of a typical  polystyrene foam sheet manufacturing
     process	    84

5—1  Schematic flow diagram of  typical carbon adsorption/
     solvent recycle process 	    89

5-2  Schematic flow diagram for polystyrene foam sheet model plant . .    98

5-3  Proposed CFC-12 carbon adsorption/recovery system for a
     polystyrene foam sheet extrusion plant	   101

5-4  CFC-12 adsorption on BPL*  activated carbon  	   102

8-1  Typical residential wall construction.  Basic wall with
     siding (top).  Basic wall  with brick veneer (bottom)  	   162

8-2  Insulative contribution of individual wall components 	   163

8-3  R-values per inch for various materials (at 24°C (75°F) mean
     temperature)	   164

8-4  Equivalent thicknesses for various materials (at 24°C (75°F)
     mean temperature)	   167

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                                    TABLES
Number                                                                  Page

2-1  Summary of Alternative Products as CFC Emission Control
     Options in Rigid Polyurethane Foam Manufacture  	     9

2-2  Summary of Low Ozone Depleting CFCs as a CFC-11 Emissions
     Control Option in Rigid Polyurethane Foam Manufacture 	    13

2-3  Summary of Alternative Blowing Agents for CFC-12 Emissions
     Control in Polystyrene Foam Sheet Manufacture 	    16

2-4  Summary of Add-on CFC Emissions Control Options in
     Polystyrene Foam Sheet Manufacture	    19

2-5  Summary of Alternative Products as CFC Emission Control
     Options in Polystyrene Foam Manufacture	    20

2-6  Controls Likely to be Adopted for Rigid Polyurethane Foam
     Bunstock and Laminated Board		    25

2-7  Controls Likely to be Adopted for Rigid Polyurethane Poured
     and Sprayed Foams	    27

2-8  Controls Likely to be Adopted for Rigid Extruded Polystyrene Foam
     Boardstock	    32

2-9  Controls Likely to be Adopted for Rigid Extruded Polystyrene
     Foam Sheet	    33

2-10 Controls Likely to be Adopted for Other Rigid Nonpolyurethane
     Foams	    35

3-1  Nonpolyurethane Foams and Corresponding CFC Blowing Agents and
     Mixtures	    46

3-2  Historical and Projected United States Rigid Polyurethane Foam
     Production:  1955 - 2015	    47

3-3  Major Producers of Rigid Polyurethane Foam Products 	    48

3-4  Major Suppliers of Polyurethane Liquid Foam Systems 	    52

3-5  1985 Rigid PU Foam Production and CFC Consumption in the U.S. .  .    55
                                     vii

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                              TABLES (Continued)

Number                                                                  Page

3-6  Polystyrene Foam Sheet, Film, Board, and Block Producers Including
     Extruders	    56

3-7  1985 Estimated Consumption of CFC Blowing Agents for the
     Manufacture of Polystyrene Foam	    62

3-8  Estimated CFC Non-Weighted Consumption & Emissions from Rigid
     PU Foam Production in the U.S	    66

3-9  Estimated CFC-11 and CFC-12 Emissions From Manufacture and
     Use of Rigid Polyurethane Foams in the U.S	    69

3-10 Estimated Half-Lives of CFC in Rigid Nonpolyurethane Foam   ...    68

3-11 Estimated CFC-12 Emissions From Manufacture and Use of Extruded
     PS-Foam Boardstock in the U.S	    71

4-1  Summary of CFC Emission Sources and Example Distribution in
     Polystyrene Foam Manufacturing	    85

5-1  CFC Emission Sources in PS-Foam Sheet Manufacture 	    91

5-2  Model Polystyrene Extruded Foam Sheet Plant Operating Parameters.    97

5-3  Polystyrene/CFC Material Balance  	   100

5-4  Carbon Adsorption System Design Parameters  	   104

5-5  Estimated Capital Costs for Equipping a PS-Foam Sheet Extrusion
     Plant with a CFC-12 Carbon Adsorption System	   106

5-6  Estimated Annual Operating and Maintenance Costs for Equipping
     a PS-Foam Sheet Extrusion Plant with a CFC-12 Carbon Adsorption
     System	   107

6-1  Model Polystyrene Extruded Foam Sheet Plant Operating
     Parameters	   116

6-2  Estimated Capital Costs for Equipping a PS-Foam Sheet Extrusion
     Plant with a Pentane Blowing Agent System	   117

6-3  Estimated Operating and Maintenance Costs for Equipping a PS-Foam
     Sheet Extrusion Plant with a Pentane Blowing Agent System ....   118
                                     viii

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                              TABLES (Continued)

Number                                                                  Page

6-4  Estimated Capital Costs for a PS-Foam Sheet Extrusion Plant
     with a Carbon Adsorption System for Pentane Recovery  	   119

6-5  Estimated Operating and Maintenance Costs for Equipping a
     PS-Foam Sheet Extrusion Plant with a Pentane Carbon Adsorption
     System	   120

6-6  Physical Properties of CFC-12 and Hydrocarbon Blowing Agents  . .   122

7-1  Evaluation Factors for Substitute Rigid Polyurethane Foam
     Blowing Agents  	   135

7-2  Evaluation Factors for Substitute Polystyrene Foam Blowing
     Agents	   144

7-3  Evaluation Factors for Substitute Polyolefin Foam Blowing Agents.   151

7-4  Evaluation Factors for Substitute Rigid Phenolic Foam Blowing
     Agents	   152

8-1  1985 Market Distribution for Polyurethane and Poly-
     isocyanurate Insulation Foams 	   155

8-2  Potential Substitutes for Rigid PU Foam Products	   156

8-3  Non-Residential Roofing Insulation Market 	   158

8-4  Estimated Energy Losses From Using Alternative Insulation in
     Industrial and Commercial Roofing 	   161

8-5  Estimated Relative Material and Energy Costs for Substitute
     Sheathings	   166

8-6  Contribution to Total Insulation System Made by PU Foams in
     Various Applications  	   169

8-7  Relative Costs of Alternative Refrigerator  Insulations  	   170

8-8  Potential Substitutes for PS-Foam Products  	   174

8-9  Retail Costs 'for a Variety of Single Service Plates	   177

8-10  1985 Market Distribution for Extruded Polystyrene Insulation
     Foams	   179

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                                   SECTION 1
                              PROJECT DESCRIPTION

BACKGROUND

     Over the past decade, depletion of stratospheric ozone through  the  action
of  fully-halogenated  hydrocarbons  (halocarbons)  has been the  subject  of
extensive study and wide  debate.   This  phenomenon involves a complicated  set
of interactions that are  driven  by ultraviolet radiation and occur within the
upper atmosphere.   Not only are the interactions extremely complex,  but  direct
observations of them are  difficult.   Current evidence suggests  that man-made
halocarbons could contribute to  depletion of the  stratospheric  ozone layer,
although many scientific uncertainties remain.

     A family  of  halocarbons known  as  chlorofluorocarbons  (CFCs)  are  the
primary suspects in the* ozone  depletion theory.  Since  they are stable,  CFCs
have a long  life  in the  atmosphere  and are not  readily decomposed by  the
levels of ultraviolet radiation  present in the lower atmosphere.  Once  a CFC
molecule has been transported into the  stratosphere, it can be  acted  upon by
the higher  intensity  ultraviolet  radiation releasing  halogen  atoms  which
catalyze the breakdown of ozone  to diatomic oxygen.  Such depletion  of the
protective layer of stratospheric  ozone would  result in increased ultraviolet
radiation to earth  which  may cause  adverse effects including  increases  in
melanoma cancer, reduce crop yields, photochemical  degradation of  plastics,
and changes in the global climate.

     An  important  aspect  of  the  ozone  depletion problem is  the lag time
between  the  manufacture   of  CFCs  and their  ultimate arrival in the  upper
atmosphere.  During this  lag time which lasts from several  to hundreds  of
years,  the CFCs move  through a  series  of  reservoirs.    The  first  major

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reservoir  consists  of newly manufactured CFCs  being  held in storage.  Here,
they  are retained  for a period which is on the order of months.  Next may be
a reservoir  of  CFCs which are "banked" in the end-use product.  The retention
time  here  can be brief, or in products  such  as rigid polyurethane foams,  the
holdup time  can last  for  hundreds of  years.   Finally, cumulative emissions of
CFCs  from  all  sources  have created a lower atmospheric reservoir from which
CFCs  continuously diffuse into the upper atmosphere.   The significance of  this
lag time is  that there can  be a considerable  delay between the release of  CFCs
and the  occurrence of ozone depletion which they might cause.   Therefore,  even
if  all  controllable  emissions  are  reduced promptly,  the  emissions  from
uncontrollable  sources will continue  for some  time into the future.

      CFCs  are widely  used in several industries including  rigid foam manufac-
turing.   In  that  industry,  CFC-11   (fluorotrichloromethane)   and CFC-12
(dichlorodifluoromethane),  CFC-113  (trichlorotrifluoroethane), and  CFC-114
(dichlorotetrafluoroethane) are  used  as  physical blowing agents to reduce  foam
density  and  impart thermal  insulating  properties.   CFC-11 is  the  primary
blowing  agent for rigid polyurethane  and polyisocyanurate foams.   The exotherm
from  the polymerization reaction  causes  volatilization of the CFC,  and the
vapor is trapped within the cellular  matrix of the polymer foam.   The cellular
structure  provides  the foam with  its rigidity, and the CFC-11 vapor trapped
within the cells gives these  foams  their exceptional  thermal insulating
properties.   For nonpolyurethane foams such as extruded polystyrene (PS) foam,
CFCs  are also used as  a  primary blowing agent.   CFC-12 is the predominant
blowing  agent used in extruded CFC-blown PS foams.  The main function of these
CFCs  is  to produce numerous small  closed cells which reduce the foam's density
while providing good  structural  strength.  The amount of blowing agent in a
given formulation depends on  the property specifications of the product.

     The CFC-11 in rigid  polyurethane and polyisocyanurate foams is character-
ized  as  being banked,  i.e., the CFC  gas is sealed in the  foam's  closed cells
with  a half life of  approximately 100 years.   From these  cells, the blowing
agent slowly  diffuses over  a  period of centuries.   Therefore,  the quantity of

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banked CFC-11 grows rapidly with each year's  foam production,  and essentially
serves  as  an  uncontrollable  source of emissions.   Historically,   some
polyurethane foams have  been blown with CFC-12 as an  auxiliary  to  CFC-11.
However, the use of CFC-12  has experienced a substantial decline  and current
use is limited primarily to poured polyurethane foams.  For the  purposes of
this report, it is assumed  that CFC-12  also has a half-life in these foams of
about 100  years  (47).   Similarly, the  CFC-12 used  to blow  polystyrene
boardstock is  banked.  This  blowing agent's  estimated half-life in this
product is 40 years,  so there  is also a  steady  increase in  size of this  CFC-12
bank as long as the use  of  PS boardstock increases.  Worldwide data compiled
by the Chemical Manufacturers Association shows that  of the nearly 1.2 million
metric tons  of CFC-11 used in  rigid  closed cell foams  since  the  mid-1950s,
about 53 percent  is currently banked in  the foam.   Of the  244  thousand metric
tons of  CFC-12 used   in  closed cell foams, about six  percent is  currently
banked (1).

     Additionally,  the CFC-11  and  CFC-113 used to blow  phenolic foam is also
characterized as  being banked.  However,  since  CFCs are essentially  insoluble
in phenolic  foam,  the CFC gas  is  sealed in the foam's  closed cells for the
life of the foam.

     Emissions of  CFC-12 blowing  agent  from the  extruded  polystyrene  foam
sheet (as compared to  PS foam board)  manufacturing process are characterized
as being prompt, i.e.,  the CFC gas  is  released during, or soon after,  foam
formation.    Therefore,  in  this  industry the  quantity  of  CFC-12 emitted
annually essentially  equals the amount consumed annually.   This contrasts  with
the  CFC banking which occurs  with rigid  polyurethane and  polystyrene
boardstock foams.

     Emissions of CFC  from  polyolefin  (i.e.,  polyethylene  and polypropylene)
and polyvinyl chloride foams are  also characterized  as being  prompt.  These
emissions may consist  of CFC-11,  CFC-12, CFC-114, or a mixture  depending on

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 the  foam type and thickness.  Thus, like PS  foam sheet,  the quantity of CFC
 emitted  annually  essentially equals  the amount  consumed annually.

      Chlorofluorocarbon  use in the rigid foam  industry is increasing in the
 United States  and worldwide.  In 1985  in the US, approximately  43,000 metric
 tons  of  CFC-11 and 7,000 metric tons of CFC-12 were used to manufacture rigid
 polyurethane foams.   For the same year, the  consumption  of CFC-12 in poly-
 styrene  foams  was roughly 9,200 metric tons.  Additionally in  1985, a total of
 approximately  5,000 metric  tons of CFCs  (comprised of CFC-11,  CFC-12,  and
 CFC-114) were  used for polyolefin  foams and an  additional  1,400  metric tons of
 CFCs  (comprised of CFC-11 and CFC-113)  were  used for  phenolic  foam.  It  is
 estimated  that in 1985  the  rigid  foam  industry accounted for 51  percent  of
 total domestic consumption  of CFC-11 and 11  percent of the  total domestic
 CFC-12 consumption (2).

 PROJECT  OBJECTIVES

     The primary  objective  of this study was to evaluate technical options to
 reduce emissions  of CFCs associated with rigid polyurethane  and polystyrene
 foam  processes and products.  In this  study,  the following emission  controls
were  emphasized:   hydrocarbon blowing  agents  for  PS   foams,  recovery  and
 recycle  of CFC—12 in PS foam manufacturing,  and alternatives to  CFC blown
 rigid foam  products.   Technical  options  to reduce CFC  emissions  from
 polyolefin,  PVC,  and phenolic foam processes  and products  were also evaluated.

     An  in-depth  evaluation  of the factors involved  in  these  CFC controls was
 performed.   These factors  include estimated  emissions  of CFCs  from  various
 foam  production processes and end-uses,  and the availability of controls  for
these sources.  For all  control technologies, engineering  and economic aspects
have  been  examined, as  well as barriers to  control implementation.  The
 relative effectiveness of each control  technique was examined.  A profile of
 the rigid  foam industry  including  number and  location of active  firms, process
technology,  and projected growth,  has also been prepared.

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     Based on these evaluations,  promising controls were  identified  for the
various foam categories.   For each of these, a more  detailed evaluation was
performed which  addressed the  key technical  factors,  safety,  economics,
current status, and control  cost  effectiveness.   The effectiveness of control
consists of both the degree to which emissions can be curtailed, or controlled
CFG emission, and the costs per unit averted.

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                                   SECTION ?.
                              SUMMARY OF RESULTS

     In the production of rigid foams. CFCs are used  as physical blowing
agents.  The action of these blowing agents generates numerous  small  closed
cells in the foam thereby providing structural strength and low density.  In
insulating applications, the CFCs are also desirable  due to their  good  thermal
insulating properties.  For rigid polyurethane foams, the most  commonly used
blowing agent is CFC-11.  For CFC-blown polystyrene foams, the  predominate
blowing agent is CFC-12, while mixtures of CFC-11/12/114 are used  for
polyolefin foams and mixtures of CFC-11/113 are used  for phenolic  foam.

RIGID POLYURETHANE AND POLYISOCYANURATE FOAMS

     Since their introduction in the early 1940s, rigid polyurethane  foams
have experienced tremendous growth in both production and applications.  Fire
retardant polyisocyanurate foams which are based on a chemistry similar to
that of polyurethane foams, have played a major part  in this growth.  Because
of the similarities in chemistry, processing, and product applications, this
report will use the word polyurethane (PU) to refer to both polyurethane and
polyisocyanurate.  The superior insulating characteristics of PU foams  have
allowed them to be used in a variety of insulating applications ranging from
household appliances to large commercial buildings.   In 1985, rigid poly-
urethane foam production in the U.S. reached approximately 336,000 metric
tons.  Approximately 90 percent of this production is used as thermal
insulation.  The remainder is used in packaging, flotation devices, and a
variety of other applications.

     In general, rigid polyurethane foam production can be divided into four
types of processes:  laminated foam panels, poured/injected foams, sprayed
foams, and bunstock.  Further, the consumption of rigid polyurethane  foams can

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be broken down into seven application areas.  These are:  building  insulation.
refrigerated appliance insulation, industrial insulation, packaging,
transportation insulation, and other miscellaneous applications.

     CFC-11 is the primary blowing agent for rigid polyurethane foam manufac-
ture.   A smaller amount of CFC—12 is used particularly in pour—in-place
applications.   In 1985, the estimated total U.S. consumption of CFC-11 and
CFC-12 for rigid PU foam manufacture was 43,000 and 7,000 metric tons, respec-
tively.

     Rigid polyurethane foams have a very low permeability; therefore, the
CFCs used in their manufacture are trapped and held for a very long period of
time.   The half life of CFC-11 in rigid polyurethane foam is estimated to be
in excess of 100 years.  This means that with each year's production, a
growing reservoir or bank of CFC-11 is being formed.  This bank serves as a
very large and virtually uncontrollable source of CFC emissions.  It is
estimated that currently, for U.S. production, tiearly 461,000 metric tons of
CFC-11 and 74,000 metric tons of CFC-12 are banked in rigid polyurethane foam.
Further,  if the use of these foams continues to grow as it has in the past,
the quantity of banked CFCs will have tripled to 1.4 million metric tons of
CFC-11 and 228,000 metric tons of CFC-12 by the year 2000.

     Because the rigid polyurethane holds the CFCs tightly, the emissions of
CFCs during foam production are low.  For 1985, the estimated foam  production
emission rates for CFC-11 and CFC-12 for all PU foams were 3,900 and 2,300
metric tons, respectively.  The remaining CFC emissions for 1985 come from
in-use emissions from the product.  For CFC-11 and CFC-12, these emissions
come from a slowly emitting bank and result in 2,900 and 500 metric tons of
emissions, respectively.   Therefore, the 1985 total CFC-11 and CFC-12 emis-
sions  for rigid polyurethane foam are 6,800 and 2,800 metric tons,  respect-
ively.

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Polyurethane Foam Product Substitutes

     Because rigid FU manufacturing  emissions are relatively  small and  in-use
emissions occur slowly over an extremely long time period, it is  difficult  to
effectively control these emissions.  However, one option which can  provide a'
reduction in future CFC emissions, is to switch to substitute products  which
contain either smaller quantities of CFCs or none at all.  Table  2-1  summa-
rizes the aspects of various substitutes.  A majority of rigid polyurethane
foam is used as insulation for commercial and residential buildings.  In  this
application, FU foams are found in a wide variety of specific uses and  instal-
lation configurations.  Because of this, applicability and selection of a
substitute will be dependant upon the particular insulation project.  Among
the various properties which are characteristic of rigid FU foams, perhaps  the
most important are unequaled insulation efficiency per unit thickness,  fire
retardancy, structural rigidity, and ease of installation.

     In cases where substitute insulation materials of equivalent thickness
are used for FU foam, the probable result will be higher energy costs.  Use of
thicker substitute insulation or alternative construction methods can prevent
increased energy costs, but often only under penalty of higher installation
and material costs.  Many states have enacted building codes which specify
minimum insulation efficiencies for  the walls, ceilings, and  other components
of residential and commercial buildings.  Because these standards have  been
set with CFC-blown insulation in mind, the specifications cannot  always be  met
with alternative materials in conventional design and construction.
Additional regulations or specifications concerning fire retardancy  and
mechanical strength can preclude the use of substitute materials without
design modifications.

     Industrial and commercial roofing comprises nearly 65 percent of the
rigid polyurethane and polyisocyanurate insulation foam market.   There  are  a
number of non-CFC containing materials which are also used in this application
area, but each has limitations with  respect to its insulating properties, fire

-------
TABLE 2-1.  SUMMARY OF ALTERNATIVE PRODUCTS AS CFG EMISSION  CONTROL OPTIONS  IN RIGID  POLYURETHANE
            FOAM MANUFACTURE
= 	 ..

Applications
Industrial Roof/Ceilingt


Industrial Halls:

Commercial Roof /Ceiling:


Commercial Ha' 'si


Commercial Floors!




Alternatives
Fiberglass
Perlite
Expanded PS
Extruded PS
Fiber board
Cellular Glass
Insulating Concrete
Fiberglass
Rock Wool
Perlite
Vermiculite
Insulating Concrete
Fiberglass
Perlite
Expanded PS
Extruded PS
Fiberboard
Cellular Glass
Insulating Concrete
Fiberglass
Rock Wool
Perlite
Vermiculite
Expanded PS
Extruded PS
Fiberboard
Cellular Glass
Fiberglass
Rock Wool
Expanded PS
Extruded PS

CFC X
Emission
Reduction
Potential
100
100
100
40
100
100
100
100
100
100
100
100
100
100
100
40
100
100
100
100
100
100
100
100
40
100
100
100
100
100
40

Relative _
Control
Materials
Savings
Low
High
Low
Medium

Low

Low
High
Low
Medium

Low
High
Low
Medium

Low
High
Low

Costs
Energy
Costs
Low
High
Medium
High
High
High
Low
Medium
High
High
High
Low
High
Medium
LOW
High
High
High
Low
Medium
High
High
Medium
Low
High
High
Low
Medium
Medium
I —..



Control
Applicability
Dependent upon
application


Dependent upon
application.
but generally
good.

Dependent upon
application


Dependent upon
application,
but generally
good.


Dependent upon
application.



Availability
All alternatives
currently
available.


All alternatives
currently
available.

All alternatives
currently
available.


All alternatives
currently
available.


All alternatives
currently
available.



Barriers to
Implementation
Higher energy
costs or
higher
construction
costs for
building.

Higher energy
costs or
higher
construction
costs for
building.
Higher energy
costs or
higher
construction
costs for
building.

Higher energy
costs or
higher
construction
costs for
building.


Higher energy
costs or
higher
construction
costs for
building.

-------
                                                      TABLE 2-1  (Continued)
Application*
Residential Roof /Ceiling I





Residential Walla:








Alternative Insulating
Technologies!



Residential Floors:





Refrigeration Insulation:

Packaging

CFC X
Em is 8 ion
Relative
Control Costs
Reduction Materials Energy
Alternatives Potential Savings Costa
Fiberglass
Rock Wool
Cellulose



fiberglass Board
Expanded PS
Extruded PS
Fiberboard
Per lite Board
Cellular Glass
Gypium
Plywood
Foil Faced Laminated Board
Insulating Brick
Thicker Halls/Fiberglass
Batts



Fiberglass
Rock Wool
Foil Faced Laminated Board



EPS
Extruded PS
Fiberglass
EPS Foam Peanuts or Blocks
Plastic Film Bubble Wrap
Wood Shavings
100
100
100



100
100
40
100
too
100
100
100
100
100
100



100
100
100



100
40
100
100
100
100
Low





Low
High
Low
Medium
High

High
Low
Medium
Low
Low



Low

Medium



Medium
Medium
Low
Low
Low
Low
Low
Medium
Medium



Low
Medium
Low
High
High
High
High
High
High
Low
Low



Low
Medium
High



Low
Low
Medium
NA
NA
NA
Control
Applicability
Dependent upon
application.




Dependent upon
application, but
generally good.






Dependent upon
application, but
generally good.



Dependent
upon appli-
cation.



Can be generally
interchanged

Can be generally
interchanged

Availability
All alternatives
currently
available.



All alternatives
currently
available.






Insulation brick
not currently
available in
U.S.. fiber-
glass is
available.
All alternatives
currently
available.



All materials
currently
available
All materials
currently
available
Barriers to
Implementation
Higher energy
costs or
higher
construction
coats for
building.
Higher energy
costs or
higher
construction
costs for
building.



Possible
higher
construction
costs.


Higher energy
costs or
higher
construction
costs for
building.
Higher manu-
facturing
costs
No apparent
barriers

"Control  costs  are broken into two groups:   (1) material savings—because  all alternative products  have  a lower cost than PU products;
 (2) energy  cost—because all alternative  products have a lower insulating efficiency per unit thickness than PU products.

-------
retardancy,  mechanical strength or ease of installation which might restrict
its utility  as a substitute in a particular installation.  Because of the
complexity of the roofing market, choice of an alternative will require
evaluation on a case by case basis.  Also, since polyurethane and poly-
isocyanurate foams have the highest insulation value per unit thickness, use
of an equal  thickness of the alternative insulations discussed in this report
will cause an approximately 30 to 60 percent increase in energy costs.  If
greater thicknesses of an alternative insulation material are used, the added
energy costs can be eliminated; however this can substantially increase the
capital and  installation costs.

     In residential wall sheathing applications which comprise about 20
percent of the PU insulation market, probably one of the best near term
alternatives to rigid PU foam is expandable polystyrene bead board.  This
material is  roughly 43 percent less expensive than polyurethane insulation
board and for an equivalent thickness, has about half the insulative capacity.
Using expandable PS bead board, the total wall insulation system would have
about 15 percent higher energy losses.  Other substitute materials include:
extruded polystyrene board, fiberglass board, various fiber boards, plywood,
gypsum, and laminated paper board.  With  the exception of the extruded poly-
styrene board, all of these alternatives  offer 100 percent reduction in CFC-11
emissions.  Because extruded polystyrene  board does use some CFCs, it offers
approximately a 40 percent CFC-11 emission reduction potential.

     For insulation of refrigerated appliances and transport vehicles, the
best alternatives are expandable bead polystyrene, extruded polystyrene, and
fiberglass.   Again, these alternatives will require thicker walls, or there
will be higher energy losses.  An added drawback to these alternatives is
higher manufacturing costs.  Polyurethane foams may simply be injected as
liquids into the cavity of a refrigerated appliance, yet the alternatives must
be manually cut and placed into  the cabinets.
                                       11

-------
     A novel approach to increased energy efficiency and reduce CFC
consumption in a home appliance is the use of a vacuum board.  The vacuum
board is a relatively thin product which has e high R-value per inch  (30 to
35) created by a vacuum contained in the board.  Three different models of
vacuum board have been tested by the U.S. DOE.  Of these products, the
Japanese board appears to be the most advanced and has been used commercially.
However, the use of vacuum boards in Japan is decreasing because of problems
with leakage.  The vacuum board is composed of fine silica powder  (lOOu)
sealed in an evacuated impermeable bag.  The bag is adhered to one side of the
wall cavity, and then polyurethane foam is poured around it.  One problem with
this technique has been that the CFCs in the foam have bled into the
"impermeable" bags.  The result is a substantial loss in the  insulating
Duality of the board.  In the U.S., General Electric is currently doing
research, development, and testing on their own patented vacuum board
technology.

     In packaging applications, the thermal insulating characteristics of
polyurethane foams are usually not important and a variety of alternatives
exist.  Included in these are non CFC blown loose-fill expanded polystyrene,
expandable bead polystyrene foam blocks, shredded and wadded  paper, cellulose
wadding, die—cut cardboard, and wood shavings.  All of these  alternatives
offer 100 percent reduction in CFC-11 emissions.

CFC Blowing Agent Substitutes

     Use of low ozone depleting CFCs as blowing agents is another possibility
for reducing CFC emissions from rigid polyurethane foams.  For rigid
polyurethane foam, the potential alternative CFCs include CFC-123 and
CFC-141b.  These were selected on the basis of having chemical and physical
properties similar to those of CFC-11; however, each has potential drawbacks
which are discussed in this report.  Table 2-2 gives a summary of  this
option.  Because these alternative CFCs are not commercially  available,
                                                                      i
implementation of this control technology would be a longer term solution.
                                       12

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    TABLE 2-2.   SUMMARY OF LOW OZONE DEPLETING CFCS AS A CFC-11 EMISSIONS
                CONTROL OPTION IN RIGID POLYURETHANE FOAM MANUFACTURE
Factor
Lower Ozone Depleting
CFC Compounds
Percent Emissions  Reduction
Control Cost  ($/mt)
Control  Applicability
Availability  and  Status
Barriers  to  Implementation
Nearly 100 percent depending
on substitute.

High or unknown, possibly in-
crease blowing agent cost 5-10
times.

Good, if substitute chemical
is deemed to have acceptable
properties.

Poor, possible candidate CFCs
are not commercially available.

High cost, or not available;
some chemicals toxic or
flammable; long development
time.
                                      13

-------
     An additional option exists for reducing  CFC-11 use  in  pour-in-place
appliance insulation foams.  These  foams which are  used in appliances  such as
refrigerators, are commonly produced with a blowing agent composed of  both
CFC-11 and CO..  The COo is produced when water added  to  the formulation
mixture reacts with the isocyanate.  Many pour-in-place foam systems already
have 10 to 15 percent of the CFC-11 replaced by water-generated CO..   An
additional 15 to 18 percent of the  CFC-11 can  be replaced using more water.
The drawbacks and limitations of this option are discussed in this report.

NONPOLYURETHANE FOAMS

     Nonpolyurethane foams include  polystyrene,  polyethylene,  polypropylene.
polyvinyl chloride and phenolic foams.  This report focuses  primarily  on
extruded polystyrene foams due to the market size and  relative consumption and
emissions of CFCs during the manufacture and use of these foams.  Since their
introduction, these foams have seen rapid growth as new applications were
discovered, and there is yet a large potential for  expansion into new  areas.
The other nonpolyurethane foams are not dealt  with  extensively in this report
because limited information is available owing to limited size of some of the
foam markets and the relative number of producers (i. e..  much of the
information is proprietary).

Rigid Polystyrene Foams

     Polystyrene is extruded into both sheet and board profiles.  Extruded PS
sheet is a thermoformable material  which is used to make  a variety of  single
service and packaging items such as stock food and  produce trays, egg  cartons.
hinged carry-out containers, plates, cups, and bowls.  Over  80 percent of the
total extruded PS foam made (blown  with CFCs or hydrocarbons)  is manufactured
as sheets.  Extruded PS board is used as an insulation material much in the
same way as foamed polyurethane insulation.
                                       14

-------
     In 1985,  the total U.S. production of extruded polystyrene boardstock was
nearly 49,000 metric tons.  In the same year, the total U.S. production of CFC
blown polystyrene extruded sheet was approximately 104,100 metric tons.  The
total U.S.  consumption of CFC-12 to form the PS products was 9,200 metric
tons.  Because the blowing agent is able to permeate through the foam  rela-
tively quickly, the CFC-12 from sheet manufacture is emitted early in  the
product's shelf life. On the other hand, because polystyrene board is  thick,
the CFCs are retained for a longer period of time resulting in banking of the
CFC-12.  The estimated half-life for the CFCs in polystyrene board is  40 years
(5).

     Because the CFC half-life in polystyrene board is relatively long, the
same concern with banked CFCs applies to this foam as does apply to rigid
polyurethane foams.   However, the amount of CFCs which are banked is  much
smaller.  It is estimated that currently nearly 27,000 metric tons of  CFC-12
are banked in polystyrene foam board.  This bank is estimated to roughly
triple to 90,000 metric tons by the year 2000.  The emissions from the CFC-12
bank for PS foam will continue to grow as long as  the use  of PS boardstock
grows.

     For the U. S., the 1985 CFC-12 emissions for rigid polystyrene foams were
estimated at 4,300 metric tons.  Of this total. 3,700 metric tons were emitted
from PS foam sheet manufacturing and thermoforming, and 600 metric tons were
emitted from the PS extruded board manufacturing process  and bank.

Blowing Agent Substitutes—
     For polystyrene foam sheet, the use of  low ozone depleting blowing agents
can reduce the emission of  ozone depleting CFC-12.  The use of low ozone
depleting blowing agents  includes using non-fully  halogenated CFCs, hydrocar-
bons, and inert gases.  Table 2-3 summarizes the aspects  of various alterna-
tive blowing agents.
                                       15

-------
                      POLYSTYRENE FOAM SHEET MANUFACTURE
Factor
  Pentane
Substitution
     Pentane
Substitution With
Carbon Adsorption
  Depleting
CFC Compounds
  CFC/HC and
CFC/C02 Blends
Percent Emissions    100
Reduction

Control Cost         $238/mtf
($/mt)
Control
Applicability
Availability and
Status
Barriers to
Implementation
                        100
                        $305/mt'
   Good
  Good
   Excellent* is
   currently widely
   used
   Pentane emissions
   may require
   add-on controls
   for VOC emission
   control;
   reformulation and
   equipment
   conversion costs;
   increased fire
   hazards
  Excellent.
  widely used
  High capital
  expense;
  ventilation
  modification
  needed; waste
  disposal
                      92-100               15-30
                      High or unknown.     Low
                      possibly increase
                      blowing agent
                      cost 5-10 times
Good, if
Substitute
chemical has
correct
properties

Poor, possible
candidate CFCs
are not
commercially
available

High cost, or not
available; some
chemicals toxic
or flammable;
long development
time
Good
Good
Reformulation and
conversion cost;
more difficult
process and
quality control
a
  Specific control costs based on model plant calculations.  Fire insurance costs not included.

-------
     One option  that  offers  considerable  promise  in  reducing CFC-12 emissions
in the manufacture  of polystyrene  sheet is  substitution of  the  CFCs with a
hydrocarbon blowing agent.   Currently, hydrocarbons  such as n-pentane, iso-
pentane or n-butane are viable candidates for  replacing CFC-12  in polystyrene
foam sheet production.  These options  can eliminate  use of  CFC-12 in this
application, thereby  providing 100 percent  reduction in emissions of this
ozone depleting  compound.  However,  the resulting pentane emissions, if not
controlled, may  contribute to ground level  atmospheric  pollution.

     When polystyrene foams  were first introduced in the mid-1960s, they were
blown almost exclusively with pentane.  However,  the fire hazards associated
with pentane have caused a gradual conversion  to  CFC-12 as  a blowing agent.
In spite of the  trend away from using  hydrocarbons,  it  is possible to make
virtually all thermoformable polystyrene  foam  sheet  using a hydrocarbon such
as pentane as a  blowing agent.

     "Converting  a plant so that it may use  pentane rather than  CFC-12 as a
blowing agent would require  modifications including  new tanks,  pumps and
associated piping,  explosion-proof electrical  equipment, a  modified
ventilation system, and an improved fire  protection  system.  The capital cost
involved in these modifications could  possibly be offset by the fact that
pentane is I/A to 1/5 the cost  of  CFC-12  and 20 percent less pentane is
required to blow the  same quantity of  foam.

     With pentanes, there may be additional costs associated with add-on
controls to reduce  total VOC emissions.   Pentane  is  regulated as a ground
level ozone precursor, and therefore,  will  require some type of control in
ozone nonattainment areas.   Because  of its  reactivity,  ground level ozone is
considered to be a  pollutant and will  react long  before it  could travel to the
upper atmosphere.   Table 2-3 points  out the costs and availability of pentane
with an add-on VOC  control device.
                                       17

-------
     Use of alternate lower ozone depleting CFCs is also a potential method
for reducing CFC-12 emissions from rigid polystyrene manufacturing.  Candidate
substitute CFCs include CFC-22. CFC-124, FC-134a, and CFC-142b.  Both CFC-124
and FC-134a are promising as substitutes for CFC-12; however* they are  not yet
commercially available.  CFC-22 and CFC-142b are available, but they have
physical properties which might make them unsuitable for extruded polystyrene
insulation board.  However, they might prove satisfactory as polystyrene foam
sheet blowing agents.  Since much polystyrene foam sheet is used for packaging
products which come into contact with food, thorough tozicity testing and FDA
approval would be required for the new blowing agent.  Implementation of this
alternative is expected to be an option available in the longer term.

     Finally. CO. is used to reduce but not eliminate the use of CFC-12 in PS
foam manufacturing.  This technology is currently available and can reduce
emissions by 15 to 25 percent.  In addition, blends of CFC and hydrocarbons
can also be used to reduce CFC emissions.

Add-On Controls for CFC Reduction—
     Add-on CFC control possibilities are recovery and recycle of CFC-12
through the use of a carbon adsorption system, or destruction of CFCs through
incineration.  A carbon adsorption and recovery system would require a  sub-
stantial capital investment, but this cost could be partially offset if the
recovered CFC-12 could be reused.  An incineration system, on the other hand,
would have generally high operating costs with no potential recovery credit.
Table 2-4 summarizes the important factors concerning these two options.

Polystyrene Foam Product Substitutes—
     The only other currently available CFC control technique for CFCs  from
polystyrene foam sheet is substitution with products which do not contain
CFCs.  Table 2-5 summarizes the aspects of substitution with various non-CFC
containing products.  Most polystyrene foam sheet products serve essentially
the same purpose as the materials they have replaced.  Indeed, in many  appli-
cations, polystyrene foam and its competitors can be found in use
                                      18

-------
  TABLE 2-4.  SUMMARY OF ADD-ON CFC EMISSIONS CONTROL OPTIONS IN POLYSTYRENE
              FOAM SHEET MANUFACTURE
Factor
  Carbon Adsorption
    With Recycle
    Incineration,
Thermal or Catalytic
Percent emission
reduction
40
30-60
Control cost  ($/mt)
$ 55/mta and offers a
potential recovery
credit
Very high, no
recovery credit
Control applicability     Good
                            Poor
Availability and
status
Good, established
technology.
Fair, established
technology.
Barriers to
implementation
High capital expense;
ventilation modifi-
cation needed;
waste disposal.
Very high operating
and capital cost.
Specific control costs based on model plant calculations.
                                       19

-------
                 TABLE 2-5.   SUMMARY  OF ALTERNATIVE PRODUCTS  AS CFC EMISSION CONTROL OPTIONS  IN
                               POLYSTYRENE FOAM MANUFACTURE
Application
Tharnoformed Sheet
Stock Food Tray it







Egg Carton* t

Single Servict Goods:
Paper. Cupa, and Bowl a:



Hinged Containarat






Altarnativaa

Hydrocarbon Blown PS
Solid Plastic Trayi
Plaatic Pil« Wrap
Plaatie Bag*
Coatad Paper Traya
Butchar Papar
Controlled AtBoaphera
Packaging
Hydrocarbon Blown PS
Papar

Hydrocarbon Blown PS
EPS
Papar
Solid Plaatie
Hydrocarbon Blown PS
Paparboard Container*
Solid Plaatie Containara
Papar Wrap*
Foil Wrapa
Plaatic Hrapa
Combination Laminated Wraps
Parcant
Emiaaion
Reduction

100
100
100
100
100
100

100
100
100

100
100
100
100
100
100
100
100
100
100
100
Control
Coat

Low
Medium
Low
Low
Low
Low

Medium
Low
Low

Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Control
Applicability

Excel lent
Excellent
Excellent
Excellent
Excellent
Excellent

Good
Excellent
Excellent

Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Availability

Excellent
Excellent
Excellent
Excellent
Excellent
Excellent

Developmental
Excellent
Excellent

Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Barriara to
Implementation

Coat, aesthetic*
and preferencea
of consumer





Nona
None


Consumer
Preference


Aesthetics
Consumer
Preference



Board Stockt

  Insulation Sheathing
-See Polyurethane Insulation
 Sheathing Alternatives in
 Table 2-1

-------
side-by-side.  An example is PS and paper egg cartons which can both be found
in many stores.

     Other product substitutes include different types  of materials.  Perhaps
the best product substitutes for CFC blown polystyrene  foam products are
hydrocarbon blown polystyrene foam products.  Hydrocarbon blown foam is
virtually identical to CFC blown foam; however, some end-users still request
CFC-blown foam only.  For stock food trays, some of the alternatives are solid
plastic trays, plastic film wraps, plastic bags, coated paper trays and
alternative technologies such as controlled atmosphere  packaging.  For egg
cartons, the best substitute materials are hydrocarbon  blown polystyrene foam
and paper fiber.  For single service goods, the alternatives include hydrocar-
bon blown polystyrene, expandable bead polystyrene, paper, solid plastic,
paperboard, and various laminated foil and paper products.  All of the substi-
tutes for polystyrene foam sheet products provide  a 100 percent reduction in
CFC emissions.

Polystyrene Boardstock CFC Control Alternatives—
     Since polystyrene board is used as an insulation material, the best
approach to controlling the CFC emissions associated with this product is
substitution with materials which do not contain CFCs.   The discussion of
insulation material replacements for polyurethane  foams also applies here, and
again, probably one of the best alternatives is expandable polystyrene bead
board.  The table (Table 2-1) of PU foam board substitutes can be  reviewed for
other alternatives.

Other Nonpolyurethane Foams

     Other nonpolyurethane foams include polyolefin  (i.e., polyethylene and
polypropylene), polyvinyl chloride, and phenolic foams.
                                      21

-------
Polyolefin Foams—
     Folyolefin foams are extruded into  two  types:  plank  and  sheet.  These
foams are used primarily for cushion and protective packaging.   In  1985.
approximately 22,000 metric tons  (48.5 million  pounds) of  polyolefin  foam were
produced (12).  Of this, polyethylene plank  accounts for approximately 40
percent (49).  In the same year, a total of  approximately  5,000  MT  (11 million
pounds) of CFCs (a mixture of CFC-11, CFC-12, and/or CFC-114) were  used as
blowing agent.  Because the blowing agent  is able to permeate  through the foam
relatively quickly, the CFCs are emitted during manufacture  or within a year
thereafter.  As such, annual CFC emissions are  assumed to  equal  annual CFC
consumption.

     For polyolefin foam, the use of low ozone  depleting blowing agents can
reduce the emission of ozone depleting CFCs.  However, because of the required
cushioning properties of these foams, the  gas pressure within  the cells must
remain constant to provide dimensional stability.  As such,  alternative
blowing agents must escape the product at  essentially the  same rate as that of
established blowing agents.  Potential substitutes include CFC-142b and
CFC-124.   However, they have not been tested and are expected  to be long term
options at best.

     Finally, a wide variety of packaging  alternatives such  as non-CFC blown
expanded polystyrene, shredded and wadded  paper, cellulose wadding, die-cut
cardboard,  wood shavings, pre-foamed expanded polystyrene  packing blocks and
plastic film bubble wrap can be used as  alternatives to polyolefin  foams in
some instances.  However, protective packaging  is a complex  and  diverse
market.  For one time, special packaging or  for a delicate packaging
requirement, alternative materials may not be able to provide adequate
protection.  This is especially true in  applications where polyethylene plank
is used since it represents one of the most  cost effective,  highest
performance materials used in cushion packaging.
                                       22

-------
Phenolic Foam—
     In the past, phenolic  foam was used in the United States primarily as a
base material for floral arrangements.  However, the introduction of phenolic
foam in thermal insulation  applications in 1981 has resulted in an increase in
the production of phenolic  foam in recent years.  In 1985, approximately
10,000 MT  (22 million  pounds)  of  phenolic foam were produced (12).  In that
same year, a total  of  approximately 1,400 MT  (3 million pounds) of CFCs
(comprised of CFC-11 and CFC-113) were used as blowing agents.  Phenolic foam
currently holds an  8 percent  share of the total roofing and sheathing
insulation market  (50).

     Like PU foam,  phenolic foam  retains most of the CFCs used as blowing
agent and the emissions of  CFCs during foam manufacture are low.  In addition,
the foam retains the CFCs for the duration of its useful life.

     Since phenolic foam is used  as an insulation material, the best approach
to controlling the  CFC emissions  associated with this product is  substitution
with materials which do not contain CFCs.  The  discussion of insulation
material replacements  for polyurethane foams  also applies here.   Table 2-1 of
PU foam board substitutes can be  reviewed for other alternatives.

     The use of low ozone depleting CFCs as blowing agents is another
possibility for reducing CFC  emission from phenolic foam.  The potential
alternatives include CFC-123  and  CFC-141b.  Because these alternative CFCs are
not commercially available  and thus have not  been tested, implementation of
this control would  be  a longer term solution.

CONTROLS LIKELY TO  BE  ADOPTED BY  INDUSTRY

     In meeting potential future  CFC regulations, the various industry
segments will use a combination of control options.  This will depend on the
overall emission reduction  potential versus cost, the impact on the foam
industry and end-use markets,  and ease of implementation of the control
options.  Based on  this analysis, the more favorable options have been
                                       23

-------
identified for each application of rigid polyurethane and polystyrene foams
and are presented in Tables 2-6 through 2-9.  In addition. Table 2-10 presents
controls likely to be adopted for other nonpolyurethane foams including
polyolefin. polyvinyl chloride, and phenolic foams.

Rigid Polyurethane Foam Bun stock and Laminated Board

     Table 2-6 lists control options which industry might adopt in response to
CFC regulations.  However, the actual practice of choosing an insulation
material is a complex issue involving a number of considerations such as the
design of the structure to be insulated, requirements of the builder or
customer, construction codes, regional climate, and material availability and
cost.

     Since rigid polyurethane insulating foams exist in a competitive building
materials market, any short-term regulation would cause the other insulating
materials to gain a larger share of the market. It is expected that use of
thick fiberglass batts in building walls and some industrial tanks will
replace some of the use of rigid PU foam insulation with little, if any affect
on the R-value of the system.  Other insulation materials will also be used in
greater thicknesses (especially in roofing applications) as substitutes for
rigid PU foam.  The degree to which these product substitutes displace rigid
PU foam insulation will depend heavily upon the stringency and timing of  the
regulation.

     Other chemical substitutes will become available as mid- to long-term
control options.  It is likely that manufacturers of rigid PU bunstock and
laminated board will prefer use of CFC-123 as  a long-term alternative blowing
agent.  It is non-flammable, giving it an advantage over CFC-lAlb  in building
and industrial insulation applications even though CFC-lAlb may become
available sooner.  It is anticipated that foam manufacturers wiTl  be able to
produce -a foam with CFC-123, but it will be more expensive and have a slightly
lower insulating ability per unit thickness.   If rigid  PU foam bunstock and
laminated boardstock are manufactured with  this chemical  substitute, they will
be less cost competitive with  other building materials.   Some displacement by
alternative insulation materials would naturally occur.

                                      24

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       TABLE 2-6.  CONTROLS LIKELY TO BE ADOPTED FOR RIGID POLYURETHANE
                   FOAM BUNSTOCK AND LAMINATED BOARD
Control                                               Availability
Thick Fiberglass Batts/Thick Walls                         ST
Conventional Stud Spacing

Thick Fiberglass Batts/Thick Walls                         ST
Wide Stud Spacing

Thick Fiberglass Batts - Industrial                        ST
Insulation Systems

Other Insulation Materials/                                ST
Conventional Thickness

Other Insulation Materials/                                ST
Equivalent Insulating Capacity

CFC-123                                                    LT
*ST = Short Term, LT = Long Term
                                      25

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     Add-on engineering controls are not  considered  as  options  likely  to be
adopted because of their high cost, low emission reduction  potential and
because they may not be useful in a scenario which involves large-scale
replacement by product and chemical substitutes.

Rigid Polyurethane Poured and Sprayed Foams

     Table 2-7 lists control options which industry  might respond  to future
CFC regulation.

Building and Industrial Insulation—
     Since rigid polyurethane insulating  foams exist in a competitive  building
materials market, any short-term regulation would cause the other  insulating
materials to gain a larger share of the market. It is expected  that use  of
thick fiberglass batts on building walls  and some industrial tanks will
replace some of the use of rigid FU foam  insulation  with little, if any,
affect on the R-value of the system. Other insulation materials will also be
used in greater thicknesses especially in roofing applications  as  substitutes
for rigid FU foam.  Rigid FU poured and sprayed foams will  probably continue
to be used for special cavity fill or coverage of complex surfaces due to the
lack of available alternatives for these  uses.

     A short-term control option which may have some limited effectiveness  is
using CFC-22 instead of CFC-12 as a frothing agent.  Although the  use  of
CFC-12 as a frothing agent has been declining in recent years special
applications still requiring a frothing agent can reduce use of CFC-12 by
replacement with CFC-22 which has a lower ozone depletion potential.   In the
long term, however. FC-134a has been proposed as a better frothing agent
substitute for CFC-12.

     Other chemical substitutes will become available as mid- to long-term
control options.  It is likely that manufacturers of rigid  FU poured and
sprayed foams for building and industrial insulation will prefer use of
                                      26

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       TABLE 2-7.  CONTROLS LIKELY TO BE ADOPTED FOR RIGID POLYURETHANE
                   POURED AND SPRAYED FOAMS

Control                                                Availability*
                      Building and Industrial Insulation
Thick Fiberglass Batts/                                     ST
Thick Walls

Thick Fiberglass Batts/                                     ST
Industrial Insulating Systems

Alternative Insulating Materials/                           ST
Conventional Thickness

Alternative Insulating Materials/                           ST
Equivalent Insulating Capacity

CFC-ll/CFC-22                                               ST

CFC-ll/FC-134a                                              LT

CFC-123                                                     LT

                                   Packaging
Expanded Polystyrene (EPS) Bead
Other Packaging Materials
E20 Only
CFC-123
Refrigerated Appliance Insulation
CFC-11/H20
CFC-ll/CFC-22
CFC-ll/FC-134a
CFC-141b
CFC-123
Refrigerated Transport
CFC-ll/CFC-22
CFC-ll/FC-134a
CFC-141b
CFC-123
ST
ST
ST
LT
ST
ST
LT
LT
LT
ST
LT
LT
*ST = Short Term, MT = Mid Term, LT = Long Term

                                        27

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CFC-123 as a long-term alternative blowing agent.   It is  non-flammable, which
gives  it an advantage  over  CFC-141b in building and industrial  insulation
applications, even  though CFC-141b might become available sooner.   It  is
anticipated that foam  manufacturers will be able to produce  a foam  with
CFC-123 but it will be more expensive and have a slightly lower insulating
ability per unit thickness.   If rigid PU poured and sprayed  foams are
manufactured with this chemical substitute,  they will be  less cost  competitive
with other building materials.  Some displacement  by alternative insulation
materials would naturally occur.

Packaging—
     The packaging market is  also  a very cost  competitive market, hence any
short-term regulation  would cause  other packaging  materials  to  gain a  larger
share  of the market.   EPS bead can be molded into  shapes  similar to rigid PU
poured packaging.   Other packaging materials such  as plastic film bubble wrap
can be used to provide other desirable properties.

     Still, rigid PU foam packaging will be desirable for special packaging
uses.  Manufacturers will have the option of using less CFC-11  and  using more
water  in the foam formulation.  This causes production of additional CO. which
acts as the substitute blowing agent.   In fact,  it may be possible  to  replace
100 percent of the  CFC by using enough water (49).

     Other chemical substitutes will become available as  mid- to long-term
control options. It is possible that manufacturers of rigid  PU  foam packaging
will use CFC-141b as a blowing agent,  since it has potential to become
available earlier than CFC-123.  This presupposes, however,  that toxicity
testing results show no harmful effects or that they are  not a  concern to the
application.  The fact that the chemical is slightly flammable  should  not
restrict its use as a  packaging material.   CFC-141b and CFC-123 are expected
to be  more expensive than CFC-11,  hence, packaging blown  with CFC-141b or
CFC-123 will be less cost competitive with other packaging materials.  Some
displacement by alternative packaging materials would naturally occur.
                                       28

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Refrigerated Appliance  Insulation—
     Alternative insulation materials were not  considered as viable control
options in this application since  a major change to currently available
materials which are less  insulating per unit  thickness  (e.g.. fiberglass
batts) is contrary to the aims  of  current research.  Refrigeration unit
manufacturers would revert to this control approach only if the more
technically favorable alternatives were unavailable.

     In the short term, one control option is to use more water in the foam
formulation thereby increasing  the production of CO-, to reduce the use of
CFC-11 as a blowing agent for rigid PU poured foam.  Since CO  has a higher
thermal conductivity than CFC-11,  an  increase in foam density is required to
regain some of the insulating efficiency lost.

     However, emphasis  on new materials  and  designs for refrigeration systems
including higher grade  insulation  has  resulted  from more stringent appliance
energy standards set by the federal government. Researchers are already
devising ways to increase the efficiency of  refrigeration units in order to
conserve energy.  New materials such  as  vacuum  board panels are being
considered, as well as  new cabinet designs.   It is likely that new materials
or  system designs will  play an  important role in the refrigeration insulation
options  of  the future,  even in  the absence  of CFC  regulation.

     Another  short-term control option which may have some limited
effectiveness is using  CFC-22 instead of CFC-12 as a. frothing agent.
Apparently use of CFC=12  as a frothing agent has been declining in recent
years due to  formulation  development  (49).   Special applications still
requiring a frothing agent, however,  can reduce use of  CFC-12 by replacement
with CFC-22 which has an  ozone  depletion potential that is lower than that of
CFC-12.  In the long term, however, FC-134a  has been proposed as a better
frothing agent substitute for CFC-12.
                                       29

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     Other chemical substitutes will become available as mid- to long-term
control options.  These include CFC-123 and CFC-141b.  The fact that CFC-141b
is slightly flammable and potentially toxic may restrict it use in  this
application.  These CFCs are expected to be more expensive than CFC-11;
however, the total cost of the insulation is only a small fraction  of  the cost
of the refrigeration unit.

Refrigerated Transport—
     Alternative insulation materials were not considered as control options
due to loss in volume and weight carrying capacities that transporters would
endure, and because installation techniques of alternative materials will be
laborious and costly.  The transportation industry would begin to use
fiberglass batts or other materials instead of rigid PU foam only if very
stringent regulation is imposed immediately.

     A short-term control option which may have some limited effectiveness  is
the use of CFC-22 instead of CFC-12 as a frothing agent.  Although  the use  of
CFC-12 as a frothing agent has been declining in recent years, special
applications still requiring a frothing agent can reduce the use of CFC-12  by
replacement with CFC-22.  In the long term, however, FC—134a has been  proposed
as a better frothing agent substitute for CFC-12.

     Chemical substitutes which will became available mid- to long-term are
CFC-123 and CFC-141b and may be the best option for this application.  It is
expected to be less expensive and should be available sooner than the
nonflammable CFC-123.  The flammability of CFC-141b should not be a major
concern in refrigerated transport insulation applications.  It is anticipated
that manufacturers would be able to produce a foam with CFC-141b or CFC-123
that has a slightly lower insulating ability and would be about twice  the cost
                                       30

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of foam blown with CFC-11.  Only a slight increase in thickness would be
needed to produce a foam with equivalent insulating capacity, resulting in
very little interior volume loss and increased weight.  Again, the  increased
cost will be minor compared to the cost of the entire refrigerated  transport
unit.

Rigid Polystyrene Foam Boardstock

     Table 2-8 lists  control options which industry might  adopt  in  response to
future CFC regulation.

     Likely short-term control options are product substitutes and  alternative
wall/roof construction. Use of other insulation  products which do not  contain
CFCs is  possible because  a wide variety of substitutes  is  currently available
at competitive prices in  the market place.   However,  if such conversions
occur, higher costs may be encountered due to either  energy losses  or
increased construction costs to prevent additional energy  losses.

     In  the long-term a likely control option is a chemical substitute such as
FC-134a  or CFC-141b.  These  two chemical  substitutes  were  identified as
possible candidates,  but  current  information indicates  that there has  been
only a limited amount of  application testing of  the alternatives.  Therefore,
it is expected that  additional development and testing  of  the potential
chemical substitute  is needed.  At  present,  FC-134a may be the preferred
long-term option  (49), since  it has been  reported that  CFC-141b  is  slightly
flammable.

Rigid Polystyrene  Foam Sheet

     Table 2-9 lists  control  options which industry might  adopt  in response to
future CFC regulation.
                                       31

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   TABLE 2-8.  CONTROLS LIKELY TO BE ADOPTED FOR RIGID EXTRUDED POLYSTYRENE
               FOAM BOARDSTOCK
Control                                                Availability*
Thick Fiberglass Batts/Thick Walls
Conventional Stud Spacing                                   ST

Thick Fiberglass Batts/Thick Walls
Wide Stud Spacing                                           ST

Other Insulation Materials with
Equivalent Insulation Capacity                              ST

Other Insulation Materials with
Conventional Thickness                                      ST

FC-134a                                                     LT
*ST = Short Term, LT = Long Term
                                      32

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   TABLE 2-9.  CONTROLS LIKELY TO BE ADOPTED FOR RIGID EXTRUDED POLYSTYRENE
               FOAM SHEET
Control                                                Availability*


Substitutes for Egg Cartons                                 ST

Substitutes for Single Service Plates, Cup, etc.            ST

Substitutes for Hinged Containers                           ST

Substitutes for Stock Food Trays                            ST

Hydrocarbons without Carbon Adsorption                      ST

Pentane without Carbon Adsorption                           ST

CFC-124                                                     LT

FC-134a                                                     LT

CFC-22                                                      KT



*ST = Short Term, LT = Long Term
                                      33

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     In the short term, the use of substitute products  is  the control  option
which would most likely occur.  There are a large number of  potential  product
substitutes for foamed polystyrene sheet food packaging such as:   paper.
cardboard, plastic film, paper-backed metal foils,  and  composite wrappings.
All of these materials are currently used in most of  the market segments  that
use foamed polystyrene sheet.  Technical factors such as thermal insulating
value and product protection deserve consideration, but usually the  choice for
a particular material depends on aesthetic preference.

     For FS foam sheet manufacturers who currently  use  CFCs,  an option which
could be favorable is conversion to substitute blowing  agents such as  pentane
and other hydrocarbons.  It is possible that these  chemical  substitutes will
be viewed unfavorably by some producers because of  concerns  about  fire
hazards, volatile organic emissions, and foam processability and quality.

     In the long term, it is possible that alternate  CFC blowing agents will
gain a substantial market share.  From a technical  standpoint, this  will  occur
if these CFC substitutes offer comparable ease of processing and foam  quality.
Economically, it is probable that these new CFCs will be more expensive than
currently used blowing agents.

Other Nonpolyurethane Foams

     Other nonpolyurethane foams include polyolefin (i.e., polyethylene and
polypropylene), polyvinyl chloride, and phenolic foams.  Table 2-10  presents
likely control options the industry will adopt for  the  various foam  categories
to meet future CFC regulations.
                                      34

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  TABLE 2-10.   CONTROLS LIKELY TO BE ADOPTED FOR OTHER RIGID NONPOLYURETHANE
               FOAMS
Control                                                Availability*
                               Polyethylene Foam

Alternate Packaging Materials                               ST
Rubber or Plastic Gaskets                                   ST
Rubber or Plastic Flotation Devices                         ST
CFC-124                                                     LT

                              Polypropylene Foam

Carbon Adsorption                                           ST
Alternate Packaging Materials                               ST
CFC-124                                                     LT

                            Polyvinyl Chloride Foam

Rubber or Plastic Gaskets                                   ST
Rubber or Plastic Flotation Devices                         ST
CFC-124                                                     LT

                                 Phenolic Foam

Thick Fiberglass Batts/Thick Walls                          ST
Conventional Stud Spacing

Thick Fiberglass Batts/Thick Walls                          ST
Wide Stud Spacing

Other Insulation Materials—
Equivalent Insulation Capacity                              ST

Other Insulation Materials—
Conventional Thickness                                      ST

CFC-123                                                     LT
*ST = Short Term, LT = Long Term
                                       35

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 Polyethylene Foam—
      Likely short-term control options for polyethylene foam include product
 substitutes such as other low density flotation materials,  or rubber gaskets.
 This  is  also true for packaging.   Many product substitutes  are currently
 available for packaging material  including water-blown polyurethane foam,
 expanded polystyrene (EPS)  beads,  and paper-based cushioning.

      In  the long-term,  likely control options are CFG type  chemical
 substitutes.   Several chemical substitutes were identified  as possible
 candidates:  CFC-124a,  CFC-142b,  or CFC-22/142b blends.   However,  there has
 been  only a limited amount  of performance testing.   Therefore,  it  is expected
 that  further testing of the chemical substitute is needed.   Overall economics
 may determine if use of a more expensive blowing agent is practicable.

 Polypropylene Foam—
      Polypropylene foam is  a unique CFC application in that a carbon
 adsorption system was designed into the first commercial-scale plant for
 economic reasons.   This system is  currently realizing an overall CFC recovery
 of greater than 80 percent  as a result of the unique processing conditions
 (51).  Further reduction of CFCs  in the short term could be achieved through
 the use  of product substitutes since several  product substitutes are currently
available for packaging material.

      In  the long-term,  likely control options are CFC type  chemical
substitutes.   Several chemical substitutes were identified  as possible
candidates:   CFC-124a,  CFC-142b, or CFC-22/142b blends.   However,  there has
been  only a limited amount  of performance testing.   Therefore,  it  is expected
that  further  testing of the chemical substitute is  needed.   Overall economics
may determine if use of a more expensive blowing agent is practicable.
                                       36

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Polyvinyl  Chloride Foam—
     A likely  short-term control option for polyvinyl  chloride foam is a
product substitute made from rubber or plastics.   For  both gaskets and
flotation  devices PVC foam is a relatively new material  that was not available
a few years  ago.   Product substitutes are currently  available for both
applications.  Since PVC foam serves a relatively  limited,  but specialized
market, product  substitutes could be readily adopted by  consumers.

     In the  long-term,  a likely control option is a  CFC-type chemical
substitute,  such as CFC-124.   Several chemical substitutes were identified as
possible candidates and CFC-124 is felt to be a technically feasible
substitute,  based on its physical properties.   However,  current information
indicates  that there has been only a limited amount  of application testing
with the alternative CFCs although chemical blowing  agents have been used
previously.   Since the quality of the foam product depends on the substitute
as a blowing agent, it is expected that testing of a potential substitute is
needed.

Phenolic Foam—
     Likely  short-term control options for this application are product
substitutes  and alternative wall/roof construction.  Since phenolic foam
insulation is  relatively new and equivalent thermal  insulation systems are
available, a large change in the availability or  cost  of phenolic foam should
not cause  technical problems in the building trade.

     At least  two chemical substitutes,  CFC-123 and  CFC-141b were identified
as possible  long-term options,  but current information indicates that there
has been only  a  limited amount  of application testing  of the alternatives.
From a technical  standpoint,  this application is  concerned with effects on
                                       37

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insulating performance and safety of a potential substitute blowing  agent.
Therefore, it is expected that testing of chemical substitutes  is needed.  At
present, CFC-123 may be the preferred long-term option since it has  been
reported that CFC-141b is slightly flammable.
                                      38

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                                   SECTION 3
                         INDUSTRY AND EMISSION  PROFILE

OVERVIEW OF RIGID FOAM MANUFACTURE

     Rigid  foams  are used  in numerous applications  ranging from building
insulation to egg  cartons.   The majority of rigid foams are polyurethane (PU)
(including  polyisocyanurate)  and polystyrene (PS).   Less prevalent  are  the
phenolic, polyolefin,  and  other thermoplastic foams; these  are not  discussed
in detail in this  report.   Common  to all foams is a  cellular structure which
is created  by the  presence of an expanding gas in the polymerizing mixture or
polymer melt.  The expanding  gas, or blowing  agent,  is  either the  product of  a
chemical reaction  in the polymerizing mixture,  or is an inert substance which
is added to the reaction mixture.  This  substance can be  a gas, or it  can be  a
liquid which will  vaporize to generate a gas.  Frequently,  in the manufacture
of rigid foams, the  blowing agents used  are chlorofluorocarbons  (CFCs).

Background on Polyurethane  and Polyisocyanurate Foam Production

     Polyurethane  foams  are addition polymers produced by  the chemical  reac-
tion of  an  isocyanate and  a  polyol.  Similarly, polyisocyanurate foams  are
produced from an is ocy amir ate and  a polyol.  Because of  the similarities of
polyisocyanurates  and polyurethanes, the  term  rigid polyurethane (PU)  foam
will, for the  purposes  of  this  report,  refer to  both  polyisocyanurate and
polyurethane foam.

     Ninety  percent  of  rigid  polyurethane   foam  is used  as insulation
materials, while the remainder is  used as materials  for  packaging and flota-
tion.
                                       39

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      The  production of rigid polyurethane foams usually  involves  one  of four
 processing  operations:  laminated  foam core panel manufacture, poured  foam
 production,  sprayed  foam  application,  or bunstock  production.   Building
 insulation  is by  far the  largest  consumption  category  for these  foams,
 accounting  for 57 percent  of  the total rigid  polyurethane production.   By
 production  method. 90 percent  of the  total  polyurethane foams produced is
 divided almost evenly among laminated,  poured,  and sprayed foams.  Bunstock
 accounts  for the  remaining ten percent.  The  CFC content for polyurethane
 foams varies with the production method, but generally falls  in  the five to
 twenty weight percent range.  CFC-11 is the most commonly used blowing agent.
 However,  CFC-12  is also used in addition  to  CFC-11 to a limited  extent  for
 poured foams.  CFC-12 is used  for low  temperature  spraying and for frothing  in
 pour-in-place applications.  The low  boiling  point  of  CFC-12 causes the
 reacting polymer mixture to expand  to  a consistency similar to that  of shaving
 cream.  This allows  injection  of the  foam  into  panels  and other  closed
 containers  with a minimum  of  pressure buildup.  Laminated  board  production
 relies on  the  adhesive characteristics of  polyurethane.   Laminates are
 commonly  produced with surface skins of metal, paperboard, fabric, or plastic
 film  (6).   Poured foam technology  is  used  to  produce foams  inside  of  an
 enclosed  area such as a refrigerator housing or a building wall space.  Here,
 the foam  components are mixed  and  poured  as a liquid  into a cavity  where
 foaming subsequently  takes  place.   Sprayed foam technology is similar to that
 of poured foam.  Here, the  liquid foam  mixture  is  sprayed onto the surface to
be insulated  such as  pipework or a storage tank.  Bunstock operations produce
a very large block of  foam which may be cut  and formed  into desired  products.

     In the  early 1940s,  rigid polyurethane  foams were produced  on a small
 scale, but  by the end of the  1940s,  the primary  chemicals  used  to produce
polyurethanes—isocyanates  and polyols—became  available on  an  industrial
scale.  The  discovery of the  superior insulating  characteristics of  these
foams  allowed them to be  used in a  variety of  insulation applications
including the lining  of  refrigerators  and  freezers,  industrial  equipment
 (tanks and  piping),  and  transportation equipment  (tank  trucks,   railcars.
                                      40

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etc.).  Since  the early 1960s,  rigid polyurethane  foams have experienced
continuous and  rapid growth  as  a result of  several breakthroughs.  These
include: 1) the  introduction of blowing agents  such as  CFC-11 and CFC-12;
2) the development  of  polymeric methylene diphenyl  diisocyanate  (MDI)  which
improved the foam properties  and  simplified processing; and 3) the  development
of surfactants  which helped  to  control cell size,  configuration,  and  uni-
formity.

     Increased pressure has been  applied to the building  materials  industry  to
manufacture products with superior fire retardancy  characteristics.  This has
led to the growth in consumption of polyisocyanurate foams*  These foams  are
closely related to polyurethane foam, but they are  more fire  retardant.  They
are chemically  stable up to 150°C (302°F).  Isocyanurate  rigid  foams  have
processing limitations that  compromise  their use as  spray  and pour-in-place
foams.  However,  their fast reactivity and  high viscosity are  ideal  for
continuous laminated panel and board  production.

     The  physical structural properties  of  rigid  polyurethane foams are a
function  of  foam density.   CFC blown  rigid  polyurethane insulation foams
usually have  densities ranging between 0.032 and 0.048  g/cc  (2  to 3 Ib/cu.
ft.).  Approximately 8 to 16  percent  fluorocarbon blowing agent is  required  in
the reactant  formulation  to  produce  rigid  polyurethane foam  in this density
range.  In  insulation applications,  the  most important  property for rigid
polyurethane  foams  is the  thermal. conductivity  (often expressed as the  U
factor or the K factor).   The U  (or K)  factor  is greatly influenced by  the
blowing agent,  cell  size,  cell  contents,  and foam  density  (7).  Thermal
                                                            2
conductivity  is  expressed  in units  of W/m-K (Btu-in/hr-ft -°F).   In  the
construction  industry,  insulation materials  are  frequently characterized by
their R-value.  The  R-value expresses  the thermal  resistivity or  insulating
efficiency of  a  material.   A large  R-value indicates  a good insulating
ability, and polyurethane foams are among the best  insulators  with an R-value
of 7.2/inch.  This  value  is  simply the inverse of  the thermal conductivity
                                       41

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value  (U-factor or K-factor);  therefore,  the units expressing the R-value are
m-K/W  (hr-f t2°F/Btu-in).

Background on Nonpolyurethane Foam Production

     There are several nonpolyurethane rigid foams which are blown with  CFC
blowing agents.  The most important types from the  standpoint of CFC emissions
have been  the polystyrene,  polyolefin.  phenolic and FVC  foams.   A common
feature of all these foams is that new uses  for them are  continuously  being
discovered.   There  is  yet  a large  potential  for expansion  of these
nonpolyurethane foams into new product areas.  Also, many of the product areas
that have been recently developed have not  fully penetrated the market.  For
these reasons, growth in  the use of  CFC-12  and the other fluorocarbon blowing
agents is expected for manufacturing of nonpolyurethane  foams.

     The qualities which  have made these foams superior to the products which
they have replaced include:

     •    water-resistance,

     •    thermal insulation,

     •    low density,

     •    shock resistance,

     •    noise resistance,

     •    static electricity resistance, and

     •    competitive cost.
                                       42

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     Non-polyurethane foams of primary interest in this report are polystyrene
 foams.   These foams are  produced by an extrusion process.  In this process,
 polystyrene  resin is melted in an extruder, and  a  CFC  or  hydrocarbon  blowing
 agent  is injected into  this polymer melt.   The blowing agent dissolves into
 the molten polymer,  and when the melt leaves the extruder,  the blowing agent
 flashes  causing  the  plastic to  foam.   The  extruder  die  configuration
 determines  the shape  of  the foam.   For foam  sheet production,  the die  is
 annular,  and  the resulting tube of  foam is  slit to form two  sheets.
 Polystyrene  foam board,  however,  is simply extruded through  a die with  a
 straight  slit.   Typically polystyrene foams are produced with initial blowing
 agent  contents ranging from five to twenty percent by weight.   In PS foam
 sheet, the  CFC content typically ranges between 5  and 10 weight percent.  The
 most commonly used blowing  agents are hydrocarbons and CFC-12.  Polystyrene
 sheet, which  is  used to manufacture  packaging items such  as meat trays,
 carry-out  food trays, and  egg cartons,  is generally blown  to a  density of
 0.048  to 0.16 g/cc (3 to 10 lb/ft3)  (8).

     Polyolefin  and PVC  foams are  also  produced by an  extrusion process
 similar  to  that used  for polystyrene foam.  The most  commonly used blowing
 agents are  CFC-11, CFC-12,  CFC-114.  or a mixture.   These  foams are produced
 with initial blowing agent  concentrations  ranging  from approximately  15 to 20
 percent by weight for polyethylene and PVC foams to as  much as 50 percent for
                                                                           •3
 polypropylene  foams.  Densities  of  about  0.016 to 0.14 g/cc (1 to 9  lb/ft )
 are typical  of polyolefin  foams  which are used for cushioning and wrapping
 (9).

     In addition,  phenolic resin foams are produced by  a  process similar to
 that used in the production of laminated FU foam.  The blowing agent  consists
 of CFC-11. CFC-114,  or a mixture. Initial blowing agent concentrations range
from 10 to 15  percent by weight  depending  on the CFC used.  Like polyurethane
foams,  phenolic  foams  are used in insulating applications  since  they  have  an
R-value of 8.3 per inch.
                                       43

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Blowing Agents

     The cellular structure of rigid  plastic foams is produced by the action
of  a blowing agent.  There are  both  chemical and physical  blowing  agents.
Chemical blowing agents  undergo  a chemical reaction liberating a gas causing
the  polymer  to  foam.  Physical blowing agents, which do not react chemically,
include compressed gases and volatile liquids.  Gaseous  blowing agents,  which
are  injected into the  polymerizing mixture  or  the polymer melt,  include
nitrogen and carbon dioxide.  Liquid blowing  agents  include CFCs,  chlorinated
hydrocarbons, and aliphatic hydrocarbons.    These are also injected into  the
polymerizing mixture or  the polymer melt.   Liquid blowing agents used in  the
manufacture  of  rigid foams are  available  as polyol blends  supplied by  the
chemical suppliers or are available as a commodity  chemical  for blending with
the  other chemicals at the point of manufacture of the foam.

     Polyurethane and polyisocyanurate  insulation foams  are generated  through
the  action  of a physical  blowing agent (CFC-11).   Some  processes also  use
CFC-12 as a  supplementary  blowing agent,  but its use is  declining.   Foaming
occurs when  the  heat of the polymerization reaction vaporizes the CFC-11.
The  use of a CFC blowing agent generates a cellular  structure  in the polymer-
izing liquid re act ant mixture.   In rigid PU foams, the extensive cross-linking
between  the  polymer  chains  essentially freezes  this cellular structure,
trapping the blowing agent inside.  The closed cells give  the foam  a  rigid,
yet  light-weight structure, and  the CFCs  trapped in the numerous tiny closed
cells provide superior insulating properties.

     Historically, many  of the extruded polystyrene foam products have  been
blown with hydrocarbons such as n-pentane and isopentane,   and to a lesser
extent, butane.  A variety of CFCs have been  used either  alone as the  primary
blowing agent, or in a mixture with other  CFCs or pentanes.  Besides n-pentane
and  isopentane,  CFC-12  is the most commonly  used blowing  agent  for the
nonpolyurethane foams.   Additionally,  gases such as carbon  dioxide are  often
used in conjunction with hydrocarbons and  CFCs.   Smaller quantities of CFC-11,
                                       44

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CFC-11A, CFC-113. and CFC-115 are also used (5).  Table 3-1 lists  the various
foam products  and the types of blowing agents which are used  to manufacture
them.

RIGID FOAM INDUSTRY PROFILE

Polyurethane Foams

     In  1985,  rigid  polyurethane  foam  production  in the U.S. reached
approximately  336 thousand metric  tons  (741  million pounds)  (3).   That
represents an  average  increase of 7.5 percent  per  year since 1975 when the
estimated production was 154 to  174  thousand  metric tons (340 to 383 million
pounds)  (10).  Table  3-2 shows the  historical  and  projected production for
rigid  polyurethane  foam  in the  U.S.   Approximately  90%  of  all  rigid
polyurethane foam is used  as  thermal insulation (11).  The primary producers
of rigid  polyurethane foams  include Celotex,  Rmax Inc..  Apache  Building
Products  Co.,  Atlas  Roofing. Manville  Corporation  and Thermal  Systems
Incorporated.  There  are  at  least  28 major suppliers  of polyurethane
spray/pour systems.  The largest of  these are Olin, Brin-Mont  Chemicals. Inc..
General Latex. Reichold. Isocyanate  Products. Inc.. and Stepan.   Tables 3-3
and 3-4 list the major producers of  polyurethane foam  and liquid foam systems,
respectively.

     In general,  rigid polyurethane  foam  production can be divided into four
types of processes:  laminated foam  core panel, poured/injected  foams, sprayed
foams,  and bunstock.  The  typical  CFC-11  content in the chemical  formulation
for bunstock and laminated foam is 14 percent, but  it  is 12 percent for poured
or sprayed systems.  CFC-12 is used in conjunction with CFC-11 for poured and
sprayed systems,  and  its  typical  formulation content is  5 percent  and  1
percent, respectively.

     The consumption  of  rigid polyurethane  foam can  be  broken down into
roughly seven  applications areas.   These  include:  building insulation, home
                                      45

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      TABLE 3-1.  NONPOLYURETBANE FOAMS AND CORRESPONDING CFC BLOWING
                  AGENTS AND MIXTURES
Foam Type
Blowing Agent
Polystyrene
Polyethylene



Polypropylene


Phenolics


Polyvinylchloride
   Pentane
   Butane
   CFC-11
   CFC-12

   CFC-12
   CFC-114
   CFC-115

   CFC-11
   CFC-114

   CFC-11
   CFC-113

   CFC-11
   CFC-12
Source:  (5)
                                     46

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     TABLE 3-2.  HISTORICAL AND PROJECTED UNITED STATES RIGID POLYURETHANE
                 FOAM PRODUCTION:  1955 - 2015
Year
1955
1960
1965
1970
1975
1980
1985
1990*
1995
2000
2005
2010
2015

(1000 metric
0
5
41
95
154
244
336
476
596
748
879
1034
1216
Rigid PU Foam Production
ton/year) (10 Ibs/yr)
0
10
90
210
340
550
741
1049
1314
1649
1938
2280
2680
^Projected values obtained from summing  the medium  growth projected figures of
 each rigid urethane foam category.

Sources:  (2,3)
                                      47

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        TABLE 3-3.  MAJOR PRODUCERS OF RIGID POLYURETHANE FOAM PRODUCTS
        Company
Plant Location
                                                                      Product
RIGID BUN, BOARD. AND LAMINATES

American Western


Atlas Roofing
The Celotez Corporation
  Building Productions Div.
Carpenter Insulation


Dyplast


Elliott Co. of Indianapolis. Inc.
  Elfoam Ufetbane Division

General Plastic

Homasote Company

Manville Building Materials Corp.


NRG Barriers, Inc.


Polymer Building Systems, Inc.

Rmaz, Inc.
Fontana, CA
Mesa. KL

Camp Hill. PA
LaGrange, GA
Moline. IL

Belvedere, IL
Linden. NJ
Jackson, MS
Conyers, GA
Charleston. IL
Elizabethtown. KY
Pennsauken, NJ
Texarkana, AR
Trace, CA

Elkhart, IN
Temple, TX

Miami, FL
Anderson, SC

Indianap olis, IN
                                         Tacoma. WA

                                         Trenton, NJ

                                         Rockdale, IL
                                         Jamesburg. NJ

                                         Sanford, ME
                                         Hazleton, PA

                                         Riverside, CA

                                         Greenville. SC
                                         Reno. NV
                                         Richardson. TX
                                                                     Laminates
                                                                     Laminates
                                                                     Laminates
                                                                     Laminates
                                                                     Bunstock

                                                                     Bunstock
                                                                     Laminate

                                                                     Bunstock
                            Bunstock

                            Laminates

                            Laminates


                            Laminates


                            Laminates

                            Laminates
                                                                   (Continued)
                                     48

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                              TABLE 3-3 (Continued)
          Company
Plant Location
                                                                       Product
 Resco  (AM. West.)


 Temple-East ex.  Inc.

 Thermal  Systems
The Dow Chemical Co.


Wintec

Admiral



Amana


General Electric
Sanyo

Whirlpool
White
Consolidated
Denver, CO
Mesa, AZ

Diboll, TX

Salt Lake City, UT
Denver, CO
Covington, KY
Dallas, TX
Jacksonville, FL
Springfield, MA

Columbus, OH
La Porte, TX

Bremen, IN

Gallesburg. IL
Williston, SC
Chesapeake, VA

Amana, IA
Decatur, AL
Louisville, KY
Bloomington, IN
Cicero, IL

San Diego, CA

Ft. Smith, AR
Evansville, IL

St. Cloud, MN
                                                                      Laminates


                                                                      Laminates

                                                                      Laminates
                                                                      Bunst ock
                                                                      Laminates

                                                                      Refrig.
                                                                      Freezers
                                                                      Refrig.

                                                                      Refrig./
                                                                      Freezers

                                                                      Refrig.
                                                                      Refrig.

                                                                      Refrig./
                                                                      Freezers

                                                                      Freezers
                                                                    (Continued)

-------
                             TABLE 3-3  (Continued)
        Company
Plant Location
Cal-Style Furniture Mfg. Co.




Cosco Home Products




Craddock Finishing Corp*




Decor Originals




Jasper Corporation




Paeco Industries. Inc.




Prestige Furniture Co.




Thomasville Furniture Industries




FLOTATION




Emerson & Cuming




Faron Molding Division




OMC Stern Drive
Compton, CA




Columbus, IN




Evansville. IN




Conover, NC




Jasper. IN




Toms River. NJ




Newton, NC




Thomasville, NC









Canton, MA




Brooklyn, NY




Waukegan, IL
Product
SMALL INSULATED CHESTS. COOLERS. AND BOTTLES




Aladdin Industries                       Nashville, TN




The Coleman Co.. Inc.                    Wichita, KS




Gott Corporation                         Winfield, KS




Headway Chemical Co.                     New York, NY




King— Seeley Thermos Co.                  Macomb, IL




CHAIR SHELLS. FURNITURE. AND HIGH DENSITY RIGID PARTS
                                                                    (Continued)
                                       50

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                             TABLE 3-3  (Continued)
        Company
Plant Location
Product
Peterson Brothers Boat Works




Robinson Industries. Inc.




Samson Ocean Systems, Inc.




TRANSPORTATION




ACF Industries, Inc.




F/G Products. Inc.




Fruehauf Corporation




Fruit Growers Express Co.




Kentucky Manufacturing




Timpte, Inc.




PACKAGING




Acer Industries. Inc.




Airtex Industries, Inc.




Leggett & Platt. Inc.




Sealed Air Corporation




Perry Chemical & Mfg. Co.




Strux Corporation




Voplex Corporation
Shell Lake. WI




Coleman, MI




Waltham. MA









Milton, PA




Rice Lake, WI




Detroit. MI




Alexandria, VA




Louisville, KY




Denver, CO









Toroson, MD




Minneapolis, MN




High Point. NC




Danbury, CT




Lafayette, IN




Lindenhurst, NY




Rochester, NY
Source:  (12)
                                        51

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        TABLE 3-4.   MAJOR SUPPLIERS OF POLYURETHANE LIQUID FOAM SYSTEMS
                    Company
    Plant Location
BASF Wyandotte  Corporation

Brin-Mont Chemicals,  Inc.


Gallery Chemical  Co.

Chemetics Systems,  Inc.

Cook Paint & Varnish  Co.

E. R. Carpenter Company, Inc.

Flexible Products Company

Foam Enterprises

Foamseal Inc.

Freeman Chemical  Company

Frostee Foam

General Latex and Chemical Corporation
Insta-Foam Products, Inc.

Isocyanate Products, Inc.

Marchem Corporation

Mobay Chemical Corporation

North Carolina Foam Industries. Inc.

01in Corporation
Troy, MI

Greensboro, NC
Riverside, CA

Gallery.PA

Compton. CA

Kansas City. MO

Richmond, VA

Marietta, GA

Minneapolis. MN

Oxford, MI

Port Washington, WI

Antioch, IL

Ashland. OH
Billerica, MA
Cucamonga, CA
Charlotte. NC
Dalton, GA

Joliet. IL

New Castle. DE

Maryland Heights, MO

New Martinsville. WV

Mt. Airy. NC

Benicia, CA
Brook Park, OH
                                                              (Continued)
                                     52

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                             TABLE 3-4  (Continued)
       Company
Plant Location
PPG Industries

Polyblends, Inc.

Polymer Chemical Corporation

Polymer Development Laboratories.  Inc.


Polythane Systems, Inc.

Reichhold Chemicals. Inc.
Renosol Corporation

H.H. Robertson Co.
  Freeman Chemical Corporation,  subsidiary
Stepan Chemical Company
  Industrial Chemical Division

The Dow Chemical Company
Springdale. PA

Livonia, MI

Santa Fe Springs. CA

Huntington Beach. CA
Newburgh. NY

Spring. TX

Azusa. CA
Carteret. NJ
Ferndale. MI
Tacoma. WA

Ann Arbor. MI

Burlington, IA
Chatham, 7A
Saukville, WI

Millsdale, IL
Columbus. OH
Houston, TX
Source:   (12}
                                    53

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 and commercial refrigeration  insulation,  industrial  insulation,  packaging.
 transportation insulation,  and other  applications.   Table 3-5  shows the
 application areas and CFC consumption for 1985.

     Building construction  insulation  is  the  largest market  for rigid
 polyurethane foams.   This insulation is primarily  board and laminated board
 products  for insulating  roofs, walls,  and doors in residential, commercial.
 and industrial buildings. But  as  flame retardant properties have  improved,
 construction applications for rigid  foam have broadened.   Rigid polyurethane
 foam also  finds  wide  use  in commercial  and  household  refrigeration
 applications.   This  market uses mostly liquid foam  systems for pour-in-place
 applications.   Consumption of  rigid foam in the transportation area is mainly
 for insulation of trucks  and railroad tank and  freight cars.  A smaller amount
 is  used for sprayed  insulation of industrial storage  tanks, pipes  and ducts.
 Additional  uses  include  insulation  for  travel  trailers  and  motor homes.
 Packaging  applications of rigid foam include foamed-in-place  packaging  for
 industrial  equipment or scientific instruments.  Rigid foams are also used as
 marine flotation  devices  and consumer items such as portable coolers (6).

     The  consumption of  rigid  polyurethane foams  in each  of these areas  is
 given as  follows.  In 1985, the production of insulation  for buildings (191
 thousand  metric tons)  accounted  for nearly  57  percent of the  total  rigid
 polyurethane foam produced.  Refrigeration insulation,  the second largest  user
 of  rigid polyurethane foams,  accounted  for only  16 percent  of  total
 production.    The remaining  insulation  categories,   industrial   and
 transportation, each consumed  roughly nine percent of  total production.   The
 remaining rigid polyurethane foam  consumption areas are packaging,  and others
 such as  marine flotation.   Packaging used about  six percent of the  total
 production.   The  remaining one percent of rigid polyurethane foam  production
went into various  applications  such as  flotation.
                                      54

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                      TABLE 3-5.  1985 RIGID PU FOAM PRODUCTION AND  CFC  CONSUMPTION IN THE U.S.

                                                       (1000 mt)
en
Ul

Building Insulation
Refrigeration Insulation
Transportation Insulation
Industrial Insulation
Packaging
Other
Total
1985
Rigid PU
Production
191
54
29
27
20
15
336
Estimated Production by Each
Bunstock
19.1
0.0
0.0
1.4
0.0
3.6
24.0
Laminated
91.4
0.0
0.0
0.0
0.0
3.6
95.1
Poured
19.1
54.4
19.8
3.0
20.0
3.6
119.8
Method
Sprayed
61.0
0.0
9.7
22.9
0.0
3.6
97.2
Total
CFC Consumption
CFC-11
25.1
6.5
3.5
3.3
2.4
1.9
42.7
CFC-12
1.6
2.7
1.1
0.4
1.0
0.2
7.0
       Sources: (3,10.13).

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TABLE 3-6.  POLYSTYRENE FOAM SHEET, FILM. BOARD AND BLOCK PRODUCERS INCLUDING
            EXTRUDERS
                Company
    Plant Location
Airlite Plastics Co.
Albany International
Alcoa Building Products, Inc.
Alsco Arco Building Products
American Excelsior Company
Amoco
Amotex Plastics
Amxco, Inc.
Atlas Industries
Bird. Inc., Vinyl Products Group
Burton Packaging Co., Inc.
Cellar Corporation
Commodore Plastics
Creative Industries
Crystal X Corporation
Dart Container Corporation
Denver Plastics, Inc.
Dipak Mfg. Co., Inc.
Dixie/Marathon
Omaha, KB
Agawam, MA
Pittsburgh, PA
Akron. OH
Arlington, TX
Chippawa, Falls, WI
Beech Island, SC
Lamirada, CA
Winchester. VA
Nashville. TN
Arlington, TX
Ayer, MA
Bardstown, KY
Maspeth, NY
Reedsburg, WI
Holcomb. NY
Chicago, IL
Darby, PA
Mason, MI
Leola, PA
Horse Cave, KY
Lavonia, GA
Plant City, FL
Waxahachie, TX
Corona, CA
Tumwater, WA
Aurora, IL
Lodi, CA
Hudson. CO
Westport, NY
Baltimore, MD
St. Louis. MO
                                                                   (Continued)
                                      56

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                              TABLE 3-6  (Continued)
                Company
    Plant Location
The Dow Chemical  Co.,  U.S.A.
Drew Foam Companies*  Inc.
Dyrelite Corporation
EFP Corporation
Erie Foam Products, Inc.
FPI
Falcon Mfg, Inc.
Foamade Industries
Foam Fabricators, Inc.
Foam Holders and Specialties
Free-Flow Packaging Corp.
Frostee Foam, Inc.
Genpak
The Oilman Brothers Co.
Glendale Plastic^
Gotham Chicago Corp.
W.R. Grace & Co.
Midland. MI
Allyn's Poinyt, CT
Magnolia, AH
Torranee, CA
Hanging Rock, OH
Joilet, IL
Seattle. WA
Pevely, MO
Carte ret, NJ

Monticello, AR

New Bedford. MA

Elkhart, IN

Erie, PA
Vicksburg, MS

Byron Center, MI

Auburn Hills, MI

St. Louis, MO
Melrose Park, IL
New Albany, IN
Compton, CA
El Dorado Springs, MO
Erie. PA
Bloomsburg, PA

Cerritos, CA

Redwood City, CA

Antioch, IL

Montgomery. AL
Longview. TX
Los Angeles. CA
Middletown, NY
Manchaug, MA

Oilman. CT

Ludlow. MA

Chicago. IL  .

Reading. PA
Indianapolis, IN
                                                                   (Continued)
                                      57

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                             TABLE 3-6 (Continued)
    Company
Plant Location
Handi-Kup Co.
Holland Industries. Inc.
Huntsman Container
Hydra-Matic Packing Co.. Inc.
Kalamazoo Plastics
Keyes Fibre/Dolco
Lifoam
The Lin Mfg. Co.
Linpac (Florida Container)

MacDonald Plastics
Manchaug Corporation
Mars Cup Company. Inc.
Master Containers, Inc.
Mobil Chemical Co.
Monsanto Company
Morval-Durofoam Limited

Nyman
Olsonite Corporation
Owens-Illinois
Pac-Lite Products, Inc.
Pelafoam, Inc.
Pioneer Plastics
Plasteel Corp.
Plastica Company, Inc.
Corte Madera. CA
Gilman, IA

Bethayres. FA
Kalamazoo, MI
Decatur, IN
Lawrenceville. GA
Pico Rivera, CA
Wenatchee, WA
Dallas, TX
Baltimore. MD
Clinton, OK
Scabring, FL
Wilson, NC
New Baltimore. MI
Manchaug, MA
Huntington Station, NY
Mulberry, FL
Canandaigua, NY
Covington, GA
Frankfurt, IL
Temple. TX
Bakersfield, CA
St. Louis, MO
Kitchener, Ontario,
  Canada
East Providence, RI
Detroit, MI
Toledo, OH
Marine City, MI
Richmond, CA
Bedford, IL
Inkster, MI
Hatfield, PA
                                                                  (Continued)
                                      58

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                              TABLE 3-6 (Continued)
                 Company
    Plant Location
 The Flastifoam Corp.
 Plasti-Kraft Corp.
 Plastilite Corp.
 Plastronic Packaging  Corporation
Poly Foam, Inc.
Polyfoam Packers, Corp.
Poly Molding Corp.
Preferred Plastics, Inc.
Radva Plastics Corporation
Rector Insulations
SF Products, Inc.

Shelmark Industries, Inc.
Solo Cup
Snow Foam Products, Inc.
Sonoco Products Co.
M.H. Stallman Co.
Sweetheart Plastics, Inc.
Tekni-Plez
Tempo Plastic Co., Inc.
Tex Styrene
Thompson Industries
Toyad Corporation
Rockville, CT
Ozona, FL
Omaha. NB
Stevensville, MI
Sparta, WI
St. Charles, IL
El Paso, TX
Grand Prairie, TX
Minneapolis, MN
Lester Prairie, MN
Wheeling, IL
Haskell, NJ
Putnam, CT
Norristown, PA
Mt. Vernon, NY
Memphis, TN
North Kansas City, MO
Jackson, MS
Columbus, OH

El Monte, CA
Hartsville, SC
Providence, RI
Wilmington, MA
Owings Mills, MD
Chicago, IL
Conyers, GA
Dallas, TX
Los Angeles, CA

Burbank, CA
New Brighton, MN
Phoeniz, AZ
Latrobe, PA
                                                                   (Continued)
                                     59

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                             TABLE 3-6  (Continued)
                Company
                                                             Plant Location
Tuscarora Plastics. Inc.
UC Industries. Inc.

U.S. Mineral Products Co.
Western Foampak
 Wilshire Foam Products. Inc.
                                                        New Brighton, PA
                                                        Parsippany. NJ
                                                        Tallmage, OH
                                                        Rockford, IL
                                                        Stanhope. NJ
                                                        Oelwein. IA
                                                        Greensboro. NC
                                                        Malverne. AR
                                                        Fresno. CA
                                                        Yakima. WA
                                                        Carson. CA
Source:  (12)
                                     60

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Nonpolyurethane Foams

     Nonpolyurethane  extruded foam  products include  polystyrene  sheet and
film, polystyrene boardstock, polyethylene  plank and sheet,  polypropylene  foam
sheet, and FVC foam.  Nonpolyurethane  foams also include phenolic  resin foams.

     Polystyrene sheet  is normally thermoformed into common food  packaging
items such as  egg  cartons,  meat and produce trays,  and  fast-food  containers.
Polystyrene foam sheet with laminated  faces has  also been used  as  a corrugated
cardboard  substitute  for poster  boards used in the graphic arts industry.
Polystyrene film has a non-slip surface which  is useful  for wrapping material
and  food  tray lining.  Polystyrene  foam boardstock, especially when  foamed
with chlorofluorocarbon blowing  agents, is used as  a  construction  insulation
material (14).

     In their 1980 report, Rand cited  a publication which listed 105 producers
of polystyrene sheet, film and block  (13).   Three companies produce a majority
of the polystyrene  foam manufactured in the United  States.   These are Mobil
Chemical Company, Amoco,  and W.R. Grace Formpac  Division.  Table 3-6 lists the
major polystyrene  foam manufacturers.   In the  past year,  the  13 largest
PS—foam producing companies have  installed as many  as 75 new PS-foam lines to
meet increasing  demands.   Sources  have indicated  that  at least 70  to 75
percent of the PS  foam produced is made using non-CFC blowing agents  (18,23).
The top three producers (Mobil, Grace,  and  Amoco)  generate an estimated 70 to
90 percent of  all  PS  foams—using primarily hydrocarbon blowing agents (23).
However, data from  Rand indicates that the fraction of  PS  foam sheet  blown
with pentane decreased  rapidly  in the  1970s from 45 to  50 percent  in 1973 to
about 35 percent in 1977  (13).   For purposes of this  report. Radian is using
70 percent as  the  current fraction of  PS  foam sheet produced with hydrocar-
bons.  Among the list  of  major  foam producers who use CFC blowing agents  are
Mobil Chemical Co.,  Huntsman Container Corporation,  W.R.  Grace  Co., Dow
Chemical U.S.A., and  Owens-Illinois.   Table 3-7 shows estimates of total  CFC
blowing agent consumption derived from sales data for polystyrene  foams (3,9).
                                       61

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     TABLE 3-7.   1985 ESTIMATED  CONSUMPTION OF  CFC BLOWING AGENTS FOR THE
                  MANUFACTURE  OF  POLYSTYRENE FOAM (1.000  mt)

Boardstock
Sheet
Stock Food Trays
Egg Cartons
Single Service
Plates, Cups, etc.
Hinged Containers
Other Foam Sheet
Total Sheet
Totals
Total
Product
49.1

77.1
36.3

53.9
28.6
12.2
208.2
257.3
% of
Product
Blown
With
CFCs
100%

50%
50%

50%
50%
50%


Product
Using
CFCs
49.1

38.6
18.2

27.0
14.3
6.1
104.1
153.2
Foam
Formulation
% CFC
Content
6%

6%
6%

6%
6%
6%


Estimated
CFC-12
Consumed
2.95

2.31
1.09

1.62
0.86
0.37
6.25
9.20
Source:  (3,23)
                                       62

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     Of all  the rigid nonpolyurethane foam products,  polystyrene foam sheet
products consume the  largest quantity of CFC blowing agents.  The manufacture
of  these  products  (i.e.,  the food trays,  egg cartons and  single service
products)  required approximately 3,800 metric tons (8.3 million  pounds)  of
CFCs in 1985.   Extruded polystyrene boardstock consumed roughly  3.000  metric
tons of CFC blowing agents  in 1985.

     Polyolefin  foams can be  broken down  into  two  types:   plank  and  sheet.   In
1985.  approximately 22,000 metric tons  (48.5  million pounds) of  polyolefin
foam were produced  (12).   Of  this,  polyethylene  plank  accounts  for
approximately 40 percent (49).  Plank refers to foam 2.5  (1 inch) thick up to
10.1 cm (4 inches)  thick.   The end uses of  plank consist of  cushion  packaging,
70  percent;  construction,  6  percent;  sports  and  leisure, 12 percent; and
returnable dunnage, 12  percent (49).  A significant  end  use  of PE plank is  the
military, which accounts for  approximately 30 percent of  cushion packaging.
This is due  primarily to the multiple drop protection and high  load bearing
ability PE  foam offers.   The primary manufacturers are:   The Dow Chemical
Company, Sentinel  Foam  Products, and Valcour,  Incorporated.   These  companies
produce about 80 percent of PE plank.

     Polyethylene  and polypropylene  foam  sheet account for  the  remaining 60
percent of the  polyolefin  foam  market  (49).   Foam sheet  is normally 1.3  cm
(1/2 inch) thick or less with most material being 0.3 cm  (1/8 inch)  or less.
Approximately  99  percent  of  polyolefin  foam  sheet  is  used  for surface
production/packaging  with the remaining  1  percent for  sports and  leisure
applications  (49).  The primary  manufacturers  of  PE sheet are:   Sealed Air
Corporation,   Sentinel Foam Products,  Richter  Manufacturing  Corporation,  and
Valcour,Incorporated.    These  companies  produce about 80 percent  of  PE  sheet.
Ametek Incorporated is  the  sole  producer  of PP foam  sheet.

     In the past,  phenolic  foam  was  used in the United States primarily as a
base material for  floral arrangements.  However, the introduction of phenolic
foam  in thermal insulation  applications several  years  ago,  especially
                                      63

-------
following  the  development of  closed-cell phenolic foam  in 1981 by Koppers
Company has  results in an increase  in the production  of phenolic foam  in
recent  years.    Koppers Company  has  a patented  process  for  producing
closed-cell phenolic foam insulation.

     Building  construction insulation accounts for  the  majority  of  the
phenolic foam market.   This  arises since  closed-cell phenolic  foam provides
hetter insulating value than  many other materials with an R-value  of  8.3 per
inch  (50).  In  addition,  phenolic foam maintains its R-value over  the entire
life  of  the foam  (50).  Application  of  phenolic  foam include  frame  wall
sheathing  and under-roof insulation.  In  1985,  approximately 10,000  metric
tons  (22  million pounds)  of  phenolic  foam were produced  (12).   Of  this,
approximately 60 percent was  used as roofing insulation and the  remaining  40
percent as sheathing (12).

     Finally, polyvinyl chloride foam is  used  in  a variety of  applications
including:  gasket and  sealing materials,  athletic  padding,  flotation  devices,
and pipe insulation.   Greater durability, ease  of  use,  and lower  cost have
resulted in the replacement of rubber  with PVC foam in many sealant and gasket
applications.  Moisture resistance and low density  also make PVC foam  suitable
for use in flotation applications such as  life jackets and buoys.

CFC EMISSIONS CHARACTERISTICS

     The CFC emissions characteristics of rigid foams can be  conveniently
divided into production, in—use, or disposal emissions.

Production Emissions

Polyurethane Foam—
     The primary  characteristic  of  rigid polyurethane  foams is  that the
blowing agents are trapped in the finished foam's  closed cells with  only  a
                                      64

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minor amount of the blowing agent escaping during production.   There  is varied
information on how much CFC is lost during foam production.  In general,  only
a small amount is lost  during the polymerization phase.  This  amount  depends
upon the foam's stability  during rise,  the percentage and  type of  CFCs used,
the mayinmm temperature within the  foam, and the extent  of  mechanical rupture
of foam  cells  after curing  the foam.  Table  3-8  shows the  estimated CFC
emissions associated with  each of the production methods.

Nonpolyurethane Foams—-
     There are several  sources  of CFC emissions during  nonpolyurethane foam
manufacturing processes.   A typical polystyrene sheet extrusion process will
experience blowing  agent  losses  of approximately  60  percent  of the  total
consumed (5,16).  These  losses  occur during extrusion, curing, thermofonning,
and scrap reprocessing.  Emissions  from manufacture  of polystyrene boardstock
were assumed to be approximately 5  percent of  the CFC  consumed (13).   However,
based on current information,  these emissions may be  as high as 15  percent
(49).

     Emissions of CFCs  from a typical plant which manufactures  polyolefin or
FVC foam originate  from the extrusion process and  from foam  storage, while
those from phenolic foam are similar to PU foam in that  only a small  amount of
the blowing agent is lost  during foam production.   Variation in emissions can
be caused by the degree to which the  CFC  is premixed in the  extruder,  the
difference in temperature  profile of the extruder,  the  die shape,  the sheet
thickness,  and specific operating conditions.

In-Use Emissions

Polyurethane Foam—
     Prior to  the banning of  aerosol propellant CFCs and the upsurge in
production of rigid insulation  foams,  the  predominant uses of CFC-11 led to
immediate release  of  the  chemical  to  the  atmosphere.  However, its  use  in
closed cell foams is changing the emissions scenario to  one in which there is
an accumulation  of  the blowing  agent  and  a steady very long  term release.
Informal estimates  from DuPont  suggest  that  the  half  lives  of  CFCs in
                                      65

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                TABLE 3-8.  ESTIMATED CFG NON-WEIGHTED CONSUMPTION i EMISSIONS FROM RIGID PU FOAM PRODUCTION
                            IN THE U.S.  (1000 mt)
o>

X CFC Content in the
Fonulaticn
X of Total CEC Bttitted
During Production
Building iMulatiai
Refrigerated Insulation
Industrial Insulation
Packaging
Transportation
Other
Total
1985
Rigid PU
Product im


191
54
27
20
29
_4
336
EatiBBtad (ZO-U Conunad
Bunatodk
14.0

2.7
0.0
0.2
0.0
0.0
0.5
3.4
Ijndneted
14.0

12.8
0.0
0.0
0.0
0.0 •
0.5
13.3
Found
12.0

2.3
6.5
0.4
2.4
2.4
0.4
14.4
Spayed
12.0

7.3
0.0
2.7
0.0
1.2
0.4
11.7
Eatiatted
OO-12 Ganauaed
Poured
5.0

1.0
2.7
0.1
1.0
1.0
0.2
6.0
&«*^M«^M|
upoiyad
1.0

0.6
0.0
0.2
0.0
0.1
0.0
1.0
Ertinted 00-11 BdMiaM
Bunatock

19.0
0.5
0.0
0.0
0.0
0.0
fill
0.6
Laadnated

2.5
0.3
0.0
0.0
0.0
0.0
0.0
0.3
Found

11.2
0.3
0.7
0.0
0.3
0.3
0.0
1.6
fl|>uiyvd

10.0
0.7
0.0
0.3
0.0
0.1
0.0
1.2
Brtinted 00-12
BdMiena
PoUTBd

36.2
0.3
1.0
0.1
0.4
0.4
cayed

20.0
0.1
0.0
0.0
0.0
0.0
0.0
0.2
       Source: (3,10.13).

-------
one-inch-thick unclad  rigid polyurethane foam range from  75  to 150 years
(16,5). The future emissions  of  CFC-11  will therefore lag behind the cumula-
tive production and sales.  This creates a  situation  in which  it is impossible
to immediately control  or  reduce the emissions of CFC-11 to the atmosphere,
should such an action be desired.  Additionally, the  uncertainties in estimat-
ing the annual release will be greatly  increased.

     One study examined the CFC-11 emissions characteristics of  four different
types of foam insulation (4).  The four foams  selected were representative of
much of  the  closed cell polyurethane foams used for insulation.  The manu-
facturers of the foam  claimed that the fraction of  CFC-11  in the foams was
about 15 percent by weight.  Measurements taken by the experimenters, however,
indicated that the CFC-11 content was approximately 8 to  12 percent by weight.
Each sample piece was  cut  to a one foot by  one foot  square and  placed into a
specially designed apparatus  which would measure the concentration of CFC-11
in an  air  stream which was swept over  the  sample.   The  experimental results
indicated that release of blowing agent from the foam samples  is characterized
by a pattern consisting of three phases.   The first is quick release followed
by a transition  phase and  finally a period of steady release.  During  the
first phase which will last about two months,  the release  rate  is relatively
large but decreases rapidly;  therefore, in  the long  run,  this  period does not
account  for much of  the cumulative emissions  of the blowing agent.   Several
months later following the transition period,  the rate of  release  of  CFC-11
becomes nearly constant  and this last phase represents the  long term behavior
of the foam.

     The main result  of  this study is  that, in undisturbed and  intact foams,
the CFC-11  remains  in the  foam  for  a very long time with  a  half  life  of
perhaps  100 or more years.   One sample actually indicated  a CFC half life of
320 years.   Therefore, a small percentage of the total CFC-11  used  in a given
year for rigid polyurethane foam production will be released quickly into the
atmosphere; the remaining CFC is held in  a  slow-leaking  reservoir.   The total
                                       67

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quantity  of this "banked"  CFC-11 increases each  year,  and may  eventually
become  a  large  and  almost uncontrollable source of CFC (4).

     Table  3-9  shows,  for the years between 1955  and  2015,  estimated annual
CFC  emissions  from  rigid  polyurethane  foam assuming  a CFC content  of 13
percent CFC-11  and  two percent CFC-12 with CFC half lives of 100 years for
both  CFC-11 and CFC-12.  These results are rough  estimates because  of the
uncertainties  in the  assumptions,  but they do indicate the potential for
tremendous  growth of the banked CFCs.  In 1985* approximately 461,000  metric
tons  of CFC-11 and  74,000  metric  tons of CFC-12 were banked  in PU  foams.
Assuming  moderate  growth rates  in the various  consumption  areas,  the bank
should  triple  in size, by the year 2000, to over  1.4  million  metric  tons  of
CFC-11  and  228.000 metric tons of  CFC-12.

Nonpolyurethane Foam—
     Because  CFC-12 and the  other CFC blowing  agents are able  to permeate
through the polystyrene, polyolefin,  and PVC foams relatively  quickly,  the CFC
which remains in the cells  after manufacture  (40 percent of  the  total consumed
during  PS foam  sheet production)  is emitted early  in the product's  shelf-life.
DuPont  has estimated  half—lives  of  blowing  agents  in several  of  the
nonpolyurethane foam products (5).  These estimates are reproduced in Table
3-10.   In each  case, the half life of the CFC is sufficiently small that none
remains upon disposal  of a  rigid nonpolyurethane product, except in  the case
of thick cross-section insulating  board.

    TABLE 3-10.  ESTIMATED  HALF-LIVES  OF CFC IN RIGID  NONPOLYURETHANE FOAM
Foam Type
Polystyrene Sheet
Polystyrene Board
Polyethylene (CFC-12)
Polyethylene (CFC-114)
Polyvinyl chloride
Approximate Half-Life in Product
1.5 months
40 years
1 week
4 weeks
1 week
Depends on dimension  of product.
 Source:   (5, 43)
                                      68

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                                                                       ,a
                   TABLE 3-9.   ESTIMATED  CFC-11 AND  CFC-12 EMISSIONS" FROM  MANUFACTURE  AND USE OF  RIGID

                                POLYURETHANE FOAMS IN THE U.S.  (1.000 mt/yr)
en
vo
Year
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
2015
Rigid
PU Prod.
0
5
41
95
ISA
244
336
476
596
748
879
1034
1216

Annual
Use
0
1
5
12
20
31
43
61
76
95
112
132
155

Cumulat.
Use
0
1
15
64
160
303
485
749
1097
1532
2057
2674
3400

Cumulat .
Banked
0
1
15
62
155
291
461
706
1025
1420
1890
2434
3068
CPC-ll
Cumulat.
Emitted
0
0
0
1
5
12
24
43
72
112
168
240
333
CPC-12
Annual Emissions
Bank
0.0
0.0
0.1
0.3
0.9
1.8
2.9
4.5
6.6
9.2
12.4
16.0
20.3
Mfg.
0
0
0
1
2
3
4
5
7
9
10
12
14
Total
0
0
1
1
3
5
7
10
13
18
23
28
34
Annual
Use
0
0
1
2
3
5
7
10
12
15
18
21
25
Cuaulat. Cumulat.
Use Banked
0
0
2
10
26
49
78
120
176
246
330
429
546
0
0
2
10
25
47
74
113
165
228
303
391
492
Cumulat .
Emitted
0
0
0
0
1
2
4
7
11
18
27
39
53
Annual Emissions
Bank
0.0
0.0
0.0
0.1
0.2
0.3
0.5
0.7
1.1
1.5
2.0
2.6
3.3
Mfg.
0
0
0
1
1
2
2
3
4
5
6
7
8
Total
0
0
0
1
1
2
3
4
5
7
8
10
12
        "Estimated emission values are non-weighted.



        Source)  (3.10,13)

-------
      Therefore,  the only nonpolyurethane products  which banks CEC emissions
 over a one year period  are  polystyrene boardstock and  phenolic  foam.  The
 other nonpolyurethane foam products lose all  of their CFCs within one year.
 In—use emissions from polystyrene boardstock in a  given year  are the sum of
 emissions  from  the  newly made boardstock  plus the  banked emissions from
 boardstock made  in  previous years.  Two-inch (5.1  cm) thick PS boardstock has
 a  40-year  half-life emitting 2 percent  of  its CFC content within one year.
 Table 3-11 estimates the projected emissions  from PS boardstock  assuming 6
 weight percent CFC-12  content and  a 40 year  CFC half-life.

 Disposal Emissions

 Polyure thane Foam—
      Generally.  CFCs are banked in rigid polyurethane foams.   For undisturbed
 foams,  leakage  of  CFC from the closed cells is a  very slow process;  the CFC
 half-life  may be 100 years or more.  Thus, the  life of the  CFCs in the foam is
 essentially equal  to the life of  the  product  containing the  foam; disposal
 emissions  will  only occur when the  foams are  crushed or  burned.  Since  a
majority of foams  are  used in the construction industry (57 percent in 1985).
 the  CFCs will  remain in the foams until the homes  or buildings burn  down or
are  demolished.  It may  be possible, however, to remove  the foams (much  in the
way  that asbestos  products are removed  from a  building) prior  to demolition,
and  transport them to a  CFC recovery facility.

     The second largest  consumption area for rigid  foams (16  percent  in 1985)
is refrigeration insulations.  A  Rand report  (16)  estimates  that a  refrig-
erator lasts about  10  to 15  years and contains about  1-1/2 pounds of CFC in
its  foam.  Typically,  after  the  unit has been disposed of, its  motor,  com-
pressor, and tubing are  removed for scrap, and  the housing is  then sent to a
landfill dump where  it  is crushed (releasing the CFCs)  and buried.   In  other
scenarios,  the unit  is buried intact or  abandoned  and left to deteriorate.
Here  again, it may be technically possible to  collect old  refrigerators and
remove them to a CFC recovery facility.
                                      70

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       TABLE 3-11.  ESTIMATED CFC-12 EMISSIONS  FROM MANUFACTURE AND USE OF EXTRUDED PS-FOAM
                    BOARDSTOCK IN THE U.S.  (1,000 mt/yr)
Year
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
2015
PS-Foamed
Board
Prod.
4
6
9
14
18
32
49
72
92
118
140
166
197

CFC-12
In Foam
0.2
0.4
0.6
0.8
1.1
1.9
2.9
4.3
5.5
7.1
8.4
9.9
11.8

Cumulat.
Use
0
2
4
8
13
21
32
51
76
108
147
193
248

Cumulat.
Banked
0
2
4
7
11
18
27
43
64
90
120
155
196
CFC-12
Cumulat.
Emitted
0
0
0
1
1
3
4
7
12
18
27
38
53

Annual
Product
0.0
0.0
0.1
0.1
0.2
0.3
0.4
0.7
1.0
1.4
2.0
2.5
3.2

Emissions
Mfg.
0.0
6.0
0.0
0.0
0.1
0.1
0.1
0.2
0.3
0.4
0.4
0.5
0.6


Total
0.0
0.0
0.1
0.2
0.2
0.4
0.6
0.9
1.3
1.8
2.4
3.0
3.8
 Non-weighted

Source:  (3)

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 Nonpolyurethane Foams—
      Similar to rigid PU foams.  PS boardstock and phenolic foam insulation can
 retain a  substantial  amount  of its blowing agents until the time of disposal.
 The half  life of CFCs  in PS foam  is  dependent upon the foam's thickness  and
 density;  this can range from 5 years  for 0.033 g/cc (2 lb/ft3).  1.3 cm  (1/2
 inch)  thick foam, to  250 years  for 0.048  g/cc (3 lb/ft3), 7.6 cm (3 inch)
 thick  foam (43).   PS foam sheet, on the  other hand, has a half life on  the
 order  of  1.5 months,  and there would  be  a negligible amount of CFCs retained
 in  the foam  sheet  products  upon  disposal.   The  same would  be  true for
 polyolefin and PVC  foams which also have a half-life less than one  month.

 CHARACTERIZATION  OF WORLD CFC  EMISSIONS FROM RIGID FOAMS

     Consumption  of CFCs for the manufacture of rigid foams as a percentage of
 total  CFCs appears  to be relatively similar for the U.S.  and  the rest of the
 world  (2).  The estimated 1985  consumption of CFC-11 for rigid foams in the
 world  is  133,000  metric tons and for CFC-12 is 53,000 metric tons.

     Since the mid  1950s approximately 1.2 million  metric tons of  CFC-11 and
 244.000 metric tons of CFC-12  have been  consumed  in the worldwide  production
 of  rigid  foams (1).   The accumulated  consumption of CFC-11 for  rigid foams
 accounts  for  roughly  20 percent  of the total  CFC-11 ever  produced.  About  53
 percent of the CFC-11 consumed  for rigid  foams is banked in  these  foams.
 Similarly,  the accumulated consumption of CFC-12  in the production of  rigid
 foams  is  about three  percent  of the total  CFC-12  ever produced.  Six percent
 of the cumulative CFC-12 used  in rigid foam production is  banked.

     The  emissions  cf  CFCs  from  rigid foam  occur  from the manufacturing
operations  and from the CFCs  banked  in the product.   In 1985, the  CFC-11
emissions  from manufacturing  accounted for approximately 10 percent of  the
consumption or 13,300 metric tons.  For the same  year,  the CFC-12  emissions
from manufacturing  are estimated at 90 percent of the total world consumption
 or 47,700 metric tons.
                                       72

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     The CFC-11 emissions  from the bank are estimated at 0.5  percent  of  the
total CFC-11 and 2 percent  of  the  total CFC-12 in the bank.   Therefore,  the
1985 world CFC-11 emissions from the bank  are  approximately 3,400 metric  tons
and the CFC-12 emissions from the bank are approximately 400 metric tons.

     The 1985 total world CFC-11 and CFC-12 emissions from  rigid foam manufac-
turing are 16,700 metric tons and 48,100 metric tons, respectively.
                                      73

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                                    SECTION 4
                   DESCRIPTION OF CURRENT PROCESS TECHNOLOGY

RIGID POLYURETHANE FOAM PRODUCTION

     Polyurethane  foams are  cellular plastics,  generally  produced by  the
reaction  of  a  polyol and a polyisocyanate in the presence of a blowing agent,
a  catalyst,  a  surfactant  and other  specialty additives  such as  flame
retardants.   The  most  commonly  used  isocyanates  in  polyurethane  foam
manufacture  are  toluene diisocyanate  (TDI)  and polymeric methylene diphenyl
dilsocyanate (MDI).    Most  rigid  polyurethane  foam  is made  using PMDI.
Typically the  ingredients  are blended continuously in  a  high  speed mixer  and
discharged while the mixture  polymerizes  and expands.   The blowing agent  is
blended into the polyol, or it is metered as a separate  stream to  the mixing
heads of  the foam machine.  Rigid foams  have  a wide  range of densities,
formulations, and uses.  In general,  rigid polyurethane foam production  can  be
divided into four  types of processes:  laminated foam  core panel manufacture.
poured foam  production, sprayed  foam application,  and bunstock  production.
The following paragraphs describe these processes.

Laminated Boardstock

     Rigid polyurethane  laminated boardstock production is  similar  to flexible
foam bunstock  production.   In this process, the liquid polyol  and  isocyanate
mixture is  poured as  a thin layer onto  a facing material which is moving
continuously on  a conveyor.   A short  distance beyond the point of foam appli-
cation, an upper facing material is applied to the  top of  the expanding foam
mixture.   Film facing  materials  include asphalt or tar  paper,  aluminum,  steel,
fiberboard,  or gypsum.  As it moves along the  conveyor, the foam expands to a
thickness controlled by  nip rollers and upper and lower conveyers.   Figure 4-1
presents a schematic of  a  typical laminated boardstock  operation.
                                       74

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                                               A - Polyol Mixture
                                               B - Isocyanate Mixture
1) agitated material tanks;  2) metering pumps;  3) traversing mix-head;  A)  top facing roll;  5) bottom
facing material; 6) adjustable nip rollers; 7)  oven and conveyer;  8)  expanding foam and adjustable
panels; 9) transverse cutter; 10)  cut foam.
                            Figure 4-1.   Laminated foam boardstock line.

-------
     Laminated  board stock production emits  relatively small  quantities  of
CFCs.  The  emissions occurring during initial mixing of foam  ingredients are
roughly  one percent.  The  losses  occurring  as  the foam  is  dispensed is
approximately 1.5  percent,  bringing the total manufacturing emissions to 2.5
percent  of  the  initial charge  (10).

     For laminated rigid polyurethane foams, a  large  percentage of the CFC
blowing  agent  is  trapped in the foam for up to hundreds  of  years.   The
relatively  small quantities of CFCs  emitted  during the manufacturing steps
could  possibly   be controlled  through  add-on  controls such  as  carbon
adsorption.  However, control  of  in-use,  or  product emissions  would require a
different approach.  Using  lower  ozone  depleting blowing agents or replacing
the  foam products with  non-CFC containing materials are  two  approaches  to
emissions control.   Laminated foams  are  used as sheathing insulation for
buildings and homes.  They have high insulating efficiencies  and replacing
them with  alternative non-CFC sheathing materials  would   require  greater
thicknesses to  obtain equivalent  insulation.   Alternative  sheathing materials
include  expandable polystyrene (EPS)  board, extruded PS board, fiberboard, and
others.  The very  long half life of  CFCs in  rigid  polyurethane  foams  causes
mich of  the CFC to be retained in  the  foam even at the end of the foam's
useful life.  This gives rise to the possibility of recovering blowing agent
from discarded  foam  products.   This would require initiation  of a foam scrap
collection  program in which collected foam would be transported to  a facility
      the foam would be crushed and the CFCs adsorbed on carbon beds.
?our-in-place/ Injected Foams

     The pour-in-place or injected foam process involves pouring  or  injecting
ihe liquid polyurethane  mixture  into spaces within rigid  structures  such as
refrigerator walls,  refrigerated tanks,  and building walls.  Foaming  pro-
gresses in place to  fill all  crevices  and form a continuous mold.  The final
product is a continuous  foam  structure with excellent insulating properties.
figure 4-2 shows the equipment used in a foam injection operation.
                                      76

-------
                                        A - Polyol Mixture
                                        B - Isocyanate Mixture
                                                                                              $
                                                                                              o
1) agitated material tanks; 2) metering pumps; 3) mix-head/injector; A) refrigerator housing; 5)
vent holes.
                               Figure 4-2.  Foam injection operation.

-------
     Pour/inject ion  systems  have widely  varying emission  rates.   This  is
because  of  the  variety of cavities  into  which the foams are poured.  These
systems also employ  CFC-12 as  a frothing agent (17).  The  rigid polyurethane
foam is ejected from a frothing device pre-expanded about 20 to 30 percent and
has the  consistency  much  like  an aerosol foam.  It is estimated that,  for a
typical  freezer insulating  operation,  10 percent of  the CFC-11 and  35  to 85
percent of the CFC-12 is emitted  (9,10).  An  additional  one percent  of  CFC-11
and one  percent of  CFC-12 is  lost  in  mixing and handling.   The  frothing
process  is  in  decline because  of advances in poured-in-place  formulations
(18).

     For poured foams, carbon adsorption  could be used to collect CFCs emitted
during both  manufacture  and disposal  of the product.   Reduction  of in—use
emissions would require using alternate,  low  ozone depleting blowing agents or
non-CFC  containing  products.   Before the introduction  of  polyurethanes,  re-
frigerated appliances were insulated with glass  fiber insulation.  However, an
emphasis on  new materials and  designs for refrigeration  systems  including
higher grade insulation  has resulted  from more stringent  appliance energy
standards.   Thus,  it is  likely new  materials or system  designs will play an
important role in the refrigeration  insulation options for  the future.

Sprayed Foams

     Rigid polyurethane  foam may  also  be produced by  spraying the  liquid
chemical mix directly from the mixing head onto the surfaces requiring insula-
tion.   Sprayed foams are  often  used  for on-site application of rigid thermal
insulation.   Typical surfaces which require a  foam  spray include  storage
tanks, piping,  or  roofs.  As  with  pouring operations,  froth spraying has
become a convenient  method  of achieving  the  desired  density  and  skin thick-
ness.   Figure 4-3 shows setup and use of  a typical foam  sprayer.

     The mixing and  handling emissions of CFCs is spraying operations are as
low as 0.5  percent  of the total  used  in formulation.  This  is because the
                                       78

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VO
                                              A - Polyol Mixture
                                              B - Isocyanate Mixture
                                    1) material tanks, 2) metering pumps, 3) mixhead/sprayer.

                                         Figure 4-3.   Sprayed-foam operations.

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 pray system  uses  a liquid mixture which is usually prepared  by a supply
 lompany.  These  suppliers prepare mixtures in large volumes allowing tighter
 :ontrol of CFG emissions.

     Spraying losses  are dependent upon  the conditions during the spraying
 .pe rat ion.  It is estimated that  10 percent  of the CFC-11 and 20  to 90 percent
 >f the  CFC-12 are  emitted during  spraying  (9.10.22).   Because  the CFC-12 is
 tsed as a frothing agent, its emissions are  expected to he relatively high.

     The nature  of  the sprayed foam operation all hut  eliminates the  possi-
 >ility of emissions recovery during spraying.  Additionally, disposal recovery
 'ould he  severely  limited because removal of sprayed-on  foams from their
 :ubstrate would most likely rupture the foam cells and  release  the CFCs.   The
 >rimary control  options would be  using alternative blowing agents or non-CFC
 jis ulation.

 Sunstock Foams

     Rigid polyurethane  foam bunstock is manufactured  on  both a  small  and
 -arge scale.  The  manufacturing facility for rigid PU  foam bunstock is  very
 similar to that  for flexible PU foam bunstock manufacture.  In  this process, a
 .iquid polyol mixture  is poured  as a  thin layer onto a continuously moving
 :onveyor where  it  expands to form a  continuous  block, or bun,  of foam.
 Adjustable top panels  control bun height.  After oven curing,  the foam may be
sliced to specific thicknesses by  a variety  of sawing methods.  The slices are
 :hen either cut  into  flat boards  or profiled for such applications as pipe
 Insulation.  Figure 4-4  shows  the layout  of a typical bunstock  production
 init.  Improvements in laminate technology have led to  the decline in bunstock
aanufacturing.

     A majority of the CFC emissions from the manufacture of bunstock occur as
=he foam is being dispensed onto  the moving  conveyer.   This loss  amounts  to 13
percent of  the  CFCs initially  included in  the  foam  ingredients  (10).   An
                                      80

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A

/7\

B
CO
                                                  A - Polyol Mixture
                                                  B - Isocyanate Mixture
        1) agitated material tanks; 2) metering pumps; 3) traversing mix-head; 4) top paper roll; 5) exhaust
        hood; 6) bottom paper roll; 7) conveyer; 8) expanding foam; 9) transverse cutter;  10) cut foam bun;
        11) adjustable top panels.

                                    Figure 4-4.  RiRid polyurethane bunstock foam line.

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additional five  percent is lost as the closed cells are broken in the cutting
and  trimming  operations.   The emissions  occurring  during  initial mixture of
foam ingredients are roughly one  percent bringing  the total emissions to 19
percent  of the initial  charge.

      The CFC  control options for  bunstock foams are  the  same  as those for
laminated sheet  foams.  Carbon  adsorption could  be  used to reduce manufactur-
ing  and disposal emissions.  Reduction  of product  emissions would require
alternate blowing agents  or non-CFC insulation materials.

RIGID POLYSTYRENE FOAM  PRODUCTION

      Polystyrene foam is  formed by one of two general methods.   It  is  either
extruded into sheet, film, or  boardstock; or it is formed from expandable
beads.

Extruded Polystyrene

      In  the extrusion process,  polystyrene resin is mixed with  additives  and
melted to a low  viscosity in  a  two-stage  screw extruder.   The fluorocarbon (or
hydrocarbon)  blowing agent is injected under high pressure into the extruder,
where it is dispersed in  the  polymer melt.  This mixture is cooled and forced
through  a die under controlled pressure  (14).  The die can be  of  several
shapes; a round  die  forms rod-shaped foam,  a  slit die  is used to form a block
or slab,  and  an annular-shaped  die is used to form a tube which is  slit  to
make  foam sheets.  As the molten polymer  exits the  die,  the dissolved blowing
agent vaporizes  causing  the  plastic  to  foam.  The final stages  involve
cooling, shaping, cutting, or winding  the  foam  into the desired form.  Ex-
truded foam is  normally  aged 24 hours prior  to  thermoforming the final pro-
duct.  Approximately 80 percent of all extruded PS  foam produced consists of
foam  sheet.   This material is  thermoformed into a  variety  of products in-
cluding  single  service  items (such as plates,  bowls,  and cups) fast  food
cartons, egg  cartons,  and meat  trays.  The remaining 20 percent of  PS foam
                                       82

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production is  primarily boardstock which is not thermoformed.  This  material
is most commonly used  as a construction  insulation material.

     The  thermoforming step of  most  PS foam  sheet  manufacturing processes
generates a substantial, amount  of foam scrap.   In  some  cases,  30  to 40  percent
of the  extruder feed  will eventually become  scrap  pieces.   Because this
occurs, manufacturing  processes commonly include a grinding and repelletizing
step after  the final  cutting  and thermoforming steps.   The recovered  scrap
foam pellets  are recycled  to  the extruder feed.  The  typical  extruder  feed
mixture is 65% virgin  PS and  35% recycled PS.   A flow  diagram  of  an  extruded
polystyrene  sheet  manufacturing process using  scrap recovery is shown  in
Figure 4-5.

     In polystyrene-foam manufacture. CFCs  are  emitted at various points in
the process.   Table  4—1 summarizes the emissions  generated in each  phase of
sheet and boardstock  manufacturing.   As  can  be seen  from the table,  the
relatively thin  extruded sheet has much more  prompt emissions of CFCs  which
occur during  the extrusion and  thermoforming  operations.   However,  based on
recent information,  the emissions from extrusion,  aging, and thermoforming may
be roughly  equal  (52).   In  addition,  these  emissions may be  lower and
considered fugitive  rather than being controllable as indicated in Table 4-1,
with a high  percentage  of  CFCs leaving the plant with the finished  product
(52).   Boardstock, on  the other hand, is much thicker and holds  the  majority
of CFC in the foam cells as a bank of CFC.

Expandable Polystyrene

     The majority  of polystyrene  foam is  extruded;  however, a great  deal of
molded foam products are manufactured from expandable polystyrene (EPS)  beads.
Insulating materials,  packaging,  drinking cups, ice chests,  and flotation
material are  typical EPS  foam  products.   The beads are  formed during  the
manufacture of  the polystyrene itself,  in the suspension polymerization phase
(19).   The blowing agents, primarily pentane,  are incorporated directly  into
the beads.
                                       83

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                       CFG • 12
                     VIRGIN
                   POLYSTYRENE J—
                     RESIN
                                                                                                                 SCRAP REStN
                                                                                                                 STORAGE SILOS
oo
                                                                                                                    SCRAP RESIN
                                                                                                                 P REPELLETIZER
                                                                                                                    (OPTIONAL)
                     POTENTIAL CFC RECOVERY POINTS

                     A  OUTSIDE AND INSIDE EXTRUDED BUBBLE
                     B  THERMOFORMINQ MOLDS
                     C  REPELLETIZER EXTRUDER VENT
                     D  EXHAUST FROM PNEUMATIC TRANSFER
                        OF REQROUND SCRAP FILM TO 6IUOS
NOTE:
1 CFC CAPTURE SYSTEM IS NOT EXISTING.
 NEED TO BE DEVELOPED.
                     Figure  4-5.   Flow  diagram  of  a typical  polystyrene foam sheet manufacturing process,

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     TABLE 4-1.  SUMMARY OF CFC EMISSION SOURCES AND EXAMPLE  DISTRIBUTION
                 IN POLYSTYRENE FOAM MANUFACTURING
Percent Percent
From From
Extruded Extruded
Sheet Boardstock
Manufacturing Losses
Extrusion Losses
Intermediate Storage
Thermoforming
Regrinding Scrap
Reextruding Scrap
Prompt Foam Cell Losses
(within first year)
Banked Emissions


34 5
4 0
5
15
1 — —
41 2
0 93
100.0 100.0
Source:   (18,32)

Note:   These estimates may vary among producers based on blowing  agent  content
       and process conditions.
                                       85

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     The foaming  process begins as the beads are  heated  with steam and par-
tially expanded.   The  pliable beads are then transferred to  molding  stations
and stored for approximately  6  to  24 hours while the beads cool and  reach  an
equilibrium.  Finally,  the beads are  conveyed  to the mold,  usually  by  air,
where they expand to their final form.  The preexpanded  polystyrene  bead is
heated in the mold by  steam through perforations  in the  mold,  or  by  means  of
steam probes.  During  this final expansion, the beads melt together  slightly
which allows them to adhere to each other, while  at  the  same time, a smooth
outer skin is  formed along the mold walls.  Once the  polystyrene bead has
expanded to nearly fill  the mold, the  steam is  stopped  and the  beads  expand to
their final size.

     In addition  to  the use of pentane as  a blowing  agent, a mixture of CFCs
and hydrocarbons  are also  used  as blowing  agents by several expandable PS foam
manufacturers to  produce expandable PS foam loose fill packaging  (49).  These
products are produced  by  two methods:  1) pressurized extrusion  of  a high
density pellet which is later expanded or  2) extrusion with  expansion at the
extruder die.
                                      86

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                                   SECTION 5
                    CONTROL/RECYCLE TECHNOLOGIES FOR  CFC-12
                    IN POLYSTYRENE FOAM SHEET MANUFACTURING

     A possible approach to reducing CFC-12 emissions  in the manufacture of
polystyrene foam sheet is to apply capture/recovery or destruction systems as
an add-on to the foam process.   Such systems can be categorized as follows:

     •    carbon adsorption with CFC-12 recovery;

     •    direct flame or catalytic incineration of CFC-12 in plant
          exhausts;

     •    absorption (liquid scrubbing) with CFC-12 recovery; and

     •    vapor condensation and recovery.

The following discussion will  stress application of adsorption recovery, al-
though some discussion of other  alternatives is warranted to point out the
difficulties of applying these technologies to CFC-12  emission control.

CARBON ADSORPTION AND STEAM DESORPTION SYSTEMS

     Activated carbon adsorption has been applied  commercially for recovery of
expensive solvents for many years.  Such systems have  potential for applica-
tion to CFC-12 capture and recovery.  However, the use of carbon adsorption
and CFC-12 recovery has not been implemented commercially for the manufacture
of polystyrene sheet.  The probable main reason for this is the high capital
expenditure required for the adsorption/regeneration/recovery hardware, as
compared to the relatively low total value of the  recovered CFC-12.
                                        87

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Process Engineering and Operating Factors

     The physical principle applied in adsorption/recycle processes  is based
on the adsorptive affinity of an activated carbon surface for  organic
molecules, such as CFC—12.  These compounds are preferentially separated from
a gas stream and retained on the surface of activated carbon particles.  In
practice, a large volume of carbon particles are contained within a  vessel,
referred to as the adsorbent bed, to provide a large carbon surface  area.  The
CFC-12 molecules are retained, or adsorbed, on the carbon and  then are re-
leased, or desorbed. when the carbon particles are heated.  Steam is generally
used to heat the carbon particles and displace the desorbed organic  material.
By condensing this stream, the organic material can be separated from the
steam condensate (decanted), recovered, and reused.

     A schematic illustrating the main features of this process appears in
Figure 5-1.  At least two adsorbent bed vessels in parallel, each containing
activated carbon particles, are required to provide alternating cycles of
adsorption and regeneration.  A boiler and/or other heating equipment is used
to provide stream and/or heated air for bed regeneration.  Usually,  the regen-
eration stream is arranged to flow countercurrent to the direction of the
treated air stream (although co-current regeneration is sometimes used).  A
cool or chilled water condenser* is included to condense the mixture  of steam
and CFC—12 after desorption from the carbon beds.  Finally, a  decanter unit
separates the two phases, returning the reclaimed CFC-12 phase to the foam
line CFC feed tank, or to further purification if needed.

     A number of key engineering factors can be identified in  applying an
adsorption process to recovery of CFC-12 in PS foam plants.  The most impor-
tant of these are:

     •    reducing the volume (flow rate) of air to be treated,

     •    design of an efficient regeneration/condensation unit,
                                      88

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           Exhaust from
             Tunnel
00
                                 Adsorber No. 1
                         /////////////
                                 Adsorber No. 2
                                           «i!
                                  Steam
                                Rngeneralor
                                              Steam
  Exhaust Gas
 to Atmosphere
«i!
                                                               t
                                                               t
                                                               f
                                                  Feed Water to
                                                Steam Regenerator
                                 Cooling Water
                 I
                 I
                 I
                1

                i
                 i
 Condensale
X
                                                                                 Decanter
                                                                                             to Storage
                    Figure 5-1.   Schematic flow diagram of typical  carbon adsorption/solvent
                                 recycle process.

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      •    possible corrosion problems due to decomposition of the
           CFC,  and

      •    uniformity and quality  of  the reclaimed CFC-12.

In  addition,  if trace contaminants,  such as  resin fines or residual  styrene
monomer,  exist  in the exhaust gas streams, pretreatment of the gas stream
before the carbon beds will be required.

      In general,  the capital costs of the CFC-12 vapor  collection system and
the carbon adsorption system are  proportional to the volume flow of  air to be
treated.   The distribution of CFC-12 emissions with the process also affects
the efficiency  of recovery.   Emissions characteristics  may differ widely be-
tween various foam processes.   Table 5-1 summarizes typical emission distribu-
tions for a PS-foam sheet process.   For most existing PS foam processes,  the
exhaust  concentration .of CFC-12 is relatively low.  As  shown in Table 5-1,
CFC-12 concentrations are 1000 ppm or less in all areas of the facility.
Effective design of a carbon adsorption/recovery system must therefore
incorporate ventilation designs which reduce volume and minimize dilution of
the emitted CFC-12.

      Proposed equipment modifications that would minimize  air flow and  deliver
the highest possible concentration of CFC-12 to  the carbon adsorber  involve
thorough  enclosure of the largest  CFC emissions  sources to reduce the volume
of ventilation  air.   Any smaller  sources,  such as the scrap extruder, which
already have  high CFC concentrations  in their exhausts,  can also be  combined
and routed  to a recovery device.

     Another  possible means  of  decreasing the total air flow to the  carbon
adsorbers is  to cascade the  dilute exhaust from  one zone or collection  station
to  another  with a higher CFC concentration.  Also, air  curtains can  be  incor-
porated in  the  overall  system to help contain emissions within the work area,
and subsequently,  the bulk of the  air would  be exhausted from around the
                                       90

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         TABLE 5-1.   CFG EMISSION SOURCES IN PS-FOAM SHEET MANUFACTURE
Operation
Extrusion
Rolled Film Storage
Thermoformer
Regrinding Scrap
Re extruding Scrap
Final Product
Emissions
(% of CFC Fed)
34
4
5
15
1
41
CFC-12
Concentration (ppm)
200a
35
75
85b
1000C

Source:  (32)

a Measured at slitter.

  Measured at storage silo vents.

  Measured at extruder vent.

Note:   These estimates may vary among producers based on blowing agent content
       and process conditions.  Based on recent data, the emissions may be
       lower, with the extrusion, intermediate storage, and thermoforming
       emissions being roughly equal and considered fugitive rather than
       controllable (52).
                                        91

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 rocess CFG sources.   Such an elaborate flow scheme is not incorporated in the
 esign and cost analysis discussed in this report, but is suggested here to
 .ndicate the potential for enhanced overall emission control.

     Regeneration of  the carbon beds can be accomplished by purging with
 .ow—pressure steam.  Generally, the purge steam is applied in  the  opposite
 low direction to the CFC-laden exhaust gas.  An alternative procedure would
 >e to regenerate the  beds using a heated inert gas stream (such as air or
 litrogen) rather than steam.  After steam regeneration, it is  desirable to dry
 :he carbon bed, using ambient air.  This feature is common to  many existing
 :ull-scale solvent recovery systems, and if omitted, the bed capacity will be
 idversely affected.

     Corrosion problems with CFC-12 are typically less severe  than are regu-
 -arly encountered in halocarbon solvent recovery systems.  Although CFC-12 is
 relatively stable, when it comes into contact with elevated temperature sur-
 faces, the molecules may crack, or decompose, to hydrofluoric  acid (HF) and/or
 lydrochloric acid (HC1).  These compounds are particularly corrosive to duct
 7ork.  For this reason, it is generally recommended that adsorbent bed vessels
 >e constructed of corrosion resistant materials (10).

     Quality and uniformity of the reclaimed CFC-12 is an important issue in
:he economic feasibility of recovery systems because of the potential operat-
ing cost credit for recovered blowing agent.  It is possible that  the CFC-12
recovered by carbon adsorption would not require repurification before reuse,
and therefore would be a cost credit.  However, additional onsite  processing
Including drying and  distillation, may be required to produce  an acceptable
oroduct.  Additionally, if the material can not be reused, it  would have to be
sold to a recovery or disposal company, resulting in an added  cost.
                                      92

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Control Costs and Effectiveness

     From a technical standpoint,  there  are two key factors that determine the
effectiveness of carbon adsorption control  of  CFC-12 emissions at a particular
facility.  These are the efficiency of CFC-12  emission capture and the removal
efficiency of the activated  carbon bed.   The emissions would be collected from
the process exhaust and plant ventilation gas  streams.  Local collection effi-
ciencies within the plant limit  the fraction of emissions that can be con-
trolled.  The effectiveness  of emission  control would vary from plant to
plant, but it is estimated that  for a typical  two extruder, four thermoformer
plant, roughly 42 percent of the CFC-12  emissions could be recovered.  This
estimate is discussed further in the following subsections of this report.

     The cost effectiveness  of this control method can be expressed as the
dollar cost per unit CFC-12  emission averted.   Control expenditures consist of
the annualized capital recovery  and operating  costs less the credit obtained
for reclaimed blowing agent.  In an analysis of a CFC-12 carbon adsorption/
recovery system for a two extruder plant, the  cost of CFC control is estimated
to be $0.72 per kilogram ($0.33/lb)  of CFC-12  controlled.  If the recovered
CFC-12 is reusable the control cost could be much lower or even generate an
overall credit.

     Clearly,  significant increases in CFC-12  price and/or recovery efficiency
would provide economic incentive for implementation of control by fearners, and
would also speed recovery of the investment.   It is apparent that optimal
design of the ventilation system for high capture efficiency with minimal
capital cost is advantageous.  Pilot plant  studies would be useful to syste-
matically define the critical design parameters in achieving high recovery
efficiency at lowest system  cost.
                                       93

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Safety and Environmental Factors

     There are no apparent effects on the health and  safety of workers  in  the
polystyrene foam industry connected with use  of carbon adsorption/recovery
technology.

     Wastes from the carbon adsorption process consist of  spent  carbon  and
aqueous condensate.  Recycle of steam condensate from the  CFC-12 recovery
operation is feasible, although it may be advisable to include a purification
step or purge stream in the recycle loop to avoid recycling of organic  impuri-
ties.  Disposal of condensate is also possible providing local and Federal
regulations allow it.  If distillation is used, residues from purification of
the reclaimed blowing agent may represent another potential disposal  cost.

     No studies to date have examined the impact of waste  disposal associated
with carbon adsorption in CFC-12 recovery applications.  It is likely that
spent carbon could be disposed of by incineration in  the process steam  boilers
at the foam plant.  It may also be possible to thermally regenerate the spent
carbon in order to avoid high replacement costs.  Land disposal  of the  acti-
vated carbon waste may not be possible due to the current  EPA ban on  chlori-
lated wastes.

Current Status

     To date there has been no commercial scale carbon adsorption and recovery
system in continuous operation at a polystyrene foam  facility.   Additionally,
:here has been no research to technical development in the area  of CFC-12
:arbon adsorption for polystyrene foam sheet  extrusion facilities.  The fact
:hat nearly 60 percent of the CFC-12 used for blowing this foam  is lost in the
>rocessing area indicates the potential for raw material cost savings.  The
•rimary barrier to adaptation of this technology appears to be the capital
.nvestment involved and no regulatory incentive for control.
                                       94

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Economic Factors

     The chief economic factor  in  implementation of carbon  adsorption for
control of CFC-12 emissions from rigid polystyrene foam sheet plants is the
producer's ability to recover the  capital expenditure, and  remain competitive.
The polystyrene foam industry is sufficiently mature and competitive that
individual producers must  seek  to  minimize costs, even on a short term basis.
To remain competitive, small foamers might find it difficult, if not impos-
sible, to pass along capital recovery costs; it is these smaller plants for
which the credit for reclaimed  blowing agent is smallest in comparison to the
necessary capital investment.

     While the capital expense  of  retrofitting a plant for  a  carbon adsorption
system might be a barrier  for medium and  small foamers, actual  overall annual
savings may be experienced due  to  reduced blowing agent consumption.  In prac-
tice, the economics will vary considerably from plant to plant  because of the
wide variety of processing facility configurations and sizes.   Also, in order
to gain the benefit of the CFC  recovery,  the foamer must have the ability to
generate the capital for the recovery system.  A typical facility will require
at least several hundred thousand  dollars for this system.

     For foam processors who are currently using CFC blowing  agents, there  is
the alternative of using hydrocarbon blowing agents.  Although  the hydro-
carbons are cheaper, the foamer may be hesitant to switch to  hydrocarbons
because of fire hazards.   Additionally, small foamers may not be able to se-
cure proper insurance for  their operations.  Many larger firms  that use hydro-
carbons are self insured.  Finally, even  if the foamer chose  to switch to
hydrocarbons over carbon adsorption with  CFC-12, the foamer may still be re-
quired to control hydrocarbon emissions as a result of current  VOC emissions
regulations.  The VOC control technology  is carbon adsorption or incineration.
                                       95

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Engineering and Cost Analyses

     It is anticipated that the greatest potential for economical capture and
recovery of CFC-12 emissions in extruded PS foam plants exists at the foam
artruder, scrap silo vents, and scrap repelletizer vent.  While additional
laterial could he collected by using extensive plant ventilation schemes, the
ligher capital expenditure may1not be justified, since the incremental in-
:rease in recovery would be low.

     For this study, calculations are performed for a model plant which con-
sists of two extruders and four thermofoamers.  This represents a typical
?S—sheet facility.  The total production of thermoformable foam sheet would be
f.100 metric tons (9 million pounds) per year.  At 6 percent blowing agent
:ontent in the initial foam formulation, this plant would use about 245 metric
rons of CFC-12 per year.  This example facility will be used to assess the
economic feasibility of CFC-12 capture and recovery using carbon adsorption.

     The important parameters characterizing the example foam plant used in
:his engineering analysis are summarized in Table 5-2.   These parameters are
•epresentative of a mediun to small sized facility, and the production rates
ire typical for these plants.  As mentioned earlier, the areas showing the
>est potential for CFC recovery are the extruder, the scrap silo vents, and
:he scrap repelletizer.   These sources represent 50 percent of the total emis-
sions (because 40 percent of the emissions are from the product) and 85 per-
:ent of the manufacturing emissions*  The exhaust system capture efficiency is
iStimated to be about 88 percent for the CFC emissions from the controlled
:ources.   Further activated carbon adsorption beds can be designed to adsorb
.t  least 95 percent of the CFC-12 present in the exhaust air stream.  There-
ore,  the system's net capture efficiency would be about 42 percent of the
IFC-12 consumed.   This is approximately 102 metric tons of CFC-12 per year.

     Figure 5—2 shows a schematic flow diagram for the model plant.  The flow
liagram shows all raw material addition points and CFC emission sources.
                                      96

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            TABLE 5-2.  MODEL  POLYSTYRENE EXTRUDED FOAM SHEET PLANT
                        OPERATING PARAMETERS
Annual Production, mt  (Ibs.)

Production Rate, kg/hr  (Ib/hr)

Number of Extruders

Foam Sheet Web Width, m (ft)

Extrudate Velocity, m/min  (ft/min)

Typical Initial Foam Formulation

     Polystyrene
     Blowing Agent
     Additives

Number of Thermoformers

Percent Scrap in Feed
4,100 (9 million)

  680 (1500)

2 ® 340 kg/hr (2 @ 750 Ib/hr)

  1.2 (4)

  0.6 (2)

CFC-12 Blown

   93Z w
    6Z w
    1% w

    4

   35
                                      97

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VO
00
                    Figure 5-2.   Schematic flow diagram for polystyrene foam sheet model plant.

                                 (Streams 6,  14,  15 sent to carbon adsorption system)

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Table 5-3 contains a material balance for the model  plant  showing  the  flow
rates of polystyrene and CFC-12 through the various  processing steps.  From
the material balance, the total CFC amount sent to the carbon  adsorber is 0.30
kg/min., while the total exhaust flowrate is 55 nr/min.  (approximately 2000
cfm).

     Figure 5-3 depicts the proposed carbon adsorption/recovery  system for
CFC-12.  Two beds in parallel are required for the design  throughput;  one bed
operates in adsorption mode while the other is being regenerated.   Steam for
desorption and bed regeneration is provided by a boiler unit.  The  regenera-
tion steam is routed through the beds countercurrent to the  direction  of
treated air flow (for more efficient desorption), and then through  a
water-cooled condenser.  The condensed steam and CFC-12 vapor  are  separated in
knockout vessel.   The condensate is recycled to the  boiler feedwater makeup
line, and the CFC-12 vapor passes on to a compression system.   In  the  compres-
sion step,  the CFC is passed through a drier, and then compressed  to a liquid.
The liquid is then cooled and, depending upon its purity,  either recycled to
the CFC-12 feed storage tank, or sent to disposal tanks.

Carbon Bed Design—
     Based on the performance of carbon adsorption systems in  other service,
carbon bed recovery efficiencies in excess of 95 percent can be  easily at-
tained.   For the example system, the removal rate of CFC-12  from the air
stream is 0.29 kg/min (0.63 Ib/min) and the exhaust  air flow is  0.91 Nm3/s
(1,900 scfm),  which is assumed to enter the bed at about 21°C  (70°F).  Adsorp-
tion capacity for a given activated carbon as a function of  temperature and
CFC concentration in the gas stream can be determined from experimentally
derived relationships referred to as isotherms.   The CFC-12  isotherms  for
Calgon BFL® activated carbon used in the example system appear in Figure 5-4.

     Using the available isotherm data,  a realistic  design basis can be de-
rived from CFC-12 adsorption beds.   At a concentration of  1070 ppm, the CFC-12
partial pressure is 0.72 Fa (0.015  psia)  based on a  bed temperature of 21°C
                                       99

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                                 TABLE 5-3.   POLYSTYRENE/CFG MATERIAL BALANCE
SUMBNaoe
PS. kg/min
CTC, kg/idn
CTC Capture Eff.. X
CTC Collected, kg/Bin
Bctaurt Flow. Bf/ain
. cfa
Bdieurt CTC Gone,, g/n
•~* mu
O • H""
0
1
Fnch
PS
Feed
7.37
—
—
—
—
—
—
—
2
Regrind
PS
Feed
3.97
0.027
__
—
—
—
—
—
Cabined*
PS
Feed
5.67
0.014
—
—
—
—
—
—
4 5
Bctnided
CRT PS
Feed Shett
— 5.67
0.327 0.225
_ _
— —
— —
— —
— —
— —
6
Bctnxter*
tbdmiam
—
0.116
88
0.102
16
565
6.38
1250
7
PS
Fran toll
Storage
11.3
0.422
—
—
—
—
—
—
8
ac
FroBRall
—
0.0272
0
—
—
—
—
—
9 10 11
Ihnw ttmoD- QTC
CuiiBd CUIB Ibamfom
Product Hwto tOmiam
7.37 3.97 —
0.252 0.136 0.034
_ — o
— — —
_ _ _
— — —
_ _ _
— — —
12 13 14
Product Scnp
«•»•••*** I^UfcBJ* GBUMmMMmM
— 3.97 —
0.252 0.0337 0.102
0 — 88
— — 0.0898
— — 17.0
— — 600
— — 5.28
- — 1030
15
Pellet iwr
Britticoa
—
0.0068
88
0.0060
5.66
200
1.06
207
*Repreaent« 1/2 total amount.

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CFC RICH EXHAUST
 GAS FROM FOAM
 PROCESS AREAS
MAKE-UP
 WATER
                         CFC CLEAN
                        EXHAUST GAS
                                                                    CFC -12


                                                              CONDENSATE
                                                               KNOCKOUT
                                                                 TANK
                                                                               DRYER
                                                                               COMPRESSOR
                                                                                CONDENSER
                                                                         REFRIG.
                                                                                    RECOVERED CFC
                                                                                     TO STORAGE
                                                                                     OR DISPOSAL
              SLOWDOWN
            Figure 5-3.  Proposed  CFC-12 carbon adsorption/recovery system for a polystyrene
                         foam sheet  extrusion plant.

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100
 0001
.001
                                     .01                O.I



                           PARTIAL PRESSURE OF CFC-12, PS IA
                                                      10
1C
                Figure 5-4,   CFC-12 adsorption on BPL© activated carbon.



                Source:   (54)

-------
 (70°F).  For these  conditions the BPL* carbon  adsorption  capacity  can  be  esti-
mated to be about 10 weight percent.  An appropriate design  rule is  that  the
working bed capacity is one half of this value, or 5 weight  percent.   This
allows for residual CFC-12 remaining in the bed after each regeneration cycle,
 (i.e., the CFC heel) and for the loss of carbon capacity  due to contamination.
                                                              3          3
Typically, packed carbon particles have a density of 490  kg/m  (30 Ib/ft  );
therefore, each cubic meter of bed volume will adsorb 24.5 kg of CFC-12  (1.5
Ib. CFC-12/ft3).
     To provide the required capacity without excessive bed  size,  the  system
includes two carbon beds in parallel, one bed being on-line  (adsorbing) with
the remaining bed being regenerated.  Beds of the  size and type  for  this
service require about one hour for steaming and one hour  for cooling,
therefore, each bed would be on-line adsorbing for two hours and off-line
regenerating for two hours.

                                          q
     For air flows in the range of 0.91 Nm /s (1,900  scfm),  carbon adsorption
beds are usually loaded in large horizontal steel  tanks,  at  a depth  of about
0.6 to 1.8 meters (2 to 6 feet).  To achieve 95 percent recovery in  the bed, a
reasonable maximum gas velocity is 0.38 meters/sec (75 fpm).   Also,  since  the
cost of operating the exhaust fans is dependent on the pressure  drop across
the beds, a more shallow bed is preferred.  Therefore, a  bed cross-section of
     2       2
2.3 m  (25 ft ) was selected for the example design.  This results in  a bed
depth of about 0.6 meters, and the superficial gas velocity  would be approxi-
mately 0.38 meters/sec (75 fpm).

     Since the expected recovery rate is 0.29 kg/min  (0.63 Ib/min),  each bed
is sized to adsorb 17.4 kg (37.8 Ibs) of CFC-12 during each  two  hour on-line
period.  This requires about 721 kg (1590 Ibs) of  carbon  per bed,  which would
                        3       3
occupy a volume of 1.5 m  (53 ft ).  For two beds  the total  quantity of
activated carbon purchased would be 1,442 kg (3,180 Ibs).  Table 5-4
summarizes the carbon adsorption system's design parameters.
                                       103

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            TABLE 5-4.  CARBON ADSORPTION  SYSTEM DESIGN PARAMETERS
Total Gas Flowrate. m /min  (cfm)                                  54.6  (1,900)
Gas Temperature. °C (°F)                                               21  (70)
CFC Loading inlet, kg/min (Ib/min)                               0.300  (0.661)
CFC Concentration, g/m  (ppmv)                                     5.49 (1070)
CFC Partial Pressure. Pa (psia)                                   0.77  (0.016)
Number of Beds                                                               2
Superficial-Velocity, m/sec (fpm)                                    0.38  (75)
Bed area, 01  (fO                                                   2.32  (25)
Carbon depth, m (ftl       -                                        0.64 (2.1)
Carbon density g/cm  (Ib/ft )                                        0.47  (30)
Carbon working capacity for CFC-12. kg CFC/kg  carbon                     0.05
Carbon bed CFC removal efficiency. Z                                        95
Total carbon per bed. kg (Ib)                                      721  (1,590)
Adsorption time per cycle, min                                             120
Regeneration time per cycle, min                                            60
Cool down per cycle, min                                                    60
Steam requirement per regeneration, kg/kg  carbon                          0.3
Total stream use per cycle, kg  (Ibs)                                 216 (477)
                                     104

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Carbon Bed Regeneration—
     To desorb the CFC-12. and regenerate the carbon beds, three options are
available.  One is to circulate a hot. inert gas through the bed to supply the
heat of desorption.  Second, the hot inert gas can be combined with a reduced
pressure atmosphere in the absorber, created by a vacuum pump, to obtain high-
er recovery efficiencies.  Finally, the procedure used more often and that
selected for this example, is to flow superheated, low-pressure steam upward
through the bed counter-current to the flow of CFC-laden exhaust gases during
adsorption, to strip off the CFC-12.  The CFC-12 rich steam is then routed to
a water cooled heat exchanger to condense the steam.

     The steam required to regenerate the beds was estimated to be 216 kg  (477
Ibs) per cycle, based on a typical factor of 0.3 kg steam per kg of carbon.
Therefore, a steam supply of at least 250 kg/hr  (550 Ib/hr) is required.

Capital Costs—
     Total capital cost estimates for the model plant retrofit carbon adsorp-
tion/recovery system for CFC-12 are presented in Table 5-5.  These figures
were developed by applying generally accepted installation and indirect cost
factors to the total purchased equipment costs.  The total capital investment
for a two-bed carbon adsorption system is estimated to be $227,000.  These
costs are based on first-half 1985 dollars and are assumed accurate within +/-
30 percent.  Indirect capital costs account for about 35 percent of these
totals.   The largest components of the purchased equipment costs are the
carbon adsorber beds and associated process equipment, and the CFC-12
compression and purification system.  This latter item may not be required for
most plants.  The capital costs for retrofit installations can be expected to
vary significantly, due to different plant configurations.

Annualized Operating Costs and Cost Effectiveness—
     Annualized costs for operating a CFC-12 system were developed for the
model plant.  These costs, and the bases used, are summarized in Table 5-6.
                                     105

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 TABLE 5-5.  ESTIMATED CAPITAL COSTS FOR EQUIPPING A PS-FOAM SHEET EXTRUSION
             PLANT WITH A CFC-12 CARBON ADSORPTION SYSTEM
                                                                     Cost
                                                                   ($1.000)
Direct Capital
     Adsorber (beds, condenser, fan, decanter,                        80
       control system)
     Compressor System                                                50
     Ventilation System                                               10

TOTAL DIRECT CAPITAL                                                 140

Indirect Capital (Z of direct capital)
     Engineering and Supervision at 10%                               14
     Miscellaneous Field Construction Expenses at 5%                   7
     Contractor Fees at 10%                                           14
     Contingencies at 20%                                             28
     Startup Expenses at 2%                                            3
     Interest During Construction at 102                              14

TOTAL INDIRECT CAPITAL                                                80

TOTAL DEPRECIABLE CAPITAL                                            220

     Working Capital*                                                  7

TOTAL CAPITAL INVESTMENT                                             227
aEstimated at 25 percent of the total direct operating and maintenance  costs.
                                     106

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 TABLE 5-6.  ESTIMATED ANNUAL OPERATING AND MAINTENANCE COSTS FOR EQUIPPING A
             PS-FOAM SHEET EXTRUSION PLANT WITH A CFC-12 CARBON ADSORPTION
             SYSTEM
                                                                       Cost
Direct Operating and Maintenance Costs                               ($1,000)

     Operating Labora at $13.00/hr                                        6
     Maintenance"                                                         4
     Electricity                                                          2
     Steam                                                               12
     Process Water                                                        2
     Cooling Water                                                       __1

TOTAL DIRECT COSTS                                                       27

Indirect Costs

     Capital Recovery Factor0                                            37
     Overheads'1                                                           2
     G&Ae                                                                 A
     Insurance and Property Taxes*                                       _5

TOTAL INDIRECT COSTS                                                     48

TOTAL OPERATING AND MAINTENANCE EXPENSES                                 75

CREDIT FOR RECOVERED CFC-12                                            (167)

OPERATING CREDIT                                                        (93)
alncludes operating labor and supervision.
''Includes maintenance labor, materials, and supervision and is estimated at 3
 percent of the direct capital costs.
cEstimated at 16.275 percent of the total capital investment.
^Estimated at 38 percent of labor expenses.
Estimated at 50 percent of operating labor and 25 percent of the maintenance.
fEstimated at 2 percent of the total capital investment.
                                     107

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    The various  categories of direct and indirect operating expenses assoc—
ated with  the  carbon adsorption/recovery system were estimated in terms of
irst—half  1985 dollars.   Maintenance and operating costs and steam consump-
ion are the largest  direct operating cost items,  and these costs would in-
rease with foam  output.   Capital  recovery,  calculated for 10-year service
ife and 10 percent interest*  is by far the  largest single fixed cost item.
ccounting  for  about  50 percent of the annualized  operating costs.

    Also to be considered in  evaluations of net operating costs and cost
ffectiveness is  the  credit for reclaimed blowing  agent.   The value of CFC-12
ecovered may vary depending upon  its quality and  the process requirements.
nder the most  ideal  situations, assuming 100 percent use of recovered CFC-12,
he model plant would save about $167,000 per year.   If this material had to
e shipped  off  site for disposal by incineration,  the added cost could be as
igh as $60,000 per year (based on $150 per  barrel disposal cost).

    The control  cost effectiveness of a retrofitted capture and recovery
ystem for  CFC-12 can be expressed as the cost (or credit)  per unit weight of
FC-12 recovered, or  alternatively,  as the cost  (or credit) per unit of CFC-12
mission averted.  The cost effectiveness of a recovery system for a PS foam
lant is not only a function of the efficiency of  the control system itself,
ut is dependent  on the mass flow  of CFC-12.   For  the model plant, the esti-
ated cost  per  unit of CFC-12  emission averted is  $724 per metric ton ($650
er ton) of CFC-12 controlled  or $0.72/kg ($0.33/lb).   If credit is given for
he recovered CFC-12,  the control  cost actually  becomes a credit of $912 per
etric ton  ($827/ton)  of CFC-12 controlled.   This  is equivalent to a credit of
0.91/kg ($0.41/lb) of CFC-12  emissions averted.   If off-site disposal of the
aste CFC is required,  the control cost will increase to $1,311 per metric ton
$1,190 per ton).
                                     108

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Barriers to Implementation and Time Frame

     Capture and recovery of bloving agent emissions from extruded polystyrene
foam plants using carbon adsorption represents a technically viable option for
substantially reducing CFC-12 emissions.  The main barrier to implementation
is the high capital expense associated with retrofit of suitable control sys-
tems to existing foam plants.

     In terms of cost effectiveness to the foam producer, installation of
carbon adsorption systems can currently be justified for perhaps a substantial
number of foam plants.  This is mainly because the credit for reclaimed CFC-12
is sufficient to yield a reasonable payout period for the initial system in-
vestment.  For smaller plants, or  those with somewhat lower annual production,
the original investment may not be completely recoverable.  Availability of
capital presents a serious problem for many small and moderate size foam
producing firms.  The uncertainty  of many foam producers concerning their
future market position could preclude commitment of capital that may  take
years to recover.

     An appropriate time frame for implementing this control technique would
be highly dependent on the structure of economic incentives or reimbursements
for plant retrofits.  One way to affect this would be to cause the market
price for CFC-12 to increase markedly, thus increasing the raw material credit
for recovery, and penalizing firms for continued purchase of fresh material.
Other alternatives include tax advantages or accelerated equipment deprecia-
tion schedules.

     Presuming that economic barriers could be made less prohibitive, it
should be possible to retrofit and bring control systems on-line for  most
PS-foam facilities within five to  seven years.  This includes some time for
experimental evaluation of important design and environmental factors, as well
as additional pilot scale and full scale demonstrations.
                                      109

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     It  is  also possible  that  the  realignment in the foam industry caused by
 ae  high cost  of controlling blowing agent emissions will stimulate research
 nvestment.  Such efforts could result  in the introduction of new foam pro ri-
 ots and/or processes  to  the foam  market.

 NCINERATION OF PLANT  EXHAUST

     Destruction of  chlorofluorocarbon  emissions by thermal or catalytic in-
 ineration  is  a physically possible  control option.  However, several crucial
 robiems can be identified that limit its consideration as a technically
 ractical control method.   Since CFC-12 is nonflammable, high incineration
 emperatures are necessary to  cause  thermal cracking.  Also, a large volume of
 xhaust  air must be  treated to effectively control blowing agent emissions.
 his results in an excessively large fuel usage cost.

     In  general, nonflammable  CFC  compounds are not easily destroyed through
 onventional incineration techniques.  Although CFC—12 decomposes above 540°C
 1000°F), this is only true in a reducing atmosphere, such as a fuel-rich
 lame.   The resulting  gases contain  hydrochloric (HC1) and hydrofluoric (HF)
 .cids.   These  are secondary pollutants  which are highly corrosive, and would
 .ave to  be  scrubbed  from  the flame exhaust.  Tests by DuPont indicated that
 uch fuel—rich flames  can destroy  over  99 percent of the chlorofluorocarbons
 •resent  in  typical process streams (32).

     Catalytic incineration mechanisms  include disproportionation of CFC-12 in
:he  presence of aluaintm  chloride  (Aid.,)  to form carbon tetrachloride (Cd^)
,nd  carbon  tetrafluoride  (CF^).  This is a relatively exotic and expensive
irocess.  Under oxygen-free conditions, finely divided metallic iron at very
ligh temperatures will react with  chlorofluorocarbons to form metal halides
.32).  Aside from the  extremely high energy costs, this latter process would
require  expensive treatment of the high—volume exhaust to remove oxygen.
                                     110

-------
     It is possible to thermally crack CFC-12 at temperatures  above 760°C
(1400°F), but there are no published data which characterize the  residual
products of the cracking reactions.  This process would  require large kiln-
like equipment to treat most or all of the exhaust stream.  A  proposed  alter-
native to direct flame incineration would be the use  of  a heated  sand bed  or
fluidized bed.  No tests of such a process for CFC destruction have been re-
ported.

     Each of these proposed incineration destruction  techniques involve very
energy intensive processing of large volumes of exhaust  air.   While these
methods may very effectively destroy CFC—12, the costs would be extremely
prohibitive.  Host or all of the input energy for thermal processes would  be
wasted, since the flexible foam production process could not utilize the waste
heat.  Because of the preponderance of negative factors, incineration tech-
niques were not pursued further in this study.
                                      Ill

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                                   SECTION 6
             HYDROCARBONS AS POLYSTYRENE FOAM SHEET BLOWING AGENTS

     One option that offers considerable promise in reducing CFC-12 emissions
.n the manufacture of polystyrene foam is substitution of the chlorofluoro-
:arbon with a non-ozone depleting blowing agent.  Use of alternative blowing
.gents would eliminate, or significantly reduce the CFC emission associated
•ith a given PS foam operation.   Currently,  hydrocarbons such as n-pentane.
sopentane,  or n—butane are viable candidates for replacing CFC-12 in PS foam
reduction.   These options can eliminate the use of CFC-12 in this application
hereby providing 100 percent reduction in emissions of this ozone depleting
ompound.

     Polystyrene foam is extruded into both board and sheet profiles.   Because
jctruded PS foam board is used as an insulation material, the use of hydrocar-
ons  as blowing agents would reduce the board's insulating effectiveness,  and,
herefore,  would not be a desirable substitute.   However, with PS foam sheet,
ydrocarbons are excellent candidates for use as substitute blowing agents.
hen  PS foams were first introduced in the mid-1960s,  they were blown almost
xclusively  with pentane.   But by the late 1960s,  the industry began a gradual
onversion  to CFC-12 as a blowing agent.   This was due primarily to the fire
azards associated.with pentane.   The trend  towards using nonflammable CFC-12
.s a  PS foam blowing agent has continued to  present,  and now only the very
arge,  self  insurable,  companies  such as Mobil,  tt.R.  Grace,  and Amoco are
till using  hydrocarbons.   While  these companies have historically been able
o produce foamed polystyrene products safely and competitively,  local ordi-
ances  regulating volatile organic compound  (VOC)  emissions have created
ncentives for  even these large companies to convert  some of their facilities
ran hydrocarbons to CFCs.
                                      112

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     In spite of the trend away from, using hydrocarbons,  it  is possible  to
make all thennoformable polystyrene foam  sheet using a hydrocarbon  such  as
pentane as a blowing agent.  The following paragraphs discuss the various
aspects of converting a medium sized polystyrene foam sheet  manufacturing
plant from CFC-12 to pentane.

PLANT EQUIPMENT AND OPERATION MODIFICATIONS

     One of the primary concerns with using pentane as a  blowing agent is its
flammability.  This concern is reflected  in most of the changes which would
have to be made to convert a plant using  CFC blowing agents  into one using
pentane.  Another important issue is any  state, or local  ordinances which
regulate volatile organic compound (VOC)  emissions.  Presence of VOC regula-
tions in a given area might require that  a plant using pentane be equipped
with an add-on control system which allows for recovery or destruction of the
pentane.  Concern over the uncertainty of future VOC regulation by  states and
localities probably contributes to companies' hesitation  about seriously
considering conversion to hydrocarbon blowing agents.

     Some of the required facility modifications when converting from CFC-12
to pentane include:  purchase and placement of the pentane tanks and their
associated pimps,  piping, and instrumentation; altering wiring to insure that
electrical connections and devices would  be explosion proof; purchase of non-
electric foam transport vehicles; installation of static  electric discharge
devices in areas such as the film roll-up and unrolling stations; installing a
ventilation system for reducing pentane concentrations; and  installing a fire
protection system (20,21).  Since the CFC injection port  on  the extruder can
also be used for pentane injection, no major changes to the  extruder would be
required (22).

     In addition to modifications in the  process and plant facilities, conver-
sion to pentane might require changes in  plant operation.  One facility
converted to pentane for a three year period in all of its PS foam  sheet
                                       113

-------
lanufacturing  facilities.   They  found that the hazards of using pentane
-equired  up  to a 30  percent reduction in production operating speeds.  (20).
iowever,  another source  indicated that no change in operation rates would be
lecessary (22).

X)NTROL EFFECTIVENESS

    An advantage  of pentane substitution in polystyrene foam sheet production
.s that significant  reductions in CFC emissions could be realized over the
tear-term.   Because  pentane has  been used widely in FS foam sheet
.anufacturing,  the availability  of this control technology is excellent.   A
ubstantial  number of  people in  the PS foam sheet industry have experience in
he use of pentane or  other hydrocarbon blowing agents, and this reservoir of
jcpertise should ease  the  process of converting to hydrocarbons.

    In terms  of quantities of PS foam sheet produced, roughly 50 percent of
olystyrene  foam sheet is  currently blown with hydrocarbons.   However,  only  a
ew of the largest companies produce this hydrocarbon-blown foam, and  it  is
robable  that  the  numerous medium and small sized companies use CFC-12.   The
rimary reason for this  is that  only the large companies can afford to provide
heir own fire insurance as well as extensive fire protection equipment and
•ersonnel  training.

    There is  considerable disagreement between CFC-12 users and hydrocarbon
sers concerning the benefits of their particular blowing agent.  Therefore,
here is  a degree  of inertia among foamers to continue using the blowing agent
hat they have been  using.   Companies using either blowing agent have  made
onflicting  claims of  higher production rates, lower scrap rates, and  less
xpensive product.   The  main objection to switching from CFC-12 to pentane is
he cost  of  modifications  required to provide the facility with fire protec-
ion.  This  includes explosion-proofing all electrical equipment as well  as
nstalling a fire  extinguishing  system (20,22,23,24,25).  Further study of the
ost of fire protection  in PS foam sheet plants is warranted.
                                      114

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COST OF CONTROL

     To examine the  cost  of  converting a facility  from  CFC-12 to pentane, two
basic scenarios are  examined:  (1)  substitution with no  pentane recovery, and
(2) substitution with  a pentane carbon adsorption  system.  Table 6-1 shows  the
model plant characteristics  and production parameters used to assess costs  in
this study.  Briefly,  the plant consists of two  extruders and four  thermo-
formers.  Each extruder produces 340 Kg/hr (750  Ibs/hr) of PS foam  sheet, and
the total production is A100 metric tons per year  (9.0  million Ibs/yr).

     The estimated cost for  controlling CFC-12 emissions through substitution
with pentane is strongly  affected by the savings acquired through the  use of a
smaller quantity of  a  cheaper  blowing agent.  Savings  occur because pentane
costs roughly 77 percent  less  than CFC-12, and approximately 20 percent  less
blowing agent is required per  pound of foam product.

     Table 6-2 shows the  estimated capital cost  to convert  the model A, 100
metric tons per year CFC-12  polystyrene foam sheet facility to a pentane using
facility.  The majority of the estimated $977,000  modifications are associated
with fire and explosion protection devices.  Table 6-3 presents the operating
and maintenance costs  for the  same facility.  The  capital  costs are annualized
with a capital recovery factor.  Assuming a credit for the  blowing  agent cost
differential and the reduced scrap, the realized net  annual  operating  and
maintenance costs are  $33.000.

     These costs are adversely affected if regulations require  the  addition of
a carbon adsorption  system for pentane recovery.  Table 6-A details the
capital cost of a carbon  adsorption system designed for the model  facility.
This system is similar to the  one described in Section 5  and would, be  used  to
capture pentane emissions from the extruder and from the  regrinder  and regrind
storage.  The estimated total  annual cost for the  carbon adsorption system  is
$86,000  (see Table 6-5) which is equivalent to a cost of  approximately
$0.6A/kg  ($0.29/lb)  of CFC-12 emission averted.   The annualized  costs  for the
                                       115

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            TABLE 6-1.  MODEL POLYSTYRENE EXTRUDED FOAM  SHEET PLANT
                        OPERATING PARAMETERS
Annual Production, mt  (Ibs.)

Production Rate, kg/hr  (Ib/hr)

Number of Extruders

Foam Sheet Web Width, a (ft)

Extrudate Velocity, m/min (ft/min)

Typical Initial Foam Formulation

     Polystyrene
     Blowing Agent
     Additives

Number of Thermoformers

Percent scrap in Feed
4.100

  680

2 S 340 kg/hr
  each
  1.2

  0.6

CFC-12 Blown

   93% w
    6Z w
    1Z w

    4

   35
(9 million)

(1500)

(2 S 750 Ib/hr)
 each
  (4)

  (2)

Pentane-Blown

    94Z w
     5Z w
     1Z w

     4

    25
                                      116

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  TABLE 6-2.  ESTIMATED CAPITAL COSTS FOR EQUIPPING A PS-FOAM SHEET EXTRUSION
              PLANT WITH A PENTANE BLOWING AGENT SYSTEM
              (Cost in $1,000. mid-1985)
                                                                        Cost
Direct Capital

   Pentane Tank & Piping                                                  42

   Explosion Proof Wiring                                                195

   3 Non-electric Foam Transport Vehicles                                 45

   Ventilation System                                                    471

   Fire Protection System                                                210

TOTAL DEPRECIABLE CAPITAL3                                               963


   Working Capitalb                                                       15

TOTAL CAPITAL INVESTMENT                                                 978
a Installed cost which includes indirect costs of engineering, supervision,
  construction fees, interest during construction and contingencies.

  Estimated at 25 percent of the total direct operating and maintenance costs.
                                       117

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    TABLE 6-3.  ESTIMATED OPERATING AND MAINTENANCE COSTS FOR EQUIPPING A
                PS-FOAM  SHEET EXTRUSION PLANT WITH A PENTANE  BLOWING AGENT
                SYSTEM (Cost in $1.000. mid-1985)
                                                                         Cost


Added Direct Operating and Maintenance Costs

  Operating Labor8 at $13.00/hr                                            30
  Maintenance                                                              29

TOTAL DIRECT COSTS                                                         59

Indirect Costs

  Capital Recovery Factor0                                                159
  Overheads                                                                11
                                                                           22
  Insurance and Property Taxes                                             20

TOTAL INDIRECT COSTS                                                      212

CREDITS

  Bloving Agent Differential                                             (162)
  Scrap Reduction (28% of Total Direct and Indirect Costs)                (76)

TOTAL OPERATING AND MAINTENANCE EXPENSES WITH CREDITS                      33
^Includes operating labor and supervision.
 Includes maintenance labor, materials, and supervision and is estimated at 3
 percent of the direct capital costs.
^Estimated at 16.275 percent of tbe total capital investment.
 estimated at 38 percent of labor expenses.
^Estimated at 50 percent of operating labor and 25 percent of tbe maintenance.
 Estimated at 2 percent of the total capital investment.
                                    118

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      TABLE 6-4.  ESTIMATED CAPITAL COSTS FOR A PS-FOAM SHEET EXTRUSION
                  PLANT WITH A CARBON ADSORPTION SYSTEM FOR PENTANE RECOVERY
                  (Cost in $1,000, mid-1985)
                                                                         Cost
Direct Capital

  Adsorbers
  Organics Purification                                                   170
  Ventilation System                                                      	

TOTAL DIRECT CAPITAL                                                      170

Indirect Capital  (% of direct capital)
  Engineering and Supervision at 10%                                       17
  Misc. Field Construction Expenses at 5%                                   9
  Contractor Fees at 102                                                   17
  Contingencies at 20%                                                     34
  Startup Expenses at 2%                                                    3
  Interest During Construction at 10%                                      jj

TOTAL INDIRECT CAPITAL                                                     97

TOTAL DEPRECIABLE CAPITAL                                                 267

  Working Capital3                                                        	8

TOTAL CAPITAL INVESTMENT                                                  275
aEstimated at 25 percent of the total direct operating and maintenance costs.
                                     119

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 TABLE 6-5.  ESTIMATED OPERATING AND MAINTENANCE COSTS FOR EQUIPPING A PS-FOAM
             SHEET EXTRUSION PLANT WITH A PENTANE CARBON ADSORPTION SYSTEM
             (Cost in $1.000. mid-1985)
                                                                         Cost
Direct Operating and Maintenance Costs

  Operating Labor* at $13.00/hr.                                           6
  Maintenance                                                              5
  Electricity                                                             12
  Steam                                                                    4
  Process water                                                            2
  Cooling water                                                           __1

TOTAL DIRECT COSTS                                                        30

Indirect Costs

  Capital Recovery Factor0                                                45
  Overheads'1                                                               2
  G&Ae
  Insurance and Property Taxes                                            —

TOTAL INDIRECT COSTS                                                      56

TOTAL OPERATING AND MAINTENANCE EXPENSES                                  86
flncludes operating labor and supervision.
 Includes maintenance labor, materials, and supervision and is estimated at 3
 percent of the direct capital costs.
^Estimated at 16.275 percent of the total capital investment.
^Estimated at 38 percent of labor expenses.
  jtimated at 50 percent of operating labor and 25 percent of the maintenance.
  Jtimated at 2 percent of the total capital investment.
                                      120

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carbon adsorption system  do not  include  a credit  for the recovered  pentane.
The pentane could be reused as a blowing agent  if the quality  of  the  recovered
product is adequate.   If  not, the  pentane could be burned in an on-site boiler
or be disposed off-site at an added  cost.  Another possibility not  examined in
this report, but warranting further  study is  incineration of the  pentane
contained in the plant exhaust.

HEALTH AND SAFETY FACTORS

     Pentanes are only slightly  toxic  and are classified as  simple  asphyxiants
and anesthetics.  The TLV for the  time-weighted average eight  hour  exposure to
pentanes is 600 ppm or 1800 mg/m3  (51  mg/SCF);  the short-term  (15 minute)
                                       3
exposure limit is 750 ppm or 2250  mg/m  (64 mg/SCF).   The major safety risk of
pentanes is their high flammability  which is  due  in part to  their volatility.
Adequate ventilation and  isolation from  sources of heat and  ignition  are
necessary to minimize the risk of  fire and explosion.

     n—Butane is a colorless, flammable,  nontoxic gas.   It is  classified as a
simple asphyxiant and an  irritant.   At high concentrations,  it is an  anes-
thetic,  and will cause drowsiness  in a short  time in concentrations of one
volume percent.  Two hour exposures  at concentrations of up  to five volume
percent cause no apparent injuries.  The recommended TLV is  600 ppm.  Like the
pentanes, n-butane is extremely  flammable and precautions should  be taken to
prevent fire and explosion.  Table 6-6 provides the various  health  effect.
chemical, and physical property  data for CFC-12.  n-pentane,  isopentane, and
n—butane.

CURRENT STATUS

     Originally, all PS foams were blown exclusively with pentane.  However.
partly because of the fire hazards associated with pentane,  a  conversion to
CFC-12 began in about 1967.  The extent  to which  this conversion  has  pro-
gressed is subject to differing  estimates.  A 1980 Rand report indicates that
                                       121

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   TABLE 6-6.  PHYSICAL PROPERTIES OF CFC-12 AND HYDROCARBON BLOWING AGENTS
                              CFC-12      n-Pentane     Isopentane  n-Butane
Formula

MW                            120.91          72.15          72.17     58.12
Boiling Point  (°C)             -29.8           36.1           27.8        -1
Fusion Point (°C)               -158           -130         -159.9      -138
Specific Gravity  (g/cc)        1.311          0.626         0.6201     0.584
Vapor Density  (air = 1)          4.2           2.48            2.6       2.0
Vapor Pressure  (atm)          5ei6°C   0.526ei8.5°C         1S280C  3.5@38°C
Ignition Temperature C°C)         NA            260            420        NA
Flashpoint (°C)        non-flammable            -40            -57       -73
Upper Explosion Limit. %          NA            7.8            8.3       8.5
Lover Explosion Limit. %          NA            1.5            1.4       1.9

Price
  (rail car quantities). $/lb   0.74           0.17           0.18        NA

OSHA PEL (ppm)                  1000           1000             —        —
     TLV (ppm)                  1000            600            600       600
NA = Not. available.

Source:  (27,28.29,30,31)
                                      122

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by 1973,  only 45  to 50 percent  of  the  PS  foams  produced were blown with
pentane.  The same  report  shows that this market  share dwindled further  to 35
percent by  1977  (13).   Recent communications with industry, however, have
indicated that a  very  large  share  of the  blowing  agents used for PS foam sheet
are hydrocarbons  (18,23,26).

     Because pentane is flammable  and  there are concerns with VOC emissions
regulations, many polystyrene-foam extrusion plants have been converted  from
using hydrocarbon blowing  agents to using CFC blowing agents.  Contacts  with
industry  have indicated that  very  few  plants have been converted from CFC to
pentane.  However,  several industry contacts indicated that the three major
polystyrene foam  extruders (Mobil,  Amoco, and Grace) still use large quanti-
ties of the hydrocarbon blowing agents isopentane, butane, and n-pentane,
respectively.  These three companies alone are  estimated to produce 70 to 90
percent of all polystyrene foam sheet  (21,22,26).  If this is so, then it is
probable  that a majority of the polystyrene-foam  blowing agent market is still
held by hydrocarbons.   The fact that a large fraction of the PS foam produced
is blown  with hydrocarbons illustrates the viability of pentane blowing
agents, flammability notwithstanding.

ECONOMIC  FACTORS

     There are many  economic  factors that can influence the selection of a
particular PS foam blowing agent.   While  foam quality is of importance,
evidence  indicates that  foams produced with hydrocarbons are sufficiently
similar in quality to  those foamed  with CFC-12.   The blowing agent of choice
for small and medium producers  is CFC-12 because  of the fire hazards of
hydrocarbons.  These hazards not only  drive up  the cost of insuring the
facility,  they mandate the expensive plant retrofitting discussed earlier in
this section.

     Several important economic considerations  regarding the control of  CFC-12
emissions by hydrocarbons  such  as pentane can be  identified.  These include:
                                       123

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     •    net raw material cost savings,

     •    extrusion and thennoforming production rates,

     •    costs for additional plant ventilation,

     •    costs for carbon adsorption to control pentane emissions, and

     •    personnel requirements and additional training.

Jfhile all of these considerations are more or less interrelated with the
specific characteristics of a given foam manufacturing plant, there are two
additional considerations over which the foam manufacturer has no control.
Ihese are the cost of pentane and the special needs and requirements of the
foam end-use markets.  A dramatic rise in the cost of pentane relative to
3FC-12 would decrease the economic incentive for a conversion.  Also, a
specific end user might specify CFC-12 as a blowing agent because of their
^articular needs.   This would also be a disincentive for conversion to pen-
:ane.

     Contact with industry has made it evident that both foam producers using
2FC-12 and those  using hydrocarbons feel that they cannot convert their
acility and still manufacture foams economically.   However, since foams are
>roduced economically and competitively with both types of blowing agent it
••eerns  possible  that a conversion could be made.

ARRIERS TO IMPLEMENTATION

    From an overall perspective of the United States foam market, there
ppear to be no extreme technical  or economic barriers to near-term impleman-
ation of pentane substitution as  a means of controlling CFC-12 emissions.  An
sception would be in localities where VOC regulations would prohibit or limit
he  use of hydrocarbons.   Future voluntary substitution of pentane will
robably not occur given current market conditions,  because manufacturers may
                                      124

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not be willing to use flammable pentane blowing agents,  and  they  may  be
skeptical about possible cost savings from switching to  pentane.  Also,  there
may be potential market decline because end-users may be unwilling  to use
pentane blown product.
                                       125

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                                   SECTION 7
                       ALTERNATIVE CFC BLOWING AGENTS

    The two characteristics of chlorofluorocarbons that can cause depletion
f atmospheric ozone are their high stability and  the presence of chlorine in
he CFC molecule.  Therefore, the ozone depletion  potential of this particular
lass of chemicals can be neutralized by making the CFC molecule marginally
ess stable, so that it would not survive long enough to reach the upper
tmosphere.  Conversely, it should  not be so uns.table as to degrade in the
over atmosphere and contribute to  smog.  Hydrocarbon-containing CFC compounds
ave been identified as having satisfactory intermediate stability because
hey degrade to a large extent in the troposphere  through reaction with
ydroxyl radicals.

    Alternatively, if chlorine could be reduced or omitted from the molecule
he resulting species could not release the chlorine radicals that are hypoth-
sized to react with the stratospheric ozone.  Fluorocarbon compounds, which
o not contain chlorine, may be suitable substitutes for blowing agents such
s CFC-11 and CFC-12, since the chain reaction involved in the ozone depletion
s more quickly terminated.

    An ideal potential replacement  for CFC blowing agents needs to have the
oilowing characteristics:

    •    Product, safety, and toxicity performances competitive
         with that of commercial CFCs;

    •    Reduced or eliminated ozone depletion potential;

    •    Cost effectiveness with respect to its value and use; and
                                      126

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     •    Commercial manufacturing process which  is  available or can
          be developed.

     Additionally, the CFC substitute should  have the  same physical foaming
parameters as CFC-11 and  CFC-12.   These include boiling point, thermal con-
ductivity, gas efficiency,  diffusion rate from product, and  solubility in
formulation and product.

     Polyurethane and polyisocyanurate insulation foams are  generated through
the action of a physical  blowing  agent (CFC-11).   Some processes also use
CFC-12 as a supplementary blowing agent,  but  its  use is declining.  Foaming
occurs when the heat of the polymerization reaction  vaporizes the CFC-11.  The
use of CFC blowing agents creates a closed cell structure.   The closed cells
give the foam a rigid, yet  light-weight structure, and the CFCs trapped in the
numerous tiny closed cells  provide superior insulating properties.

     Historically, much of  the extruded polystyrene  and other nonpolyurethane
foam products have been blown with hydrocarbons such as n-pentane and
isopentane, and to a lesser extent,  butane.   A variety of CFCs have been used
either alone as the primary blowing agent, or in  a mixture with other CFCs or
pent an es.  Besides n-pentane and  isopentane.  CFC-12  is the most commonly used
blowing agent for the nonpolyurethane foams.   Additionally,  gases such as
carbon dioxide are sometimes used in conjunction  with  hydrocarbons and CFCs.
Smaller quantities of CFC-11. CFC-114.  CFC-113. and  CFC-115  are also used  (5).

RIGID POLYURETHANE FOAM BLOWING AGENTS

     For polyurethane foams, the  most commonly used  CFC blowing agent is
CFC-11.  It has a variety of chemical and physical properties which make it
desirable as a blowing agent, and a potential substitute would need to have
similar properties in order to serve suitably as  a replacement.  Since the
purpose of seeking alternatives to CFC-11 is  mainly  to reduce the potential
for harming the earth's ozone layer,  the first criteria for  judging the
                                       127

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uitability of an alternate is its ozone depletion factor.  This factor
ndicates the potential for ozone depletion relative to that of CFC-11  (with
n ozone depletion factor of 1.0).

    Since a majority of the blowing agent used in rigid polyurethane foam
anufacture is trapped in cells and banked for extremely long periods of time,
ubstitution with low ozone—depleting compounds is an action which would have
ong-term effects on the fate of stratospheric ozone.  However, before a
ubstitute blowing agent can begin to reduce the potential threat to the ozone
ayer, it must be widely accepted and adopted for use by the rigid
olyurethane foam industry.  This acceptance is dependent upon the alternate's
osts and its performance during processing as well as in the final foam
roduct.

recessing Considerations

    One of the primary characteristics of a physical blowing agent is its
elative stability.  For purposes of consistent product quality, it is essen-
ial that the blowing agent does not react with any of the foam ingredients.
t is equally important that the blowing agent does not decompose spontan-
eously (44) and, in the case of insulating foams, the foam must retain its
FC-11 to maintain the advantageous thermal properties for long periods of
ime.

    Thermal properties are also important during foam processing.  A blowing
gent with a low boiling point and a high latent heat of vaporization acts  as
 heat sink and protects the foam from high temperatures which can be gener-
ted by the exothermic polymerization reaction.  Some polyurethane foams can
corch, melt, or burn if temperatures become too high.  Unlike polyurethane
cams, the chemical structure of polyisocyanurate foams makes them quite
esistant to scorching and burning.
                                     128

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     To be effective  as  a blowing agent,  a compound must  have  an  appropriate
vapor pressure  in  the foam ingredient solution.   The vapor  pressure  can  be
predicted from  the boiling point and the  solvent  power of the  candidate.  If
the boiling point  is  too high or the solvent  power  too strong,  the blowing
agent will tend to remain in the polymer,  making  the product soft or even
soggy.  Conversely, a very low boiling point  will cause the blowing  agent to
vaporize before the foam polymer is  rigid,  which  will result in collapsed
cells.  The blowing agent should not boil  from solution below  about  30°C
(86°F) and must boil  before reaching 60 to 80°C (140 to 176°F)  (44).

     The quantity  of  blowing agent required to make a given foam  is  primarily
a function of the  agent  molecular weight  and  gas  efficiency (44).  For a
blowing agent,  the  gas efficiency equals  the  contribution to cell volume
divided by the  ideal  gas volume resulting from complete vaporization of  the
blowing agent.  A  good rigid foam blowing  agent will have a gas efficiency
greater than 90 percent.

     For rigid  polyurethane foams, a large majority of the  blowing agent is
incorporated into  the foam.   Additionally,  the blowing agent trapped in  the
foam cells tends to escape very slowly (depending upon its  diffusivity through
the polymer) from  the foam product.   Therefore, in  the manufacturing plant,
the limited amounts of blowing agents which would be released  during
processing could be removed by proper ventilation.   The only possible
exception is in processing operations where large amounts of foam are cut or
handled in such a way as to release  significant amounts of  the  blowing agents.
For this reason, the  toxicity and flammability of a blowing agent are
relatively minor concerns  from the standpoint of  the health and safety of the
foam workers.   However,  since these  foams  are used  as insulation  materials in
such applications  as  refrigerators and houses,  toxicity and flammability are
of concern.   In the home environment,  exposure levels are much  lower than
those in industrial settings because of the long-term chronic exposure which
would occur in  the household.
                                      129

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Product Considerations

     A large majority of rigid polyurethane foams are used as insulation
naterials.  Their effectiveness as insulation is dependent upon the insulating
abilities of the gas in the foam cells, the polyurethane matrix which  cost-
prises the cell walls, and on the density of the foam.  However, the polymer
in the cell walls comprises only a small fraction of the foams total volume;
therefore, the insulating properties of the cell gases are of critical  impor-
tance.  The insulating ability of a blowing agent is a function of both its
thermal conductivity and its retention in the foam.  To be effective as a
rigid—polyurethane insulating-foam blowing agent, a compound must have  both a
Low thermal conductivity and a low diffusivity.  The influx of air into the
foam cells is also an important factor in reducing the insulating properties.
sut it is independent of the nature of the blowing agent.

     Loss of the foam's insulating ability may disrupt the building trade
narket. refrigeration appliance trade, and refrigerated transport.  Some
Building codes rely on the existence of rigid polyurethane sheathing materials
for standards related to insulation requirements.  Some states, such as
3alifornia, have promulgated laws requiring increased energy efficiency in
aome refrigeration appliances.   Without the insulating capability possible
*ith the present rigid polyurethane foams, walls of refrigerators may  have  to
DC thickened to accommodate more insulation material.  Interior capacity  would
ae reduced due to space restrictions on exterior dimensions.  A similar
scenario might result in the refrigerated transport industry, where reduced
Interior capacity would result  in higher transport costs.

Implementation

     Two final considerations  are the implementation time frame and the
xLowing agent  cost.   These are probably the most difficult to predict  because
Doth are heavily dependent upon the manufacturer of the potential compound.
iowever,  the time frame for adaptation by the foam producers is more easily
                                      130

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predicted.  In general, if  a new blowing  agent  meets the processing and
product standards of the foam manufacturing  industry,  it can be adopted with
little delay; however, if it fails to meet these  standards,  it will be quickly
rejected.  Three alternative CFCs have been  identified as potential replace-
ments for the CFC-11 used in rigid polyurethane foams.   These are CFC-123,
CFC-133a, and CFC-141b.

CFC-123

     CFC-123  (2,2-dichloro-l,1,1-trifluoroethane)  is a promising candidate
substitute for CFC-11 as a  rigid polyurethane blowing  agent.   However,  it is a
newer chlorofluorocarbon which  is not currently available in commercial
quantities.  This compound  is expected to have  a  low ozone depletion factor.
Some development work will  probably be required by the polyol manufacturers to
compensate for the increased solvent power of the alternative CFCs.  There  are
already suitable polyols, at least on an  experimental  basis,  so this should
take little time.  No change in the isocyanate  is required.

     The performance of CFC-123 during foam  processing,  is very similar to
that of CFC-11.  The boiling point of CFC-123 is  28°C  (82°F), which is within
the acceptable range for a  rigid polyurethane foam blowing agent.   Its solvent
action on polyurethane, like that of CFC-11, is moderate.  Its molecular
weight is 152.9, and its gas efficiency is 95 percent  of the theoretical
                                                                       3
value.  The quantity of CFC-123 required  to  blow  a 0.033 g/cc (2 Ib/ft )
poured foam is 27 parts per 100 parts polyol.   Sprayed foams require up to  50
parts per 100 parts polyol.  This is more than  double  the 22 parts per 100
parts polyol required of CFC-11.

     Because its thermal conductivity is  20  percent higher than that of
CFC-11, the insulating properties of polyurethane foams blown with CFC-123
would be somewhat less satisfactory.  However,  the diffusion rate for this  CFC
is slow; therefore, the foam's  insulation properties should degrade no faster
than those of CFC-11 blown  foams.  In tests  for acute  and short term toxicity,
                                      131

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DuPont has found  CFC-123  to have  a low toxicity.   Further,  this  blowing agent
is rated as nonflammable.

      Some limited testing of  CFC-123  as a blowing agent for rigid polyurethane
foams has revealed both positive  and  negative results.   As  expected,  CFC-123
exhibited good miscibility with polyols,  while having an acceptable boiling
point for foam production.  However,  the degree of flowability of the foam
produced using CFC-123  was very poor.   This may prohibit foams blown  with
CFC-123 from being considered alternatives for rigid foams  which are  poured or
sprayed.  It was  also concluded during testing that foams produced with
CFC-123 had an unacceptably high  initial thermal conductivity.   Clearly,  more
comprehensive testing of  CFC-123  and  mixtures including other CFCs will be
necessary to establish  the extent of  potential application  of CFC-123 as an
alternative blowing agent.

CFC-141b

      CFC-lAlb (1,1-dichloro-l-fluoroethane) is another potential replacement
for CFC-11 as a rigid polyurethane foam blowing agent.   A manufacturing
process does exist  for  CFC-lAlb,  though it is considered developmental (46).
Its ozone depletion factor is expected to be low.   However, this blowing agent
has some drawbacks with respect to its processing and product performance.
tfhile its boiling point of 32°C (93°F)  is within the desirable range,  its
solvent action is rated as high,  so there is the possibility that CFC-lAlb
might cause the foams to be soft.   Its  molecular weight is  117.0,  and its gas
efficiency is 95 percent of the theoretical value.   The quantity of CFC-lAlb
required to blow a 0.033 g/cc  (2 Ib/ft  )  foam is  20 parts per 100 parts
polyol.   This is about 2 parts/100  parts  polyol less than is required of
3FC-11.

     The thermal conductivity of CFC-lAlb is 18 percent higher than that of
3FC-11.  so the foams produced with  CFC-lAlb would have  lower thermal  effi-
ciency.   However,  this blowing  agent's  low diffusivity  through polyurethane is
                                       132

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similar to that of CFC-11;  therefore,  long  term deterioration of  insulating
efficiency of CFC-141b blown  foams  should occur no faster than for  foams blown
with CFC-11.

     The primary problem with CFC-141b is its  uncertain toxicity  and  flamma-
bility.  This CFC is considered to  be  a weak mutagen.   As mentioned earlier,
most of the blowing agent is  trapped in the foam for  an extended  period of
time; therefore, toxicity concerns  would arise during mixing and  handling of
the blowing agent or during foam  cutting operations where large quantities of
foam cells are being ruptured.  CFC-lAlb is flammable,  however, the flame is
weak and easily suppressed, so explosion is unlikely.   The small  flammability
potential may not be a problem during  manufacturing,  but the flammability of
the product itself is a concern to  manufacturers.   Rigid polyurethane and
polyisocyanurate foams have been  considered exceptional in their  ability to
retard flame.  Use of a flammable blowing agent would defeat this advantage.

CFC-133a

     The last, and probably least desirable of the three rigid polyurethane
foam blowing agents under consideration in  this report  is CFC-133a
(l-chloro-2,2,2-trifluoroethane).   No  commercial manufacturing process for
this blowing agent is currently available in the U.S. although CFC-133a has
been commercially produced  as a chemical intermediate in the U.K. for several
years (46).  Its ozone depletion  factor is  expected to  be low.  However, this
alternative also has limitations  which adversely affect its suitability as a
rigid polyurethane foam blowing agent.

     The boiling point of CFC-133a  is  6.1°C (43°F), and it has a  strong
solvent action on polyurethane.   From  a processing standpoint,  these  two
factors could cause the foam  product to be  inferior or  completely unsuitable.
The low boiling point would tend  to cause the  blowing agent to foam prior to
completion of polymerization  which  could result in a  collapsed foam.   The
solvent action could cause  the agent to remain within the polymer matrix.
                                       133

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thereby producing a softening effect.  Further. CFC-133a has a gas efficiency
of only 90 percent.  This is five percent lower than that of CFC-11; however.
                                                               o
the quantity of CFC-133a required to blow a 0.033 g/cc (2 Ib/ft ) foam is 21
parts per 100 parts polyol.  This is about 1 part/100 parts polyol less than
is required of CFC-11.

     The thermal conductivity of CFC-133a is 22 percent higher than that of
CFC-11, so the foams produced with CFC-133a would have lower thermal effi-
ciency.  However, this blowing agent's low diffusivity through polyurethane is
similar to that of CFC-11; therefore, long term deterioration of insulating
efficiency of CFC-133a blown foams should occur no faster than for foams blown
with CFC-11.  During limited testing of foams blown with CFC-133a, insulating
ability was found to be satisfactory; however, it was slightly lower than that
of CFC-11 blown foams.  In contrast to CFC-123. the flow characteristics of
foams blown with CFC-133a were acceptable.

     The major drawback to use of CFC-133a as a rigid polyurethane foam
blowing agent is its relatively high toxicity.  This CFC is considered to be
embryotoxic.   Toxicity concerns would be greatest during mixing and handling
of the blowing agent or during foam cutting operations where large quantities
of foam cells are being ruptured.   This blowing agent is considered to be
nonflammable.

Conclusions for Rigid Polyurethane Foam Blowing Agents

     To evaluate the suitability of a potential blowing agent for rigid
polyurethane foams,  a number of physical and chemical characteristics need  to
be considered.   Table 7-1 summarizes the various characteristics of the CFCs
which were considered as alternative blowing agents.

     CFC-123 is probably a good alternative to CFC-11 as a rigid polyurethane
blowing agent.   The processing and product characteristics of this alternative
closely resemble those of CFC-11, yet the ozone depletion factor of CFC-123 is
                                      134

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                 TABLE  7-1.   EVALUATION FACTORS FOR SUBSTITUTE RIGID POLYURETHANE FOAM BLOWING AGENTS
u>
Ul
Alternative CFC Blowing Agents
Factors
Reactivity with Ingredients
Stability
Boiling Point, °C (°F)
Solvent Power
Gas Efficiency (% of theory)
Molecular Weight
Quantity for 0.033 g/cc (2 Ib/ft
Foam (parts/100 parts polyol)
Thermal Conductivity W/m-°C
(Btu/hr-ft-°F)
Diffusivity Through Polymer
Toxicity
Flammability
Ozone Depletion Factor
CFC-11

None
Stable
23.8 (74.8)
Moderate
95
137.4
22
0.0078
(0.0045)
Low
Low
Non-
flammable
1.0
CFC-123
None
Stable
28 (82.4)
Moderate
95
152.9
27
0.0093
(0.0054)
Low
Low
Non-
flammable
Low
CFC-141b
None
Stable
32 (89.6)
Strong
95
117.0
20
0.0092
(0.0053)
Low
Potentially
Mutagenic
Slightly
flammable
Low
CFC-133a
None
Stable
6.1 (43.0)
Strong
90
118.5
21
0.0095
(0.0055)
Low
Embryotoxic
Non-
flammable
Low
           Note that only the Ames test results have reported this result.   Further testing is required before
           conclusions can be drawn.

           These estimates are made qualitatively relative to CFC-11.
          "Use of CFC blowing agent in sprayed applications can be nearly double these
           amounts due to higher foam manufacturing losses.

-------
ixpected to be much lower than that of CFC-11.  One disadvantage of using
TC-123 is that the foam has a slightly lower insulating ability.  The other
JLternatives, CFC-141b and CFC-133a. may not be suitable blowing agents
•ecause of their toxicity and their strong solvent action.  An additional
irawback to CFC-133a is its low boiling point which could compromise foam
 uality.  In general, the economic competitiveness of foams blown with more
ixpensive substitute CFCs would have to be examined relative to possible
J-ternative insulation products such as fiberglass board or expandable poly-
:tyrene bead board.

     Once a suitable alternative agent is available,  development work will
>robably be required by the polyol manufacturers to compensate for the in-
xeased solvent power of the alternative CFCs.   There are already suitable
>olyols, at least  on an experimental basis, which can increase cros si inking
lensity and offset some problems.   No change  in the isocyanate is required and
10 significant equipment changes  are necessary.   Bench-scale experimentation.
is ing very modest  amounts of blowing agent means that industry evaluations can
>e done on pilot plant  quantities  and need not await  full commercial produc-
ion.   In rigid insulating foams,  the manufacturer would need considerable
:ime  to evaluate the  aging properties of the  product.   A total of two years in
tddition to blowing agent development are predicted for product development.

•OLYSTYKENE FOAM BLOWING AGENTS

    Extruded thermoplastic  foams,  such as polystyrene foams, use a variety of
•lowing agents including both hydrocarbons and chlorofluorocarbons.  For
>olystyrene foamed sheet products,  the most  commonly  used hydrocarbon blowing
igent  is pentane and  the most commonly used  chlorof luorocarbon is CFC-12.
'olystyrene boardstock  products are blown almost exclusively with CFC-12.
ince  hydrocarbons, such as  pentane,  are not  suspected to be depleters of
:tratospheric ozone,  this section will focus  on substitutes for CFC-12.  A
-ariety of chemical and physical  properties have made this compound desirable
is a blowing agent for  polystyrene foams,  and a potential substitute
                                     136

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would need to have similar properties in order to serve suitably as a replace-
ment.  This is especially important for polystyrene boardstock products,
which, like rigid polyurethane boardstock products, depend upon CFCs for
superior insulating properties.

     Unlike rigid polyurethane foams, most polystyrene foams do not retain
their blowing agents for an extended period of time.  Faster diffusion of CFC
occurs primarily because the polystyrene foam products are thinner  (e.g.,
sheet and film less than 2.5 cm  (1 inch) thick).  For the most part, any
blowing agent incorporated into  polystyrene foam sheet during manufacture will
be emitted within a year.  On the other hand, polystyrene boardstock, which
may be as thick as 5.1 cm (2 inches) or more, will retain CFC-12 much longer.
The half-life of CFC-12 in such  products has been estimated to extend greater
than 40 years.

     Because of prompt emissions from the sheet products, use of low ozone
depleting CFCs as blowing agent  substitutes for CFC-12 can provide  short term
reductions in the potential threat to the stratospheric ozone layer.  However,
the substitute must be widely accepted and adopted for use by the polystyrene
foam industry.  This acceptance  is dependent upon the alternate's cost, per-
formance during processing, and  ability to produce a quality final  product.

Processing Considerations

     The blowing agent for polystyrene foam should be chemically stable under
the conditions present during polystyrene manufacturing.  For purposes of
consistent product quality, it is essential that the blowing agent  does not
react with any of the foam ingredients.  It is equally important that the
blowing agent is not easily thermally decomposed (44).

     To be effective as a blowing agent, a compound must have an appropriate
vapor pressure in the molten resin at the point of extrusion.  In most cases,
this vapor pressure should be at least 670 psia.  This limits blowing agents
                                       137

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or most resins to those with boiling points between -40°C to +50°C (-40°F to
122°F).  If the boiling point is too low, the blowing  agent would not  be an
asily compressed vapor; therefore, it would be difficult  to meter into the
jctruder.  Conversely, if the boiling point is too high, the vapor bubbles
ill expand too slowly or not at all.

    Because polystyrene sheet thermoforming operations require the presence
>f a blowing agent in the foam, the permeability of the blowing agent through
he polymer is an important factor.  Permeability is a  function of the  blowing
.gent's diffusivity through the polymer, its solubility in the polymer,  aging
haracteristics, and rate of air infusion.  If either the  diffusivity or the
olubility is too high, thermoforming will be difficult, because there  will
ot be enough blowing agent retained in the foam cells.  High solubility
.nd/or diffusivity would also make potential substitutes unsuitable for
anufacture of polystyrene insulating boardstock.  If the  CFC escapes through
he foam cells, the valuable insulating properties would be lost.   In fact,
ecause most of the blowing agent should be retained in the foam for the
ntire life of the project (i.e., 50 years or more), diffusion rates should be
exy small to ensure long-term product performance.

    The quantity of blowing agent required to make a given foam is a function
f the agent's molecular weight and gas efficiency  (44).   For a blowing agent,
he gas efficiency equals the contribution to cell volume  divided by the ideal
as volume.   A good blowing agent for polystyrene foam  will have a gas  effi-
iency greater than 90 percent.

    Because a majority of the blowing agent is emitted in foam extrusion and
heet thermofozming plants, the primary fire hazards associated with the use
f a flammable (i.e.. hydrocarbon) blowing agent are encountered in the sheet
anufacturing facilities.  In fact, the flammability of the foam product is
.ore a function of the flammability of the polymer than that of the blowing
.gent trapped in the foam cells  (45).  Although it is certainly preferable
hat a blowing agent be nonflammable, it is possible to safely manufacture
                                     138

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foams with a flammable blowing agent given proper  equipment  and sufficiently
trained personnel.  This is  supported by  the  fact  that  some  major  producers of
thermoformable polystyrene foam sheet use hydrocarbons  as  their primary
blowing agents.  Hydrocarbons are many times  more  flammable  than the
alternative CFCs discussed in this section.

Product Considerations

     Most polystyrene foam sheet is used  for  packaging  or  serving  food prod-
ucts.  Meat trays, egg cartons, hamburger shells,  and disposable plates are
examples of this application.  Because some blowing  agent  is retained in  the
final foam product and these products come in intimate  contact  with food-
stuffs, the FDA must approve any new chemical which  would  be used  as a blowing
agent.  Prior to such approval, a candidate substitute  blowing  agent would
have to undergo extensive toxicity testing, and even a  slight degree of
toxicity would probably jeopardize the acceptance  of a  potential alternative
CFC (45).

     Polystyrene foam boardstock is used  primarily as an insulating material
for residential and commercial structures.  In these applications, polystyrene
boardstock has the advantage of high insulating quality (per thickness) due to
the CFC vapor trapped in the cells.  Of course,  an alternative  blowing agent
with lower insulating capability (i.e.. higher thermal  conductivity) could be
used, but the material's competitive advantage would be lessened in the
building materials market.  Thus, an optimum  substitute would possess
insulating qualities similar to or better than those of CFC-12.

Impl ement at i on

     Two final considerations are the implementation time  frame and the blow-
ing agent cost.  These are probably the most  difficult  to  predict  because both
are heavily dependant upon regulatory considerations and the chemical manufac-
tures' willingness to produce new blowing agents.  However,  the time frame for
                                       139

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adaptation by  the  foam  producers  is  more easily predicted.   Because full-scale
experimentation  is costly and  requires full-scale production equipment and
large  quantities of raw materials, the evaluation by  industry of alternative
polystyrene blowing agents will be dependent on the availability of the alter-
native agent.  Four alternative CFCs have been identified as potential
replacements for the CFC-12 used  in  polystyrene foams.   These are CFC-22,
CFC-124. FC-l34a.  and CFC-l42b.
CFC-22
     A currently available chemical which might  successfully  be  used as  a
polystyrene foam blowing agent  is CFC-22.   Its boiling  point  is  -40.8°C
(-41.4°F), which is quite low.  but may  be acceptable.   Substances with boiling
points much lower than -40°C  (-40°F) may  be difficult to meter into  the
extruder, because they are difficult to compress to a liquid  state.   Test
results reporting the amount of CFC-22  required  to  blow polystyrene  foam,  and
the gas efficiency were not found.  It  does, however, have  a  low ozone
depletion factor.

     The solvent power of CFC-22 is quite low. but  its  diffusivity through
polymer materials is high.  This coupled  with the fact  that its  thermal
conductivity is 9 percent higher than CFC-12 make CFC-22 a  poor  choice as a
blowing agent for polystyrene boardstock  insulating foam.   The high  diffus-
ivity of CFC-22 may make thermoforming  difficult also.   It  does  have the
advantage of being a safe chemical; both  non-toxic  and  non-flammable.

SFC-124

     The chemical and physical  properties  of CFC-124 (2-chloro-l.1,1,2-
:etrafluoroethane) indicate that it might  be a suitable replacement  for  CFC-12
as a polystyrene foam blowing agent.  However, it is a  new  chlorofluorocarbon
for which a manufacturing process has not  yet been  developed.  This  compound
is expected to have a low ozone depletion  factor.   The  boiling point of  this
                                      140

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CFC is -11°C  (12.2°F) which is  within the acceptable range for  a polystyrene
blowing agent.   Its  solvent power and diffusivity are both low,  so there
should be retention  of  the agent  in the foam cells.   The  molecular weight  of
this CFC is 136.5, and  its gas  efficiency is 90 percent of the  theoretical
value.  The quantity of CFC-124 required to blow a 5 Ib/ft  foam is 6  parts
per 100 parts resin.  This is about 20 percent  more  CFC required by weight
than is required with a CFC-12  formulation.

     Because the thermal conductivity of CFC-124 is  six percent  higher than
that of CFC-12.  the  insulating  properties of polystyrene  foams  blown with
CFC-124 will be  less satisfactory.   This may not be  a factor for most
polystyrene sheet foam  because  insulation is not critical;  however,  this may
make it less attractive as a boardstock blowing agent.  Additionally,  the
diffusion rate for this CFC is  slow;  therefore,  the  foam's insulation  proper-
ties should degrade  no  faster than those of CFC-12 blown  foams.   In tests  for
acute and short  term toxicity.  DuPont has found CFC-124 to have a low  tox-
icity.  Further, this blowing agent is rated as nonflammable.

FC134a

     FC-134a (1.1,1,2-tetrafluoroethane)  is another  chemical with properties
which appear to  make it a potentially viable candidate for replacing CFC-12  as
a polystyrene foam blowing agent.   Because this compound  contains no chlorine,
its estimated ozone  depletion factor is zero.   Its boiling point is within the
required range at -26.3°C (-15.3°F),  and its solvent power and  diffusivity are
both acceptably  low.  The molecular weight of FC-134a is  102.0.  and its  gas
efficiency is 95 percent of the theoretical  value.   The quantity of FC-134a
required to blow a 0.08 g/cc (5 Ib/ft )  foam is 4.2  parts per 100 parts  resin.
This is about 0.8 parts per 100 parts resin less than is  required of CFC-12.

     The thermal conductivity of  this compound  is 14 percent lower than  that
of CFC-12, so foams  blown with  FC-134a would have superior insulating  charac-
teristics to those blown with CFC-12.   Additionally,  the  diffusion rate  for
                                      141

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this FC is slow through polystyrene; therefore, the foam's insulation  proper-
ties should degrade no faster than those of CFC-12 blown foams  (2).  These  two
characteristics make it especially suited to replace CFC-12 as  a blowing  agent
for polystyrene foam boardstock.  Tozicity testing for this compound is
incomplete, but in tests for flammability, this blowing agent has been rated
as nonflammable.

CFC-142b Alone or Mixture with CFC-22

     Other proposed substitutes include use of CFC-l42b, either alone  or  in a
mixture with CFC-22.  CFC-142b is currently manufactured and sold in a 60/40
mixture with CFC-22 as an aerosol propellent.  Less is sold as  pure CFC-142b
because of its flammability.  Technical feasibility as a blowing agent is not
completely known,  however, some formulations may be cost-effective alterna-
tives to CFC-12.  Concerns include strong solvent action and rapid diffusion
of CFC-22.  For CFC-142b. the ozone depletion factor is expected to be low.
Its boiling point  is -9.2°C (15.4°F). but is has a moderate solvent power and
diffusivity which might compromise the foam's thermoformability.  The  molecu-
lar weight of this CFC is 100.5, and its gas efficiency is 80 percent  of  the
theoretical value.  The quantity of CFC-142b required to blow a 0.08 g/cc (5
     o
Lb/ft ) foam is 5  parts per 100 parts resin.  This is equivalent to the
quantity of CFC-12 which would be required.

     The thermal conductivity of CFC-142b is 15 percent higher  than that  of
3FC-12, so the insulating characteristics of foams blown with CFC-142b would
ae inferior to those of foams blown with CFC-12.  Additionally, the diffusion
rate for this CFC is moderate; therefore, the foam's insulation properties
7ould probably degrade faster than those of CFC—12 blown foams.  In tests for
icute and short term toxicity, DuPont has found CFC-142b to be  a weak  mutagen.
Further, this blowing agent is rated as slightly flammable.  Its flammability
.imits in air range from 6.9 weight percent to 15.5 weight percent.
                                      142

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     Though both CFC-22 and CFC-142b appear to have properties which are less
than satisfactory for blowing polystyrene foam, together in a mixture the
properties of one chemical may compensate for those of the other.  For in-
stance. CFC-142b is flammable, but adding a sufficient quantity of CFC-22
forms a non-flammable mixture.  Also, CFC-142b is less diffusive through
polymer than CFC-22 and may alleviate problems with thermoforming.  Both have
relatively high thermal conductivity; therefore, a mixture of CFC-142b and
CFC-22 would still be a less desirable choice as a blowing agent for
polystyrene foam boardstock used as insulation.

Innovative Blowing Agent Blends

     Most of the alternative blowing agent chemicals discussed so far have
drawbacks associated with them:  alternative CFCs are relatively expensive and
could adversely affect foam quality, and hydrocarbons can increase fire
hazards in the manufacturing plant.  A promising approach to reducing these
drawbacks is the use of a blend of a less ozone-depleting CFC with a
hydrocarbon.  The benefit of this blend would be that the hydrocarbon could
possibly prevent the CFC from adversely affecting the foam quality, and the
CFC could reduce the emitted concentrations, hence the fire hazards of the
hydrocarbon.  The optimum chemicals and relative concentrations would have to
be established through research and testing.  Operating costs for this option
are apparently minimal, however, FDA approval will be needed for food
packaging.

Conclusions for Polystyrene Foam Blowing Agents

     To evaluate the suitability of a potential blowing agent for polystyrene
foams, a number of physical and chemical characteristics need to be consi-
dered.  Table 7—2 summarizes the various characteristics of the CFCs which
were considered as alternative blowing agents.
                                       143

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            1KBLC. /-/.
                                                 DU.DO.LJ.J.UIU I uij i o JL j. i\m«u
Factors
Reactivity with Ingredients
Stability
Boiling Point. °C (»F)
Solvent Power
Gas Efficiency (% of theory)
Molecular Weight
3 3
Quantity for 0.08 g/cm (5 Ib/ft )
Foam (parts/100 parts resin)
Thermal Conductivity W/m-°C
(Btu/hr-ft-°F)
Diffusivity Through Polymer
Toxic ity
0
Flammability
Ozone Depletion Factor
CFC-12

None
Stable
-29.8
(-21.6)
Low
—
120.9
5
0.0097
(0.0056)
Low
Low
Non-
flammable
0.86
Alternative CFG Blowing Agents
CFC-22
None
Stable
-40.8
(-41.4)
Low
—
86.5
—
0.0105
(0.0061)
High
Low
Non-
flammable
0.05
CFG- 124
None
Stable
-11
(12.2)
Low
90
136.5
6
0.0102
(0.0059)
Low
Low
Non-
flammable
Low
FG-134a
None
Stable
-26.3
(-15.3)
Low
95
102.0
4.2
0.0083
(0.0048)
Low
Incomplete
Non-
flammable
0.0
CFC-142b
None
Stable
-9.2
(15.4)
Moderate
80
100.5
5
0.0111
(0.0064)
Moderate
Low
Slightly
flammable
Low
These  estimates are  made qualitatively relative to CFC-12.

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     Both CFC-124 and FC-134a appear to be viable as candidates for replacing
CFC-12 as a polystyrene foam blowing agent.  With respect to the desired
chemical and physical properties, FC-134a is equivalent or superior to
CFC-124.  However, cost comparisons are not yet possible, and toxicity testing
is incomplete for FC-134a.  Even a slight toxicity could jeopardize its
potential as a blowing agent.

     Both CFC-22 and CFC-142b considered alone as blowing agents for polysty-
rene foam appear to be less promising.  The low boiling point and high dif-
fusivity of CFC-22 may cause problems in both the manufacturing process and
produce a product of inferior quality.  CFC-142b has a high thermal conductiv-
ity, making it a poor choice for blowing insulating foams, but its main draw-
back is its slight flammability.  Both chemicals are currently available  and
are sold together as a mixture.  There is potential that a non-flammable  mix-
ture of these chemicals may be suitable for use as a polystyrene foam sheet
blowing agent.

     Finally, a mixture of CFC-22 and hydrocarbons appears to be an additional
blowing agent alternative.  The benefit of this blend would be that the
hydrocarbon could possibly prevent the CFC foam adversely affecting the foam
quality, and the CFC could reduce the emitted concentrations, hence the fire
hazards of hydrocarbons.

POLYOLEFIN AND PHENOLIC FOAM BLOWING AGENTS

     Extruded thermoplastic foams such as  polyolefin foams,  (i.e.,
polyethylene, polypropylene, etc.) use a variety of chlorofluorocarbon blowing
agents  including CFC-11,  CFC-12, CFC-114,  and CFC-115.   The  polyolefin foam
industry also employs mixtures of these CFCs as blowing  agents.  The most
common  blowing agent is a mixture of CFC-12/114.  A variety  of chemical  and
physical properties makes these  compounds  desirable as blowing agents for
polyolefin foams.  For instance, since the diffusion rate  of  CFC-114 out  of
these foams is close to the  diffusion rate of air in, the  foams maintain
                                       145

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structural stability.  A potential substitute would need  to have similar
diffusion properties in order to serve suitably as a replacement.

     Like polystyrene foams, polyolefin foam sheet products tend to emit most
}f their blowing agents during, or soon after, manufacture.  The boardstock
products tend to retain blowing agents.  Use of low ozone depleting CFCs as
jlowing agent substitutes in polyolefin foam sheet products can provide short
:erm reductions in the potential threat to the stratospheric ozone layer.
iowever, before a substitute blowing agent can begin to reduce the potential
ihreat to the ozone layer,  it must be widely accepted and adopted for use by
:he polyolefin foam industry.  This acceptance is dependent upon the alter-
late's cost and its performance during processing as well as in the final foam
product.

     Phenolic foams are blown using CFC-11 and CFC-113.  A variety of chemical
ind physical properties make these CFCs desirable as a blowing agent for
ihenolic foam,  and a potential substitute would have to have similar
properties since phenolic foam depends upon CFCs for superior insulating
properties.   Like polyurethane and polystyrene boardstock, phenolic foams
retain the CFC for a long period of time.

Processing Considerations

     Polyolefin foams are typically used in cushioning and wrapping applica-
:ions.   For  these foams,  the criteria for judging potential substitute blowing
igents are similar to those  described for polystyrene foam except that solvent
if facts are  much less important and diffusion losses can be much more signifi-
:ant.   Aging or diffusion additives are generally used to adjust CFC emission
rate  to the  air infiltration rate.   Even with CFC-12 substantial losses result
.n  a  partially collapsed foam which must be stored until it reezpands.
iecause the  CFC emission rates from thin polyolefin foam sheet are high.
Blowing agent flammability is a greater concern than it is with polystyrene
                                      146

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foams.  Likewise toxicity  is a  concern because of  the potential  for worker
exposure.

     Polyolefin foams  include several  types  of polymers and  therefore  differ-
ent blowing agents may be  best  suitable for  certain polyolefin foam types.
Also, the final product may dictate  the choice of  blowing agent  (e.g.,  CFC-11A
is required for thick  polyolefin profiles).

     For phenolic foams, processing  considerations are similar to  those of
polyurethane and polystyrene insulating foams.

Product Considerations

     Because a large majority of polyolefin  foams  are thin sheet products, the
blowing agent is emitted early  in  the  foam's life,  and makes no  significant
contribution to the properties  of  the  foam product.

     Phenolic foam, on the other hand,  is  used as  an insulating  material.  In
this application, phenolic foam has  the advantage  of high insulating quality
(per thickness) due to the CFC  vapor trapped in the cells.   Thus,  an optimum
substitute would possess insulating  qualities similar to or  better than those
presently achieved with CFC-11  and CFC-113.

Implementation

     Two final considerations are  the  implementation time frame  and the
blowing agent cost.  These are  probably the  most difficult to predict  because
both are heavily dependent upon the  manufacturer of the potential  alternative.
However, the time frame for adaptation by  the foam producers is  more easily
predicted.  Because experimentation  requires full-scale production equipment
and large quantities of raw materials,  the evaluation by industry  of alterna-
tive polyolefin blowing agents  will  be dependent on the availability of
alternate CFCs.  CFC-12A and CFC-142b  have been identified as potential new
                                      147

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CFG replacements for the CFCs currently used in polyolefin foams.  CFC-123 and
CFC-141b have been identified as potential replacements for the CFCs currently
used in phenolic foams.

CTC-12A

     CFC-124 is a potentially suitable replacement for CFC-12 as a polyolefin
foam blowing agent.  However, it is a new chlorofluorocarbon for which a
manufacturing process has not yet been developed.  This compound is expected
to have a low ozone depletion factor.  The boiling point of this CFC is -11°C
(12.2°F) which is within the acceptable range for a polyolefin blowing agent.
Its diffusivity through these foams is high, so there could be problems with
collapsed foams.

     The molecular weight of this CFC is 136.5, and its gas efficiency is 65
percent of the theoretical value.  The quantity of CFC-124 required to blow a
                     o
0.018 g/cc (1.1 Ib/ft ) foam sheet, 0.08 cm (1/32 in.) thickness, is 40 parts
per 100 parts resin.   This is about five parts per 100 parts resin less than
is required of CFC-12.  In tests for acute and short term toxicity, DuPont has
found CFC—124 to have a low toricity.  Further, this blowing agent is rated as
nonflammable.

3FC-142b

     The discussion of the properties of CFC-142b provided relative to poly-
styrene foams is applicable also to polyolefin foams with the following
jxceptions.  Since polyolefin foams are typically not used as insulating
aaterials. the high thermal conductivity is not an issue.  As previously
lentioned. the diffusivity of the CFC will be higher than the polyolefin
laterial,  which could potentially cause processing problems, (i.e., sagging).
igain,  the slight flammability of the chemical must be considered with respect
:o the particular polyolefin foam manufacturing process and product being
                                      148

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made.  Since the CFC is not retained in thin polyolefin sheet products, this
is more of a processing (worker safety) concern.

CFC-123

     CFC-123 may prove to be a good blowing agent for phenolic foam although
it has a higher thermal conductivity (less insulating value) and is expected
to cost more than CFC-11  (44).  However, the diffusion rate for this CFC is
slow; therefore, the foam's insulation properties should degrade no faster
than those of CFC-11 blown foams.  Chemical manufacturers and rigid insulation
foam manufacturers have both recently renewed efforts to study application of
this compound.

CFC-141b

     Like CFC-123, CFC-141b may prove to be a good blowing agent, but it has
the disadvantages of higher thermal conductivity, increased toxicity, and
slight flammability (44).

Conclusions for Polyolefin and Phenolic Foam Blowing Agents

     CFC-124 appears to be a suitable substitute blowing agent for polyolefin
foams due to the favorable chemical and physical characteristics.  CFC-142b
may also be an acceptable blowing agent substitute if its diffusive nature is
not extreme enough to cause sagging of the product.  Also, the issue of its
flammability must be addressed with respect to the particular polyolefin
process in which it is to be used.  Table 7-3 summarizes the various charac-
teristics of the CFCs which were considered as alternative blowing agents.

     Based on similar substitutes proposed for other rigid foams blown with
CFC-li, potential CFC substitutes are CFC-123 and CFC-141b.  Table 7-4
summarizes the various characteristics of the CFCs which were considered as
alternative blowing agents.  One disadvantage of using CFC-123 is that the
                                        149

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foam has a lower insulating ability.  In addition, CFC-lAlb may not be
suitable because of its toxicity.  In general, the economic competitiveness  of
foams blown with more expensive CFCs would have to be examined relative to
possible alternative insulation products.
                                      150

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           TABLE 7-3.   EVALUATION FACTORS FOR SUBSTITUTE POLYOLEFIN FOAM BLOWING AGENTS
Current CFC Blowing Agents
Factors
Reactivity with Ingredients
Stability
Boiling Point, °C (°F)
Gas Efficiency (% of theory)
Molecular Weight
3
Quantity for 0.018 g/cm
(1.1 Ib/ft ) Foam (parts/
100 parts resin)
Diffusivity Through Polymer
Toxicity
CFC- 11
None
Stable
23.8
(74.8)
—
137.4
, 	
—
Low
a
Flaminability Non-
flammable
CFC- 12
None
Stable
-29.8
(-21.6)
51
120.9
45
High
Low
Non-
flammable
CFC- 114
None
Stable
3.8
(38.8)
84
170.9
39
Low
Low
Non-
flammable
CFC-115
None
Stable
-38.7
(-37.7)
85
154.5
___ l 	
Low
Low
Non-
flammable
Alternative CFC
Blowing Agents
CFC- 124
None
Stable
-12
(10.4)
65
136.5
40
High
Low
Non-
flammable
CFC-142b
None
Stable
-9.2
(15.4)
80
100.5
_
High
Low
Slightly
flammable
These estimates are made qualitatively relative to CFC-11 and CFC-12.

-------
                  TABLE 7-4.   EVALUATION fc'AUTORS bUK
                                                                 tuv^iu rnc,nuiuxu
to
Alternative
CFC Blowing Agents
Factors
Reactivity with Ingredients
Stability
Boiling Point, °C (°F)
Solvent Power
Molecular Weight
Thermal Conductivity
W/m-°C (Btu/hr-ft-'F)
Diffusivity Through Polymer
Toxic ity8
Flamiaability
Ozone Depletion Factor
Cost ($/kg)
CFC- 11

None
Stable
23.8 (74.8)
Moderate
137.4
0.0078
(0.0045)
Low
Low
Non-
flammable
1.0
1.40
CFC- 113
None
Stable
47.6 (117.7)

187.4
0.0076
(0.0044)
Low
Low
Non
flammable
Low
2.06
CFC- 123
None
Stable
28 (62.4)
Moderate
152.9
0.0093
(0.0054)
Low
Low
Non-
flammable
Low
4.14
CFC-141b
None
Stable
32 (89.6)
Strong
117.0
0.0092
(0.0053)
Low
Potentially
Mutagenic
Slightly
flammable
Low
3.31
         Source: (44)

         Jl
          Note that only the Ames test  results  have  reported this result.
          conclusions can be drawn.
Further testing is required  before
          These estimates are made qualitatively  relative to CFC-11.

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                                   SECTION 8   .
                  SUBSTITUTES FOR CURRENT RIGID FOAM  PRODUCTS

ALTERNATIVES TO CFC BLOWN RIGID POLYURETHANE FOAM PRODUCTS

     A majority of rigid polyurethane foam products are used as  insulation in
various applications.  These include:  industrial, commercial, and  residential
building insulation; refrigerated appliance insulation; industrial  insulation;
and insulation for refrigerated transport vehicles.   Packaging is an  addi-
tional use of rigid polyurethane foams.  In each application area,  there are
alternative materials which can serve as substitutes  for urethanes.   However,
the unique properties of rigid polyurethane foams often make them more  de-
sirable and less expensive than potential substitutes.  This is  especially so
with insulation foams where any alternative material  would  cause substantial
increases in energy costs or construction costs.
                                      /•
     Low thermal conductivity and good mechanical properties are the  primary
advantages that rigid polyurethane foam has over other insulation materials.
Polyisocyanurate foams have the added benefit  of excellent  fire  resistance.
Other advantages include:

     •    Ease of production and simplified designs,

     •    Low density,

     •    Less required thickness,

     •    Reduced waste materials, and

     •    Resistance to moisture.
                                      153

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     The most common use of polyurethane board is commercial and industrial
roofing, but these foams are also used extensively in residential sheathing
ind roofing.  Table 8-1 shows the market distribution for PU foam insulation.
loofing and sheathing as well as some industrial pipe and storage tank insula-
:ion applications offer the best possibilities for substitution of either
Alternative materials or insulation systems.  Alternatives include materials
aade with little or no CFCs.  Table 8-2 lists specific alternatives to
)olyurethane foam products in several application areas and the CFC emission
reduction potential.  The following sections discuss the applicability of
various substitutes for rigid polyurethane foam products.

Alternative Industrial and Cfi^^ercial Roofing Insulations

     A large majority of the PU insulation produced is used in industrial and
commercial roofing.  Before the mid-1970s, however, this was not the case.
Then,  most roofs consisted of hot-mopped asphalt or coal-tar pitch, and often
10  insulation was used.  When insulation was desired, the available materials
/ere primarily fiberboard, perlite, fiberglass, and cellular glass.  Increas-
_ng energy costs and advances in technology have stimulated development of
jnproved roofing methods, and there is currently available a tremendous
variety of membrane materials, insulation products, and applications tech-
liques.   Rigid PU foams are used mainly in three general types of industrial
md commercial roofing:  built-up roof (BUR), modified bitumen and elastomeric
ystems.   Table 8-3 shows the use distribution of insulation products in the
roofing industry.

     Traditionally, built-up roofing membrane has been used to protect the
lat and nearly-flat roofs found in industrial and commercial construction.
>UR uses layers of felts (paper, glass fiber, polyester, or asbestos) alter-
lated with layers of hot-applied or cold-applied bituminous materials (asphalt
>r  coal-tar based).  The surface layer is also embedded in a heavy coat of
isphalt or coal-tar pitch.  This top layer is usually covered with gravel, but
lay be left smooth.  Typical BUR systems are installed in different ways
                                      154

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           TABLE 8-1.  1985 MAEKET DISTRIBUTION FOR POLYURETHANE AND
                       POLYISOCYANURATE INSULATION FOAMS
    Market
Market Distribution
     (Percent)
Industrial and Commercial Roofing

New Residential

Retrofit Residential

Masonry Wall

Metal Buildings

Farm Buildings

Non-Residential Retrofit

Miscellaneous
        65

        22

         3

         3

         3

         3

         1

        <1
       100
Source:  (48)
                                     155

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                    TABLE 8-2.  POTENTIAL SUBSTITUTES FOR RIGID  PU FOAM  PRODUCTS
Applications
Alternatives
   CFC Emission
Reduction Potential
Industrial Roof/Ceiling:
Industrial Walls:
Commercial Roof/Ceiling:
Commercial Walls:
Fiberglass
Perlite
Expanded PS
Extruded PS
Fiberboard
Cellular Glass
Insulating Concrete

Fiberglass
Rock Wool
Perlite
Vermiculite
Insulating Concrete

Fiberglass
Rock Wool
Cellulose
Perlite
Expanded PS
Extruded PS
Fiberboard
Cellular Glass
Insulating Concrete

Fiberglass
Rock Wool
Perlite
Vermiculite
Expanded PS
Extruded PS
Fiberboard
Cellular Glass
         100%
         100%
         100%
          40%
         100%
         100%
         100%

         100%
         100%
         100%
         100%
         100%

         100%
         100%
         100%
         100%
         100%
          40%
         100%
         100%
         100%

         100%
         100%
         100%
         100%
         100%
          40%
         100%
         100%
                                                                                     (Continued)

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                                                 TABLE  8-2  (Continued)
         Applications
Alternatives
   CFG Emission
Reduction Potential
         Commercial Floors:
         Residential Roof/Ceiling:
         Residential Walls:
Cn
         Residential Floors:
         Refrigeration  Insulation:
          Packaging Materials:
Fiberglass
Rock Wool
Expanded PS
Extruded PS

Fiberglass
Rock Wool
Cellulose

Fiberglass
Rock Wool
Expanded PS
Extruded PS
Fiberboard
Cellular Glass
Gypsum
Plywood
Foil Faced Laminated Board

Fiberglass
Rock Wool
Foil Faced Laminated Board

Expandable PS Bead
Extruded PS Board
Fiberglass

EPS Foam Peanuts or Blocks
Plastic Film Bubble Wrap
Polyolefin Foam Sheet or Blocks
Wood Shavings
         100%
         100%
         100%
          40%

         100%
         100%
         100%

         100%
         100%
         100%
          40%
         100%
         100%
         100%
         100%
         100%

         100%
         100%
         100%

         100%
          40%
         100%

         100%
         100%
         100%
         100%

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      TABLE 8-3.  NON-RESIDENTIAL  ROOFING INSOLATION MARKET (1986  TOTAL =
                  3900 MILLION BOARD  FEET)
Material
Poly is ocy anurate
Perlite
Expanded PS
Extruded PS
Fiberglass
Fiberboard
Composite
Polyurethane
Phenolic
Other
Total
Total
Market
Share (Z)
32
13
12
10
10
9
8
4
2
<±
100
Built-up
Roofing (Z)
33
19
—
9
15
8
11
3
<1
	 1
100
Modified
Bitumen (Z)
33
19
—
9
14
9
10
3
<1
<1
100
Single-Ply
Sheets (Z)
31
6
26
11
4
9
5
5
3
<1
100
Source:  (48)
                                     158

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consisting  of: membrane  adhered to deck without insulation;  insulation adhered
to  deck with membrane  applied  to insulation;  base sheet  adhered to deck,
insulation  over base sheet,  and top membrane  over insulation;  and  membrane
adhered to  deck with insulation applied over  the membrane.

     Modified bitumen  systems  are similar to  BUR systems except that  the
individual  plies are factory laminated and the modified  bitumen is applied  in
one layer.  The composite modified bitumen sheets can be either self-adhesive
or  heat applied.

     The  third major roofing method is known  as elastomeric  roofing.   This
technology  uses a  single ply of thermoplastic or thermosetting synthetic
membrane.   There are four major methods by which elastomeric systems  are
installed:  loose  laid and ballasted,  partially adhered  (with  adhesive or
asphalt), fully adhered, and mechanically fastened.   As  with BUR and  modified
bitumen systems, the insulation can be placed either  above or  below the roof
membrane.

     It is  evident that  there  is available a  tremendous  variety of roofing
systems and installation methods are available.   Because of  this,  the utility
of  an insulation material must  be considered  on a case by case basis.
Extruded and expanded PS foam are good examples of alternatives which are
suitable in some applications and not  in others.   The relatively low  melting
point and low solvent resistance of PS foam may prevent  its  use in hot applied
BUR and modified bitumen systems as well as in fully  adhered elastomeric
systems where solvent adhesives are used.   However, with the proper
construction configuration,  this can be overcome.  Additionally, PS foam
cannot pass Factory Mutual and  Underwriters Laboratories fire  resistance
requirements without the use of underlay or overlay boards (usually perlite or
fiberboard) or both.

     In the different types  of  industrial and commercial roofing,  the poly-
urethane or polyisocyanurate insulation provides over 90 percent of the roof's
                                       159

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insulation.  This is because the other components  (membrane and bitumen  or
adhesive) are  thin and have relatively low thermal resistances.  Therefore,
the use  of alternative materials can cause higher energy  costs unless  a
greater  thickness of the alternative is used.  Table 8-4  shows the  energy
losses which would be incurred from using equivalent thicknesses of alterna-
tive  insulation materials.

Alternative Residential Building Insulation

      In  the residential building insulation market rigid  FU laminated
boardstock insulation is used primarily as an insulative  sheathing  material.
It is usually  placed on the exterior side of a building's wall studs or
supports.  The sheathing material is then covered by the  building's exterior
finish such as brick, stone, stucco veneer, or siding made of wood  or  metal.
Figure 8-1 shows the configuration of a typical residential wall.

     Other applications for FU foam boardstock include  insulating underlayment
beneath  roof shingles, sub-slab insulation, slab or basement perimeter insula-
tion, and ceiling insulation.  The insulating sheathing adds to the insulative
capacity of the insulation which has been placed between  the studs  (usually
fiberglass batts), but the primary purpose of this sheathing is to  insulate
over the studs.  Because wooden or metal studs are poor insulators,  and  they
comprise up to 20 percent of a building's exterior wall surface, using in-
sulative sheathing can provide considerable heating and air conditioning
energy savings.  Figure 8-2 illustrates the insulative  contribution of each
element of a typical residential wall.

     There are numerous alternatives to FU sheathing, but no other  non-CFC
blown sheathing material has as high an insulative efficiency  (R-value per
inch of thickness).  Figure 8-3 compares the relative insulative capacities of
several common sheathing materials including polyurethane foam, polystyrene
foam, expandable polystyrene foam, phenolic foam, fiberboard, plywood, gypsum,
and foil laminated paper board.  Other sheathing materials include  insulating
                                       160

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    TABLE 8-4.  ESTIMATED ENERGY LOSSES  FROM USING ALTERNATIVE  INSULATION
                IN INDUSTRIAL AND  COMMERCIAL ROOFING
Board
Insulation Material
Phenolic Foam
PU Foam
Fiberglass Board
Cellular Glass
Perlite
Expanded PS Foam (EPS)
Extruded PS Foam
Fiberboard
R-Value
Per Inch
8.3
7.2
4.4
2.9
2.8
3.9
5.1
2.8
Percent
Increase In
Energy Lossesa
-
0
35
54
55
41
26
55
Assuming insulation comprises 90 percent  of  the  roof's  total  insulation
value.
                                      161

-------
     FOIL • FACED
   FOAM SHEATHING
    UNPAGED GLASS
      FIBER BATT
         EXTERIOR _S\
          SIDING
                                   GYPSUM BOARD

                                    POLYETHYLENE
                                   VAPOR HETARDER
                                                      FOUNDATION
                                                         WALL
       FOIL-FACED
     FOAM SHEATHING
      UNPAGED GLASS
        FIBER BATT

        METAL TIE
      FASTEN TO STUD'
          BRICK VENEER
                                    GYPSUM BOARD

                                  POLYETHYLENE
                                 VAPOR RETARDER
                                                     FOUNDATION
                                                       WALL
                                                         I

                                                         S
                                                         Q
Figure  8-1.
Typical  residential wall construction.  Basic  wall with
siding  (top).  Basic  vail with brick veneer  (bottom).
                                   162

-------
         3/8'—BJ
  Inside
  Air Film
  Gypsum
  Drywall-
 Vapor
 Retarder
• 3 -1 / 2" •
•3/4-HPJ 1/2' Ul	
                                   •PU
                                    Sheathing
                                   •Wood
                                    Siding
                                   •Outside
                                    Air Film
                                             086-W63A
     Inside surface film
     Gypsum board
     6-mil vapor retarder
     2x4 wood framing
     R-13 glass fiber batt
     PU foam sheathing
     Lapped wood siding
     Outside surface film

     R-Value
         R-Values
         Through
          Frame

          0.68
          0.45

          4.35
    R-Values
    Through
     Wall

     0.68
     0.45
—
5.40
0.81
0.17
13.00
5.40
0.81
0.17
         11.86
    20.51
Total Wall U-Valve = 20Z/11.86 + 802/20.51 =  0.0559
Total Wall R-Valve =17.9
      Figure 8-2.  Insulative contribution of  individual wall components.
                                    163

-------
o
3
a:
              Phenolic
Extruded  Fiberglass
  PS        Board
 Board
                                                                      f———T
                                                                  Fiberboard  Plywood
Gypsum    Laminated
            Paper
            Board
                   Figure 8-3.   R-values per inch for various materials (at 24°C (75°F)  mean temperature).

-------
boards made from corkboard. fiberglass, perlite. or vegetable fibers  (36).
Since the primary purpose of FU sheathing is to insulate  the wall,  it  is
convenient to compare alternatives according to their  insulative abilities as
well as their cost.  However, other factors which might need to be  considered
in a given situation are: local codes and restrictions on certain materials,
availability, flammability, vapor retardancy, durability,  and installation
costs.  Table 8-5 shows the estimated material and energy costs associated
with using alternative sheathing materials.  Most sheathing products have
lower material costs, but their use generally results  in  higher energy losses,
hence higher heating and cooling costs.

     Another way to investigate alternatives to PU insulation sheathing is to
compare options on a basis of a fixed value for the walls total insulative
capacity.  Since FU foam sheathing has the highest R-value, per unit thickness
of all non-CFC blown alternatives, most alternatives will require greater
total wall thicknesses.  This might mean using greater thicknesses  of  the
sheathings discussed earlier.  Figure 8-4 shows the thickness of various
sheathing materials required to equal the R-value of 3/4  inch thick PU
sheathing (R-5.4).

     Another option is to increase the thickness of the fiberglass  batts used
between the wall studs.  This would require use of thicker studs, possibly
changing the wall's construction and cost.  The wall shown in Figure 8-2 has a
total wall R-value of approximately 18.  To obtain the same wall R-value
without sheathing or any sort of external thermal barrier would require
fiberglass batts and wall studs which are 6.5 inches thick.  This is nearly
double the width of the standard 2x4 wall stud.

     Another possibility is using alternative construction materials.  An
example is Klimanorm®, a lightweight building block recently introduced to the
US from West Germany.  Block-type residential and commercial construction is
common in Europe.  This quartz sand/lime agglomerate block replaces all of the
major components in a standard wall: sheetrock, stud frame, fiberglass batts.
                                      165

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TABLE 8-5.  ESTIMATED RELATIVE MATERIAL AND ENERGY  COSTS  FOR
            SUBSTITUTE SHEATHINGS
Sheathing Material
Phenolic Foam
Laminated PU Board
Extruded PS Board
EPS Board
Fiberglass Board
Fiberboard
Plywood
Gypsum (exterior)
Laminated Paper Board
Building Felt
Thickness
(inches)
0.75
0.75
0.75
0.75
1.0
0.5
0.5
0.5
0.5
—
2 Material
Cost Savings
-
0
11
43
-46
24
12
29
22
90
Estimated
R-Value
(75 °F)
6.2
5.4
3.8
2.9
4.4
1.3
0.6
0.5
0.3
0.2
% Increase in
Wall Energy
Losses (75°F;
—
0
10
15
6
25
30
30
31
32
                             166

-------
    c
    O
    s
    u
5
    s
    o
    2
8 -


7 -


6 -


5 -


4 -


3 -


2 -


1 H

o
                  Phenolic      PU     Extruded  Fiberglass
                                         PS        Board
                                        Board
                                                  I
                                                EPS
Flberboard  Plywood
   l          I
Gypsum   Laminated
        Paper Board
                        Figure 8-4.  Equivalent thickness for various materials (at 24°C (75 F)  mean
                                     temperature).  All values are relative to 0.75 inch laminated PU board.

-------
and sheathing.  Depending on the wall thickness,  this  material  gives wall
R-values of R-22 to R-30 (37).

Other Building and Industrial Insulation

     Industrial and commercial roofing insulation as well  as  residential
insulation comprise nearly 90 percent of the polyurethane  and polyisocyanurate
foam building insulation market.  The remaining 10 percent is used  in a
variety of applications such as commercial cavity walls, curtain walls,
commercial metal buildings, farm buildings, and cold storage  facilities.   The
contributions which FU foam makes to total insulation  value of  each of these
installations are shown in Table 8-6.  In addition, FU sprayed  foams are  often
used in industrial applications such as storage tank and pipe insulation.   The
use of suitable alternatives in these applications would incur  energy losses
proportional to those shown in the previous sections unless greater
thicknesses are used.

Alternative Refrigerated Appliance Insulation

     Currently, rigid FU foam insulation is used  in a  majority  of refrig-
erators and freezers.  In 1982, polyurethanes held approximately 65  to 75
percent of the refrigeration insulation market  (16).   This market share is
expected to increase further as demand for higher energy efficiency  appliances
grows.   California and several other states have,  or will  have, laws requiring
appliances be more energy efficient in the near future.  These  laws,  if imple-
mented, argue against many of the available insulating materials, or,  con-
versely, will result in thicker walled appliances with significant  loss in
usable capacity.   The advantages of FU in this application area are:

     •    Its high R-value allowing thinner walled appliances,

     •    Ability to be used in pour—in-place applications.
                                      168

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          TABLE 8-6.  CONTRIBUTION TO TOTAL INSULATION SYSTEM MADE BY
                      PU FOAMS IN VARIOUS APPLICATIONS
                                                              Contribution
Application                                               To Total Insulation


Commercial Cavity Wall                                             76%

Commercial Curtain Wall                                            42%

Commercial Metal Buildings                                         90%

Farm Buildings                                                     90%

Cold Storage Buildings                                             95%
                                     169

-------
     •    Structural strength contributed to the appliance, and

     •    Moisture resistance.

     In the past, refrigeration appliances were insulated exclusively with
 iberglass.  Presently, only 20 to 30 percent of the refrigeration insulation
 ised is fiberglass (16).  Based on current trends, refrigeration unit
 lanufacturers would revert to the use of fiberglass only if there were no
 ?ther technically feasible alternatives.

     From the manufacturing standpoint, the increased labor cost of installing
 fiberglass insulation balances against the higher material costs for foam
 Insulation (16).  However, for a given wall thickness the fiberglass insulated
 anit will necessarily consume more energy.  The same holds true for other
 potential alternatives such as extruded PS board or expandable bead PS board.
 Table 8-7 shows the relative costs associated with alternative insulation
 naterials for a typical refrigerator.  Expandable PS and extruded PS board
 Doth are more difficult to install than fiberglass.  However, they have better
 insulation properties.

      TABLE 8-7.  RELATIVE COSTS OF ALTERNATIVE REFRIGERATOR INSOLATIONS3
                   Rigid    Extruded   Expanded
                  PU Foam   PS Foam    PS Foam   Fiberglass
Material Cost
Labor Cost
Energy Cost
1
1
1
1
4
1.4
1
4
1.9
1/3
3
2.3
 Assuming no change in the dimensions of the appliance cabinet.
Source:  (16)
                                      170

-------
     Changing to an alternative insulation requires balancing the manufactur-
ing costs against the energy costs.  Using an alternative insulation without
altering the appliance's wall thickness reduces the material costs, minimizes
the increase in labor costs, allows the manufacturer to use an existing
appliance line, and does not alter the cold storage volume available to  the
customer.  However, the customer will pay more in energy costs because the
unit is not as well insulated.  On the other hand, if the wall thickness is
increased to provide equal insulation, the energy costs will be the same, but
the manufacturer must redesign and retool for an entirely new appliance.  In
addition, a complete redesign may be required since FU foam provides 80—90
percent of the structural support in present-day appliances.

     As a result of more stringent appliance energy standards, an emphasis has
been placed on new materials and designs for refrigeration systems.  Re-
searchers are currently devising ways to increase the efficiency of re-
frigeration units to conserve energy.  New materials such as vacuum board
panels are being considered, as well as new cabinet designs.
                                       S
Alternative Transportation Insulation

     In the transportation business, poured and sprayed FU foams serve as
insulation for refrigerated truck trailers, rail cars, tank cars, barges and
ships.  Since these are essentially mobile refrigerators, much of the
discussion of refrigeration insulation applies here.  Polyurethane foams
endure very well the vibration and shocks associated with transportation, and
they also contribute structural support by adhering to the walls.  The
alternatives such as fiberglass, EPS, or extruded PS will require thicker
walls or higher refrigeration costs.  Additionally, fiberglass batts will tend
to collapse due to vibration and absorb H_0 if walls are damaged  (16).

     If the thickness of the walls is increased, then the space available for
freight decreases, and the weight of the vehicle increases.  Otherwise,  the
wall thickness can be maintained and the cooling costs are higher.  Both
options result in a net increase in transportation costs, and switching  to an
alternative such as extruded or expandable polystyrene will require optimiza-
tion to minimize the increased cost.

                                      171

-------
Alternative Packaging Materials

     In packaging applications, pour—in-place polyurethane foams are widely
used.  Their ability to fill non-uniformly shaped voids, ease of use,
availability in a range of compressive strengths, light weight, and creep
resistance make them suitable for a wide range of packaging applications.

     A unique use for these foams is for one-time packaging or for packaging
of odd shaped.items which require rigid support.  For these applications,
alternative materials such as preformed rigid packaging might be expensive or
provide inferior protection.

     For regularly shaped items or items not requiring rigid support, there is
a wide variety of packaging alternatives such as non-CFC blown loose-fill
expanded polystyrene, shredded and wadded paper, cellulose wadding, die-cut
cardboard, wood shavings, pre-formed expanded polystyrene packing blocks, and
plastic film bubble wrap.

     Packaging is a custom operation and the packaging material chosen re-
flects the specific needs of the packer.  However,  the ease of use of poured
foam systems has probably encouraged use in "non-essential" applications where
other packing materials would be just as suitable,  albeit at possibly higher
aaterial or labor costs.

ALTERNATIVES TO CFC BLOWN POLYSTYRENE FOAM PRODUCTS

     Since the 1960s, polystyrene foam sheet products have gradually replaced
competing products fabricated from traditional materials.  The benefits  of
polystyrene foams such as light weight, strength, ease of forming, moisture
resistance, low cost, and thermal insulation properties have spurred this
growth.  Not only are foam producers increasing  service to existing markets,
:hey are working to penetrate new areas such as  salad trays for self-service
supermarket salad bars, pizza boxes, ice cream containers, and reheatable
packages for use in microwave ovens (9).  With few  exceptions, the polystyrene
                                       172

-------
 foam  serves essentially the same purpose as the material it  replaced.   Indeed,
 in many  applications,  polystyrene and its competitor can be  found in use
 side-by-side.   An  example is egg cartons.  In many stores one  can find both
 paper and polystyrene  egg cartons in the same display case.

      A distinction should be drawn here between CFC blown polystyrene  foam
 sheet and non-CFC  blown PS foam sheet.   CFC blown foams comprise  only  50
 percent  of the  PS  foam sheet market,  and the remainder of the  market is held
 predominantly by hydrocarbon blown foams.  Therefore, in considering
 alternatives to CFC blown PS foam sheet,  a suitable substitute is foam
 produced with hydrocarbons.   In each application of polystyrene foam
 materials,  there can be found a variety of suitable substitutes.   These
 application areas  include:   stock food  trays;  egg cartons; single service
 plates,  cups, and  bowls;  hinged containers;  and insulation board.   Table 8-8
 lists specific  alternatives  to CFC-blown polystyrene foam products in  several
 application areas.
                                      r<
      The following sections  discuss the applicability of various  substitutes
 for CFC  blown polystyrene foam products.   Since it is not known to what extent
 specific PS-foam sheet products are blown with hydrocarbons, this discussion
will  simply examine suitable replacements for the foam products regardless of
 the blowing agent  used to fabricate them.

 Stock Food Trays

      Polystyrene sheet has found wide use as a packaging tray  for meats and
 produce.  Because  it is stiff,  light  weight,  and waterproof, polystyrene foam
 trays are particularly well  suited for  packaging flaccid and irregularly
 shaped meats.   In  the  past,  stock food  trays were composed of  paper fiber
materials which became soggy and weak and they absorbed the juices from the
meat.  However, currently available plastic  laminated paper products should
not have  this drawback.   Solid plastic  trays can also serve the same purpose,
but they  are heavier (using  more plastic) at an equivalent strength to foams.
                                      173

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 Application
 Alternatives
Thennoformed  Sheet:
      Stock Food Trays
     Egg Cartons


     Single Service Goods:

     Plates. Cups, and Bowls
     Hinged Containers
Board Stock:

     Insulation Sheathing
 Hydrocarbon  Blown  PS
 Solid  Plastic Trays
 Plastic Film Wrap
 Plastic Bags
 Coated Paper Trays
 Butcher Paper
 Controlled Atmosphere
 Packaging

 Hydrocarbon  Blown  PS
 Paper
Hydrocarbon Blown PS
EPS
Paper
Solid Plastic

Hydrocarbon Blown PS
Paperboard Containers
Solid Plastic Containers
Paper Wraps
Foil Wraps
Plastic Wraps
Combination Laminated Wraps
-See Polyurethane Insulation
    Sheathing Alternatives-
    CFC Emission
Reduction Potential
     100%
     100%
     100%
     100%
     100%
     100%

     100%

     100%
     100%
     100%
     100%
     100%
     100%

     100%
     100%
     100%
     100%
     100%
     100%
     100%

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Other potential replacements for foamed polystyrene stock food trays are
plastic film wrap, heat sealed plastic bags, or butcher paper (though it
prevents viewing of the product).

     There is a trend in the fresh food packaging industry which might eventu-
ally lead to a great reduction in the use of polystyrene foam stock food
trays.  This trend is towards a new packaging method called controlled atmos-
phere packaging (CAP).  In CAP, the product such as a cut of red- meat is
sealed along with an inert atmosphere in a plastic tray.  The tray and its lid
are composed of a barrier plastic which prevents exchange of gases.  The
result is a greatly extended shelf life.   Another possible benefit of this
technology is that it would allow centralized packaging.  This could provide
substantial savings over the current in—store preparation and wrapping methods
which employ polystyrene foam trays and plastic wrapping film.  In a recent
trial of CAP red meat packaging in 86 of its stores, Kroger Company, a
Cincinnati-based supermarket chain said that it achieved a six to ten cent per
pound overall cost savings (40).

Egg Cartons

     Retail egg packaging, once the exclusive domain of paper fiber egg
cartons, has seen a large increase in the use of polystyrene foam egg cartons.
Interestingly, paper egg cartons whose market share with the major grocery
chains had fallen as low as 5.5 percent, have recently seen a comeback.  The
current market share for paper cartons is estimated at 65 percent.  Although
the cost of each of the cartons is roughly equivalent, the reason for this
turnaround is increased aggressiveness by the paper industry.  Armed with
research results showing that paper egg cartons incur one-third the egg
breakage of plastic cartons, the marketers of paper cartons have been working
to regain more of this market.  While the makers of polystyrene foam materials
stress visual appeal and moisture resistance, the paper industry's research
indicates that the customers' only real concern when buying eggs is that none
of them be broken (41).
                                      175

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'lates.  Cups,  and Bowls

     Polystyrene-foam plates,  cups,  and bowls consume one-third of all the
ixtruded PS-foam sheet produced.   All of these products have viable paper or
>lastic  alternatives which are currently available and competing in the
larketplace with PS—foam products.   The major benefits of extruded PS foam are
.ts  high strength to weight ratio, thermal insulating properties, and low
:ost.

     In  the plate market,  PS-foam products compete against both the inexpen-
;ive common paper plate and the thicker more expensive paper plates such as
3iinet*  dinnerware.   Laminated paper plates and solid plastic plates are also
:ompeting in the market place.  Table 8-9 compares retail costs for a variety
>f single—service plates.   One company,  James River Corporation, markets under
:heir Dixie Division both coated  paper and polystyrene—foam plates at very
limilar  prices.   This indicates the  suitability of paper as a replacement
laterial.  Just  as with disposable plates, the disposable bowl market is
.ivided  among  paper,  laminated paper,  foamed polystyrene, and solid plastic
•roducts.

    The major contender for replacing extruded polystyrene foam cups is
ixpandable bead  polystyrene cups.  These cups are readily available and have a
arge share of the disposable  cup market.   Like PS-foam sheet cups, they have
pod insulation  properties  as well as  being lightweight and sturdy.  Where
hermally  insulating  cups are  not required, there are available a number of
olid plastic  cups as well  as  paper  cups.

inged Containers

    The hinged  polystyrene-foam  take—out tray was pioneered by McDonald's
orporation and  is now widely used throughout the food industry.  These
ontainers have  seen  a tremendous growth,  and innovative applications such as
'cDonald's McD.L.T.•  will add to  this  trend.   McDonald's aggressive
                                     176

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TABLE 8-9.   RETAIL COSTS FOR A VARIETY OF SINGLE SERVICE PLATES
Manufacturer
                                           Retail Cost (c/Plate)
Brand Name
PS-Foam  Solid Plastic
                                                                Paper
Mobil


James River Corp.

Keyes Fiber

Solo Plastic Cup Co.

Generic
Hefty* (plain)
(Printed)

Dixie* (Printed)

Chinet* (Printed)

Solo* (Printed)

Paper (Plain)
  2.5
  4.5

  3.4
               5.6
                                                                 3.3

                                                                 5.5

                                                                 —

                                                                 1,3
                              177

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 advertising campaign for  the McD.L.T.®  is  essentially based on the thermal
 insulating properties  of  polystyrene  foam  and on the package's design which
 allows  separation of a hamburger's  hot  and cold elements.

      Some of the advantages provided  by hinged polystyrene-foam containers  are
 thermal insulation, time  savings for  food  service employees,  impermeability to
 moisture, strength, light weight, and visual  appeal.   These containers have
 good  visual appeal because they can be  colored and printed, and they do not
 become  soggy and wrinkled as would  a  paper wrap.

      Substitutes for these hinged trays include:   non-CFC blown PS foam trays;
 paperboard and solid plastic containers: as well  as laminated paper,  plastic,
 and foil wraps.  All of these substitutes  are widely used in take-out food
 applications.  Burger  King serves a number of its sandwich products in plastic
 laminated paper boxes  which somewhat  resemble the PS-foam enclosures.   Some of
 their sandwiches are also wrapped in  paper.  Other fast  food chains,  such as
 Arby's or Wendy's, serve their sandwich products  wrapped in a foil-laminated
 paper sheet.  All of these products seem to provide the  same essential func-
 tion, so companies have chosen between  them on a  basis of cost, aesthetics,
 and marketing potential.

      Printed or decorated polystyrene-foam hamburger containers are roughly
 equivalent in price to their counterpart laminated paperboard boxes.   However,
both  of these options  are more expensive than simple foil-laminated paper
 sheet wraps (42).

 Insulation Board

     Extruded FS foam board functions primarily as an insulation material.
Like rigid polyurethane foam insulation, PS-foam  is used as frame wall sheath-
 ing, foundation sheathing, and over or  under  roof insulation.   Table  8-10
 shows the market distribution for PS  foam  insulation.  The relatively high
moisture resistance of PS foam gives  it added usefulness for  below grade
                                      178

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        TABLE 8-10.  1985 MARKET DISTRIBUTION FOR EXTRUDED POLYSYTRENE
                     INSULATION FOAMS
    Market
Market Distribution
     (Percent)
Industrial and Commercial Roofing

New Residential

Retrofit Residential

Masonry Wall

Farm Buildings

Non-Residential Retrofit

Miscellaneous
        35

        24

        10

        25

         2

         3

       	1
       100
Source:  (48)
                                      179

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insulation applications  for basements,  foundations, and  earth—sheltered homes.
Materials which  compete  with  PS  foam  in the  insulation market  are:  fiber-
glass,  fiberboards,  expandable polystyrene foam  (EPS), and  rigid  polyurethane
foams.

     The alternatives  to rigid polyurethane  foams which  were discussed earlier
in this section  also apply to extruded  PS foams.  Again,  options  involve
tradeoffs between  energy, materials,  and labor costs.  This is because, with
the exception  of rigid polyurethane and phenolic foams,  alternatives to
extruded PS foams  have relatively  inferior insulating properties.

     One candidate for replacement of extruded PS foam is expanded polystyrene
board.  This substitute  already  competes in  the insulation  market and uses no
CFCs.   Its thermal resistance per  inch  of thickness is approximately 24
percent lower  than that  of extruded PS  foam, but when installed as sheathing
in a wall system,  for  example, the total wall R-factor would be only five
percent lower  than that  of a  similar  wall system using an equal thickness of
extruded PS foam sheathing.   A further  illustration of the  potential for
substituting EPS for extruded PS insulation  is that one-inch-thick EPS has an
R-factor of about  3.8, and three-fourths-inch thick extruded PS has an
R-factor of about  3.8.   Therefore, at a slight increase  in  material cost,
there is equivalent  energy and labor  costs with 100 percent reduction in CFG
emissions.

ALTERNATIVES TO  OTHER  CFC BLOWN  FOAM  PRODUCTS

     Phenolic foam is  used primarily  as  an insulation material.  Like rigid
polyurethane foam  insulation, phenolic  foam  is used as frame wall sheathing
and over or under  roof insulation.  Phenolic foam currently hold an 8 percent
share of the total roofing and sheathing insulation market  (50).  The
alternatives to  rigid  polyurethane foams which were discussed  earlier in the
section also.apply to  phenolic foam.
                                      180

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     Polyolefin foams are used primarily for cushion packaging and surface
protection.  This market is  a complex and diverse one where  selection of  the
material of choice is often  difficult.  For one-time packaging or for a
delicate packaging requirement, alternative materials may not be able to
provide adequate protection.  This is especially true where  polyethylene  foam
plank is used since it represents one of the highest performance materials
used in cushion packaging.

     In other instances, a wide variety of packaging alternatives such as
non-CFC blown expandable PS  foam, wood shavings, pre-fearned  expanded
polystyrene packing blocks,  and plastic film bubble wrap can be used as
alternatives to polyolefin foams.

     Although polyolefin foams are one of the most costly packaging materials
used, on a volume basis, the physical attributes of these foams often make
them the most cost effective when all possible factors are considered.
                                      181

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                                   SECTION 9
                        ADDITIONAL CFC CONTROL METHODS

     There are alternative methods for reducing the CFC emissions associated
with rigid polymer foams.  These methods are either developmental or  require
further investigation to assess their suitability.  For rigid polyurethane
foams, one CFC reduction approach which warrants further  research is  the
recovery of CFCs from foam-containing products prior to their disposal.  For
nonpolyurethane foams a CFC emission control technology which has potential is
the use of blowing agents which are neither CFCs nor hydrocarbons.

RECOVERY OF CFC-11 UPON PRODUCT DISPOSAL

     In rigid polyurethane foams, CFCs have a very low diffusion rate;  there-
fore, the blowing agents are banked for extremely long periods of time.  This
fact gives rise to the possibility of recovering the CFCs at  the time of
disposal of the foam containing product.  Application areas in which  it might
be possible to recover CFCs upon foam disposal include refrigerated transport
vehicle insulation, building and home insulation, and refrigerated appliance
insulation.  While it may be possible to recover CFC-11 from  these insulation
foams, it is probably not economical as long as the value of  CFC-11 is less
than one dollar per pound.

     Refrigerated transport vehicles such as ship and barge containers, truck
trailers, tank trucks, tank cars, and boxcars probably offer  the best opportu-
nity for CFC recovery.  When a particular transport vehicle reaches the end of
its useful service life, it could be transported to a recycling facility which
would be capable of processing both the scrap metal and the CFC-containing
foam insulation.  At the recycling facility, the foam would be pulverized to
release the blowing agent which would then be recovered in a  carbon adsorption
system.
                                      182

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     The economics of recovery or destruction of the 18 to 36 kg  (40 to 80
pounds) of CFCs in these vehicles would benefit from the simultaneous recovery
of recyclable scrap metal.  The ownership of these types of vehicles is
somewhat consolidated (more so than for privately owned refrigerators), so
collection of the units is relatively simple.  Also, the vehicles are mobile
and can be moved easily to a central recovery facility.

     Another area in which there is some potential for disposal recovery is
demolition of commercial and residential buildings which are insulated with
polyurethane foam.  The recovery method here would be similar to that in which
asbestos-containing materials are removed from buildings which are being torn
down.  The polyurethane foam sheathing and roofing would be removed with care
being taken not to cause excessive damage to the foam, and then it could be
transported to a facility in which the CFCs would be released by crushing the
foam and then recovered through carbon adsorption.

     The economics for this method of CFC-11 emission control would be less
favorable than for transportation insulation because of the added labor and
transportation costs.  The insulation foam used in a 2000 square foot home
would contain approximately 23 kg (50 pounds) of CFC-11, while a large
building or apartment complex would contain much more.  Also, the
applicability of this method has two major limitations.  First, the buildings
would have to be dismantled piecemeal rather than demolished, and second, most
structures which contain polyurethane insulating foams are relatively new, and
are therefore still serving a useful purpose.

     Another possibility for disposal recovery of CFCs is refrigerated appli-
ances.  Typically, these appliances have lives of nearly 15 years, and at the
end of their useful life, are disposed of in a variety ways.  Often, old units
are buried or left to decay at a dump site.  In other cases, the merchant who
supplies a new appliance will take the old unit to a salvager who removes the
refrigeration equipment (motor, compressor, condenser, and evaporator) for
their scrap value.  The cabinet is then compacted and buried in a landfill.
                                      183

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     A typical refrigerator  contains  less  than two  pounds  of  CFC-11  in  its
insulation foam; therefore,  for  a  recovery operation  to  be efficient, large
numbers  of refrigeration units would  have  to be collected  centrally  and
crushed  in a compactsr which is  equipped with a carbon adsorption  recovery
unit.  Because of the costs  which  would be incurred in transporting  these
appliances to a central  recovery facility,  this control  does  not appear to be
economically feasible.

USE 01 NON-CFC, NON-HYDROCARBON  BLOWING AGENTS FOR  NONPOLYURETHANE FOAMS

     Nonpolyurethane foams emit  most  of their CFCs  prior to disposal;
therefore, reduction of  emissions  from the product  and the manufacturing
process  is the best approach to  CFC emission control.  This can be
accomplished through the use of  non-CFC containing  blowing agents.   The use of
hydrocarbon blowing agents is discussed in Section  6  of  this  report; however.
this technology presents fire hazards and  is vulnerable  to regulations  on VOC
emissions.  Carbon dioxide and nitrogen are potential  blowing agents which
might reduce both CFC and VOC emissions.

     These gases are auxiliary blowing agents which may  be used with either
CFCs or  hydrocarbons for nonpolyurethane foam manufacturing.   The  result is a
reduction in use, and therefore  a  reduction of emissions,  of  CFCs  or
hydrocarbons.  There is  also a cost savings because these  gases are
considerably .cheaper than the blowing agents they substitute.  Carbon dioxide
(about $0.10/lb). for example, may be blended in concentrations up to 15 to 25
percent with CFC-12 ($0.74/lb) when used with a system using  about five to
seven percent CFC.  It is reported that European processors have used blowing
agent blends containing  up to 30 percent CO..   jn addition to lower  costs.
another benefit contributed  by CO- is an improvement  in  surface sheen.

     Currently, solubility problems prevent the use of 100 percent CO.  as a
blowing  agent for low density foams.   Carbon dioxide has a low solubility in
the molten polymer resin, and the  miscibility of CFC helps to solubilize the
                                       184

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CO„ in the polymer melt.  Also, because carbon dioxide has less of a
plasticizing effect than CFC, higher extruder temperatures are required for
operation.
                                      185

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                                  REFERENCES

1.   Production Sales, and Calculated Releases  of  CFC-11 and CFC-12 Through
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                                   186

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14.   Gordon, J.B.  Foam Processing - Expandable Foam Molding.  Modern Plastics
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                                       187

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32.  Radian Corporation.  Technical Note:  Proposed Conceptual Design to
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                                      188

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48.   Written communication from Jim Walters Corporation Research, January
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                                      189

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