PBS4-1S6089
Capture-and-Containment Systems for
Hazardous Material Spills'on Land
MSA Research Corp., Evans City, PA
Prepared for
Municipal Environmental Research Lab,
Cincinnati, OH
Apr 84
of Cesnstwrce
T^ckitsl ferfwmstkm
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r- L- t: 4 -116 ••: i j
EPA-600/2-84-084
-April 1984
CAPTUPE-AfiD-CONTAT?,'MtNT SYSTEMS FOR
HAZARDOUS MATERIAL SPILLS ON LAND
by
Mervin 0. Marshall
MSA Research Corporation
Evans City, Pennsylvania 16033
Contract Nc. 63-03-250?
Project Officer
John t. Bruoqer
Ofl and Hazardous Materials Spills
Municipal Envlrcmf^ertal Research Laboratory (Cincinnati)
Edison, New Jersey 08fi37
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 452C3
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TECHNICAL REPORT DATA
(Picas* Tfdd /nu/uctiuns on tne rciene before co
ZE:
I ij O R1 N O
3 RCCtPlf NT'S
FPA-6QQ/2-84-Q84
1 15 Lt AMD SU8TM Lt
CAPTURE-AND-CONTAINMENT SYSTEMS FOR
HAZARDOUS MATERIAL SPILLS ON LAND
Al.iTHORlS>~~
Mervin D. Marshall
5 REPORT DATE
_Anril 1984.
6. PERFORMING ORGANIZATION CODE
B. PERFORMING ORGANIZATION REPORT NO.
8608 9
PERFORMING ORGANIZATION NAME AND ADDRESS
MSA Research Corporation
Evans City, PA 16033
1O. PROGRAM ELEMENT NO.
CBRD1A
tl. CONTRACT/GRANT NO.
68-03-2507
12 SPONSORING »GI NCV NAME AND ADOH6SS
Municipal Environmental Researc" Laboratory—Gin.,, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ori 45268
II. TVPE OF REPORT AND ft «IOD COVERS O
Fir-al - Jan. 1977-April 1QRQ
14. SPONSORING AGSWCV CODE
EPA/600/14
15 SUPPLEMENTARY NOTES
Project Officer: John E. Brugger (201) 321-6634
16 *BSlW£ report covers the investigation of methods for sealing the surface of soils an
preventing the percolation of spilled hazardous materials into the ground. The objecti
was to develop a portable, self-contained, universal sealing system•"which could be
operated by one man, retain the spilled iraterial through a 24-hr removal period, and
pose no subsequent hazard to the user or to the environment.
Sprayable sealant systems were investigated extensively but proved to be imprac-
tical. Of the sealants investigated, only polyurethane foam showed any promise of
sealing soil surfaces particularly under the severe weather conditions that generally
accompany bulk transport accidents. However, the quant;ty of chemical required to seal
soil (especially grassy substrates) far exceeded the amount considered practical for a
portable system.
Polyethylene film in the shape of a one-end-closed tube proved to be the most
practical means of containing and collecting hazardous material spills. An apron
attached to the open end was equipped with draw and tie ropes to position the device
under or close to the spill. A small tube connected at the closed end allowed for
transferring collected spilled material to auxiliary containers. A double-walled bag
consisting of a heat-sealed inner bag and a reinforced outer bag appeared to be the
combination most suitable for further development. Total collapsed volume of the final
package, a pillow-shaped containment bag 20 ft long and 6 ft wide, was less then 2
ft-*, the unit M
-ttr
10 lU.
KEV WORDS AND DOCUMENT ANALYSIS
17.
DESCRIPTORS
li.lDFNTIFIEnS/OPf N ENDED TERMS
c. COSATI Ficid.'Croup
1* OlSTRiBUTlON STATEMENI
RELEASE TO PUBLIC
31 NO OF PAGES
79
70 «
St Cu«UT v c L* S5 (Tftit part!
UNCLASSIFJtD
72. PRICE
Form
|»-7J|
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PJ sci. AIMER
The information in this document das been funded wholly or in part by the
United States Environmental Protection Agency under Co-tract No.
68-03-?b07 to MSM Kesearcn Corporation, It has been subject to the
Agency's peer and acministrative review, and it has foetii approved for
publication as an EP* document. Mention of trade names or commercial
products does not constitute endorsement or reco(w:en(Jat':on for use.
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FOREWORD
The U.S. Environmental Protection Agency was created because of in-
creasing DuL)lic and government concern about the rijnqers of pollutior. to
the health arid welfare of the American people. Nc/ious air, foul water,
red films such as polyethylene, en the other hand, appear to De
D>-Jctit;dl and **ere developed furtner into a promising, first-action cap-
wure-and-coiitainment Dag.
Francis T. Mayo,
Director
Municipal Environmental Research
Laboratory
Hi
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ABSTRACT
This report investigates rethods for sealir.g the surface of soils and
preventing the intrusion of hazardous materials into ground water. The
objective ^as to develop a portable, self-contained, universal sealing
system that could be operated by one man, retain the spi'lleo material
through a ^4-hour removal period, and pose no subsequent hazar.1 to the
user or to the environment, K basic asMjirption of this investigation was
that the site preparation for any seal inn system would be minimal.
Sprayable sealant systems were investigated extensively but proved to
be impractical. Three types cf sealants wore investigated: nonreactive,
(which are dispersed or dissolved in a solvent system), reactive (which
are two or mere co'noonent systems) and repellent or surface modifiers.
Only polyuretiiane foam, a reactive type, showeo any promise of sealing
soil surfaces under the variety and severity of weather conditions that
are often ttit> cause of bulk transport accidents, but even with this
pnvrise, the Quantity of chemical required to seal soil (and especially
grassy substrates) sufficiently to contain the spilled material far
exceeded the amount considered practical for a portable system. In
addition, the xechnn^ues for appiyinq the sealant to different soil
substrates tinner various weather conditions were a biq factor in
eft-.'Ctinq 3 seal ana thus made it too complex for a simple,
first-resoonse action.
'olyethylenr film proved to he a practical barrier 1o a wide spectrum
of hazardous ^e;its and sealed against water at over a foot of head when
applied to rocicy, crassy, and weedy areas. Mien formed in the shape of a
tube approximately b ft in diameter and approximately 20 ft long, the
unit would contain water with more than 3 ft of head and have a capacity
of more than 1000 qal. An apron on the open end equipped with draw and
tie ropes allowed positioning of the unit below the leak, and a small
tube connected at the closed end allowed for directing excess spill to a
second containment site. The enclosed bag concept would also minimize
vapor hazards.
A double-walled bag consisting of a heat-sealed inner bag of clear
polyethylene and a sewn, reinforced outer bag appeared to be the combi-
nation trost suitable for furtner development. The final package had a
volume of less than ?. ft3 and weighed less than 16 Ib.
This report was submitted in fulfillment of Contract No. 68-03-2507
by KSA Research Corporation under the sponsorship o* the U.S. Environ-
mental Protoction Agency. This report covers the period
January 7, 19/7 to April /, 1980.
iv
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CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vii
1. Introduction ... ..... 1
2. Conclusions . 4
3. kecommenaations ..... 6
4. Modular Capture-and-Containment-Bag Concept 8
Concept development 8
Prototype testing 9
Seal strength of conme.-cial P£ film bags 9
Testing of laboratory-fabricated clear PE bags .... 12
Testing of f iber-rei'iforced PE baas 14
Testing of fiber-reinforced bags from commercial
fabricators . 15
Testing of double-walled bags from commercial
fabricators. . 20
Summary of capti:re-and-coTitainment-naq concept testing 21
Field demonstration 23
Appendix A - Investigation of Surface Sealing Systems 32
Appendix 8 - English to Metric Conversion Factors .... 70
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FIGURES
Number Page
1 Capture-and-containment device, showing dual-layer
polyethylene film construction and collecting aoron 10
2 Deployment of device as used in simulated field test 10
3 Apparatus used to determine the strength and integrity
of polyethylene bags 11
4 Capture-and-containment device with sewn seams being
tested to maximum containment pressure head 16
5 Rupture of the device in the transfer tube attachment area . . 16
6 Capture-and-containment device fabricated of "Griff-Weave 24". 19
7 Capture-and-containment device fabricated by Sheldahl Corp . . 21
8 Construction details of a quarter-scale test device fab-
ricated by Silco Industries 22
9 Quarter-scale capture-and-containment device fabricated
by Silco Industries 22
10 Simulated tanker accident for field test demonstration ... 24
11 Detail of grommets for attaching apron 25
12 Detail of the transfer tube attachment 25
13 Weight, size, and total volume of these devices are
easily handled by one man 26
14 Field demonstration test - deploying the capture-and-
containment device 28
15 Field demonstration test - securing the device to the tanker 28
16 Field demonstration test - detail of the apron, secured to
collect leakage around the hatch 29
17 Field demonstration test - Silco Industries device con-
taining about 200 gal 29
18 Field demonstration test - Silco Industries device con-
taining about 500 gal , 30
19 Field demonstration test - modular concept demonstrated. . . 30
20 Overview of the field demonstration site with the two
capture-and-containment devices deployed 31
21 Detail of the Katz Bag Company device containing about
500 gal 31
A-l Schematic of spray chamber 47
A-2 Compatibility test unit 43
A-3 Air pressurization apparatus used to screen test specimens . 59
A-4 Modified test apparatus 66
vi
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TABLES
Number,
1 Results of Strength Tests with Commercial Polyethylene
Bags 13
2 Summary of Tests on Fiber-Reinforced Bags From Commercial
Bag Manufacturers . 17
A-l Total Sealant Weight as a Function of Application Rate
and Sealant Thickness 35
A-2 Listing of Sealant Candidate Manufacturers 38
A-3 Survey of Sealing Materials 41
A-4 Primary Representative Hazardous Chemicals 44
A-5 Results of Compatibility-Permeability Tests with Borden
Chemical Company Latex "Polyco 2607" 52
A-6 Test Results Obtained From Samples of Cliridrol "Superamide
lOOCb" 53
A-7 Results of Compatibility-Permeability Tests with £. I. duPont
DeNemours Surfactant "Zonyl RP" 54
A-8 Results of Compatibility-Permeability Tests with Callery
Chemical i ompany Urethane "115" Formulation 55
A-9 Results of Compatibilty-Permeability Tests with Ashland
Chemical Company "EP 65-36/88". . . 56
A-10 Selected Properties of Three Allied Chemical Company
Polyethylene Polymers 57
A-11 Low-Temperature Curing of Borden Chemical Company
"Polyco 2607" 59
A-12 Low-Temperature Curing of Ashland Chemical Company
Urethane Foam "EP 65-86/88" 59
A-13 Low-Temperature Curing of Callery Chemical Company
Urethane "115" Formulation 60
A-14 Preliminary Estimates of Cylinder Sizes for Supplying
Atomizing Air 63
A-15 Calculated Power Requirements and Battery Weights for
Liquid Coating Applicator Systems 63
A-16 Results of Pilot-Scale Tests Using Urethane Sealants 67
vii
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SECTION 1
INTRODUCTION
Concern about the control of chemical spills has increased in both the
public sector and the scientific community. The incidence of accidental
land spills has increased proportionally to the growing use and transport
of chemicals. This concern is at least partly the result of several
incidents in which ground water has been contaminated by percolation of the
spilled material.
Most of the scientific activity in this area has been directed to
monitoring the fate of the spilled material or health effects resulting
from its presence. Relatively little has been done to develop methods to
alleviate the problem of contaminated ground water. Present action in-
volves either the physical removal of the soil from the spill-affected area
and disposing of it at a secured landfill, or the drilling of "cone of
influence" wells to drain off the polluted water for conventional
treatment. These techniques are slow and expensive.
This report contains the results of an investigation of methods to seal
the surface of soils and prevent the intrusion of hazardous materials into
the ground. The objective was to develop a portable, self-contained,
universal sealing system that could be operated by one man, retain the
spilled material throughout a 24-hr removal period, and pose no subsequent
hazard to the user or to the environment.
The hypothetical scenario for the use of a soil sealing system assumed
that it would be employed immediately after a spill, possibly in
conjunction with diking materials, to confine the material to the immedi-
ate vicinity of the accident. The "esponse procedure wguld utilize the
transportation personnel or local safety personnel who were first on the
scene to determine the probable course of flow, to locate a containment
site, and to initiate eapture-and-containntent procedures.
One basic assumption of this investigation has been that site
preparation for any containment or sealing system would be minimal. Con-
ceivably, some intermediate-sized debris could be moved, but the ideal
sealing system would be capable of surmounting most obstacles. Since
accidents frequently occur during inclement weather, wet or frozen sub-
strates have been considered common conditions for operation. The design
goals for the system were as follows. The system must be:
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1. Portable and capable of operation by one man (maximum weight
40 Ib).
2. Self-contained.
3. Operable in a safe manner.
4. Operable in a manner such that no permanent secondary
environmental damage results.
5. Capable of fabrication from commercially available components
to the maximum extent possible.
6. Capable of reducing soil penetration by 95% on a land area
1200 ft? under 1 ft of liquid head for a 24-hr period.
7. Capable of sealing many types of soils under varied terrain
conditions with minimum site preparation.
8. Capable of application in varied weather conditions.
9. Capable of sealing when applied before or after spill front
has passed an area; i.e., "dry" or "wet" areas.
10. Capable of preventing the spilled material from seeping under
the edoe of the sealed area.
11. Capable of being removed after the spill incident is
terminated.
The program was designed (1) to select and evaluate filin-producinq
sealing materials that could be used to form a leak-free barrier on solids
in hazardous spill situations, and (2) to design and fabricate a prototype
device to dispense the materials and Demonstrate its usefulness for
production. The project completed only two of four scheduled phases when
it became apparent that design goals could not realistically be achieved.
No sealant candidate was found that could be applied to essentially
unprepared terrain with any reasonable assurance of an effective seal even
unaer ideal conditions. Polyurethane foam was considered the best of the
candidates surveyed. But when it was applied to grassy areas, -it could not
form a dependable seal even at rates approaching 6.13 Ib/ft^—far in
excess of the O.r? Ib/ft^ rate of the design -joais, and impractical on
the basis of costs and logistics.
Manufactured films that could be used as a barrier were not speci-
fically excluded by the design criteria, but they were not to be considered
in the primary program effort. When & suitable film-producing sealant
could not be found, however, our efforts were directed towards other
methods that might achieve the program goals in a practical manner.
Of the various commercial film materials available, polyethylene (PE)
was the most economical and had the widest range of compatibility with the
representative list of hazardous materials. Moreover, it has widespread
commercial applications and is a common item of commerce. The potential
was therefore extremely good for developing a spill-control package
inexpensive enough for widespread distribution to the common carriers or
local emergency response teams, or for ready local availability to a spill
site.
Polyethylene film was first investigated as a replacement for the
sealant in the initial spill scenario, considering its suitability for
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various terrain conditions, methods for deployment under adverse weather
conditions, and formation of suitable holding ponds from sheet material.
The concept proved to be practical.
The capture-and-containment-bag concept evolved from the idea of a
polyethylene-film holding pond. P> means was needed to capture the spilled
liquid and direct it to the temporary holding ponds, which may be some
distance from the spill.
The original idea was to use a 1,5- to 3-ft-diameter plastic-film tube
with a capture apron on one end that could be pulled under and around the
spill, and to run the captured material dov.n the tube to the containment
pond. The containment-bag concept grew from a need to hold some of the
spilled liquid temporarily until the ponds could be assembled. To
accomplish this, the tube was enlarged for increased holding volume,
forming a bag, and a small tube attached to the base of this bag for
eventually transferring the captured liquid to the pond. The use of a
larger bag for both capture and temporary storage was a logical outgrowth.
The work presented in the body of this report deals with the develop-
ment of the capture-and-containment-bag concept, detailing its development,
testing, and recommenaations for further development. In our opinion, it
is a simple and practical first-response solution for controlling a large
percentage of spills from bulk transport accidents.
The initial program effort pertaining to sprayable sealants developed a
significant body of data that were negative to the program objective but
Ore worthwhile reference information. These data are presented in the
Appendix.
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SECTION 2
CONCLUSIONS
The search for a soil-sealing system to be used immediately after an
accidental transport spill showed that polyethylene film has the most
promise of bsing a basic barrier material. Containment ponds formed from
?E sheet material and bags capable of holding 1000 gal were demonstrated
successfully under adverse soil conditions. Polyethylene is readily
available, chemically resistant, and inexpensive. Moreover, its physical
properties are amenable to the inclement weather conditions prevalent in
most transport spills.
Bags formed from 6-mil polyethylene film can hold more than a 1-meter
head of water without rupturing. Reinforced polyethylene is available with
even greater rupture and tear strength.
Heat-sealed seams on the units were the weak points. Sewn seams,
though prone to seep under pressure, proved to be more dependable. Double-
lined units with a heat-sealed inner bag and a sewn seam outer bag appear
to be the most leak-free, puncture-proof, and strongest design for
containing spills under higher head conditions.
A prototype design consisted of a 20-ft-long, 6-ft-wide bag with a
10-ft-long apron that collects the spill liquid and directs it into the
bag. Tie lines on the apron are used to position the device on the rup-
tured tanker.
A transfer tube attached to the bottom of the bag allows liquid
transfer to a secondary container. This design allows a modular approach
to containing spill liquid in several tandem devices.
These bags can hold more than 1000 gal on reasonably sloping terrain.
They weigh less than 16 Ib each, occupy less than 2 ft3, and could be
produced in quantity for $50 to $200 each, depending on the complexity.
Field demonstration tests of two capture-and-containment devices
confirmed tne modular approach. More than 1000 gal of liquid were col-
lected over 5 hr and stored without loss.
Polyethylene film is also a suitable barrier for fabricating emergency
holding ponds. Polyethylene film 6 mils thick contained water with more
than a foot of head when installed over weeds, reck, and other debris.
Larqe sheets would be difficult to deploy under wind conditions.
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but mechanical fasteners are available to join smaller sheets and thus form
barriers for larger pond areas.
Use of film-producing chemicals for onsite sealing of soils wes not
practical. Applying the film-forming formulations to substrates likely to
be found on berms and ditches near highways and railways produced barriers
that leaked through holes or seepage.
Three film-producing classes were investigated:
Notireactive sealants are those that have been previously
polymerized ana are either dispersed or dissolved in water or
other solvents. These depend on solvent evaporation for film
formation. Thus they are slow to form at low temperatures, if
such nonreactive sealants are in organic solvents, the vapors may
pose a fire hazard. The films formed under ideal soil conditions
often had pinholes. Leak-free films were not possible over rough
terrain and vegetation.
Reactive sealants are composed of two or more component systems
that react on application to form a polymer. They are more likely
to form films under adverse weather conditions than are the
nor.reactive sealants, but they have several problems.
Applications to snow-, ice-, or water-covered surfaces cause
frequent holes in the film and result in poor adhesion to the
substrate. Applications to vegetated areas often do not reach the
soil, but form poorly-bridged films with frequent holes,
especially adjacent to the vegetation. Pinhole-size voids ere
commonplace in the films formed even on well-prepared substrates.
Surfactant chereic-.1 s consist of repellent crsf-^iicals that modify
the surface characteristics of materials so that they are not
wetted. These failed to seal against candidate spill liquids when
applied to soils under ideal conditions. Two of the irore
promising surfactants investigated (£. I. duPont de Nenours'
fluorocarbon Zonyl RP and Clintwood Chemical Company's surfactant
CUndrol 1,00 C& did not retain the candidate spUl liquids when
applied to well-prepa/ed soils at 22 to 25QC. Even less success
would be expected on snow, ice, rain-soaked soil, or vegetation.
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SECTION 3
The capture-and-contairr-,ent-t>i)Q concept as a f irst-resrinsr measure for
the control of hazardous spill watt-rials trr-; bulk tappers should bf>
vigorously pursued. The units are potentially inexpensive, .irv.i t^Hr use
in spill situations is reaciily obvious to spill response r-rrsrnn.?) . Tn.->y
are therefore attractive candidates (or oni-oard twroency spi 1 1-ccnta tr,-;><'r)t
units fo.1 trucks and rail tankers or for distribution *nd i,se: t>y local
emergency response teams.
The basic film strengths of fiber-reinforced K fiHs are r\ore
adequate for the intended use, Out sears nc^O aoditicna! study. Sewn, soams
a'~e strong, hut they seep. H^at-sealecJ rtco^> «r<» leak-free, !:-ut somet iw,
they tail even at low head pressures. For tm-se reasons, a cootie-walled
bag with a heat-sealed inner baq of cica--, '.ow-density It cortsir-ed witn a
sewn-s^am outer bag of f ioer-reinforced >JL ctfers tne t-est promts*; of a
reliable final design.
Before ootentirtl baq ^anuf acturori will direct so.-irus efforts to
solving the several desicn prof>l<*ws «>vi«;f>nr». \<, nwded of a p;n««nlial
mar<:>t. Ihe desian of t't? unit', snouM :••• evaluated 'n Hn«' with
present-day baa rt.anufacturinq technir,M<»", . Duality control was less than
adeciuate on sea^ns and di^^nsions of the handmade test units provioed by bag
suppliers.
An expanded proqram thould include:
(1) improvements in deV1 li/ation, etc. This
information can then be considered in design discussions wltn
cofnr»ercial film and bao fabricators.
(2) Evaluation of cc^neroally ranut actured bags to test the
capability and rol i
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Experienced spill-control personnel have recommended further evaluation
and testing of the concept. Personnel from the Pennsylvania Department of
Environmental Resources in charge of spill control ir, the Pittsburgh
district observed a test of the fabricated bag. They were impressed with
the simplicity of the concept, enough so to recommend in writing its
further development and to request units for testing on actual spills.
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SECTION 4
MODULAR CAPTURE-AND-CONTAINKENT-BAG CONCEPT
CONCEPT DEVELOPMENT
The capture-and-containment-bag concept evolved from a need to capture
spilled liquid and direct it to temporary holding ponds constructed of
polyethylene film possibly some distance from the spill. The original idea
was to use ? narrow plastic-film tube with a capture apron on one end that
could be pulled under and around the spill source, and direct the caotured
material down the tube to the containment pond. The ban concept grew from
a need to hold some of the spilled liquid temporarily until the containment
ponds could be assembled. To accomplish this, the tube was enlaraed to
increase holding, volume, forming a bag, and a narrow tube was attached to
the base of this bag to direct the captured liquid to the containment
pond. The tube would be tied off until the pond was ready.
With the success of the initial bag concept, the idea of having
additional bags to held captured spill, rather than construct
polyethylene-lined holding ponds, was even more attractive. The use of
bags rather than the open ponds gave better vapor control. In addition,
bags were easier to deploy than plastic sheeting and needed no filrc join-
ing, hardware, or diking materials to help contain the liquid. Th.?
assumptions used as a design basis for the final device were as follows:
o The total available spill material may be as much as 10,000 aal;
however, in better than 45% of the cases, the spill rate will be
such that the total spill will be .ess than 1000 gal.
o Containment for at least 1000 gal will be made available in the
capture-and-containment-bag for quick, easy deployment by one
man. Subsequent containment units will be developed in 600- to
1000-gal modules.
o For safety, the connection to the spill source will be made only
once. The capture system will thus act as an emergency containment
system, but have the added capability of directing any overflow,
if this is required, to subsequent containment devices downstream.
o Diking material will not be available for the deployment of the
initial first-action capture-and-containment system. It might,
however, be available for the development of subsequent downstream
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containment areas, wiich could t.iKe the form cf additional baqs c»
plastic-film-1Hed ponds.
0 Procedures and/or a handbook describing techniques for connecting
simple spill containment modules, or tiie use of polyethylene
sheeting and sealant/fasteners tc forr. holding ponds w,!l t-e
developed for in-field use by spill containment personnel.
The final concept — the basics of which are shown in figures 1 and 2
— consists of a polyethylene-1ined, piHod-shaped bag, about 6 ft wide and
20 ft long, with an apron on one end. The apron has rope lines attached to
each corner which allow it to be pulled through an existing spill on the
ground, directing the liquid into the attached pillow bag. Subsequently,
these lines would be used to pull tne ipron into position under the
ruptured tanker and tied to the tanker in a slightly elevated fasnior. so as
to direct the hazardous liquid leaking from the tanker into the bag. Lines
located around the opening into the bag could be used for additional
support.
The overflow 1s a 4-in -diameter polyethylene tube, approximately 30 ft
long. It can be tied off near the bag, or laid out upstream along the oag
to prevent loss of liquid. The tube can be used for emptyino the bag for
cleanup, or for directing overflow to additional storage downstream.
PROTOTYPE TESTING
Most of the problems with the prototypes involved the heat seals,
especially at the high stress points where the transfer tube was
connected. Some of this probably was due to the priorities placed on the
fabrication of these bags by tne suppliers. Since it WAS a dfvelopw?nt
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• I
Figure 1. Capture-and-containment device, showing dual-layer polyethylene
film construction and collecting apron.
Tigure 2. Deployment of device as used in simulated field tost.
10
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Low Pressure
Regulator
Laboratory
Air -
Adhesive
Tape
Low Pressure
Gauge (0-20 in.H20)
Pressure
Gauge
(0-20 ps
7 Heat Seal
Copper Wire
'(under tension)
Pressure Relief Valve
1X]
Figure 3. Apparatus used Co determine the strength
and integrity of polyethylene bags
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The results and comments are summarized in Table 1.
The results indicated that polyethylene bags are indeed strong enough
for the proposed use, but that the following generalizations should be
considered in the fabrication of any capture-and-contairiment device:
1. Quality control procedures generally used for ma<=s production
units would be insufficient for tha proposed plastic film
fabrication.
2. Heat seals are as strong as the base material when properly made.
3. Improperly made heat seals, which may pass present quality control
checks, may have devects which would not hold any liquid.
4. Plastic deformation of 4 mi 1 (0.004 in.) thic* film occurs dur:r.«j
the first 3 hr of exposure to pressure heads of approximately 30
in. H20.
5. Failure of these same films required between 75 and BO in. Hj>Q
for rapid failure.
Testing of Laboratory-Fabricated Clear PE Bags
Two prototype pillow bags were fabricated from * mil (0.004 in.)
polyethylene plastic.tubing. Standard 6-ft wide (laid flat) tubing was cut
from a stock roll ana one end heat-sealed shut with a hand-held
clamshell-type heat sealer. The other open end was cut, removing half of
the tube for about 2 ft to provide an apron.
In the first test, the bag was deployed as a rolled-up tube,
4 in. in diameter, at the spill site. Water, the simulated hazardous
liquid, was fed from a hose at approximately 1.5 gpm to the bag. As the
water head built up in the end of the bag, the bag unrolled down.a hill-
side with about a 10% grade (1 ft/10 ft). Full deployment occurred in less
than a minute. Water was allowed to flow into the bag for 3 hr. 45 min.
(340 gal) building a maximum head of 13 in. with an estimated average head
of 8 in. No chanrje occurred over 24 hr.
In the second test, a similar bag, but with a 5-ft-long apron, was
used. The bag was deployed at a 45 degree angle to the downhill slope of
the terrain. This position was chosen *.o determine the tendency for the
pillow-shaped bag to roll as it filled if not placed exactly downhill on a
sloping terrain.
Again, the bag was placed as a roll, with the apron deployed and
attached as if collecting liquid from under a ruptured tanker. The mouth
of the bag was held open by separating the film with several small rocks
and water was supplied onto the raised apron at the rate of 5 gpm. At the
5 gpm feed rate, water first overflowed the bag without unrolling it, but
with a slight push it quickly unrolled with only a 2 in. head. In b min,
with 25 gal of water, the bag rolled sideways slightly. After 22 min and
110 gal of water, further movement sideways allowed water to overflow the
top rather than run to the bottom of the bag. The tie-downs on the
12
-------
TABLE 1. RESULTS OF STRENGTH TESTS WITH COMMERCIAL POLYETHYLENE BAGS
16 in. x 9 in., nominal 0.004 in. thick)
Sample
1
2
3
4
5
6
7
8
9
Pressure
(in. H20)
15
30
30
110
35
75
30
30
80
30
80
30
30
30
85
Exposure
Time (hr)
1
3
0.5
< 0.0001
1
0.003
CO. 01
0.5
0.005
>0.01
0.0001
2.5
3
30
> 0.01
Mode of Failure
Did not fail, some deformation.
Did not fail, no further
deformation.
Did not fail, some deformation.
Failed through heat seal.
Did not fail, some deformation.
Failed through sidewall.
Poor heat seal.
Did not fail, slight, deformation.
Failed through sidewall.
Partial separation in heat seal.
Failed through sidewall.
Partial separation in heat
seal from deformation.
Failed through heat seal.
Did not fail; laboratory heat seal.
Failed through sidewall.
13
-------
apron held the bag in place at that point. Cutting the tie-downs from the
projected ruptured tanker allowed the bag to roll down the hill sideways
and empty in the process.
A third test used the same bag, but with the bag deployed straight down
the 10% grade slope. The apron was held 16 in, above ground level as if
tied on the opposite side of the tank rupture, and water was added at the
same rate (5 gpin) to the apron. It was again necessary to prop open the
bag mouth with a large rock so that the water readily flowed between the
plastic film layers.
In the first test, 315 gal of water were contained at a maximum head of
14.5 in. over a 20-hr perioo. A total of 600 gal of water with a maximum
head of 24 in. was collected in the bag before failure occurred along a
fold line in the polyethylene tube. The leak was approximately 6 ft from
the sealed end of the bag at a point with about 20 in. of head. Fold lines
of polyethylene sheeting are notoriously weak points.
Testing of Fiber-Reinforced PE Bags
Bags fabricated from fiber-reinforced plastic films were evaluated to
obtain increased strength and puncture resistance. Reinforced films are
made up of a woven plastic, mat-like reinfjrcement fabric coated on both
sides with a thin film. This construction gives the material high tear,
puncture, and abrasion resistance, the degree of which are a function of
the density of the fiber weave.
The first unit was made of a film fabricated wHh 0.125 in. vinyl
fibers on a 0.25 in. weave. The bag was 8 ft wide (laid flat) with a 10 ft
apron, a 20 ft bag section and a 30-ft-long overflow tube. This unit,
fabricated by A. Mamaux and Son, Pittsburgh, PA, was the first with a
transfer tube to direct any overflow to subsequent containment devices or
systems downstream.
The bag was double-stitch sewn, with the stitching covered witii
polyethylene mastic tape to prevent leakage. It weighed approximately
16 15 and was; relatively easy for one man to deploy.
In the first test, the bag was deployed as a rolled-up tube at the 10%
grade test site. The bag was unrolled hy the single operator in freezing
temperatures in 6 in. of snow, and the transfer tube was deployed back up
the slope alongside the bag. Water flowed into the bag at 5 gpm. At a
total of 450 gal and a maximum head of 9 in., a leak developed in the
device at the sharp inside corner of the bag where the transfer tube was
attached. The leak was in the film fabric and not in the sewn seam, but
failure was thought to be caused by the stresses resulting from the sharp
angle at the attachment point.
Moving the transfer tube to empty the contained liquid from the bag was
successfully carried out, but with difficulty. The transfer tube's flat
width of nearly a foot was obviously too large, making it heavy when filled
with liquid.
14
-------
The leak in the A. Mamaux unit was repaired, and the size of the
transfer tube was reduced to 9 in. {'laid flat). A radius was also included
al the point of attachment to reduce stress at this point.
The bag was again deployed on the same downhill slope and supplied with
water at a rate of 5 gpm onto the raised apron. Water height measurements
were taken every hour, as well as color photographs of the progress. After
3 hr, 900 gal of water filled the bag to a length of 14 ft and 22 in. deep
at maximum head. No appreciable leaks were observed; however, some seepage
was observed at the sewn seams.
A second test with the same bag was conducted to determine the maximum
head the bag would hold on the 10% slope. The apron was tied above ground
level as if tied un the opposite side of a tank rupture, and water was
added at the same rete (5 gpm}. A total of 1350 gal was collected in the
bag in 4.5 hr before a seam began to leak (Figure 4). The leak again was
at the point of attachment of the transfer tube to the bag (Figure 5).
Water filled the bag to a 17-ft length with a maximum head of 26 in.
The water was removed from the bag via the transfer tube. The transfer
time was about 9.5 min, at a rate of about 142 gpm.
Although not completely successful, these tests indicated the
feasibility of the capture-and-containment-b?g concept. Deployment was
easy, and the containment safe to a reasonable head of liquid. It was
obvious, however, that more careful attention was needed at seams and
attachment points.
Testing of Fiber-Keinforced Bags from Commercial Fabricators .
Commercially-fabricated capture-and-containment-bags of
fiber-reinforced K, similar to the ones tested, were solicited from
several commercial hag manufacturers with the hope that their expertise in
this field could c*d in solving our seam problem. Their comments were
solicited on the overall design, including the shape, type of fabrication,
and seal at the transfer tube.
Only three companies agreed to fabricate test bags, none enthusias-
tically. These bags were received over a period of nearly a year and were
tested very similarly to the test previously described. Water, as the test
liquid, at a rate of 5 gpm, was added to the bags secured on a sloping
terrain of about 10%. Periodic measurements were taken of the maximum
height of water contained versus the volume of water added, and the mode of
failure, if any, was evaluated. Modifications were then agreed to in
conjunction with the supplier, and the bag was retested. A summary of
these tests is shown in Table 2.
Griffolyn Company supplied four bags made of Griff-Weave 24, a
film with 0.125 in. high-density PE fibers on a 0.125 in. weave sandwiched
between 2-mil clear low-density PE film. The total thickness was 8 to 9
mil. The material is exceptionally tough. A tear strength of 750
15
-------
Reproduced (rom
best available copy.
U— »— "*
yr
1 II If
ft t
.
^*
^^
v«
Figure 4. Capture-and-containment device with sewn seams being
tested to maximum containment pressure nead.
I
V/////A
Figure 5. Rupture of the device in the transfer tube attachment area.
16
-------
TABLE 2, SUMMARY Of TESTS ON FIBER-REINFORCED BAGS FROM COMMERCIAL SAG MANUFACTURERS
1.
2.
3.
4.
5.
6.
Supplier
Griffolyn Company
Houston, TJC
•
•
•
SUco Industries
Newark. NJ
Katz Bag Coopany
Indianapolis, IN
Maximum Test
Type of Vtler Head
Fabrication (In.) Comments
Seams Manually
double-bar sealed
Double stitched sewn
seams - slllcone coated
Double stitched sewn
seams - PE-tape coated
Hot-air blown heat-sealed
seam
teat-sealed seams
Proprietary extrusion
process
12
12
29.5
<5
<5
48
Failed near the seam - heat distortion
Small leaks at jointed corners
Filled to capacity (~1SOO gal)
Seams leaked at about 0.4 gpra
Seams failed .zipper-like
Seams failed zipper-like
Bag on 1/4-scale
No failure
Weight
(IbL
13.5
--
~
12.6
9.8
«
(full scale bag)
8.
Mechanical seal around
transfer tu'.e
Improved 0-rlng seal
around transfer tube
12 Leakage around mechanical seal
Held for demonstration testing
-------
was reported for the film by the supplier. In our own test, a slit that
was cut in a sample of the film could not be propagated with bare hands;
nor could a six-penny nail readily puncture it with only hand pressure.
The manually heat-sealed test bag (No. 1 - Table 2) failed quickly at
about a foot of head, apparently as a result of heat-weakened film adjacent
to the seam. Bags with sewn seams fared better. One coated with silicone
(No. 2 - Table 2) leaked readily at the joints. The one with the
PE-tape-covered searns (No. 3 - Table 2), on the other hand, did rot fail
catastrophically but seeped slowly at all seams. Unfortunately, a number
of excess seams appeared to be present in the construction. This bag was,
however, filled to capacity at about 1500 gal with a maximum head of about
29.5 in. (Figure 6).
A hot-air blown heat-sealed bag (No. 4 - Table 2) was apparently not
well-sealed and opened up along the seams like a zipper early in the test.
The seal at the seam was apparently not hot enough to involve the high
density PE fibers, and the film just pulled apart. A bag submitted by
Silco Industries (No. 5 - Table 2} with similar materials and fabrication
techniques also failed in the same manner.
Katz Bag Company of Indianapolis, IN, a major fabricator of
polyethylene film bags, supplied a single-ply fiber-reinforced polyethylene
film fabricated on approximately 1/4-scale using their proprietary
extrusion process. The bag was fabricated of polyethylene sheeting
consisting of t*o layers of polyethylene (-vl mil) on either side of a
polyethylene fiber matt. The sheet had a nominal thickness of 8 mil.
Other thicknesses are available.
The bag (No. 6 - Table 2) was first tested to 2 ft and then to 4 ft
head. Small holes appeared in the seams but none developed into a
catastrophic failure. The strength of the bag material was more than
adequate for liquid containment. The material was abraided by stones and
vegetation, end "pinholes" developed within the sheet Hself during the
tests. Neither the heat-sealed seams nor these abrasive cuts in the sheet
opened further, however, when the pressure head was increased to 4 ft.
The full-scale unit (No. 7 - Table ?) supplied by Katz Bag Company used
a mechanical seal to attach the transfer tube to the bag. This seal
consisted of drawing the two pieces of polyethylene (bag and delivery tube)
around a 1-ft length of 3-in. diameter pipe. PVC pipe was used for tne
prototype device, although polyethylene or polypropylene would be used in
the final design for better chemical resistance. This device was tested
using the standard screening spill procedure and held only a 12-in. head of
water before some seepage occurred around the mechanical seal.
18
-------
Figure 6. Capture-jncl-contninnent device MJrtcated of
•Griff-Heave 24".
-------
A tnird unit fr««,i Katz tao tc'-'^any (Na. B - T.»;>lo _') incorporated -,n
"G-ring" radif ication to their nnuinal vpchanical sea) at Re trarsft-r
tube. This ba^ KJS tested success) u • ly during toe field uencnstrat io»i
using a railroaa tank-car simulated spill.
Jest ing of iX j!)Jf ^j»j lie aq and 3 se»n reinterceu-r i:,er oi;ter aag construction
were solicits Iron) co.'iwercia1 manufacturers. Tne inner DJQ fomeo the
leJK-free liner — tne outer bag provioed support for the higher
pressures. Units froT two companies »ere yurctusea. Une fro*i Sheldshl
Corporation consisted of an inner bag of nonina! 6-rcil-th>CK polyethylene
film and an outer bs<} constructed of "?oly-Iut f ", a reinforced polyethylene
film.
was done on the sloping &rf>a usou for all screening tests.
Water was directed into the ban it a QP»« with no signs of leakaqe until the
pressure heac! was increased to 31.5 in. At that tine the plastic in tht>
area of the seal between the containwnt baq and the delivery tube appeared
to lie strained, ana tiv in. head for approximately 4i> mag In the section between the delivery tu.be and the rontAinwent big was
o;>ened over 4 length of about ? ft, typical of poorly heat-sealed seaws in
polyethylene. Although the inner bag haa failed, the outer bag held well
under the pressure.
The project was terminated before corrections and improvements could be
made in the Sheldah) units. Ine prototype was of hich quality and it is
linely that shortcomings could be corrected, tt-ne permitting.
Stlco Industries of Howark, *J. fabricated a 1/4-scale, double-walled
unit with a 4 mil ft Inner "liner with a continuous heat-sealed seam, and a
Pt mesh outer b^g fabricated by a double-stitch-sewn-seam technique (Figure
8). The guarter-scale unit tested successfully !o 46.5 in. of head with no
leaks (Figure 9).
A full-scale double-walled unit submitted by Silco had »
double-st itch-sewn outer bag of f iber-reinforcej HE film. AUhouoh the
outer bag was to have been fabricated slightly smaller than thf- Inner bag
to give immediate support on filling, sjch was not the case, and the outer
bag provided only a ioose fit. On filling, the inner bag seam failed
^o
-------
Figure 7. Capture-and-contalnment device fabricated
by Sheldahl Corporation.
21
-------
i
Figure 8. Construction details of a quarter-scale test
device fabricated by Silco Industries.
Figure 9.
Reproduced I'oni | • J
besl available topy. V,,,j/
Quarter-scale capture-and-containment device
fabricated by Silco Industries.
22
-------
near the transfer tube connection after only hit) gal.
Despite the above failure, a unit from Silco Industries witn this scs^e
desiqn, but with close fitting boqs-and n>ore careful attention to inner uao
construction, was tested successfully in our field cieronstraticn.
>uTriarj^qf_^a^i|rj^jm1-Contairrwnt-Bag Concept T>st ing
Capture-and-containr'sent-bags appear to be extremely attractive "first-
action" devices for the control of eiwrgency spUls of lic,jios. *jnit
capable of containing about 1000 gal wciqh less than ^0 lo and occupy a
storage volume of less than 2 ff.3, depending on the design.
Manufacturing costs are estinateo at less than J20J, with t> range. In ariJition, their deployment is not
only simple, but obvious. They are therefore attractive candidates for
onboard emergency spill-containment units fcr truck ana rail tankers or for
distribution and use by local ome.-gency spill t;ams.
Demonstration
A field demonstration was conducted with two prototype capture-
and-containment-haqs at a site at MSA Research Corporation, The simulated
accident was a railroad tanker Uid on its side with leakage around the top
hatch (Figure 10). Water was the simulated spill liquid at a leak rate of
5 gpm.
The spill site had only a qentle slope away from the tanker, which
limited the allowable head buildup in the baqs and thus total contuinnvnt
capacity. It did, however, demonstrate the ease of placement, thp utility
of the bags, and the ability to contain significant liquid under even these
conditions by use of the modular bag concept.
The fleTd demonstration tested two units selected *s th« most prorr.ising
-- one fabricated by S1lco Industries, inc. and one from Katz Bag Company.
The SiUo Industries' unit consisted of an Inner baq fabricated from 6
mil clear polyethylene film by continuous heat sealing of all seams, and an
outer bag fabricated from fiber-reinforced PE film with double-sewn seams,
The outer bag material was a close weave 1/8 in. count * 1/8 in. wide
polyethylene fiber-reinforced 9-mH-thick polyethylene film. Both bags had
essentially the same dimensions so that the outer bag would retain the more
elastic inner unit on filling.
Grommets for tie lines were Installed at several positions along the
opening to the bag (Figure 11) and around the apron to assist in deployment
and capture of the liquid. The lower end of the bag, rather than being
23
-------
Reproduced liom f • )
t-.t-ii available copy. \_-_J
Figure 10. Simulated tanker accident for field test demonstration.
24
-------
Figure 11. Detail of groinmets for attaching apron.
Figure 12. Detail of the transfer tube attachment.
25
-------
Figure 13. Weight, size,and total volume of these devices
are easily handled by one man.
-------
cut and sealed square, was angled at about 45° where the transfer tube
was attached (Figure 12). The delivered weight was about 15 Ib and
packaged volume less than 2 ft^. It was easily carried by one man
{Fkjtrre 13).
The Katz Gag unit was fabricated from single-ply 1/8 in. count x 1/8
in. wide polyethylene fiber-reinforced polyethylene film with a total
thickness of long delivery tube was mechanically attached
to the containment bag with an "0-ring" connection as an alternative to
heat sealing.
Effort was made to simulate a spill-response working atmosphere during
the demonstration to gain an insight into problems of deployment. Safety
equipment was worn by the technicians, inducting respirators, safety
glasses, hard hats, gloves, steel-toe safety boots, and chemically-
resistant clothing. To minimize exposure, the spill source was approached
only once.by the technicians to attach the capture apron of the initial bag
to the leaking tanker.
The technicians approached the tanker, with the simulated leak of 5 gpm
in progress, dragged the apron of the Silco unit under the leaking hatch
(Figure 14), and tied it into position (Figures 15 and 16). The delivery
tube at the bottom of the unit was deployed uphill in order to serve as a
valve. Figure 17 shows the unit in final position with approximately 200
gal of contained water.
After positioning the first unit, the Katz bag was placed in tandem
below the first. This second unit was kept in reserve while the first was
being filled. Because of the sloping conditions of the spill site, the
first bag was only able to contain a little more than 500 gal of simulated
spill. Figure 18 shows the liquid level in the bag at this point.
The field test was continued by transferring the accumulated spill
liquid from the first unit into the second to verify the Popular approach
to collecting hazardous liquid from an accidental spill. The transfer tube
of the first unit was maneuvered without loss of liquid to the apron of the
second (Figure 19).
The sp1H test was continued with the simulated flow from the tanker
Increased to a rate of 15 gpm. Figure 20 shows the overall view of the
spill site and bag deployment with about 850 gal captured. The transfer
tube of the second unit was deployed upgrade to prevent liquid loss. The
test was terminated when the two units combined contained more than 1000
gal. Figure 21 shows the condition of Bag No. 2 at this point. No leaks
were evident 1n either bag.
27
-------
Reproduced (com
besl available copy.
.
„ _ -—^_ _ _ *> ,K J«— - -» . ' •• J« -
Figure 14. Field deinonstrdtion test - deploying
the capture-and-containment device.
Figure 15. Field demonstration test - securing the
device to the tanker.
28
-------
•
Figure 16. Field demonstration test - detail of the apron,
secured to collect leakage around the hatch.
Figure 17. Field demonstration test - Silco Industries
device containing about 200 gal.
29
-------
Figure 18. Field demonstration test - Silco Industries
device containing about 500 gal.
.
Figure 19. Field demonstration test - modular concept demonstrated.
3U
-------
Reproduced from /"''"X
besl available copy. \* 3
Figure 20. Overview of the field demonstration site with the
two capture-and-containment devices deployed.
"
•'•'"
Figure 21. Detail of the Katz Bag Company device
containing about 500 gal.
-------
APPENDIX A
INVESTIGATION OF SURFACE SEALING SYSTEMS
GENERAL OUTLINE AND DESCRIPTION OF PROGRAM
The initial program was designed to select and evaluate sprayable
sealing materials which coula be employed in hazardous material spill
situations and to design and fabricate a prototype application system. The
planned program consisted of the following fc^ phases:
1. Laboratory Studies
2. Pilot-Scale Testing
3. Prototype Fabrication
4. Field Demonstration.
Laboratory Studies
The first pnase of the program consisted of the selection and
evaluation of sealing materials which could fulfill the design goals. It
included a survey and selection of sealant candidates and chemical
compatibility studies and permeability tests that defined the capabilities
and limitations of candidate sealing materials.
A portion of the work at the beginning of this phase also was dedicated
to the selection of representative hazardous materials used in the
compatibility tests.
Pilot-Scale Testing
The second phase of the program continued the evaluation of candidate
sealing materials under conditions that simulated those of typical spill
situations. The sealing capabilities of the more promising candidates were
measured when they were placed on soil, stone, and grass substrates with
equipment that could be used in accidental spill situations.
Prototype Fabrication
The third phase of the program was the design and fabrication of a
prototype device which would best fulfill the objective of the program.
This design concept was to be based upon the results obtained in the first
two phases and was to be tested under simulated spill conditions to
32
-------
determine areas fur modification and parameters to be cmsidored in the
field dernonstr.it ', on.
Field IVynonstrat ion
The fourth phase of the proorar.i was to be a field test of the system on
a spill of IIJ.GGJ gal of simulated Hazardous liquiu.
Phases 1 and ? of tne program were conducted js planned. At the
conclusion of Phase ?, however, it wa:- evident that sprayable systems w?re
not the answer to the problem. AS a result, tht re"'aincer of the oriqit.al
progr.vn was aDcinooned, ana tne ervt'itas is placed on the c jpture-ano-
concept describees in tne main body of tMs report.
This Appendix describes the spray sealant effort ana presents the data
that constituted the major portion of 1'iat program.
DISCUSSION OF CANDIDATE SEALANTS
Recent advances in the development of sealing 'Materials have
significantly increased the number or products commercially available.
This, in conjunction uitn the broader scope of applicability available in
these new products, made it mandatory to survey the field for sealing
materials that could be considered canoidatei for this program.
The sealing materials which could be considered for sealing soil
surfaces against intrusion by hazardous chemicals may oe grouped into three
general classes: Nonreactive, reactive, and surtac^-inochrying c'ip'-iicals.
These classifications indicate the chemical formation of the s«.>lant film
and/or the interaction of the sealant with the substrate surface.
Nonreactive Sealants
Nonreactive sealants are those which have been previously
polymerized and are dispersed cr dissolved In either an aqueous or another
solvent system. Such materials are primarily thermoplastic in nature, and
Include such materials as:
1. BUumastic
2. Rubber
3. Acrylic
4. Cellulosic
5. Fluoroplastlc
6. Phenolic
7. Polyester
8. Polystyrene
9. Polyvinyl chloride
33
-------
Several (if Uie.se "%Urt»iieh
t''t» oCo''Ouj r-etlia rjKt'i i:0 (. . v/r\tr 1 :, .it iof to fif'jltfi f ' :' SJTft/ '!.'.' fl.r;','. . Ifif:,)1
^'jt'rus ois;.ers ions are '.u:>i>-cv. to f rer/i'M:, '•;!">*<• vt-r, ar-.r: filr; t or-at ioi,
»'iic': depots upon evaporation, reflects Uie influence- ot ;.oth tf-turraturp
ana air velocity. Mouseriold lau'x i.-iirts jr»? typical rxi-ples; tftf rate o?
*il"; »orr'stijn is very slow it lower temperatures.
Solvent svste-s UCPO.MJ en ovaporjticn of I no solvent for til"
formation. Solvents or solvent systems otf'er than water often nave
offensive oa;irs or are fla~»Mable. Many solvents will contrikute to the
potential fire cr health hazards, urson L.SCU in rc'-Donse to spills or
Tht> films prepared from dnv solvent Systf'ns aro subject to pinholc>
forr.ation, even on very well prepareo Substrates, nfien djipHcd ovor rouqh
or very porous Substrates, formation ot •» Continuous f i IP Ln?cows very
difficult to (KCOiT:plish.
^ (.' J c t < v e So a i in t s
Reactive sealants are two or more component svsters in which one
component is reacted with a second component (often with 4 catalv.t) to
yield a polymer, 'fxanplcs or this «.ype of sealtng (naterial
1. fpoxy
L*. Unsaturated polyester
3. Phenol/ .'
4. t'roa/tomaldehyde
b.
Solvents are optional In the reactive materials listed -itove.
Although t^e substrate r.$y be at a low*?r temper. iture, the Cfynponents of
these systems have 4 mtnifliu-ti temperature for nlxinq the components an
-------
A-l. TOTAL SEALANT WEIGHT AS A FUNCTION OF
APPLICATION HATE AND SEALANT THICKNESS
Application Weight of Secant Coating Thickness (in.) at
Kite Required Coating Density of
(Jo/ft2) (lb/'?uO ft*} (3 Ib/ft3)'(20 Ib/ft3) (60 Ib/ft3)
0.03 36 0.12 0.02 0.006
0.06 Tl 0.24 0.04 0.012
0.10 120 0.40 0.06 0.020
Although foam expansion to 3 Ib/ft3 does not appear to be practical at
Viese low application rates, a sealant density of 20 Ib/ft3 will generate a
njcn thicker film with a greater possibility for sealing than the unfoamed
materials at approximately 00 Ib/ft3. The latter results in only a 6-mil
film at an application rate of -1.03 Ib/ft3 (the ncrmal thickness for
polyethylene film) and about a 20-mi 1-thick film for an application rate of
0.10 Ib/ft3.
Chemicals
The third sealant typo consists of repellent chemicals which, when applied
to surfaces, modify the surface characteristics such that the surfaces are not
penetrated.
Extensive repellent technology has been developed for four classes of
materials: textiles, paper, leather, and masonry. In each, there is a broad
range of techniques and chemical systems but only two classes of chemicals --
stlfcones and f luorocarbons •- appeared promising for the proposed use. These
are used to provide the so-called durable finishes on textiles, those that are
essentially unaffected by either laundering or dry cleaning.
SI If cone systems are employed either alone or in combination with melamine
or ur
-------
againrt selected hazardous chemicals, and film cure at various
temperatures. The application equipment requirements for each were also
investigated.
The use of sprayable, film-producing chemicals for the onsite sealing
of soils was not practical. Applying the film-forming systems to
substrates likely to be found on berms and ditches near highways and
railways produced films that leaked or allowed seepage underneath.
A summary of the results for the three classifications is as follows:
(1) Nonreactive materials, those which have been previously
polymerized and are dispersed or dissolved in either an aqueous or
other solvent, had the following faults:
(a) They are often subject to freezing and deactivation during
storage or when applied.
(b) Film forming at Inwer ambient temperatures can be very slow.
(c) Film forming at higher ambient temperature can be too fast.
(d) When formulated with organic solvents, these systems require
evaporation, which poses a fire or health hazard.
(e) Film formation often results in pinholes in the film as the
solvent evaporates.
(f) Leak-free film formation was not possible over rough terrain
and vegetation. A very uneven film with shadow areas having
little or no film results.
(2) Reactive systems, composed of two or more components that are
reacted orisite to yield a polymer are more likely to form films
under adverse weather conditions, but have several problems:
(a) These systems cannot be used on snow, ice, and wet surfaces;
the spilled liquid generally lifts the film and flows
underneath.
(b) Holes in the film occur when the film is formed on top of
snow, 1ce, or water.
(c) Applications to vegetated areas produce films that do not
penetrate to the soil below and that leak badly.
(d) Even on well-prepared substrates, pinhole-size voids are
commonplace in the films.
(3) Repellent chemicals that modify the surface characteristics of
materials such that the surfaces are not penetrated by liquids
simply were not effective on soils. Silicone and rluorocarbon
repellent chemicals were evaluated with similar observations.
LABORATORY INVESTIGATION
The laboratory investigation of potential sealing materials was taken
through a series of tests designed to outline their capabilities and the
possibility for fulfilling the objective of the program. The test sequence
progressed from the subjective data obtained in the initial survey to
36
-------
pi lot-scale tests.
This ;..riase of the procjra-i "viluated each candidate in terms of the
conditions required to form a continuous seal, cnemical ccTpatibi 1 ity of
the film with representative hazardous chemicals, ana o^rneani 1 ity of the
film to liquid chemicals. Fne tests *ere n.ide under controlled conditions
for comparison of trie various typo-i of sealing :-en sales representatives to assure an Accurate appraisal of the
candiuate's performance under adverse conditions.
Samples were requested for a preliminary evaluation if, in the opinion
of us or the supplier, fie candidate could neet the Jollowinq broad
criteria:
A proi .?n ability to fora a continuous film.
Sprayabl« uider conditions practical for a portable system, or
could be wade so-wttn minor modification to the fomulatlon.
. Able to form a protective ikln on the fi^m 1n a reasonable tlm*>
period. Fifteen min at made.-i.tf conditions appeared reasonable.
Mo serious threat Jn KseM to the operator or titc environment.
Manufacturers' compatibility data were essentially Ignored since most such
data are based on and Intended for lonq-term exposures, whereas this
Intended use was short-term. Conditions such as bllsterinq or swelling,
which may affect a sealant's use In other applications, were of little
hindrance to Us use as a barrier to penetration of a chemical into the
substrate.
Candidate sealants were screened by either soraylng or brushinq the
materials on a cardboard backinq. Fhyslcal properties and set limes were
observed, and the more promising candidates were exposed to a selection of
hazardous chemicals under a foot of head pressure. This was accomplished
by simply sealing a foot-long section o* glass tube to the coated cardboard
with a sillcone caulking as a sealant it the interface, and Introducing the
test hazardous chemical into the tube.
37
-------
TABLE A-2. LISTING OF SEALANT CANDIDATE MANUFACTURERS
Contact
Potential Sealant
American Cyanaroid Company
Anderson Development Company
Ashland Chemical Company
Atlas Minerals and Chemicals
Borden Chemical Company
Gallery Chemical Company
Carboline Company
Ceilcote Company
Clintwood Chemical Company
Corrosioneering, Inc.
Dow Chemical Company
Or. Leonard Spialter
duPont Specialty Chemicals
E S B Incorporated
General Electric
Goodloe E. Moore
Hooker Chemical Company
Irathane Systems, Inc.
Johns-Manvllle
Koppers Company
Lastek Paint, Inc.
Locktlte Corporation
Mameco, International
Midland Adhesive and Chemical Corporation
Onelda Electronics Corporation
Orb Industries, Inc.
Palmer Adhesive*
Urea/formaldehyde
Silicones
Urethanes
Adhes'ives
PVC copolymers
Urethanes
Vinyl paint
Bitumastic and polyester
Surfactants
Epoxies and polyesters
Epoxies
Silicones
Fluorosurfactants
Adhesives
Silicones
Adhesives
Phenol/formaldehyde
Urethanes
Ceramic adhesives
Polyesters
Bitumastic coatings
Adhesives
Urethanes
Epoxies
Adhesives
Aerosol adhesives
Adhesives
38
(continued)
-------
TABLE A-2. LISTING OF SEALANT CANDIDATE MANUFACTURtRS
(continued)
Contact
Potential Sealant
PPG Industries
Pocono Fabricators, Inc.
Pullman-Kellogg Company
Protex-a-Cote
P.V.O. International
Randustria1 Corporation
Royal Industries
Sauereisen Cements Company
Shell Chemical Company
Shiloh Specialty Company
Tracor, Inc.
3M Company
Trowelon, Inc.
Union Carbide
Polyesters
Cements
Fluorocarbons
Coatings
Proprietary aqueous system
Urethane sealer
Fluorocarbons
Cements
Surfactants, epoxies
Sealants
Previous work
Polyesters, surfactants, and
urethanes
Polyesters
Polyphenol and phenol/
formaldehyde
39
-------
The oreliminary challenge chemicals were wator, sulfuric acid, sodium
hydroxide, trichloroethylene, methanol, naphtha, and methyl ethyl ketone.
Conclusions as to the utility of the specific sealants based on the results
of exposure to these challenge chemicals are summarized in Table A-3.
Failure of the sealant coating generally was catastrophic with loss of
liguid. For those cases where failure was observed, similar chemicals in
the classification were tested for verification. Those considered for
further testing generally passed all preliminary tests.
Although representatives of all 13 sealant types were evaluated,
promising candidates were limited to only four of these. They were:
Adhesives Borden Chemical Company's Polyco 2607
Urethanes Gallery Chemical Company's Resin 115
Ashland Chemical Company's EP 65-86/88
Surfactants duPont deNemours1 Zciyl HP
Clintwood Chemical Company's CUndrol 100CG
Plastic Sheeting
In general, it was felt that aqueous sealants, repellent chemicals, and
adhesives required additional experimental testing to provide more complete
data for evaluation. For the reactive sealant candidates, only the
urethane systems were found to combine mos4. of the characteristics required
of the sealing materials for this program. The epoxy systems were found to
have excellent chemical compatibility when exposed to the challenge
liquids, but required special care in sett'ng the component ratios and
thick layers for suitable field application. polyester systems were,
generally, quite easily sprayed, but ,iad severe temperature and chemic.il
compatibility limitations. Un? silicone formulation was found which could
be considered for field applications, but M^h viscosity and limited
chemical compatibility would restrict its sealing capabilities. '
Several commercial urethane formulations were found to be generally
applicable for the intended use. The considered opinion concerning their
me was that foaming formulations would provide the best combinution of
characteristics to fulfill the objective.
Several types of plastic sneeting were found to have general appli-
cability for the intended use. The initial attitude concerning their use
in this program, however, was that they were not of primary interest, and
that sprayed systems were to be emphasized. This attitude was later
revised and polyethylene sheeting in the form of bags became the main
thrust of the program.
At a later point in the program, since polyethylene film proved to have
such excellent compatibility against most challenge agents, polyethylene
and polypropylene prepolyrners were tested as a sprayable film. These were
obtained as low melting waxes that were melted and sprayed on a substrate
to cool and form a film.
-------
TABU A-J. SUWt OF SEALING MATERIAIS
Set I ant Type
Adhesive
Acrylic
Paint
Silicon*
Urethane
Ur«thtn«
Surfactant
Pol/ester
Coivvty
Goodloe C. Hoore
One Ida tlectronlcs
Borden Chemical
Johns -**nvi Me
Emerson I turning
Cote-P.an»er
Ctrboline
General tl» 65-46/88
S«vle kit
2onyl Kf
Cllndrol IOOC6
Flrteline 75?
1070 Resin
General
Perfor»aiKe
Questionable
Quest (nntble
Questionable
Poor
Good
Good
Good
Question able
Quest (enable
Questionable
Questionable
Poor
Question aole
Questionable
Good
Questionable
Sood
Good
Questionable
Good
QuK.tlonable
bood
Poor
Good
Question able
Conclusions I Observations
Unacceptable compatibility
Unacceptable compatibility
Unacceptable compatibility
Unacceptable compatibility
Questionable
Unacceptable
Acceptable; slow degradation
Unacceptable; core conditions
Unacceptable compatibility
Unacceptable compatibility
Uniccepl*l>l£ compatibility
Unacceptable compatibility
Unacceptable compatibility
Unacceptable vtscos!*.- and
compatibility
Unacceptable viscosity
Unacceptable compatibility
Ursccepl'hle viscosity
Acceptable
P*ior fl'alnq
Acceptable
Unacceptable cowpat fbllity
Quest lonaMe
Unacceptab'e convatibilit/
Unacceptable viscosity
Unacceptable compatibility
(continued)
-------
TABLE A-3. SURVfT OF HALING MATERIALS (continued)
See lint Type
Aqueous (two
component)
Epoxy
Ure«/
formaldehyde
Phenol/for -alde-
hyde
Plastic Ft|«s
I Sheeting
Company
Pacific Anchor Otv.
P.».0. Internat't
Corrostoneerlng
American Cyanantd
Hooker Che* leal
Aero-Jec
«!lied Cheaical
Foaned Poly-
Product *JO*
Chew-Cure
RestsU-Flafcr 4200
—
~
Polyurethane
Polyethylene
Polypropylene
Foamed Poly-
ethylene
propylene
Fowd Poly-
styrene
General
Ferforwrxe
Questionable
Questionable
Questionable
Questionable
Good
Good
Good
Good
Good
Questionable
Conclusions t Observations
Questionable
Questionable; thick coatings
required
Lnacceptable; added pollution
Unacceptable; added pol"it)on
Acceptable
Acceptable
Acceptable
Unacceptable; hot preparation
required
Unacceptable; hot preparation
required
Unacceptable; compatibility
Cerent
Pocrno Fabricators
-------
Selection of Representative Hazardous Materials for Challenge Agents
Recent growth in the use and transport of chemicals has significantly
complicated the selection of materials for representative challenge
agents. The number of commercial chemicals and the degrees of hazard which
they may present to the public or the environment make this selection
difficult, at best. Selecting the materials to be used for evaluating and
developing a system for sealing soil surfaces required a thorough search
and judicious analysis of data generated in many diverse areas.
The selection of representative hazardous materials was made from data
published by chemical manufacturers, safety associations.,and both
government and insurance agencies. These sources were used to select 30
chemicals to represent those that are transported in bulk and that would,
if spilled, present a significant threat to ground wf»ter supplies in the
area. These materials are presented in Table A-4, which includes
representatives from most chemical classes.
Data, such as the quantity transported, relative hazards such as TLV
(Theshold Limit Value), LC (Lethal Concentration), and LEL (Lower Explosive
Limit), spill probabil Hies, and biodegradability were used as criteria in
selecting these chemicals. When overall ratings were similar for several
candidates, the final selection was based upon chemical aggressiveness
toward containment systems.
A typical example may be shown for the inorganic acids class. Sulfuric
acid is an obvious choice, based on the quantity which is transported.
Nitric and arsenic acids were possible second choices. Although it was
recognized that arsenic acid represents a greater pollution hazard, nitric
acid wes chosen because of its greater chemical reactivity toward most
sealing materials. The logic in the selection was that any system capable
of containing nitric acid would also contain arsenic acid.
Sodium hydroxide was chosen to represent all three major inorganic
bases: sodium, potassium, and ammonium hydroxides. All are aqueous solu-
tions posing essentially the same reactivity and thus containment problem.
Phosphorus trichloride is a typical liquid inorganic halide
transported. We have not included any solids, such as aluminum chloride,
as challenge agents even considering that in a rain water-soluble solids
might be considered a hazard. We believe that in a rain, where solids
could be a problem, the obvious solution is to place a protective cover
over the spilled chemical.
We chose phosphorus oxychloride as our inorganic oxidizer represen-
tative, although nitric acid also would be classified as such. Silicon
oxychloride was an alternative choice. Others are also handled in bulk --
namely hydrogen peroxide, calcium hypochlorite, and sodium bichromate.
Carbon disulfide was chosen as the organic sulfur derivative because of
Us solvent properties.
43
-------
TABLE A-4. PRIMARY REPRESENTATIVE HAZARDOUS CHEMICALS
Inorganic acid:
Sulruric
Nitric
Inorganic base:
Sodium hydroxide
Inorganic halide:
Phosphorus tri-
chloride
Inorganic oxidizers:
Phosphorus oxy-
chloride
Organic acids:
Acetic
Acrylic
Organic halide:
Aldehyde:
Methylene chloride
Trichloroethylene
Acetaldehyde
Benzaldehyde
Plastic monomer:
Styrene
Vinyl acetate
Alcohol
Ester:
Amine:
Ketone:
Isopropanol
Cresols
Ethyl acetate
Ethyl acrylate
Ethanolamine
Pyridine
Acetone
Methyl ethyl ketone
Mixed solvent:
Naphtha
Turpentine
Lacquer solvent
Mixed hydrocarbons:
Gasoline
Kerosene
Aromatic:
Toluene
Xylene
44
-------
Two organic acids were selected — acetic arid acrylic. Acetic acid has
the most spill potential. Acrylic, on the other hand, has a significant
potential for spills based on intra-plant transport and poses a tougher
containment problem.
Methylene chloride and trichloroethylene, because of their excellent
solvent properties, were chosen to represent the organic halides.
An organic sulfur representative was not included. The mercaptans are
transported in bulk, but present no unusual solvent or reactivity
properties.
Acetaldehyde, benzaldehyde, and acrolein were selected over furfural,
butyraldehyde, and formaldehyde. Each candidate has either high spill
potential or poses a difficult problem to the sealant.
Isopropanol and a cresol were selected over etrylene glycol and ally!
alcohol.
Herbicides and pesticides '-/ere not selected as challenge agents. To
our knowledge, none are transported as bulk liquids and, when formulated as
liquids, are either in aqueous or hydrocarbon solution. Thus these
classifications are best represented by the solvent.
Ethyl acetate and ethyl acrylate were chosen to represent esters.
Vinyl acetate and methyl methacrylate are possible alternatives.
Ethanolamine and pyridine were chosen over acrylonitrile and aniline as
organic nitrogen derivatives. All are good choices, but ethanolamine and
pyridine present fewer problems in laboratory handling than acrylonitrile
and aniline.
For ketones, acetone and methyl ethyl ketone were selecte I.
Mixed solvents pose a significant hazard to most sealant membranes.
Naphtha, turpentine, and lacquer solvent.were selected — the latter
consisting of a mixture of acetates and ketones.
Gasoline and kerosene were chosen to represent mixed hydrocarbons as a
class. Other alternatives include JP-4 and cyclohexane.
Of the aromatics, toluene and xylene appear to be good
representatives. Possible alternatives are phenol and tetrahydro-
naphthalene.
In a last category, styrene and vinyl acetate were selected as plastic
monomer candidates that have a high spill potential and pose unique
reactivity problems.
45
-------
Laboratory Test Procedure
The sealing materials selected from the survey as potential candidates
were tested for their sprayability, film-forming capability, ana chenical
compatibility. These tests were carried out in conjunction witn the
manufacturer to test each sealant under- its optimum conditions r'or good
film formation using suitable equipment, conditions, and optirnun ratios of
components.
Sprayabi1ity Tests --
Sprayabi1ity tests were conducted in a small spray chamber, a schematic
of which is shown in Figure A-l. The unit consisted of a variable-speed
belt conveyor with a speed range of ?0 to 120 ft/min, a spray gun with
supporting and controlling equipment, and a vented spray cabinet for
controlling fumes and oversp^ay. All fumes were exhausted through an
activated charcoal filter to capture organic vapors.
The spray gun varied with the sealant. Single-component sealants were
applied using a single-component UeVilbiss Model 504 flat spray gun.
Two-component sealant candidates were applied with a Binks Model 18 FKA
gun, which also provides a flat spray pattern. The Binks gun, which
includes an internal mixing chamber, is especially required for the
two-component urethane sealant candidates because of short cure times.
Spray rates were kept nearly uniform throughout at about 1 to 3 Ib/min, and
application rates held in the range of 0.02 to 0.1 Ib/ft^. These rates
are considered in the probable range of the final piece of equipment.
The substrate was asbestos paper about 0.012 in. thick, which provided
a uniform surface for good film formation and a porous substrate for
subsequent compatibility testing. Six-in.-diameter sprayed samples were
prepared and then mcunted in the gas pressurization and compatibility test
units for evaluation.
Initial attempts to spray the candidate were done with flowmeters in
the system to measure and monitor all the liquids. After establishing the
precision of flows and stoichiometry, the liquid flows were calibrated by
weight and assumed to be constant throughout the 3 to 5 min experimental
spraying times.
Gas pressurization was considered the best means for delivering and
metering the sealants. Between 50 and 90 psig was used in the tanks
containing the sealants to obtain the desired flow rates. In addition,
about 1 to 2 cfm air was added at the nozzle to supply atomization air to
help set the spray pattern. A "flat V" pattern was found to produce
uniform application rates on sample surfaces.
Compatibility Tests --
Tests were conducted initially on small, provisional samples and,
later, with the chemical compatibility test unit shown in Figure A-2.
46
-------
EXHAUST
SUPPLY GAS
5 GAL. POTS
EXHAUST FAN
FLAME ARRESTER
4- FILTER
CONVEYOR TABLE
SPRAY CABINET
Figure A-1. Schematic cf spray chanber
-------
ir
TEST FLUID
BURETTE-
-WING NUT
BLEED
-TEFLON \ PLUG-7
-. BLOCKS \ J
STCP COCK
PAN-
Hguro A-2. Compatibility lest unit
LIQUID LEVEL
|N. CM.
12 — 30.4
H — 27.9
9
8
— 7
6
• 5
3
2
0 —
25.4
22.9
20.3
17.8
15.2
IZ7
10.2
7.o
51
^5
0
-------
This apparatus, fabricated from Teflon^stock, was designed to expose a
large surf ace area of sealant (12.5 in?) to a 1 ft head of ch-ilenge
liquid, while using only a mininum volume of chemical. The inside of the
top section wi* domed for qas escape and exposure of liquid to the total
sealant surface. Tne natinq base section is an open cylinder, with a 4 in.
instdc ml.
Film Forminq Capability —
Tne integrity of tne film was c.v'&luated by measuring the leak rate of
air U'rouqn the curt-d sample mounted in the base of the compatibility test
unit prior to the addition of challenge aqent. The apparatus, shown in
Figure A-.J, allowed pressurization tc a l?-in. water head.
Test Procedure --
Tne U">t procedure was as follows: Conditions were set up and checked
{flow rates, stcicniometry, conveyor speed, and cpray pattern) on the spray
to achieve a suitable film for the sealant under study at the
application rate. With the asbestos substrate on the base of the
i IHy tost unit and preconditioned to the desired temperature, the
wen? placed on thv movinq conveyor and the sealant r.pplitid. They
w-.-ro t'>"n r'-turni'rt *,o the des>qn temperature condition and the curing rate
monitored.
The t«»sts w^-re conducted in multiples of 4 to 8 units. This number
allowed tnrtividual monitoring of cure time, and also allowed us to assemble
the compatibility test appa-atus arid to expose the film to the challenge
liquid in a reasonable tin* period (15 to 30 min).
After asvembly of tne compdtibUity test apparatus and before the
addition of challenge chemical, the integrity of the film and seal was
tested against g-js pressure. Generally, acceptable samples leaked in the
ranqe of 0 tc 2 in./">in of water, Samples that leaked at a rate greater
than 4 In./mm were not subjected to the challenge chemical.
The hazardous challenge chemicals were added to the test unit to a 12
in. head in a fune hood. The lea», rate was monitored in the burette
continuously during the first hour, and at intervals throughout the
remainder cf the day. Lost liquid was replaced periooically to maintain a
\2 in. nead.
The test period was scheduled to run overnight, during which the
samples were unattended. If the samples exhibited a leak rate within the
49
-------
Plant A1r
Low Pressure
Regulator
0-30 in. water
Toggle
Valve
water
Manometer
Test Specimen
Figure A-3. Air pressurization apparatus used to screen test specimens
-------
allowable limit (approximately f> nl/nr) they were left expired. Those with
ledk rates in excels or b cil/nr hi<3 ttse liquid head removed t>y closing the
stopcock, and the head replaced in the morning to obtain additional
approxinate data.
For comparison, the !e:>k rate data ire reported as LpJL:3! L:2iii!i
TOO for ,'4 hr (ml/?4 hr). (his required 'extrapolation of short
term test uata to 24 hr for the many samples with high leak rites.
All samples, whether failures or successes, were opened in the hood and
Checked for visible changes. Holes were usually noticeable in test films
which failed, tven saccesstul r :n<. often nad discoloration, Blisters, and
swell inq, indicative of some attac* L~y tht cher.ncal.
Uisciission of Test Results
Results with Adhesives —
This general classification contained many chemical types, but most
were eliminated in the preliminary survey due to d known lac< of chemical
compatibility. Latex adhesv/es were the exception and ream red turtner
testing. A Borden system, Polyco i'fcu/, was found that formed a film within
minutes and was shewn to he compatible with nany organic materials.
Samples of this were tested on asbestv. paper substrates. The result* are
compiled in Tjble A-5.
Results with Repellent Chemicals — •
The preliminary survey of potential sealing materials revealed that
some materials in this classification may hav? the ability lo modify the
surface characteristics of the substrata and reduce penetration by
ha/ardous materials. Toe survey concluded that two types, floorinated
polyacrylates and superaoides, were potential candidates.
Several commercial samples received some experimental investigation,
but only two, E. 1. duPont's fluoritiated polyacrylate "Zonyl k?" and
Clintwood Chemical's superamide "Clindrol 100CO," were subjected to tests.
Neither showed any significant sealing ability when applied en sand
supstrates at rates ostween 0.01 and O.Ob q/ci^, even aqainst water. On
asbestos, however, some sealing ability was demonstrated for a limited
time. The results for Clindrol are shown in Table A-6.
The liquid transmission rates represent 3D to 80% reductions over
untreated substrates for the limiteo times shown; however, the samples
appeared to show a general solubil'ty of the Clindrol 100CG in the
challenging liquids. When the costing was dissolved, transmission of the
liquid occurrea at the same rate as with untreated paper.
The results for Zonyl HP are suwmarized
-------
TABLE
RESULTS Of CCMPATIBlLIT*-?tRK£A8Il.lTY TESTS *ITH S&RD£S
CHEMICAL CCKPM* LATEX -Pa''CO 2607*
Application Condi
Ch«l tetiq* Liquid f
4«ou*.
Hftnylmo cnlono*
L^cgucr ialvent
Styr*««
Carbon QtlulfliM
PHciptorui 01 yen tor 1
Iyiff»«i
Cruol
Nttnyl «thyl ktten«
«.»»..
So«1u* lyoroxld* 15X
Afttitdenyd*
j^lfurK td*
Hono*t*t«no 1 M1M
Uoproo*no)
Vinyl Ktm*
^ftotonoruf trtcnlorl
MtttP
Vtnyl »Ctt*tt
•UAtlK
•Hpf.Wt
S*toHf»#
&O
-------
TABLE A-6. TEST RESULTS OBTAINED FROM SAMPLES OF "CLlNDROL 100CG"
Challenge
Liquid
Benzaldehyde
Naphtha
Trichloroethylene
Average Liquid
Transmission Rate
(ml/min)
3 to 4
2 to 4
4 to 5
Breakthrough
(min)
5
20
5
Urethane Foam Systems Results —
Callery Chemical's Resin 115 and Ashland Chemical's EP 65-86/88 were
further tested as representative urethane foam candidates. Application
rates between 0.02 and 0.12 g/crr? were tested on asbestos after it^was
established in preliminary tests that rates in excess of 0.02 g/cm2 were
necessary to seal the sand surface. The compatibility test results are
suir-narized in Tables A-3 and A-9.
Polyethylene Prepolymer Results —
The chemical compatibility of polyethylene with many hazardous
chemicals was considered a definite attribute for its u^e as a sealing
material. A thorough search of commercial forms of polyethylene revealed
thet low-density polymers are available which could be used to form a film
in situ. These materials, often referred to as polyethylene waxes, have
the characteristic low softening points and low viscosities commonly
associated with natural waxes. The possibility of spraying polyethylene,
with prior heating, was investigated as well.
Three samples of these materials were supplied by Allied Chemical
Company. Some selected properties of them are listed in Table A-10.
The visco-elastic flow properties of these materials make the softening
point and melt viscosity important factors in the choice of materials for a
spray application. Lower softening points tend to lower the system
operating terrperature, which means that evaporation of all system com-
ponents will be minimal. Lower melt viscosities tend to reduce the power
requirements for spraying, which translates into payload and cost savings.
Both of these are desired, but unfortunately the capacity for forming
continuous films Is inversely related to softening point, viscosity, and
density of polyethylene polymers.
53
-------
TABLE A-7. RESULTS OF COMPATIBILITY-PERMEABILITY TESTS WITH
E. 1. DUPONT Oe NEMOURS SURFACTANT "ZCNYL RP"
Application Conditions
Approximate
Challenge Liquid Temperature, °C
Trichloroethylene
Trichloroethylene
Gasoline
Vinyl acetate
Acetic acid
Water
Water
Naphtha
Trichloroethylene
Acetic acid
Vinyl acetate
Naphtha
Water
Acetic acid
Ethyl acrylate
Monoethanolamine
Cresol
Gasoline
Methylene chloride
Benzaldehyde
22
22
22
22
22
22
22
22
25
25
25
25
25
25
22
22
22
22
22
22
Substrate Application Rate
Condition (g/cm2)
dry
dry
dry
wet
dry
dry
dry
dry
wet
wet
wet
wet
wet
wet
wet
wet
wet
wet
wet
wet
0.03
0.03
0.03
0.03
0.03
0.03
0.02
0.03
0.003
0.003
0.02
0.02
0.02
0.02
0.01
0.01
0.01
0.003
0.003
0.003
Total Liquid
Transmission
(ml/24 hr)
&
140
5
3
>!000
380
225
9
60
>1000
43
19
6
27S
25
63
13
7
7
28
54
-------
TABLE A-3.
RESULTS OF COHPATI8ILIT»-P!.RM£ASlLin TESTS WITH CALLER'
CHEMICAL COMPANY URETHAWE "1)5" FORMULATION
Appt tc»t1on Conditions
Aoorax1««te
Challenge Liquid Te*t>«rAtur»,oc
Aerolein
Carbon dlsu'flde
Pyrldlne
SodliM hydroxide I5N)
Gasoline
Phosphorus trichloride
Phctpnorut oxychlor^de
Cresol
Acetaldetiyde
Carbon d1su1f1<1e
Mono«ttianol«mlne
Sulfurlc acid
Trlchloroethylene
6«nz«ldehyoe
Acetone
M«thvlen« cMorlde
'thyl acrylate
Acetic *cid
Styrene
Hethylene cftlorlde
Isopropanol
Acetone
Cretol
Xylene
Gtso'dne
Sodium hydroxide (SM)
Benzaldenyde
Trlchloroethylen*
Sulfuric *c1d
Vinyl acetate
M.N *01metnylfonMMlde
22
22
22
22
:z
22
22
22
22
22
22
20
20
20
20
20
20
20
20
•5
•5
-5
•S
-5
-5
•2
•2
•3
-3
-3
-5
Appro*. Total Llould
Substrate Application Kate Cure Transmission
Condition (g/cnJ) Tlme(mln) (mV2< nr)
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
wet
net
»et
wet
wet
dry
wet
*ry
wet
dry
wet
wet
0.02
O.C2
0.02
0.02
O.OS
0.05
0.05
0.05
0.05
0.02
0.03
0.05
0.05
O.Cs
0.05
0-.12
O.U
0.12
0.03
0.04
0.04
0.05
0.05
0.04
O.OS
0.04
0.04
O.OS
0.07
O.OS
0.05
2
2
2
2
2
2
2
?
2
2
2
2
2
2
2
5
5
5
1
25
25
10
10
10
5
25
IS
20
10
20
20 fatUd
'.9.1
4.9
8.7
12.7
0
8.2
14.2
11.3
44.5
4.9
2.1
4.2
2.4
21.1
failed
23.0 '
6.3
7.7
2.1
7.6
0
30.0
2.3
1.6
S.9
3.6
S.I
4.6
14.5
20.9
after 2.5 h?
-------
TABLE A-9. RESULTS OF COMPATIBILITY-PERMEABILITY TESTS WITH ASHLAND
CHEMICAL COMPANY "EP65-86/88"
Appl
Approximate
Challenge Liquid Temperature, °C
Water
Sulfuric acid
Sodium hydroxide (5N)
Phosphorus trichloride
Phosphorus oxychloride
Carbon disulfide
Acetic acid
Methylene chloride
Trichloroethylene
Benzaldehyde
Isopropanol
Crtsol
Ethyl aery late
Monoethanol ami ne
Acetone
Methyl ethyl ketone
Naphtha
Lacquer solvent
Gasoline
Kerosene
Vinyl acetate
Sulfuric acid
Methylene chloride
Methyl ethyl ketone
Carbon disulfide
Cresol
Monethanolamine
Lacquer solvent
Sodium hydroxide (5N)
Gasoline
N , N-D1 methyl f ormami de
26
25
25
25
25
25
20
25
25
25
20
25
20
25
20
26
20
2!>
25
20
25
0
0
0
-5
-5
-5
-5
-5
-5
-5
ication Conditions
Substrate Appl
Condition
dry
dry
dry
wet
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
dry
wet
dry
dry
dry
dry
wet
dry
dry
wet
ication Rate
(g/cm2)
0.06
0.02
0.02
0.02
0.04
0.04
0.02
0.09
0.06
0.08
0.02
0.04
0.05
0.04
0.05
0.06
0.06
0.04
0.04
0.06
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
Total Liquid
Transmission
iml/24 hr)
6.9
153
377
7.0
1.2
28.7
3.5
29.6
2.0
9.4
6.6
2.8
11.7
1516
15.6
5.5
3.5
10.9
7.7
2.0
13.6
> 1
20.1
46.7
9.7
2.5
4.6
8.8
100
30.3
[~45 ml/hr]
A secondary objective of these tests was to determine some general
trends in the comparison of softening points, viscosities, and
composition. Such a comparison was possible since the polymers are
mutually miscible, forming mixtures with intermediate properties.
Three tests we made using combinations of the three polymers which had
softening points between 90 and 105°C. The mixtures were placed in a
steel cylinder, heated and shaken to form a homogeneous liquid, pressurized
56
-------
TABLE A-10. SELECTED PROPERTIES OF THREE ALLIED
CHEMICAL COMPANY POLYETHYLENE POLYMRS
Product
Designation
AC-1702
AC-617
AC-715
Softening
Point
850C
1020C
1090C
Density
0.88 g/ml
0.91 g/ml
0.92 g/ml
Melt Viscosity
@ 14QQC
40 cps
180 cps
4000 cps
with nitrogen, and sprayed through several types of nozzles in an effort to
obtain a continuous film. The spraying tests were conducted at polymer
temperatures of 140°C, 1250C, and 1500C. None of these mixtures
formed a thin film (<3 mm) and all films were susceptible to gaps forming
between successive spray passes. In addition, thermal contraction raised
the edges of the coatings and caused severe cracking in those which formed
the better films. None of the final samples was capable of retaining a
liquid head, although application rates were between 0.37 amd 0.8 g/cm^.
Low-Temperature Curing Studies
Those sealing materials which showed acceptable performance in terms of
chemical compatibility and permeability were farther examined to assess
their ability to form a continuous film under adverse conditions. Accidents
usually occur during inclement weather when deployment of the sealing
material would be difficult; cold and wet soil substrates were considered
to be the worst conditions for establishing a sealed surface against
hazardous materials.
Test films of Borden Chemical's Polyco 2607 latex, Ashland Chemical's
EP 65-68/88 urethane, and Callery Chemical's 115 urethar.e were prepared on
"dry" and "wet" substratos and at selected test temperatures. The Teflon
test apparatus and sand substrate were maintained for at least 1 hr at the
test temperature and then placed on the conveyor, sprayed, and returned to
the test environment to observe the curing process. The substrate
temperature and application rate were the controlled variables.
Results with Polyco 2607 —
Data obtained with Polyco 2607 are summarized in Table A-11. The
"apparent cure time" was measured as the time required to obtain a
non-tacky surface film. Using a 15 to 30 min cure time as the cut-off
point for the proposed use, a dry substrate temperature of about 7 to
10°C (45 to 500F) is the lower limit for this candidate sealing system.
Some of the coatings prepared in this series of tests were used 1n
chemical compatibility tests. These tests, comparing the chemical
57
-------
compatibility of coatings prepared at these lower temperatures with coatings
prepared at room temperature, are included in Table A-5. The results of
these exposure tests were similar to those at room temperature. The total
liquid transmitted through the coating formed at low temperatures was simi-
lar to that measured in previous tests, indicating that the coating, once
formed, is similar to that prepared at room temperature.
Results with Ashland's EP 65-86/88 —
The lew temperature curing tests for Ashland's EP 65-86/88 ere
summarized, in Table A-12.
A surface film formed on the Ashland urethane when the substrate
temperature was as low as -180C. The curing process was considerably
slower at these temperatures, but part of the apparent lag could be
attributed to the amount of catalyst used. Previous Ashland sarcp1^ cured
after approximately 1 min. at room temperature while this sample required
nearly 2 min. under the same conditions. Ashland assured us that small
increases in catalyst concentration would promote low temperature curing
without affecting the 6 to 9 month shelf life of this formulation.
Compatibility tests of coatings prepared at these lower temperatures
are compared with those prepared at room temperature in Table A-9. The
results show no general trends differentiating coatings prepared on cold
substrates from those prepared on warmer substrates. Only slight
variations were noted in most cases, except that the cold-cured urethane
appeared to withstand sulfuric acid, nonoethanolamine, and sodium hydroxide
somewhat better. This increased resistance may he attributed to the
influence of longer curing periods rather than the cure temperature. The
time interval between preparation and exposure to challenge liquids was
measured in hours for samples prepared at lower temperatures compared to
minutes for samples prepared at room temperatures.
Results with Callery's 115 —
Gallery Resin 115 was observed to form surface films on the sand
substrate at temperatures as low as -20°C (-40F) (Table A-13). These
films required considerably longer times to form than at normal cure
temperatures and showed no evidence of foaming. The cure resulted in a
pliable film with a smooth glassy surface.
The lower temperatures significantly retard the rate of cure. Water
present in the substrate reacts exothermally with the isocy*nat,e to promote
further reaction» but does not interfere with the production of an
impervious urethane coating. Samples which were kept at -20 to -25°C
(-4 to -13°F) foamed as they were allowed to warm to room temperature.
this would indicate that the components had not reacted completely and only
a surface film was formed.
Compatibility tests of the lower-temperature-cured films are compared
with those for foams prepared at room temperature in Table A-8. These
58
-------
TABLE A-ll. LOW TEMPERATURE CURING OF 60RDEN CHEMICAL
COMPANY "POLYCO 2:607"
Condition of Temperature Range
Substrate (°C) (°F)
Dry 21
17
7
4
-15
to
to
to
to
0
to
23
20
10
5
-12
70
62
45
39
5
-18
Wet 21
16
7
4
0
to
to
to
to
to
23
18
10
5
4
70
60
45
39
32
to
to
to
to
32
to
0
to
to
to
to
to
74
68
50
42
10
74
65
50
42
39
Apparent Cure Time
(min)
1 to
1 to
15 to
30 to
40 tc
15 to
>120
15 to
25 to
40 to
50 to
120 to more
15
7
50
50
50
40
20
40
50
120
than 180
TABLE A-12. LOW TEMPERATURE CURING OF ASHLAND CHEMICAL
COMPANY URETHANE FOAM "EP 65-86/88"
Condition of Temperature Range
Substrate (°C) (<*)
Dry 0 to 5
-2 to -5
-6 to -10
-10 to -15
-15 to -20
Wet -2 to -5
-5 to -10
-6 to -10
-10 to -15
-15 to -20
32 to 41
23 to 28
14 to 21
5 to 14
-4 to 5
23 to 28
14 to 23
14 to 24
5 to 14
-4 to 5
Apparent Cure Time
(min)
15 to 30
25 to 60
40 to 80
55 to 80
70 to 90
35 to 40
45 to 95
70 to 90
130 to 150
120 to 140
59
-------
tests were done after the bottom half of the Teflon apparatus was removed
from the refrigerated environment and permitted to equilibrate at room
temperature for approximately 1 hr. The dome was placed over the coating
and the liquid head established in tiie burette, exactly as had been done in
?rovio-.:5 tests.
TABLE A-13. LUW TEMPERATURE CURINb OF CALLEKY CHEMICAL
COMPANY UKETHANE "115" FORMULATION
Condition of Temperature Range
Substrate (°Cj
Ory 0
-6
-15
-20
to
to
to
to
1
2
-2
-10
-16
Apparent Cure Time
(OF)
32
21
5
-4
to
to
to
to
35
28
10
4
5
7
15
12
(min)
to
to
to
to
15
20
20
20
Wet
0 to 2 32 to 35
-6 to -2 21 to 28
-15 to -10 5 to 10
-20 to -16 -4 to 4
20 to 25
10 to 25
15 to 20
15 to 31
Only acetone and N,N-dimethylformamide resulted in failure of the
coatinq during a 24-hr exposure. In some cases the liquid transmission was
slightly less than observed with a coating prepared at room temperature.
In otners, it was slightly greater. The chemical compatibility of the
Gallery Chemical Company urethane prepared at -low temperatures was not
significantly different from that of the normally prepared urethane.
EQUIPMENT
Application Systems
The selection and evaluation of equipment to be used in applying the
candidate sealing materials to the spill site was limited to commercial
components, just as was done with the sealing materials.
Applicator systems which were considered included: 1) hand-pump
pressurized; 2} propellant pressurized; and 3} powered-pump pressurized.
These three general types of systems were evaluated for:
1) simplicity;
2) maintenance;
3) logistical support; and
4) economy.
60
-------
Data from our experimental work indicated that between 80 and 160 Ib of
material may be required to seal a spill containment area of 1200 t't^.
It was assumed that this area should Le covered in 1'j to 3u ("in. The
probable range for dispensing rates, using these assumptions, falls in the
range of 2,7 to 10.7 lb/inin.
One other parameter which does not appear in the experimental data was
used in the selection of sealing materials. A maximum liquid viscosity of
approximately 20JO cps was considered in the selection of candidate sealing
and application systems, since the power requirements for the applicator
systems are directly proportional to the viscosity.
Hand-Pumped Systems —
Hand-pumped systems, such as those used for insecticide and paint
spraying, may be used to apply these sealing materials. Units are available
with capacities between $.7 an? 11.4 liters (1.5 and 3 oal). The largest
of these would provide a system weight on the order of 18 kg (40 lb).
Although this type of system is attractive in terms of weight and
simplicity, pressure variations and the necessity for continuous or
intermittent pumping would be serious limitations.
Propellant-Pressurized Systems --
Propellant-pressurized systems such as fire extinguishers, paint
sprays, and other aerosol devices are simple, self-contained units which
offer low maintenance requirements and portability; however, detailed
design and judicious selection of components are required to achieve ell of
these attributes in a single applicator system.
Throw-away relf-contained, portable propellent-pressurized systems are
commercially available for urcthanes. Some will dispense as much as 11.5
kg (2b lb) of urethane at rates between 1.25 and 1.4 kg/min (2.7f> to 3.1
Ib/min). Although they offer a very simple and compact system, the
throw-away package is not the favored economic approach.
Most propellant-pressurized systems would be capable of delivering l.?5
to 4.9 kg/min (2.7 to 10.7 Ib/min). however, the gas capacities would be
insufficient to provide atomizing air, if it was reguired, and would be
limited to that required to propel the coating material from the tank.
An estimate of the cylinder sues required for supplying atomizing air
have been made on the assumption that 1t would require approximately
28.3 L/n>1n (1 ft3/min) of qas for each 0.5 kg/min (1 Ib/min) of liquid
flow (Table A-14). Propellant-pressurized systems far exceed the 18 kg (40
lb) weight target 1f gas cylinders are employed as the propellant source.
They are favored, however, over hand-pumped systems for ease of operation
and are more easily maintained than power-pressurized systems.
Power-Pressurized Systems --
Power-pressurized systems may be used where weight a.id space
requirements permit for most spraying or other liquid transfer
operations. These systems are of two basic types: electric motor or
-------
combustion enoine-powered. Both would require .a pufp to be included in the
system to propel the liquids and/or compress air und, b«»c*'..se of trie extra
wtMqht and added rraintenance, are less attractive than the
propel Idf-t -.;ressurized system.
The sire arid power requirements for these systems, based on the arour.to
of materials to be dispersed, their physical properties, ar.d the Oev.red
ipplication rates, have been calculated as f Anplicatinn Systems
Two possibilities were selected as a means of estimating equ KW (2 hp).
62
-------
TAiLE A-14. PRELIMINARY ESTIMATES A«r CYLINDER
SIZES FOR SUPPLYING ATOMIZING AIR
Sealant to be Liquid Flow
Dispensed (lt>) Rate Ob/win)
Gas Flow
Rate (cfm)
Cyl1nder
Description
RO
80
80
160
160
160
2.7
«5.3
10.7
2.7
5.3
10.7
2.7
S.3
10.7
2.7
5.3
10.7
Size 2 Cylinder
8 1n. x ?7 In.
Tare Wt. 78 Ib
Size 15 Cylinder
tWI.f A. 15.
Pf>««l
CC»UW.
*MO BATTKt
Ou«nf.1ty
of Co*tln
-------
The operating procedure for the system defined in Case I would be
similar to that used for the VSA Kigi-Pak loO package. Additional
operations would include cori^ction to the manifold, connection of the
CD? cylinder, and pressurization. First estimates of Uie additional
Height and cost have also or-en n.ade. The proposed system would involve a
•«eib:it penalty of about 4.6 k>) (10 It)) compared witii Lit? present kigi-Pak
liij system. Approximately V50 additional in material costs would be
incurred iri preparing the proposed system.
Operating procedures for the equipment evaluated in Case II would be
similar to those presently used by fire companies. The base system,
including power source, would be located at a safe distance but convenient
for transporting the urethane containers and spray gun to the spill site.
The nrpthane package would be the same as in Case I, except for a solvent
container nestled in the cusp between the component reservoirs.
Weight penalties for this system would result from the drag of the hose
and extra weight of a rouseable gun. These are roughly estimated to be
several pounds. The major weight penalty for power source and compressor
are estimated to be 12b to 136 kg (2/S to 300 1b).
The non-recurring equipment cost for the components included in this
type of system are estimated to be $1800. The cost penalty to the urethane
dispensing system, excluding the power source. Is estimated to be In the
range of 5600 to ilOGU.
PILOT-SCALE TESTS
Data provided by laboratory tests with the Teflon permeation apparatus
were used to develop a te
-------
Cardboard
Sampling Ared
Substrate
Structure to
Position and
Seal Sides
Figure A-4. Modified test apparatus.
-------
Irregularities wvre weII-documented in each test.
The pilot-scale tests wore designed to use water as the challenge
aqt-nt. The compatibility and permeability tests indicated that tests with
other challenge agents were unnecessary to determine the operating and
sealing capabilities of urethane systems. Wato*" was p'uced over the
surface film to a depth of 30.b CM (1 ft) and monitored throughout the
24-hr tests with a "U"-tube manometer.
The initial tests were made with local soil placed in the apparatus to
forty a level substrate. After determining that this local soil surface
could be sealed, stones and qravel. sand, water, and qrass wrre included in
the test substrate to measure their influence on the formation of a
continuous seal.
The majority of these tests were made with Gallery Chemical Company's
basic urethane foam formulation. Several tests also were done with Ashland
Chemical Company's urethane to verify tne similiarity of ureUiane
(emulations.
The kigi-Pak portaole unit, designed primarily for mine use, was used
for application of the foams. This system needs no external sourc*1 of air
but mixes the components and a volatile fluorocarbori foam agent with an
in-line helical mixer. The basic urethane formulations xere applied to the
test substrates by spraying through a Binks Model 13 spray gun, a hano-held
version of the automatic un>t used in the spray chamber. Components were
added from two reservoirs by nitrogen pressure, which was regulated to
supply the proper ration. Atcmiiing air was also supplied from the
laboratory air line to run the mixer and establish the spray pattern.
The apparatus ust-d in the pilot-scale tests (Figure A-4) was prepared
for spraying the candidate sealing systems with a piece of cardboard
covering the sealing channel. After the urethane seal was applied, this
cardboard was cut free and the sides installed. The final seal to the side
boards was made with another frothing i-rethane formulation, which
eliminated any chances for leaks at the edges of the sample. Several
sample areas were cut frcwi the cardboard and the application rate was
measured by their vslght gain.
The results of the pilot-scale tests of urethane sealing systems are
collected in Table n-16. Sealing soil substrates with urethane foams
required application of approximately 0.1 g/cm2 (0.2 Ib/ft2). Similar
application rates would seal substrates containing small stones and gravel,
but not reproducibly. The precision measured for application rates was
approximately 0.01 g/cm2 throughout the coating. The precision In
preparing seals which would survive the ?4-hr sealing test was less tian
50X, however.
The nllot scale testr. showed that experience Is a key factor 1n
applying coatings under the variety of conditions expected and In
understanding the capabilities and limitations of these foamed coatings.
66
-------
TABLE A-16. RESULTS OF PlLUT-SCALE TESTS USINb URETHANE SEALANTS
Gallery Chemical KS Urethane
Application
Substrate Rate (g/cm?) Performance
Sieved Soil <1 cm
«3/8 in.) dia.
Stones & Gravel
Sod {evenly cut)
Growing Grass
(uncut)
0.05
0.12
0.25
0.11
0.17
0.1
0.08
0.13
0.49
0.13
0.17
0.14
0.17
0.5
0.55
Failure
"
•
•
Pass
•
•
Failure
M
Pass
N
Failure
N
Failure
*
Callery Chemical Rigi-Pak Ashland Chemical £P 65-86/S8
Application Application
Kate (g/c.'~2) Performance Rate (q/cm^) Performance
0.05
0.1
O.U
0.13
0.12
0.09
0.16
0.13
0.14
0.13
0.16
0.15
0.14
0.16
.22
0.53
Failure
•
•
Pass
N
Failure
IS
•
Pass
M
Failure 0.7 Failure
tt
Pass
Failure 0.6 Failure
M
•
-------
The bridging ett'ect of the foaming action, which is so necessary to make an
effective seal with a minimum of sealant, depends heavily on such va; iables
as sealant and substrate temperatures, the presence of water, the appli-
cation rate Ob/min), and the manner (sinqle or multiple passes) in which
it is applied. Values could be provided for each condition, but only
experience will provide the necessary "feel" for people in the field where
all these variables may be changing simultaneously.
The results of the pilot-scale tests also indicated that the influences
of wind, surface area, and surface defects are difficult to measure, and
compensating means are difficult to describe to inpy.oer ienced personnel.
Whether tne unframed film coverage rate will form a continuous coating is a
judgement mac*e by the person applying, it. The operator must estimate the
influence each of these factors would have and modify the application
technigue accordingly.
Comparing frothed and normal foaming formulations of commerical ure-
thane systems showed no specific advantages for either type-. Urethane
foams appeared to have less penetration into normal substrates, while the
froths appeared to bridge larger gaps and debris. Neither showed a
definite advantage on vegetated substrates. Urethane froths, however,
appeared to be somewhat more effective for application on cold or wet
substrates.
The course of the program was altered when u-etuane foam was used in
attempts to seal grass-covered substrates. In these tests, coverage rates
in excess of 0.6 g/crn^ (1.3 lb/ft^) proved incapable of sealing these
substrates against water. With a design goal of scaling 1200 ft2, the
coverage rates experienced, even if successful in sealing, precluded its
use as an emergency portable system for grassy substrates. This limitation
was considered too severe for the anticipated use of the sealant system to
continue further development.
The basic problem areas appear to be 1n the "shadow effect," encoun-
tered during spraying, and in the nature of the foaming process. "Shado-
wing" is common to any spray application and reguires exceptional care and
conscientious application from all angles to assume complete coverage of
the surface. The foaming process for the urethane formulations used in
this program helped f.o minimize the prnblems of bridging surface
discontinuities and "shadowing"
-------
in conjunction with inclement weather severely restricts the application of
the urethane systems. This limitation \
-------
APPENDIX B
English to Metric Conversion Factors
t*«llib tmit
KulttplUr
H.UIC Mil
•crv-fiwt
Cl*lc f*»t
cukic lick
cubic xi r4
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M«« M' kill Ira
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cf.
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••trie IM otrlc >•»
70
Reproduced from
beil available copy.
T-'i'^.O GUIDE i--V!'I!;r
------- |