United States        Air And  •         EPA 400/3-90-003
            Environmental Protection    Radiaiton          March 1990
            Agency          (ANR-445)
c/EPA      Manual Of Practices
            To Reduce And Eliminate
            CFC-113UselnThe
            Electronics Industry
                                         Printed on Recycled Paper

-------
                                  MANUAL OF PRACTICES

                               TO REDUCE AND ELIMINATE

                        CFC-113 USE IN THE ELECTRONICS INDUSTRY
                                             by:
                                 Arthur D. FitzGerald, P.Eng.
                                    Murray D. Brox, P.Eng.*
                                  Stephen O. Andersen, Ph.D.
                             U.S. Environmental Protection Agency
                                        January 1990
 Arthur FitzGerald and Murray Brox are employed in the Mississauga, Ontario, Canada office of
Northern Telecom.  Contributing authors were Sudhakar Kesavan and Farzan Riza of ICF Incorporated,
Washington, D.C. We would like to thank the many individuals who provided insights and information
that helped to produce this manual, particularly Joe Felty of Texas Instruments.  This handbook was
funded by U.S. EPA and Northern  Telecom.

-------
                                           Disclaimer
        Northern Telecom and the U.S. Environmental Protection Agency do not endorse the cleaning
performance, worker safety, or environmental acceptability of any of the technical options discussed.
Every cleaning operation requires consideration of worker safety,  proper disposal of contaminants, and
waste products generated  from cleaning processes.  Moreover, as work continues, more information on
the health and safety of the alternatives will become available for use in selecting among alternatives
discussed in this document.

-------
 FOREWORD
                                                                                          Page 1
 The  Montreal   Protocol  on  Substances  that
 Deplete the Ozone Layer restricts the production
 and  consumption  of  some  ozone-depleting
 chemicals.  Chlorofluorocarbon  (CFC)   1,1,2-
 trichloro-l,2,2-trifluoroethane, commonly referred
 to as CFC-113, is one of these chemicals. Recent
 scientific  evidence suggests  that  the measures
 outlined in the Montreal Protocol to reduce the
 production of CFCs  to  50 percent  of the  1986
 levels by  1998 will not  be sufficient to prevent
 further  depletion of the stratospheric ozone layer.
 This  has  led  some  member  nations  to  the
 Montreal Protocol to  call  for a complete  phase
 out  of  CFCs by  year 2000.   There is a good
 possibility of this happening.

 The  time  has  come  to  seriously  consider
 alternatives that could be used to replace the use
 of  CFC-113  in the  electronics industry.   The
 situation provides us with a unique opportunity to
 rethink   and   reevaluate  the  processes  and
 technologies that have been used for decades.  It
 is a time to  innovate and  commercialize new
 technologies and  processes. The inevitable price
 increases  in CFC-113  as production drops may
 create a  de  facto  situation  in which CFC-113
 becomes economically less  desirable  and a more
 rapid phase out of CFC-113 may occur than is
 currently  foreseen.     Thus,  processes  and
 technologies   that  currently  do    not   seem
 economically viable might become cost competitive
 or economically more attractive than current CFC-
 113 processes.

 You, as a manufacturer of  printed circuit boards
 (PCBs)  and printed wiring assemblies (PWAs),
 need to  quickly find ways to reduce and eliminate
your  use  of CFC-113.   You can  meet  these
challenges through conservation programs followed
by adoption of one or more choices  of alternate
 technologies.

In response to this important CFC issue and the
need to  identify and develop alternative strategies
to reduce the use  of CFC-113 in  the electronics
industry, Northern  Telecom and  the U.S. EPA
have undertaken a joint program to provide users
 of CFC-113 with help to reduce and/or eliminate
 the use of CFC-113.  This effort  resulted in  the
 publication  of this manual, which is intended to
 provide company personnel involved with the CFC
 issue   with  guidelines   and   strategies  to
 minimize/eliminate   the   use   of   CFC-113.
 Information provided in this manual is based on
 practices  that have  been adopted  at  Northern
 Telecom,  and it is intended that  the procedures
 and  practices adopted by Northern Telecom will
 serve  as  an  example  for  plant  personnel in
 companies worldwide.

 This manual of guidelines takes  you through a
 simple structured program.  It focusses first on
 conservation programs where reductions of up to
 70-85 percent of your current use can be attained.
 Then it outlines for you the alternate technology
 and process  options that are available to eliminate
 the  remainder of your  CFC-113 use.   North
 American use of  CFC-113  in PCB and  PWA
 manufacturing appears to  be in the order of 2.0
 kg/m2   of  boards   produced.    Simple  and
 inexpensive  conservation techniques will reduce
 this  use by  40-50 percent, and the  addition of
 solvent vapor  carbon adsorption  will net  an
 overall  reduction  of  up  to  80-85   percent.
 Alternate  technologies such as aqueous cleaning,
 low solids fluxes/"no clean" assembly, controlled
 atmosphere   soldering,   alcohols   and
 hydrochlorofluorocarbons    (HCFCs),   and
 hydrocarbon/surfactants   will   be   needed  to
 eliminate the remaining 15-20  percent.

 Although  this manual  will  primarily  benefit
 manufacturers of PCBs  and PWAs,  others who
 process small electronic parts, for example, will
 also  find this manual helpful.

 The success of your CFC-113 elimination program
will depend  upon how effectively you coordinate
your  program.   Management commitment is
needed at all levels.

-------
                                                                         Page 2

STRUCTURE OF MANUAL
        This manual is divided into the following sections:

        •   Process Characterization;  In this section, it is stressed that you need
            to understand how you manufacture your product (design, assembly,
            soldering,  and cleaning), and where and how CFC-113 is used in this
            process;
                                                                            . I
        •   Conservation Practices & Strategies; In this section, discrete
            conservation projects are ranked so that you can choose the project(s)
            that will give you the biggest reduction of CFC-113 for the least
            amount of time and money;

        •   Non-CFC  Processes;  This section presents the choices of alternate
            non-CFC processes and technologies; and

        •   Methodology to Select Non-CFC Processes; This section outlines a
            methodology for the decision making criteria that can be used to select
            a non-CFC process.

-------
                                                                     Page 3

REQUIREMENTS  FOR PROGRAM  SUCCESS
    You can reduce the use of CFC-113 by up to 70-85 percent in your cleaning
    processes through conservation, and you can eliminate the remainder by
    adopting technologies that are now available.

    This program will only be successful if you:

      •     gain management commitment at all levels and all functions;

      .     make your staff aware of and get them involved in the program;

      •     understand how and where you use CFCs;

      .     identify individuals who will monitor the program and be responsible
           for its implementation through to completion;

      •     adopt conservation programs;

      .     set realistic targets and achieve them; and

      .     evaluate and adopt non-CFC processes.

-------
                                                                                        Page  4
PROCESS  CHARACTERIZATION
To develop an effective program to reduce and
eliminate CFC-113 use, it is vital that you develop
a good knowledge of your plant operations.
     Understanding Plant Operations:

     • Who purchases CFC-113?

     • Who takes delivery?

     • How it is handled from arrival to
       ultimate use?

     • How it is CFC-113  used? and

     • Where do losses take place?
Have the manager of your CFC-113 elimination
program  start with  a  survey.   A copy  of  a
questionnaire  that can be  used is  shown  in
Fjdiibits 1 and 2.  This survey form should be sent
to individuals in different plant locations who are
responsible for,  and  who understand, Material
Safety Data Sheets (MSDS).  All MSDS should be
checked for  l,l,2-trichloro-l,2,2-trifluoroethane
(CFC-113)  to help  identify the  trade  name.
Identify the quantities  bought in the previous
calendar year and  start reporting on a  regular
basis (monthly or quarterly).

The following steps should then be followed:

(1)    For a given  time period (year,  quarter,
       month) determine total  production  of
       boards in square meters of surface area.
       Only measure the area of one side of the
       board regardless of whether it is single
       sided,  two sided, or multiple layer  in
       configuration.

(2)    Now you can, for a given  period of time,
       divide   total   quantity   of   CFC-113
       purchased by total manufactured board
       area for the same period to determine the
        ratio of kilograms of CFC-113 used per
        squaremeter of board produced, expressed
        as kg/m2.

In North American industry this ratio appears to
be in the order of 2.0 kg/m2 for a  production
facility  operated  with today's  technology  and
minimal  attention   to   chemical   handling.
Determine your ratio  first before you start your
conservation and elimination programs.
     At this point you have to make the
     following decision:

     • If you are already at 0.5 kg/m2 then
       you likely have good conservation
       practices in place and  you will be
       ready to focus more of your time
       and effort on exploring alternate
       processes and technologies.

     • If your ratio is  higher  than 0.5 kg/m2
       you can benefit from conservation
       programs.
Calculate this  ratio and report it on  a  regular
basis - monthly is recommended.  It is important
because you will be able to monitor success as
your conservation programs  go into effect, and
your  employees  will  take  an  interest  and
participate  in  the drive  towards reaching the
objectives of reducing CFC-113 use.

Next,  do an assessment of where you are losing
CFC-113.  Do  this for the whole plant beginning
with the delivery of CFC-113.  You may wish to
develop a  simple  flow schematic as is  shown in
Figure 1. This  will give your project manager and
your technical staff an understanding of the areas
to focus on first.  If you  have more  than one
cleaning machine  you should do an analysis of
each since CFC-113 losses  may vary significantly
from machine to machine.

-------
                                                                                  Page 5
With your knowledge of consumption and where
your losses are occurring you can now select the
appropriate  conservation programs.  These are
described in the next section.
                  Figure 1: CFC-113 LOSSES IN A TYPICAL PLANT
                     Evaporative Losses
                           .1%
                                         Evaporative Losses,   Drag Out   Evaporative Losses,
                                         Seals, etc.    12%    40%        Seals, etc.   2%
Still
Process
 Solvent
                                                              3%
                                                          Spills, Leaks
         18%
       Recycle
                                                                  15% Evaporative Losses
               Holding
                Tanks

-------
                                                                                   Page 6
                           EXHIBIT 1. CFC USAGE PROFILE
A.  Identification
Name of Product:
Manufacturer:
Purchase Number: 	
CFC Components:
                         Chemical Name        Percent or Concentration
          1.  	     	
          2.  	     	
          3.  	     	
B.  Quantification of Usage Patterns
Quantity Purchased:  (please specify units)
   1988:  	           1990:  	
   1989:	1991:	
C.  CFC Disposal Practices
                                  1988        1989        1990        1991
Annual quantity shipped out
as waste for disposal:
  (please specify units)           	    	    	    	
Annual disposal costs:            	    	    	    	
Annual quantity shipped out for
reclamation:  (specify units)       	    	    	    	
Annual cost of reclamation:       	    ___^    	    	
Annual quantity lost to the
environment: (specify units)
  Through leakage:
  Through spillage:
  Through testing:
  Through drag-out and
  evaporation:
  By other means (specify)

  Unaccounted for:

-------
                                                                                 Page 7
       EXHIBIT 2. PRINTED CIRCUIT BOARD CLEANING EQUIPMENT PROFILE
A.  Identification

Equipment Name:

Model Number:

Manufacturer:
Year Purchased:
Trade Name of
Chemicals Used:
Annual Quantity of CFC
Purchased for Use in this
Equipment (specify units):
Annual Quantity of CFC Waste
Requiring Disposal or Off-site
Recycling:               	
B.  Equipment Usage Pattern

Annual Board Production
 (please specify units): 	
Average Board Area:
 (please specify units):
Check appropriate blanks:

         Single sided    _
         Double sided   ^_
         Multilayered    _
         Number of layers_

Average Number of Solder
Connections per  Board: 	
C.  Emission Controls

Do you practice the following?   If you do, briefly describe the procedures:
  Leak Testing:
  Alternate Testing Methods:
  On-site Recovery/Recycling:
  Improved Loss Control Procedures:
  Operator Awareness/Guidelines:

-------
                                                                                     Page 8
CONSERVATION  PRACTICES AND  STRATEGIES
Once you have characterized your current use of
CFC-113, you can begin to develop a conservation
strategy. At first, you should choose conservation
options  that are easy to put into place in the
short-term.  These will give immediate results and
will  provide encouragement to  employees  to
continue and accelerate their efforts.
Conservation  practices  are  divided  into  two
categories: in-line cleaning and batch cleaning.
       Operator Awareness of the CFC
       Issue and Training in the
       Handling of CFC-113:

       In general,  it has been found that
       operators are unaware of the
       financial or the environmental costs
       associated with the use of CFCs.
       Increased operator awareness and
       respect for chemicals translates into
       a reduction in consumption,  since
       operating practices and methods can
       usually be improved.

       Operators, once educated, are able to
       change the  methods  and practices.
       For instance: keeping lids and
       windows closed, turning off the
       cleaner when not in use, conducting
       maintenance regularly, and exercising
       care while working with machines
       and equipment.

       You  may also wish to review
       chemical handling procedures and
       restrict access to CFC-113 to a few
       employees.
IN-LINE CLEANING PRACTICES

Choices for in-line cleaning are listed and ranked
starting with the easiest  to  do.  These options
include:

(1)     Examine and Replace, Repair or
       Upgrade the Seals and Gaskets on
       Pumps,  Valves, Pipe Joints,
     .  Covers, Lids, and Elsewhere:

       Pump seals deteriorate  when not  in
       contact with CFC-113. A "running dry"
       condition erodes the  seal surface and the
       seal prematurely fails.

       The design  and maintenance of cleaners
       and stills requires a focus on the seals and
       gaskets on covers, lids, and panels. High
       volume leaks often occur around corners
       and joints where two seals meet.

       Check  for  compatibility  of  new and
       replacement materials.

(2)     Reduction of Air Currents:

       Excessive  air  currents  outside  in-line
       solvent cleaners disturb the vapor blanket
       within the equipment and losses increase.
       When excessive  air movement  is   a
       problem, remove  the source or consider
       the installation of baffles or partitions on
       the windward side to divert the draft away
       from the cleaning unit.

(3)     Cleaning Machine Optimization:

       Take advantage of services often offered
       by the machine manufacturers; they have
       experience in fine tuning the  cleaner  to
       minimize losses.   You  may wish  to
       complement this with services offered by
       CFC-113  suppliers  who   often  have
       programs and information  that also can
       help operators better manage the process.

-------
                                                                                            Page 9
        In optimizing  the machine,  examine the
        potential for reducing  the conveyor belt
        speed.  This will keep the board in the
        vapor zone longer for more  complete
        evaporation of solvent, thus reducing drag-
        out to a minimum.

        Check all temperature  measuring devices
        and   controls.   Correctly   calibrated
        instruments   will   optimize    machine
        performance and reduce solvent losses.

(4)      Board Cooling:

        Solvent   cleaners   often   are  placed
        immediately   following   wave  solder
        machines.   This reduces the  cooling time
        before  cleaning.   If the  boards  are
        entering the cleaner  at a  temperature
        greater than the vapor temperature, the
        heat will be transferred to the vapor and
        liquid CFC-113.   This creates  a  super
        heated vapor and an elevated temperature
        in the various chambers of the cleaner,
        resulting  in a  less efficient  operation
        which may  increase solvent losses.

        A solution  is to mount small fans  above
        and below the conveyor to cool the boards
        before they enter the  cleaning machine.
        Fans should be directed away from the
        opening(s)  of  the equipment to prevent
        disturbing the vapor blanket within the
        machine which could result  in increased
        solvent loss.

(5)      Board Orientation:

        Orientation of the board plays a key role
        in the volume of CFC-113 dragged-out of
        the cleaners.  In many instances it  has
        been found that CFC-113 adheres to the
        underside of components and connectors.
        This  could   be   minimized   through
        reorientation.

        Reorientation   can   be  as  simple  as
        changing the method by which  the boards
        are processed.  This  may require  an
        intelligent   controller  inter-faced with  a
        turntable located after  the  wave solder
        machine.  The  turntable may require a
        faster cycle time to  reduce the adverse
        effects on production.

(6)      Solvent Recycling:

        CFC-113 often  is  used to clean  flux
        residue  from washers  and  stills  when
        preventative maintenance is carried out.
        External reclamation and recycle facilities
        are often available which will provide a
        reclamation and reconstitution service for
        this contaminated solvent. You may have
        the choice  between  having  the solvent
        returned to you for  re-use  or  receiving
        credit with   the solvent  being  made
        available for resale to others.

(7)      Filter Improvements:

        Original filters  reach  the  limit of  their
        usefulness relatively quickly under normal
        operating conditions.  The use of more
        effective filters  results in fewer changes
        over  time and less solvent loss.

        For example, the use of an engine oil
        filter and a pump can filter out additional
        impurities   in  the  solvent  distillation
        process.  This can be used to increase the
        time  between preventative maintenance
        requirements, which   in turn decreases
        solvent losses.

(8)      Machine Rationalization:

        Consider using   one  solvent cleaner to
        handle  the boards  from  two or  more
        solder machines.  Large losses  are  seen
        in cleaners  that are  under  utilized  and
        have  an extended idle  mode  or  cycle
        through frequent start-ups and shut-downs.

        This  will require reworking equipment
        placement, conveyor lines, controllers, and
        other features.   If  successful,  benefits
        include not only reduction  of losses of
        solvent  but  also  removal  of  extra

-------
                                                                                          Page  10
        equipment with a reduction in operating
        and maintenance costs.

(9)     System Enhancements:

        There are a number of enhancements that
        can be made to the solvent cleaner which
        you may wish to consider.  These  are
        hardware add-ons  or  modifications that
        require capital expenditures and are  not
        the   machine   optimization   aspects
        previously described. System  enhancements
        include:

        •  increased freeboard height;
        •  increased cooling system compressor
           capacity; and
        •  additional cooling coils  on inlets and
           outlets.

        Cleaner  manufacturers  and  experts  in
        chilling/refrigeration should be consulted
        for their expertise.  Consider reviewing
        the condensing effectiveness  of your
        chiller/refrigeration  system  with   the
        assistance of a knowledgeable contractor.
        Improved condensing  efficiency through
        additional  cooling  coils at  the entrance
        and exit  of the wash and perhaps through
        compressor    resizing   will   reduce
        evaporative and drag-out solvent losses.

        Use  gas  detectors   to  give  accurate
        information on where  leaks are and how
        effective your efforts are.

(10)     Bulk Solvent  Handling:

        A bulk CFC-113 handling system, shown
        in  Figure 2, reduces CFC-113 losses  in
        drum  handling, in  transferring to  small
        containers,  and in filling  the  cleaners.
        With  appropriate  real  time  alarms,
        personnel  are alerted  to possible leak
        conditions by  monitoring consumption or
        loss in  each cleaner as  CFC-113  is
        supplied.

        Solvent is delivered by bulk  tanker and is
        then pumped into a  bulk  storage tank
       where it is held until needed.  The tank
       is non pressurized and,  in the example, is
       within  the  plant.   Distribution  to the
       cleaners is provided through a series of
       pumps  and PVC  pipes.  Therefore, the
       system eliminates  all manual handling of
       CFC-113 and minimizes losses.  Control
       is  provided   by  float   switches  within
       individual washer  units.

       A microprocessor  can be used to monitor
       the consumption of CFC-113.  This allows
       for daily  collection of consumption data
       for each cleaner.  The computer also can
       adjust  for  excessive   consumption.  In
       addition, if an alarm condition occurs, the
       cleaning system is checked for leaks.

(11)    Solvent Vapor Recovery:

       Drag-out losses are a major contributor
       to the overall loss of solvent in the system
       and vapor  capture systems  should  be
       considered.   These systems adsorb the
       non-polar  CFC-113  molecule  on  an
       activated  carbon  bed,  which  is  then
       extracted by  steam  for blending  with
       additives and re-use in  the system.

       The  intake  and  exhaust  ports   of the
       cleaner are vented to hoods where vapors
       are drawn under negative pressure through
       the activated  carbon bed.   It is  vital to
       properly design the collection hood  at
       the cleaner discharge since this is where
       drag-out  and  drying   losses are  most
       significant.

       Adsorption continues until the carbon bed
       is saturated  at  which  time the  bed is
       steam injected to  strip  off the CFC-113
       for condensing and water separation.

       Three streams are produced: pure CFC-
       113, clean air, and wastewater.   Waste
       water is treated and released to the sewer
       system;  the air is returned to the plant or
       exhausted into the atmosphere; CFC-113
       is reblended/reconstituted with additives
       and reused in the process.  There  will be

-------
                                                                              Page 11
some methanol in the waste water streams
and local legislation should be considered
in specifying equipment.
Systems can be sized  to  suit  large and
small  applications, and one adsorption
system can service more than one cleaner.
In the example developed  in this manual,
four  cleaners  are   handled   by  one
adsorption system.
It should be noted that in this example
the bulk storage tank, the stills, and the
adsorption system are all located  in an
enclosed room.  The  room air itself also
passes  through the  adsorption system
which captures and recycles any fugitive
CFC-113 losses.
             Figure 2: CFC-113 VAPOR RECOVERY SYSTEM
                            SOLVENT LOADED ROOM AIR
VAPOR TANK 3
VAPOR TANK 2
VAPOR TANK 1



STILL 3
ADDITIVE
|
l_
-fcj
                  BLOWER
                                                                              L	
                                                                              UNDERGROUND
                                                                               SPILLS TANK
                                 CFC-113 CONDENSATE TANK
                                 AND RETURN LINE
             CLEAN AIR
             EXHAUST
                                    SOLVENT LOADED PROCESS AIR
                    'I""
                     SOLVENT ROOM
                       ENCLOSURE
             WASH 4

           STAND ALONE
                           WASH 3
                                                WASH 2
                                                                     WASH1

-------
                                                                                          Page 12
 BATCH   CLEANING   OPERATING
 PRACTICES1

 Operating practices that can reduce losses  from
 batch cleaning process are described below.

 (1)     Location of Cleaning System (Air Current
        Reduction):

        As with  the case for in-line equipment,
        batch cleaners should be placed in an area
        that   is   as   draft-free   as   possible.
        Turbulence caused by drafts from adjacent
        windows,   doors,   fans,   unit  heaters,
        ventilators  or spray booths will  greatly
        increase the rate of evaporation of solvent
        vapor.

        To avoid excessive air movement, consider
        installing  baffles  or  partitions on  the
        windward side to divert drafts away from
        the cleaning unit.

        For open-top equipment,  problems  with
        drafts can  be avoided or corrected  by
        using hooded enclosures with automated
        work-handling facilities.

 (2)     Size of Workload:

        Decrease the  loss  of  solvent  vapor  by
        avoiding the processing of workloads that
        exceed  the  cleaning  system's  design
        capabilities.

        A workload that is  too large in physical
        size can displace vapor  from the cleaning
        unit by the  "piston effect."  Losses caused
        this way can be minimized by making sure
        that  the  area of the  workload  is  not
        greater than 50 percent of the horizontal
        cross-sectional area  of the sump  into
        which it is being introduced.
lThis section was prepared using information from
 the DuPont Company
        Also, the introduction of a workpiece that
        is  too   large   in   mass   will  cause
        condensation of  too much of the vapor
        blanket.  This will cause air to  infiltrate
        the cleaner.

        During reestablishment  of the  vapor
        blanket, the infiltrated air saturated with
        solvent vapors will be expelled from the
        cleaning unit.  If this occurs on a regular
        basis, contact the equipment manufacturer
        to determine  if  additional  heating  and
        condensing facilities can be  incorporated
        into the cleaning unit.

(3)      Start-Up/Shutdown Procedures:

        Solvent emissions during start-up can be
        minimized through the following steps in
        the order shown:

        •      Start-up  the  condenser cooling
              system and make sure  that it is
              operating properly.
        •      Start-up  any  auxiliary  emission
              control equipment.
        •      Check and adjust solvent levels in
              all compartments.
        •      Turn-on heaters.
        •      Start-up the spray pumps once a
              stable vapor blanket is established.
        •      Process work pieces only after the
              vapor blanket has been stabilized.

        Use the following steps, in the  sequence
       shown, when shutting down  the  system:

        •      Stop work processing and clear
              the machine of all work.
        •      Turn-off the heaters.
        •      Activate sump cooling coils where
              provided.
        •      Allow   the  vapor  blanket  to
              collapse  completely.
        •      Turn-off  the  condenser cooling
              system.
        •      Close the cover on open-top units.

-------
                                                                                          Page 13
(4)     Consolidation and/or Work Scheduling:

        Start-up always  results  in some solvent
        vapor loss as  air  is purged  from  the
        system.  When the cleaner is used on an
        intermittent basis,  emissions caused by
        frequent start-ups and shut-downs can be
        minimized  by deferring  cleaning until a
        full day's  cleaning work is  accumulated
        for processing.  Thus, there  will only be
        one start-up of the  cleaning  equipment.

        As well, you can reduce vapor emissions
        by consolidating  operations of several
        open-top units into a single, enclosed unit
        designed for continuous operation.

(5)     Positioning Work To Reduce  Drag-Out
        Loss:

        You  can reduce  drag-out losses if  the
        work being cleaned, whether  contained in
        baskets, suspended from hooks  or racks,
        or conveyed on a belt, is always positioned
        so that  it  permits  maximum  liquid
        drainage.  Solvent trapped in pockets and
        recesses results  in  excessive  drag-out
        losses.

(6)     Cover Design:

        Hinged covers, if opened too quickly, tend
        to drag some of the solvent vapor with
        them.  Consider an alternate design such
        as a cover which slides open.

(7)     Vapor Dwell Time:

        If  possible,  hold the workload in  the
        vapor  zone after the final cleaning step
        until  its temperature equals  that of  the
        vapor zone and vapor stops condensing on
        the part.   Work  taken  out  earlier will
        emerge wet with solvent condensate.

        Dwell  times that are too short are most
        often seen  in open-top  units where  the
        work is manually moved into and out of
        the  unit.    Automatic hoists  can  help
        reduce  excessive  drag-out   due   to
        insufficient dwell  time.

(8)     Movement of Workload:

        A recommended maximum speed for work
        entering and leaving the cleaner is three
        meters/min.  Higher throughput rates can
        cause  vapor/air  interfacial disturbances
        that result in high vapor  losses.

        Again, the use of automatic hoists  and
        programmed   work   transporters   is
        recommended.   The speed of the piece
        entering and leaving should be optimized.

(9)     Spraying:

        Spraying of work pieces by spray-lance or
        spray headers should be performed deep
        within the vapor zone.  This avoids excess
        disturbance of  the vapor/air interface.

        Take  care  to  avoid  having  the liquid
        solvent ricochet into the free-board zone
        or  out  of  the  machine  when  lance
        spraying.

        Avoid spraying cold solvent vapor because
        this results in  the loss of heat from  the
        vapor   blanket,   which   increases   the
        potential  risk  of collapsing  the vapor
        blanket.   Use  warm solvent (100° F to
        112° F) for spray washing.  This minimizes
        the potential for vapor blanket collapse,
        and the  loss of solvent that takes place
        when the vapor blanket is reestablished.

(10)     Integrated  Cover/Hoist Designs:

        The inclusion of an integrated  degreaser
        cover  and   hoist  design  is effective  in
        reducing working  solvent  loses.   The
        presence  of  a   motorized,  horizontal
        sliding, two-piece lid  can be integrated
        with an automated programmable hoist.
        As the hoist lowers the workload to  the
        degreaser,  the  lid slides  open to allow
        entry of the product into the vapor zone.
        When  the workload clears the  lid on its

-------
                                                                                           Page  14
        downnward   descent,   the   lid  closes.
        Subsequeent  losses  due to  the  "piston
        effect"  or sprayers  disturbing the vapor
        blankket are  minimized.   After vapor
        condensation  ceases   or   spraying   is
        terminated, the  workload can be raised
        into    the  cooling coil zone  of the
        degreaser with the lid still closed.  Again
        disturbed vapor  zone and  potential
        workload drag-out losses are minimized.
        When the solvent has vaporized and the
        product is free of liquid  solvent (dry), the
        hoist begins raising the product out of the
        degreaser, the lid opens and then closes
        after exiting.

        Such designs  can be  purchased  as  an
        integral  part  of many new degreaser
        designs.  Retrofit kits consisting of a lid,
        hoist or a combination of the two are also
        available to convert existing degreasers.

(11)     Handling of Solvent:

        Add  solvent to  the  cleaner carefully to
        minimize   disturbing    the   vapor/air
        interface. Solvent should be  pumped into
        the cleaner through a liquid-submerged fill
        connection.  Makeup solvent should be
        added to a rinse compartment,  or better
        yet, to the cleaner's condensate collection
        tank.  Cold solvent  definitely should not
        be added to a  boiling sump; it may stop
        the boiling and cause the vapor blanket
        to collapse.

        Avoid overhead  pouring of solvent via
        buckets and drums to an open-top cleaner.
        This produces turbulence at the vapor/air
        interface and  increases the possibility of
        the vapor blanket  to collapse.   Solvent
        handling in open-top containers should be
        avoided because it offers the opportunity
        for solvent evaporation and  spillage.
Keep drums  containing  solvent tightly  sealed
between transfer operations to prevent unnecessary
evaporation losses.  And  store drums with the
bung end up to eliminate the possibility spillage
of solvent through a leaky bung.  Consider a bulk
storage  system for solvent and  delivery of the
solvent  through  a piping system to  the batch
cleaners.

-------
                                                                       Page  15

RECAP ON PROGRAM  TO THIS POINT


Following the recommendations  presented above, your program at this point will have
consisted of the following sequer#e of activities:

•     management's commitment to a successful reduction of CFC-113;

•     designation of an individual with a mandate to proceed with the project;

•     a survey of your CFC-113 purchases and uses;

•     establishment of your CFC-113  use per area of board manufactured (kg/m2) and
      procedures to calculate and monitor this ratio on a regular basis; and

•     execution of conservation  projects in the most appropriate order.
You are urged to follow these steps in this sequence before pursuing new replacement
technologies and processes.  The benefits of doing so include:

•     employees learn about the issues;

      a cultural change takes place in the location and elsewhere in the company which
      is essential for the program's success;

•     employees  develop  a deep understanding of the manufacturing process  and
      equipment; and

•     significant reductions in CFC-113 use are achievable in a short period of time.

-------
NON-CFC PROCESSES
                                                                                   Page 16
In addition to conservation procedures, you want
to evaluate non-CFC processes.  There are a
number of alternatives to CFC-113 now available
for cleaning of PCBs and PWAs. It is important,
however,  that your  customer  requirements be
closely   examined   before    moving   toward
implementing these alternatives. This is necessary
because  traditionally cleanliness of PCBs  and
PWAs  is cited  as  a  reliability requirement.
Studies have shown, however, that this may not be
so, and therefore, the application of any alternate
is now dependent on addressing cleanliness and
reliability issues.
It is important that you determine and establish
on paper what tests and standards will be applied
for cleanliness and reliability. For example, while
cleaning may not be required for final product
reliability, it may still be required to do tests on
the boards; therefore, testing methods would have
to  be specified.   You will  need to take into
account  your  customers'  perception  of what
constitutes an  acceptable  product  in terms of
reliability and testing.   This  approach will be a
new way of thinking for many manufacturers.
          Once your criteria are established, consider one  or more of the following
          options which  are available today:

          •    aqueous cleaning;

          •    low residue fluxes/"no-clean" assembly;

          «    controlled atmosphere soldering;

          •    alternate solvents (chlorinated solvents, alcohols, and
              hydrochlorofluorocarbons (HCFCs)); and

          •    hydrocarbon/surfactant cleaning.

          Each  of these  offers advantages and  disadvantages.

-------
                                                                                         Page  17
AQUEOUS  CLEANING

Water is an excellent solvent for removing ionic
contaminants and water soluble fluxes.  Water, in
combination with a saponifier, can remove non-
polar substances  such  as  oil and rosin  fluxes.
Aqueous cleaning systems  generally consist of a
wash, rinse, and a dry stage (See  Figure 3).   In
the wash stage, contaminants such  as oils, grease,
and rosin react with the alkaline saponifiers (most
commonly alkanolamines) to form a water soluble
soap  via  a saponification process.   Following
exposure to saponifier, the boards are rinsed.  The
rinse  step  is  important  to  remove saponified
contaminants,  residual  saponifier  solution,  and
other water soluble residues remaining.  The rinse
step is generally carried out with deionized water
to maintain a high degree of purity.  Aqueous
cleaning is most  effective  when combined with
high pressure and/or high volume  sprays.
     Aqueous cleaning offers several
     potential advantages:

     •  aqueous cleaning  can be used to
        remove water soluble fluxes, and in
        conjunction with saponifiers, rosin
        fluxes;

     •  suitable for cleaning through hole
        and surface mount assemblies;

     •  no distillation  equipment is required
        to recycle the solvent;

     •  no costs of disposing spent solvents;

     •  reduced pretreatment costs can be
        realized if water treatment (e.g.,
        distillation,  reverse osmosis,  heating,
        etc.) is not  required.
Prior to the use of aqueous cleaning
the following items should be
considered:

• Because surface mounted
  components are placed closer to ^ the
  board than traditional through-hole
  components, adequate cleaning in the
  small gaps underneath surface
  mounted components is more
  difficult. Aqueous cleaning of
  surface  mounted assemblies (SMAs)
  depends on a number of physical
  properties including  (1) surface
  tension, (2) viscosity, (3) mechanical
  energy,  and (4) temperature.  You
  have to keep these important
  parameters in mind when designing
  aqueous cleaning processes for
  SMAs.

• Most newly designed aqueous
  cleaning systems are based on a
  closed loop recirculating wash and
  rinse stages, as opposed to a
  continuous discharge system.  The
  wash and  rinse water is continuously
  used for weeks or months without
  being discharged. This reduces the
  amount of wastewater being used,
  and therefore, reduces the energy
  and disposal cost (See Appendix 1
  for a list of vendors).

• "Zero-discharge" aqueous cleaning
  systems  are available that use closed
  loop recycling systems to minimize
  the discharge of process water (See
  Figure 4).  Such systems reduce
  water, energy, and disposal costs
  significantly.  Currently these systems
  are available for aqueous cleaning
  systems  that  use water soluble fluxes
  (See Appendix 1 for vendor).
  Systems for other types of fluxes
  (i.e., rosin and organic acid fluxes)
  are being developed.

-------
                                                                Page IB
     Figure 3: TYPICAL AQUEOUS CLEANING CONFIGURATION
    Wave
   Soldering
        Wash
        Stage
Recirculation
 1st
Rinse
Stage
 2nd
Rinse
Stage
Dryer
Cleaned
 PWA
Periodic Dumping




Waste Treatment



Public/Municipal
Waste Treatment
Facility

-------
                                                                 Page 19
Figure 4. "ZERO DISCHARGE" WATER RECYCLING SYSTEM CONCEPT
   Evaporated
     Water
    Aqueous
     PWA
    Cleaner
                  Contaminated
                    Water
                   Purified
                    Water
                                  Tap
                                  Water
                                            Closed-Loop
                                           Soil Disposal

-------
                                                                                          Page 20
LOW SOLIDS FLUXES/"NO-CLEAN" ASSEMBLY
By carefully evaluating and selecting components
and assembly processes, benign low solids fluxes
can  be  used  to  eliminate cleaning  in  some
instances.  Traditionally, the electronics industry
has used, and is still using, rosin fluxes containing
between 15 to 35 percent solids content for wave
soldering  electronics assemblies  (through-hole,
single-sided,  and  double-sided   printed  circuit
boards). Numerous low solids fluxes containing
1  to  10 percent  rosin (or  resin, or both) have
been  formulated and tested.
      Low solids fluxes have the following
      advantages:

      •  "bed of nails" testing on printed
        circuit board assemblies can be
        carried out immediately after wave
        soldering, without the problems
        created by the presence of rosin
        residues; and

      •  the need for defluxing can be
        eliminated.
Depending on the solder mask or resist and the
low solids  flux used,  little or no visible residue
remains  on  the  boards after soldering.   The
remaining residues, if any, dry and rapidly harden.
Automatic  testing can be  done without cleaning
the boards.    Because  low  solids  fluxes  are
generally considered non-corrosive and have high
insulation  resistance,  in   most   cases   it  is
unnecessary to remove them, even for cosmetic
reasons.
     Prior to using this process, you should
     note that:

      •  These fluxes may have to be removed
        to meet military specifications and
        are relatively  difficult to remove by.
        traditional CFC-113 methods.

      •  The use of incompatible cleaners can
        result in the formation of white
        residues or cosmetic  imperfections on
        the fluxed surface.  It is important
        that you consider the compatibility of
        these fluxes with cleaning media and
        cleaning equipment.

      •  One company has performed
        additional tests on  low solids fluxes.
        The test results demonstrated an
        inverse relationship between surface
        insulation resistance  (SIR) and the
        quantity of low solids flux applied
        and revealed the importance of
        process selection and process control
        in the application of a number of
        low solids fluxes.

      •  Aging studies showed that large
        quantities of some, but not  all, post-
        solder low flux residues'can  be
        detrimental.
To minimize excessive flux build-up a new fluxing
system  has   been  designed   that   uses  an
ultrasonically-controlled spray to disperse the flux
(U.S. Patent  #4,821,948, April 18,  1989).  This
system  is  commercially   available.     Other
commercial spray fluxes are also available (see
Appendix  1 for list of vendors).  Other advantages
of this system include minimal deposition of flux
on the  topside of circuit boards which can be
detrimental, and a closed flux reservoir system that
prevents  alcohol evaporation  (specific gravity
changes) and  water absorption.

-------
                                                                                           Page 21
Conventional fluxes are more tolerant of minor
variations in the process parameters  because of
their high solids content.   The choice of solder
mask is a prime concern, as a poor choice results
in unacceptable levels of solder ball formation.

You  should  not  expect  the conversion  of  a
soldering line from a conventional to a low solids
flux to be easy.  Some adaptation of the process
parameters  and  possibly the soldering  machine
itself  will  be  needed.    Some  users  have
experienced initial difficulties when  starting up
with  these  fluxes,  but a  little perseverance
generally resolves problems such as maintaining an
adequate foam head, measuring and adjusting the
flux solids,  preventing water from entering  the
flux, regulating the  quantity of applied flux, and
adjusting the preheaters to a more critical degree.

Fluxes are now available in foam, wave, and spray
application.  Wave application of low solids flux
presents minimal cost and retrofit difficulties.  As
these processes all utilize low solids fluxes diluted
with  isopropanol,  you must consider adequate
ventilation and fire suppression.  Optimization of
the process parameters using low solids flux can
be   assisted   by   using   applied   statistical
quality/process  control  techniques   (e.g.,   the
Taguchi  method).

-------
CONTROLLED ATMOSPHERE SOLDERING
                                                                                          Page 22
A new soldering process, inert gas wave soldering,
recently  has been  developed  by  a large West
German  group who is licensing the manufacture
of machines (See Appendix 1 for list of vendors).
The process operates under a nitrogen atmosphere
and applies finely divided activators via ultrasonic
injection  (See  Figure 5).   The carboxylic acid
activators include formic acid, acetic acid, citric
acid,  and adipic  acid. Other  processes are also
being  developed  that   function  on  the  same
principle  except that soldering is  carried out in
vacuum instead of a nitrogen  atmosphere.

Inert gas wave soldering has been tested by a large
West   German  electronics  manufacturer  with
numerous conventional wave soldering systems in
operation.   Preliminary test  results  show no
significant differences in  the  quality  of solder
joints. Boards tested by Northern Telecom after
inert gas wave soldering found better solderability.
These preliminary   tests  showed  an  order-of-
magnitude decrease in solder defects. In addition,
several European and North American companies
will soon  be using  the inert gas process  to wave
solder both  through-hole  and surface mounted
assemblies.  Results are preliminary and tests are
underway  to  further   quantify   the   process.
Processes   are  currently  being developed and
patented  to allow blanketing of existing  through
hole equipment. SMT technology is about to see
controlled atmosphere applications as well.
The particular features that make this
process preferable to the well
established and widely used method of
soldering under atmospheric conditions
(i.e., in the presence of oxygen) are:

• soldering takes place with
  metallically pure solder (i.e., in an
  oxide-free soldering module, oxygen
  levels in and above the bath are
  monitored  by solid electrolytes at
  less  than two ppm);

• oxide formation is greatly reduced on
  the printed circuit boards both
  before and after soldering (dross
  formation is reported to be only 10
  percent of  that generated in normal
  soldering machines, i.e., 0.5-1.0
  kg/day);

• the system  operates without
  conventional rosin or resin fluxes;
  and

• post-cleaning required for assemblies
  wave soldered on equipment
  currently in use and utilizing
  conventional fluxes (rosin, inorganic
  or synthetic fluxes) is eliminated for
  many applications.  The  residues
  remaining on the printed circuit
  boards after soldering have been
  reported to be  less than  3.5
  micrograms/square centimeter NaCl
  equivalent.

-------
                                                                          Page 23
           Ultrasonic
           Fluxer
            Flux
            Module
Preheater
Module



	 	 1
SMD
Solder
Bath

                                                              Gas
Soldering
Module
                                  Additive


                                   Airtight System


                                   Oxygen Residues

                                   Belt Conveyor
Figure 5. DIAGRAM OF A CONTROLLED ATMOSPHERE WAVE SOLDERING MACHINE

-------
                                                                                         Page 24
ALTERNATIVE SOLVENTS

There  are a wide variety of alternative solvents
that are considered as possible replacements for
CFC-113.    These  include  chlorinated solvents
(1,1,1-trichloroethane),   alcohols    and
hydrochlorofluorocarbons  (HCFCs).     These
solvents are briefly discussed in the next section.
       "possibly   carcinogenic   to   humans".
       Chlorinated  solvents  will  be  selected
       substitutes for CFC-113 in some cases.
       For  example, in  the  United  States,
       trichloroethylene continues to be used
       even with new regulations that reduce the
       allowable  worker   exposure   to  the
       chemical.
(1)     1,1,1,-Trichloroethane:

        1,1,1-Trichloroethane   is  an   effective
        substitute  for  CFC-113 in electronics
        industry operations. Although a volatile
        organic  compound, the U.S.  EPA has
        exempted 1,1,1-trichloroethane from legal
        classification   as   a   volatile   organic
        compound (VOC).   Furthermore, it  is
        nonflammable.  It  is possible,  therefore,
        that   some   substitution   of  1,1,1-
        trichloroethane will occur  as  CFC-113
        becomes  less  available and users face
        rising   prices.      However,   1,1,1-
        trichloroethane has been identified as an
        ozone depleting substance  and may  be
        added to the Montreal  Protocol in 1990.

(2)     Chlorinated Solvents:

        Trichloroethylene, perchloroethylene,and
        methylene  chloride also  are   effective
        cleaners.  They are also volatile organic
        compounds.    However, each  of these
        solvents  is  considered a  possible  or
        probable carcinogen.  The U.S. EPA has
        classified trichloroethylene in Category B2
        as a "probable human carcinogen," while
        the International Agency for Research on
        Cancer (LARC) has classified this solvent
        in Group 3, a substance  not classifiable as
        to its carcinogenicity in humans.  The
        LARC has classified perchloroethylene in
        Group  2B  as  a  substance considered
        "possibly   carcinogenic  to   humans."
        Finally,  the   U.S.  EPA has  classified
        methylene chloride in Category B2 as  a
        "probable human carcinogen," while the
        IARC has classified methylene chloride in
        Group  2B  as  a  substance considered
(3)     Organic Solvents and HCFCs:

       Organic  solvents such  as  alcohols  and
       HCFCs are  possible  replacements for
       CFC-113.     Five organic solvents  and
       HCFCs have been proposed as possible
       CFC-113 substitutes: pentafluoropropanol
       (5 FP), isopropanol, HCFC-225ca, HCFC-
       225cb,   and   HCFC-141b/HCFC
       123/Methanol blend (see Appendix 1 for
       list of chemical  suppliers).   Exhibit  3
       summarizes their physical properties which
       are compared to CFC-113.  Preliminary
       research suggests these solvents have good
       cleaning  performance.   However, long-
       term  toxicity  testing   is  still  being
       conducted on several HCFCs.

       Generally, the use of organic solvents in
       the past has been small primarily due to
       the flammability concern associated with
       the use of these solvents. For example, the
       use of isopropanol has been limited due
       to its flammability.  A large  European
       electronics  manufacturer is  operating  a
       modified, conveyorized, in-line isopropanol
       cleaner. The machine, depicted in Figure
       6, cleans both through-hole and surface
       mounted assemblies.  The system has an
       on-line still for recycling, and the system
       is designed to be explosion resistant.

-------
                                                             Page 25
                 Spraying Operation 1
                    /
Spraying Operation 2
  wl:h Distillate
                                                         Cooling
                                                         Tubes
Figure 6. DIAGRAM OF A MODIFIED CONVEYORIZED IN-LINE CLEANING
               MACHINE USING ALCOHOL SOLVENT

-------
                                                                                           Page  26
        These machines are currently commercially
        available and the equipment range covers:

        •  cold  solvent  cleaners  with  brush
           option;
        •  hot solvent cleaners with ultrasonic
           option;
        •  vapor   phase  batch  cleaners  with
           ultrasonic option; and
        •  in-line continuous cleaners with spray
           and ultrasonic option.

Ancillary equipment  for solvent recycling is also
available.
EXHIBIT 3. PHYSICAL PROPERTIES - HCFCS & OTHER SOLVENT BLENDS



Chemical Formula
Ozone Depleting
Potential
Boiling Point CO
Viscosity (cps)
a 25'C
Surface Tension
(dyne/cm)
Kauri -Butanol Value
Flash Point °C
Toxicity



CFC-113
CC12FCCIF2
0.8

47.6
0.68

17.3

31
None
Low



HCFC-225ca
CF3CF2CHC12
<0.5

51.1
0.59

16.3

34
None
Being
Conducted


HCFC-225CB
CCIFCF2CHCIF
<0.5

56.1
0.61

17.7

30
None
Being
Conducted

Pentaf luoro
Propanol
CF3CF2CH2OH
0.0

81
..

19.0

36
None
Being
Conducted


Isopropanol
CH3CHOHCH3
0

82


22.6

N/A
12
Moderate

HCFC-1416/
HCFC-123/
Methanol
CHC12F/
CHC12CF3/
CH3OH
0.07-0.08

30-32
0.42

0.42

--
None
Being
Conducted


-------
HYDROCARBON/SURFACTANTS
                                                                                       Page  27
A number  of hydrocarbon/surfactant cleaning
solutions are being developed to clean PCBs (See
Figure 7).   One such  solution,  terpenes, is a
naturally-derived solvent, which is considered a
viable alternative for cleaning some electronics
assemblies.   Terpenes  generally  are  isoprene
oligmers, but  may  include  derivatives such as
alcohols, aldehydes, and esters.
     Terpenes display the following
     characteristics:

     • work effectively in close spacing
       (clean SMDs);

     • work at low (room or slightly higher)
       temperatures;

     • are noncorrosive (pass the copper
       mirror test);

     • have low viscosity  and are low
       foaming; and

     • remove both polar and non-polar
       contaminants.
Prior to the use of this process the
following items should be noted:

• Equipment specifically designed for
  terpene cleaning is necessary because
  of material compatibility,
  combustibility, and odor concerns
  associated with terpenes (See
  Appendix 1  for list of equipment and
  chemical suppliers).

• Cleaning machines using terpene
  solvents must be "inerted"  (purged
  with inert gas such as nitrogen) for
  safe operation because of low closed-
  cup flash point (47°C) and potential
  room temperature flammability
  associated with spray mist.

• Terpenes are considered VOCs, and
  therefore, adequate containment of
  terpene mist and vapors should be
  provided to  control odor and
  minimize material losses,

• Only limited testing of these
  chemicals has been completed to
  date.  More information on health
  and safety issues will become
  available as  development of this
  option continues.

-------
                                                                             Page 28
                                    FIGURE 7
Configuration of Hydrocarbon/Surfactant Based Cleaning Process
              Wave
             Soldering
                   Wash
                   Stage:
                 Concentrated
                 Hydrocarbon/
                 Surfactant
           Solution
        Recirculation
Rinse
Stage:
Water
                     Periodic Dumping
  Dryer:

Room Temp Air
or Heated Air
Cleaned
PWA
                 Waste Treatment
                          Public/Municipal
                          Waste Treatment
                          Facility

-------
                                                                                       Page 29
METHODOLOGY TO  SELECT  NON-CFC
PROCESSES
The methodology used  to select  a non-CFC
process has  to take into  account  a host  of
important considerations that might include  the
process compatibility, flexibility and performance,
the capital costs  (i.e., the costs of the cleaning
equipment and waste treatment  equipment if
needed),   operating   costs,  and   safety  and
environmental issues.  For each alternative non-
CFC  process  these  considerations  have  to be
compared to the CFC-113 alternative to evaluate
the  technical   and   economic   feasibility   of
substitution.

To evaluate the technical and economic feasibility
of substitution, a methodology was developed at
Northern Telecom that standardized the procedure
used to compare alternatives. This methodology
can be used as the basis for preliminary screening
of various alternatives. The methodology is based
on the principle that the  two most important
factors to be evaluated  are the  technical  and
economic  feasibility  for  substitution.     The
technical  feasibility  criteria  are  evaluated  by
establishing a difficulty index that compares  the
difficulty of using a non-CFC process with a CFC-
113  process.     The  economic  feasibility  is
evaluated  by estimating the net present value of
the non-CFC process and comparing it with that
of the CFC-113 process.   The  next sections
describe this methodology in more detail.
TECHNICAL FEASIBILITY

The technical feasibility of a non-CFC process is
evaluated by establishing a difficulty index. This
is  accomplished by  first establishing a  set of
criteria that need to be considered to evaluate the
merit of a substitute; second, each criterion  is
weighted based on its importance; and third, each
criterion is  assigned  a  value  based  on  its
feasibility.  This is performed for  the CFC-113
process as well as for the non-CFC processes that
are being considered.
The factors that you might evaluate to
determine the technical feasibility
include:

• compliance to  specification (e.g.,
  military specifications);

• defect rate (i.e., the rate at which
  parts do not meet inspection
  standards);

• customer return issues;

• industry direction (i.e., likelihood of
  widespread commercialization and
  use);

• cosmetics of the PCBs cleaned;

• flexibility of the process;

• ability to clean surface mount
  assemblies (SMT);

« fallback position for the process;

• process control;

• throughput of  the cleaning process;

• health, safety, and environmental
  concerns;

• future costs associated with the
  process;

• availability of the process;

• ease of process installability;

• process compatibility; and

• floor space requirements.

-------
                                                                                         Page  30
 Next, a weight is assigned for each of the above
 criteria based on its importance (10 for the most
 important and 1 for the least important). Exhibit
 4 summarizes  the weights  assigned  to each
 criterion by Northern Telecom.
EXHIBIT 4. DIFFICULTY
CRITERION WEIGHTS
Difficulty Criterion
.Compliance to Specification
Defect Rate
Customer Return Issues
Industry Direction
Cosmetics of the PCBs
Flexibility of Process
Ability to Clean SMT
Fallback Position
Process Control
Throughput
Environment, Health, and
Safety Concerns
Future Costs
Availability of the Process
Ease of Process Installation
Process Compatibility
Floor Space Requirements
Weight
9
9
9
8
7
7
7
7
6
6
5
4
4
2
1
1
Source: Northern Telecom
Next, each of the above criteria is ranked for the
CFC-113  process and  other non-CFC processes
being evaluated.  The ranking system is based on
a scale of 1 to 10. One being the highest and 10
being the lowest ranking.  Exhibit 5 presents the
ranking  for  CFC-113  and  an  alcohol  based
process.  Once the alternative has been ranked,
the weighted difficulty criterion  is calculated by
multiplying the weight for each criterion  by its
rank and by adding up the weighted ranks for
each factor.  For example, for CFC-113 this  is
equivalent  to:
CFC-113  =  (compliance)(9*l)

          + (defect rate)(9*l)

          +	 + (floor space)(l*l)

          =  235

Similarly, for the Alcohol Process, the
value equals 236.
                                                     The difficulty index is calculated by taking the
                                                     ratio of the weighted rank factor for the alcohol
                                                     and the CFC-113 process which, in this case,  is
                                                     approximately one.

                                                     ECONOMIC FEASIBILITY

                                                     The economic feasibility is an important factor in
                                                     determining which alternative non-CFC process  is
                                                     a viable substitute. This can be accomplished by
                                                     calculating the net present value (NPV) of the
                                                     CFC-113 process and  the  non-CFC alternative
                                                     being  considered.  To  calculate the net present
                                                     value  the costs associated with the process have
                                                     to  be  determined over a period of time.   One
                                                     simple approach  is to  calculate NPV based on  a
                                                     five year  period  assuming that  the  capital
                                                     investment for the process takes place in year zero
                                                     and the  return  on investment  is  20 percent.
                                                     Based  on this the NPV is calculated as follows:
                                                        '  NPV = Cost0 + Costt / (1+i) +
Cost
                        Costs / (1+05

-------
Page 31
EXHIBIT 5. COMPARISON OP
Difficulty Criteria
Compliance to Specification
Defect Rate
Customer Return Issues
Industry Direction
Cosmetics of the PCBs
Flexibility of Process
Ability to Clean SMT
Fallback Position
Process Control
Throughput
Environment, Health and
Safety Concerns
Future Costs
Increases
Availability of the Process
Ease of Process
Installability
Process Compatibility
Floor Space Requirements "
CFC-113
1
1
1
10
1
1
1
10
1
1

1
3

1
1
1
1
CFC-113 VS ALCOHOL PROCESS
Alcohol
Rank
2
1
1
3
1
1
1
10
4
1

6
1

1
6
1
4
Comments
Alcohols Not Yet Approved =
By Military Specifications

Industry Moving Towards
Alcohols







Alcohols Combustible
Future CFC-113 Price


Major Equipment
Installation

Alcohol Process has Bigger
Equipment
Source: Northern Telecom

-------
                                                                                        Page 32
The costs associated with the CFC-113  and the
non-CFC  processes have to include: (1) capital
costs of equipment (including  costs of waste
treatment if needed), and (2) operating costs that
includes material costs, labor costs,  maintenance
costs, and utilities costs.  These cost estimates for
the non-CFC process can be developed through a
preliminary  process  design that estimates  the
design parameters of the process.  This in turn
will  lead  to  preliminary cost estimates  for  the
process and waste treatment equipment, if needed.
Operating costs can also be determined from this
initial conceptual design.
Exhibit 6 presents a comparison of the NPV
calculation for a CFC-113 process and an alcohol
process.  It is assumed that the CFC-113 process
has zero capital investment because  the process
is already installed and operational. However, this
might  not. be the  case if additional  engineering
controls   need   to  be   installed as   part  of
conservation measures to reduce the use of CFC-
113.  Based  on Exhibit 6, the NPV of the CFC-
113  process is  S329K and that of the alcohol
process is S754K.
                              EXHIBIT 6. NET PRESENT VALUE CALCULATIONS
                                     CFC-113 VS ALCOHOL PROCESS
                                                 CFC-113
                                           (Thousands of U.S. $)
                      Alcohol
                (Thousands of U.S. $)
                      Capital Costs
                              Equipment
                              Waste Treatment
                              Total Capital
                      Operating Costs
                              Solvent Costs
                              Labor Costs
                              Maintenance Costs
                              Utilities Costs
                              Total Operating
                      NPV
 35
 30
 15
 30
110

329
                      250
                      100
                      350
 25
 30
 50
 30
135

754
           Note: These costs are indicative.  They may not accurately reflect costs in specific
           situations.

           Source: Northern Telecom

-------
                                                                                       Page 33

SELECTION  OF NON-CFC PROCESSES

The selection of the non-CFC process can be made by:

•          Listing all feasible non-CFC processes;

•          Performing a preliminary analysis for each process to determine the difficulty index and the
           NPV;

•          Comparing the difficulty index and the NPV for the non-CFC process with  the  CFC-113
           process;

•          Once these have been determined for all the non-CFC processes being considered, plotting them
           on a graph that represents difficulty index versus NPV (See Figure 8).
This graph can be used to determine the range of
difficulty index - NPV combinations that can be
considered feasible.  This range is represented by
the oval shape region defined in Figure 8.  This
oval shape region has  been defined  using the
rational that a non-CFC process that has a high
difficulty index and low NPV, and a low difficulty
index and a high NPV is not feasible.
Based on such an evaluation you can perform a
preliminary screening of a wide variety of non-
CFC  processes.     Once  such  a  preliminary
screening is completed, a more detailed evaluation
of the promising processes  can be performed.
Such an evaluation  will allow you  to pin point
more promising alternatives and thus direct more
resources to evaluate them.

-------
                                                       Page 34
x

-------
                                                                                       Page 35

IN CLOSING	
Northern Telecom has successfully implemented conservation practices at its divisions.  It has designed, built
and operated a state-of-the-art vapor adsorption system, and has used the methods described here to select
non-CFC alternatives. These are the principal actions that will allow the company to eliminate the use of
CFC-113 in its manufacturing operations worldwide by the end of 1991.

You may want to contact Northern Telecom for more information as you move forward with your CFC-
113 reduction and elimination programs.  The key contacts are:

       A.  D. FitzGerald                     M. Brox
       Director,  Environmental Affairs        Project Manager, CFC Elimination
       Telephone: 416-566-3048,,-s- ,         Telephone 416-566-3232
       Fax:  416-275-1143                    Fax:416-275-1143

       Northern  Telecom's  address for both individuals is:

       Northern  Telecom Ltd
       3 Robert  Speck Parkway
       Mississauga, Ontario
       Canada L4Z 3C8

The addresses for the other authors are:

       Dr. Stephen O. Andersen
       Chief, Technology &  Economics Branch
       Division of Global Change.
       Office of  Air & Radiation
       Mail Code ANR-445
       Room 745 WT;  401  M Street, SW
       Washington, D.C. 20460
       Telephone: 202-475-9403
       Fax:    202-382-6344

       Sudhakar  Kesavan                    Farzan Riza
       Vice  President               ,       Associate
       ICF Incorporated                     ICF Incorporated

       ICFs address  for both individuals is:

       409 12th Street, SW
       Suite 700
       Washington, D.C 20024	
       Telephone:  703-934-3000
       Fax:    703-934-3590
       The authors welcome comments on this manual.

-------
                                                                                     Page 36
APPENDIX 1 - VENDORS2

1. Solvent Cleaning Equipment

        Baron Blakeslee
        2001  No. Janice Ave.
        Melrose Park, IL 60160
        (312) 450-3900

        Detrex
        P.O. Box 501
        Detroit, MI 48232
        (313) 358-5800

        Ultronix
        RD2  Box 100D
        Coopersburg, PA  18036
        (215) 965-8009

2. Alternate Solvents

        Allied-Signal
        2001 North Janice Ave
        Melrose Park, Illinois  60160
        (312) 450-3880

        Dow Chemical
        2020 Dow Center
        Midland, MI  48674
        (517) 636-8325

        DuPont Electronics
        Wilmington, DE 19898
        (302) 999-2889

        ICI Americas Inc.
        Wilmington, DE 19897
        (302) 575-8669 or
        ICI Chemicals
        Solvents Marketing Department
        P.O. Box 19
        Runcorn, Cheshire, WA7 4LW
        (0928) 512245

        Pennwalt Corporation
        Three Parkway
        Philadelphia, PA 19102
3. Aqueous Cleaners

       Advanced Chemical Company
       Ben Franklin Technology Court
       South Mountain Drive
       Bethlehem, PA 18015
       (215) 861-6921

       Baron Blakeslee
       2001 No. Janice Ave.
       Melrose Park, IL 60160
       (312) 450-3900

       DuBois Chemicals, Inc.
       511 Walnut Street
       Cincinnati, OH 45202
       (513) 762-6839

       Indusco Chemicals
       1806 Southeast Holgate Blvd.
       P.O. Box 42194
       Portland, Oregon  97242
       (503) 236-4167

       Kester Solder
       515 East  Touhy Ave
       Des Plaines, IL 60018-2675
       (312) 297-1600

       London Chemical  Company (LONCO)
       P.O. Box 806
       Bensenville, IL 60106
       (312) 287-9477

4. Aqueous Cleaning Equipment

       ECD
       13626 South Freeman Road
       Mulino, Oregon 97042
       (503) 829-9108

       Electrovert
       4330 Beltway  Place
       Arlington, TX 76018
       (817) 468-5171
2Note:  This is not an exhaustive list of vendors.

-------
                                                                                      Page 37
Appendix 1 - Vendors  (continued)

       Hollis  Automation, Inc.
       15 Charron Ave.
       Nashua, NH  03063

       Ultronix
       RD2 Box 100D
       Coopersburg, PA  18036
       (215) 965-8009

       Westek
       400 Rolyn Place
       Arcadia, CA  91006
       (818) 446-4444

5.  Low Solids/"No-Clean" Assembly

       Alpha  Metals
       600 Route 440
       Jersey  City, New Jersey  07304
       (201) 434-7508

       Cramco Inc.
       P.O. Box 88500
       Atlanta, Georgia  30338
       (404) 475-6100

       Hi-Grade Alloy Corporation
       17425 South Laflin Street
       P.O. Box 155
       East Hazel Crest, Illinois 60429

       Kester
       515 East Touhy Ave
       Des Plaines, IL  60018-2675
       (312) 297-1600

       Kester Solder Company of Canada, Ltd.
       One Prince Charles Road, Bos 474
       Branford,  Ont N3T 5N9
       (519) 753-3425

       London Chemical Company (LONCO)
       P.O. Box 806
       Bensenville, IL 60106
       (312) 287-9477
       Multicore Canada Inc.
       5730 Coopers Ave., Unit 21-22
       Mississauga, Ont. L4Z 2E9
       (416) 890-6955

6.  Controlled Atmosphere Wave Soldering

       OCS-SMT Automation Inc.
       121 Montee De Liesse
       St. Laurent, Quebec,  Canada H4t 1S6
       (514) 739-2076

       Soltec
       P.O. Box 143
       4900 AC Oosterhout
       Karolusstraat 20 The Netherlands
       31-(0)1620-83000

7.   Hydrocarbon/Surfactants

       Alpha Metals
       600 Route 440
       Jersey City, NJ  07304
       (201) 434-6778

       Asahi Glass Co., Ltd.
       1150, Hazawa-cho,
       Kongawa-ku,221, Japan
       045-381-1441

       Brulin
       2920 Dr. Andrew J. Brown Ave.
       P.O. Box 270
       Indianapolis, IN  46206
       (317) 923-3211

       Daikin Industries Ltd.
       Chemical Division
       1-1  Nishi Hitotsuya,
       Settsu-shi
       Osaka, 566, Japan
       Osaka (06) 349-1778

       DuPont Company
       Electronics Department
       Customer Service Center, B-15305
       Wilmington, DE 19898
       1-(800)-661-8450

-------
                                                                                       Page  38
Appendix 1 - Vendors (continued)

        Fine Organics Corporation
        205  Main Street
        Lodi, NJ 07644
        (201) 472-6800

        Orange-Sol
        P.O. Box 306
        Chandler, AZ  85244
        (602) 961-0975

        Petroferm
        5400 First Coast Highway
        Fernadina Beach, FL 32034
        (904) 261-8286

        3D Inc.
        2053 Plaza Drive
        Benton,  Harbor, MI 49022
        (616) 925-5644

8. Hydrocarbon/Surfactant Equipment

        Accel
        1825  E.  Piano Parkway
        Piano, Texas 75074-8129
        (214) 424-3525

        Detrex Corporation
        P.O. Box 501
        Detroit,  MI  48232
        (313) 358-5800

        ECD
        13626 South Freeman Road
        Mulino,  Oregon 97042
        (503) 829-9108

        Electrovert
        4330 Beltway Place
        Arlington, TX  76018
        (817) 468-5171

        Ultronix
        RD2 Box 100D
        Coopersburg, PA  18036
        (215) 965-8009
9.  Water Recycling Equipment

       Separation Technologists
       32 Granger Ave.
       Reading, MA  01867
       (617) 942-0023
                                                                      U.S. GOVERNMENT PRINTING OFFICE: 1990 0-944-OB

-------