;ntril Protection
Research and Development
x-xEPA
Handbook for Using
Foams to Control
Vapors from
Hazardous Spills
-------
EPA/600/8-86/019
July 1986
HANDBOOK FOR USING FOAMS TO CONTROL
VAPORS FROM HAZARDOUS SPILLS
by
Mark L. Evans and Holly A. Carroll
Science Applications International Corporation
8400 Westpark Drive
McLean, Virginia 22102
Contract No. 68-03-3113
Project Officer
Mary K. Stinson
Land Pollution Control Division
Releases Control Branch
Edison, New Jersey 08837
HAZARDOUS WASTE ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
The information in this document has been funded wholly or in part by
the United States Environmental Protection Agency under Contract No. 68-03-
3113 to Science Applications International Corporation. It has been subject
to the Agency's peer and administrative review, and it has been approved for
publication as an EPA document. Mention of trade names or commercial
products does not constitute an endorsement or recommendation for use.
ii
-------
FOREWORD
Today's rapidly developing and changing technologies and industrial
products and practices frequently carry with them the increased generation of
solid and hazardous wastes. These materials, improperly dealt with, can
threaten both public health and the environment. Abandoned waste sites and
accidental releases of toxic and hazardous substances to the environment also
have important environmental and public health implications. The Hazardous
Waste Engineering Research Laboratory helps provide an authoritative and
defensible engineering basis for assessing and solving these problems. Its
products support the policies, programs, and regulations of the Environmental
Protection Agency; the granting of permits and other responsibilities of
State and local governments; and the needs of both large and small businesses
in handling their wastes responsibly and economically.
This handbook describes the selection and use of foams to control vapors
from liquid hazardous material spills. The Information presented in this report
Is intended to assist spill response personnel in deciding which foams to use
with the various classes of spilled volatile compounds. During its preparation,
this handbook has been thoroughly reviewed by experts on the use of foams.
If warranted by users' demand, this Information can be periodically updated.
Therefore, we are soliciting users' comments, including Information on any
errors, suggestions for improvements, field experiences, introduction of new
foams to field use, etc.
If you have such comments, please mall or phone them to:
Mary Stinson
Hazardous Waste Engineering Research Laboratory
U.S. Environmental Protection Agency
Edison, New Jersey 08837
Phone: (201) 321-6683
Thomas R. Hauser, Director
Hazardous Waste Engineering Research Laboratory
iii
-------
ABSTRACT
Firefighting foams are designed to control and extinguish fires involv-
ing a variety of flammable materials. However, recent research efforts have
proven that foams are also useful in controlling vapors from spills of vola-
tile hazardous materials. Moreover, some new, special foams have been
designed for this purpose. This handbook contains a table to be used by
spill response personnel to choose foams according to the types of chemical
vapors they expect to encounter. Six general types of foams are described;
they are regular protein foams, fluoroprotein foams, surfactant (syndet)
foams, aqueous film forming foams (AFFF), alcohol type or polar solvent type
foams (ATF), and special foams such as Hazmat NF #1, Hazmat NF #2, and MSA
Type V.
The handbook provides the basis for spill responders to evaluate and
select vapor control foams by using standard test methods for foam expansion
ratios and quarter drainage times, or by comparing manufacturer's specifica-
tions for these parameters. The responder is encouraged to maximize the
effectiveness of a foam by trying different nozzles, distances of applica-
tion, and thicknesses of the foam layer.
High-expansion (greater than 250:1 for the ratio of foam volume to
initial liquid volume), medium-expansion (20-250:1) and low-expansion (less
than 20:1) foams are discussed. Finally, suggestions for when, where, and
how to apply foams for vapor control are presented.
The handbook was reviewed before final publication by experts on the use
of foams to ensure that up-to-date information was included. The handbook
was submitted in fulfillment of contract No. 68-03-3113, Task 21-2 by Science
Applications International Corporation (SAIC) under the sponsorship of the
U.S. Environmental Protection Agency. This handbook covers a period from
April 1984 to June 1985, and work was completed as of August 30, 1985.
iv
-------
CONTENTS
Page
Disclaimer ii
Foreword iii
Abstract iv
Figures vi
Tables vi
Acknowledgments vii
1. Introduction • 1
2. Types of Foams 2
3. Selection of Foams for Vapor Control 5
4. Suggestions for Applying Foams for Vapor Control 20
References 23
Appendix
Factors for Unit Conversion 26
-------
FIGURES
NUMBER PAGE
1 Typical Standard Backboard Structures for
Collection of foams Prior to Testing for
Quarter Drainage Time and Expansion Ratio .... 18
TABLES
NUMBER PAGE
1 Foam Selection Chart for Control of Hazardous
Vapors 6
vi
-------
ACKNOWLEDGMENTS
The authors wish to acknowledge the cooperation and assistance of the
following persons and organizations who have contributed to the development
of this handbook.
Michael Royer
U.S. Environmental Protection Agency, Edison, New Jersey
Ralph Hiltz
MSA Research Corporation, Evans City, Pennsylvania
Warren Isman
Fairfax Co. Fire and Rescue Department, Fairfax, Virginia
Edward Norman
National Foam System, Inc., Lionville, Pennsylvania
Gregory Hersh
Rochester Fire Department, Rochester, New York
Max McRae
Houston Fire Department, Houston, Texas
John Eversole
Chicago Fire Academy, Chicago, Illinois
Norman Lockwood
NFPA Foams Committee, Washington Crossing, Pennsylvania
James Daneker
Los Angeles City Fire Department, Los Angeles, California
William Biscontini
Walter Kidde, Inc., Wake Forest, North Carolina
James Betschart
U.S. Air Force, Space Division, Los Angeles, California
John Marshall
U.S. Air Force, Rocket Propulsion Laboratory, Lancaster, California
Thomas Baginski
Baltimore Fire Academy, Baltimore, Maryland
vii
-------
1. INTRODUCTION
The purpose of this handbook is to assist firefighters and other first
responders in the selection and use of foams for the control of hazardous
vapors. Although it is understood that the selection of firefighting foams
will always be directed more toward fire control than toward vapor control,
the information contained in this handbook should be used to select foams
that can optimize responses to both fires and hazardous vapors.
Firefighters and other first responders are often confronted with chem-
ical spills from storage tanks, tank trucks, and railroad tank cars that
contain volatile hazardous materials. Firefighting foams are commonly used
to blanket these materials, thereby greatly reducing the chance of fire or
the potential for human injury or even death through inhalation of toxic
vapors.
The mechanisms of vapor mitigation by foams are complex, and are speci-
fic to the chemical compounds involved. A complete description of these
mechanisms is beyond the scope of this handbook, however. Foams generally
function to block the surface of spilled materials, thus reducing volatiliza-
tion of spilled chemicals. Foams can prevent boiloff of spilled chemicals by
protecting the surface of a spill from heat produced by fires and solar
radiation. Foams can reduce vapor concentrations above spilled liquids by
over 90 percent, but vapor suppression is temporary, lasting between 5 to 120
minutes before reapplication becomes necessary.
Foams can be used to facilitate cleanup and surveillance at a chemical
spill. However, the use of inappropriate foams on spilled chemicals may
result in human injury through violent foam-chemical interaction, or in a
wasted investment of money when a foam is destroyed upon contact with spilled
chemicals.
It cannot be emphasized enough that vapors are suppressed at hazardous
waste spills not only to control fire hazard, but also to prevent human or
environmental exposure to toxic vapors. Understanding the basic capabilities
of certain foams will promote the safe and effective control of vapors from
spills of hazardous materials, and facilitate the collection of the spilled
material.
-------
2. TYPES OF FOAMS
Foams may be used to diminish or halt the generation of toxic or flam-
mable vapors from volatile liquids or solids (1). There are six basic types
of foams available for use on spilled volatile chemicals (2). These are
regular protein foams; fluoroprotein foams; surfactant (synthetic) foams;
aqueous film forming foams (AFFF); alcohol type or polar solvent type foams
(ATF); and special foams, which are designed to control vapors from chemicals
that would destroy conventional foams. In addition, new types of foams,
called polymeric alcohol resistant foam and film forming fluoroprotein foam
(FFFP), have been introduced (3). However, there are insufficient data on
their vapor controlling qualities for inclusion in this handbook.
All foam types are designed for use with low-expansion foam-making
equipment, which limits the expansion ratio (ratio of foam volume to liquid
volume) to less than 20:1. However, surfactant foams can also be used with
medium- and high-expansion foam-making equipment, which allows for expansion
ratios from 20 to 1000:1 (4).
Foams are produced by mixing a foam concentrate with water and air under
pressure. A container of foam concentrate is tapped by using a proportioning
device, the simplest of which is an eductor. Proportioning devices range in
complexity from the eductor to around-the-pump and balanced pressure propor-
tioners (5). The proportioner is connected to a fire hose at a point
upstream of the foam nozzle. The proportioning unit meters the proper amount
of foam concentrate that is dispensed to the fire hose. The nozzle causes
turbulent mixing of water with air just before the mixture exits as foam.
Foam concentrates are commercially available for a number of uses. The
properties of the six basic foam types are discussed below.
2.1 Regular Protein Foams
Protein foam concentrates are composed of an animal protein (keratin
hydrolyzate) with polyvalent cations and other stabilizing elements. Devel-
oped in the 1950's, protein foams are the oldest of the firefighting foams.
These foams exhibit good resistance to reignition after extinguishing a fire,
but they generally have poorer flowing ability and slower fire knockdown
ability than other types of foams (6).
-------
2.2 Fluoroprotein Foams
Fluoroprotein foams were designed for fast fire knockdown and long
protection against the reappearance of flammable vapor concentrations above
a spilled liquid. As a mixture of regular protein (keratin hydrolyzate)
foam concentrate, AFFF, and polyvalent cations, fluoroprotein foams exhibit
shorter fire knockdown times than regular protein foams and longer vapor
control times than AFFF. However, fluoroprotein foams do not knock down
fires as quickly as AFFF foams (6).
2.3 Surfactant Foams
Surfactant foam concentrates contain surface active agents (syndets).
The extent of surfactant foam expansion depends primarily on the type of
equipment used to produce the foam, but many surfactant foam manufacturers
identify their products as being either low-, medium-, or high-expansion
foams. Low-, medium-, and high-expansion foams use an eduction device to
proportion foam concentrate into the water stream. High-expansion surfactant
foams are produced by a device that blows the surfactant-water mixture
through a screen to make bubbles. Low-expansion surfactant foams are seldom
used because their resistance to burnback and their ability to knock down
fires are exceeded by other low-expansion foams. High-expansion surfactant
foams expand up to 1000 times the volume of the water entering the foam
maker; however, the normal range of high-expansion foams is between 300 and
750 to 1. (See discussion of expansion ratios under "Foam Quality", Subsec-
tion 3.2) (7).
2.4 Aqueous Film Forming Foams
Aqueous film forming foam (AFFF) concentrates are made from mixtures of
fluorocarbon surfactants and conventional surfactants and are designed for
fast knockdown of hydrocarbon fires. Developed in the 1960's, these AFFF
foams generally lose their water of composition more quickly after applica-
tion than other foams, and flammable liquids tend to be less resistant to
reignition after they have been blanketed by AFFF. These foams derive their
name from a thin film that develops over liquid surfaces that are sprayed
with AFFF. This film impedes the escape of toxic and flammable vapors (8).
2.5 Alcohol Type Foams
Alcohol type foams (ATF) were developed to extinguish hydrocarbon and
polar solvent (water miscible) fuel fires. They consist of an AFFF, regular
protein, surfactant, or fluoroprotein base concentrate with either a metal
stearate additive (salt of stearic acid) or a polymeric additive. When ATF
foams are applied to polar solvents, the additive coalesces into a gel,
forming an insoluble, low-permeability skin which inhibits vapor release (1).
-------
The stearate-based foams were developed earlier and have shorter shelf
lives and poorer flowing abilities than polymeric-based ATFs.
2.6 Special Foams
In addition to the above-mentioned types of foams, there are at least
three foams that were specifically formulated to control hazardous vapors.
These are Hazmat NF #1, Hazmat NF #2, and MSA Type V. Hazmat NF #1 and NF #2
are designed to be effective against alkaline and acid spills, respectively.
MSA Type V is used to control vapor hazards from water-reactive volatile
chemicals, and has a pH tolerance between 2 and 10 (6, 8, 9, 10). These foam
concentrates have special additives that allow them to be used on materials
that would destroy other foams. More manufacturers are planning to develop
foams especially formulated for controlling hazardous vapors.
-------
3. SELECTION OF FOAMS FOR VAPOR CONTROL
This section provides guidance to select appropriate foams to use on
chemical spills and discusses the qualities that should be considered in
selecting particular brands of foams. Table 1 provides a rating of foam
types for use on specific chemicals based on literature and personal com-
munications from manufacturers and researchers referenced in this handbook.
3.1 Foam Types
The selection of the appropriate foam type for use at a spill can make
the difference between a substantial reduction of risk from vapor ignition,
explosion, toxic effects, and an undesirable increase in risk associated with
unfavorable foam-chemical interactions. For example, application of an AFFF
foam to a spill of liquefied natural gas is not only a waste of expensive
foam, but it results in increased boiloff of flammable vapors (1,6,11).
Similarly, any foam type other than an alcohol foam is wasted on a polar
solvent spill, and only a high-expansion surfactant foam should be used to
control silicon tetrachloride vapors (1). These examples do not imply that
only one type of foam will work in each spill situation. However, for every
different spilled chemical, there are usually one or two types of foams that
exceed the vapor mitigating potential of other foam types. In addition, many
chemicals, particularly those that are inorganic and water-reactive, can be
more dangerous when blanketed with the wrong foam than they are in the
absence of foam application.
Table 1 indicates appropriate foam types for controlling vapors produced
by specific compounds. The table was constructed by compiling available
information from literature on the use of foams for controlling vapors from
hazardous substances (1,11-26). Much of this literature provides test
results on the performance of various foam types on specific chemicals. The
left hand columns of Table 1 identify the chemical groups and substances for
which data were found in the literature (see references). The chemical
groupings are provided only as a means of organizing the chemicals in the
table. Use of foams on chemicals not listed in the table is not recommended
unless the foam manufacturer provides test data on the use of a specific foam
on a given chemical.
The next two columns of the table provide the "recommended" and "satis-
factory" foam types for use on each identified chemical. These columns were
developed from vapor control test results that were often reported as visual
observations made by researchers. Therefore, the table reflects test results
that are somewhat subjective (compared to a numerical ranking of foam perfor-
mance with standard criteria).
5
-------
TABLE 1. FOAM SELECTION CHART FOR CONTROL OF HAZARDOUS VAPORS
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
ALCOHOLS
Butanol (Butyl
Alcohol)
(1120)
Methanol
(1230)
Octanol
Alcohol (ND**)
Propanol
(1274)
ALDEHYDES Acetone
AND (1090)
KETONES
Alcohol (ND)
Alcohol (ND)
Alcohol (ND)
Alcohol (10/60)
None
None
AFFF
Fluoroprotein
Protein
Surfactant H&L
None
None
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant H&L***(collapse)
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant H&L (collapse)
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant H&L (collapse)
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant H&L (collapse)
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
ALDEHYDES Methyl Butyl
AND Ketone
KETONES (1245)
(cont.)
Methyl Ethyl
Ketone
(1193)
AMINES
Ethylamines
(1036)
Ethylene Diamine
(1604)
Alcohol (ND) None
Alcohol (ND) None
Alcohol (ND) None
Hazmat NF #1 (ND)****
MSA Type V (ND)
Alcohol (ND) None
Hazmat NF #1 (ND)
MSA Type V (ND)
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant H&L (collapse)
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant H&L (collapse)
AFFF (collapse)
Fluoroprotein (early break-
through)
Protein (collapse)
Surfactant H&L (collapse)
AFFF (collapse)
Fluoroprotein (early break-
through)
Protein (collapse)
Surfactant H&L (collapse)
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
AMINES
(cont.)
00
ETHERS
ESTERS
Hydrazine
(2029) or
(2030)
Methylamines
(1061) or
(1235)
Ethyl Ether
(1155)
n-Butyl Acetate
(1123)
Alcohol (ND) None
Hazmat NF #1 (ND)
MSA Type V (ND)
Alcohol (ND) None
Hazmat NF #1 (ND)
MSA Type V (ND)
Alcohol (5/25-120) None
AFFF (5/120) None
Alcohol (5/120)
Fluoroprotein (5/120)
Protein (5/120)
Surfactant L (5/120)
AFFF (collapse)
Fluoroprotein (early
breakthrough)
Protein (collapse)
Surfactant H&L (collapse)
AFFF (collapse)
Fluoroprotein (early
breakthrough)
Protein (collapse)
Surfactant (collapse)
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant (collapse)
Surfactant H (no
information)
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
V0
ESTERS
(cont.)
HYDRO-
CARBONS
(ALI-
PHATIC)
Methyl Acrylate
(1919)
Vinyl Acetate
(1301) (monomer)
Ethane
(1961)
Ethylene
(1038)
(1962)
Heptane
(1206)
Alcohol
Alcohol (ND)
Fluoroprotein
Surfactant H
Surfactant H
Alcohol
Fluoroprotein (ND)
Protein (ND)
Surfactant H&L (ND)
None
AFFF (ND)
Alcohol (ND)
Fluoroprotein (ND)
Protein (ND)
Surfactant L (ND)
Alcohol (ND)
Fluoroprotein (ND)
Protein (ND)
Surfactant L (ND)
AFFF (ND)
AFFF (collapse)
Fluoroprotein (collapse)
Protein (collapse)
Surfactant H&L (untested)
Protein
Surfactant H&L
AFFF (accelerates boil-
off)
AFFF (accelerates boil-
off
None
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
HYDRO-
CARBONS
(ALI-
PHATIC)
(cont.)
Hexane
(1208)
Octane
(1262)
HYDRO- Benzene
CARBONS (1114)
(AROMATIC)
Ethylbenzene
(1175)
Toluene
(1294)
Alcohol
Alcohol (50/90)
Alcohol (2.5/120)
AFFF (5/120)
Alcohol (5/120)
Fluoroprotein (5/120)
Protein (5/120)
Surfactant L (5/120)
Alcohol
Fluoroprotein
Protein
AFFF (ND) None
Fluoroprotein (ND)
Protein (ND)
Surfactant (ND)
AFFF (5/60) None
Fluoroprotein (5/60)
Protein (5/60)
Surfactant L
(5/60), H (ND)
Fluoroprotein
(5/60)
Protein (5/60)
Surfactant H (25/50)
AFFF (early breakthrough)
Surfactant L (early
breakthrough)
Surfactant H
(50/30)
None
AFFF (5/40) None
Surfactant H (50/30)
Surfactant L (5/30)
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
HYDRO-
CARBONS
(ALI-
CYCLIC)
HYDRO-
CARBONS
(INDUS-
TRIAL)
Cyclohexane
(1145)
Gasoline
(1203)
Kerosene
(1223)
Naphtha
(2553)
Paint Thinner
(1263)
Alcohol (5/M20)
Fluoroprotein (5/M20)
Protein (5/M20)
Alcohol (ND)
Fluoroprotein (ND)
Protein (ND)
Surfactants (ND)
Alcohol (ND)
Fluoroprotein (ND)
Protein (ND)
Surfactants (ND)
Alcohol (ND)
Fluoroprotein (ND)
Protein (ND)
Surfactants (ND)
Alcohol (ND)
Fluoroprotein (ND)
Protein (ND)
AFFF (5/60)
Surfactant H (ND)
Surfactant L (5/30)
AFFF (ND)
None
None
AFFF (ND)
None
AFFF (ND)
AFFF (ND)
Surfactants (ND)
None
None
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
LIQUEFIED
ORGANIC
GASES
Ethylene Oxide
(1040)
Liquefied
Natural Gas
(Methane)
(1972)
None
Alcohol (ND)
Surfactant H (ND)
None
INORGANICS Carbon Disulfide
(1131)
Hazmat NF #2
MSA Type V (ND)
None
AFFF (collapse)
Protein (collapse)
Fluoroprotein (collapse)
Surfactant L (collapse)
Surfactant H (untested)
AFFF (early breakthrough)
Alcohol (early break-
through)
Fluoroprotein (early
breakthrough)
Protein (early break-
through)
Surfactant L (early
breakthrough)
AFFF (untested)
Alcohol (untested)
Fluoroprotein (untested)
Protein (early break-
through)
Surfactant H&L (untested)
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
INORGANICS Hydrochloric
(cont.) Acid
(1050)
Hydrogen
Chloride
(Anhydrous)
(1050)
Nitric Acid
(2032)
Silicon
Tetrachloride
(1818)
Hazmat NF #2
MSA Type V (ND)
Hazmat NF #2
MSA Type V (ND)
Hazmat NF #2
MSA Type V (ND)
Surfactant H (ND)
None
None
None
None
AFFF (untested)
Alcohol (untested)
Fluoroprotein (untested)
Protein (untested)
Surfactant H&L (untested)
AFFF (untested)
Alcohol (untested)
Fluoroprotein (untested)
Protein (untested)
Surfactant H&L (untested)
AFFF (untested)
Alcohol (untested)
Fluoroprotein (untested)
Surfactant H&L (untested)
AFFF (violent reaction)
Alcohol (violent reaction)
Fluoroprotein (violent
reaction)
Protein (violent reaction)
Surfactant L (violent
reaction)
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
INORGANICS Sulfur Trioxide
(cont.) (1829)
Hazmat NF #2
Surfactant H (ND)
MSA Type V (ND)
None
Titanium
Tetrachloride
(1838)
Ammonia
(1005)
Hazmat NF #2
MSA Type V (ND)
Surfactant H (30/10)
None
AFFF (8/5)
Alcohol (8/5)
Surfactant (8/5)
Fluoroprotein (8/5)
Protein (8/5)
AFFF (violent reaction)
Alcohol (violent reaction)
Fluoroprotein (violent
reaction)
Protein (violent reaction)
Surfactant L (violent
reaction)
AFFF (untested)
Alcohol (untested)
Fluoroprotein (untested)
Protein (untested)
Surfactant H&L (untested)
None
(continued)
-------
TABLE 1 (continued)
GROUP
CHEMICAL
(DOT No.)
RECOMMENDED FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
SATISFACTORY FOAM
TYPES (Minimum
Thickness/
Reapplication
Rate)(in.+/min.)*
INEFFECTIVE/
DANGEROUS
FOAM TYPES
(Reason)
INORGANIC
CRYOGENS
Bromine and
Chlorine
(1744) and
(1017)
Hazmat NF #2
Surfactant H
MSA Type V (ND)
None
Other foams are inef-
fective on chlorine,
causing accelerated
boiloff of heavier-than-
air chlorine gas.
* Reapplication times are generally based on the amount of time before a 1 percent vapor
concentration by volume is established above the spill surface.
** No data are available for foam thickness or reapplication rate.
*** H = high-expansion surfactant foam; L = low-expansion or medium-expansion surfactant foam.
**** Hazmat NF #1, Hazmat NF #2, and MSA Type V are specified by name because they were
designed for controlling hazardous vapors.
+ 1 inch = 2.54 centimeters.
-------
The recommended foam thicknesses and reapplication rates in columns 3
and 4 of the table were interpreted from graphs depicting "vapor concentra-
tion" of a given chemical on the y-axis and "time after foam application"
on the x-axis (1). These graphs represent a common method of presenting the
results of vapor control tests with foams.
The final column of the table shows foam types that are ineffective when
applied to certain spilled materials. It also provides reasons for placing a
particular foam type in this category. Some of the foam types were placed in
this category because there are no test data to indicate their effectiveness
in controlling certain chemical vapors. When using Table 1 at a spill site,
the responsible party should be careful not to use foam on chemicals not
listed in the table unless pre-response testing of the foam has been conduc-
ted.
Anyone using Table 1 to purchase foam concentrates should be aware that
vapor suppression qualities differ among different brands of foam and among
different brands of foam-generating equipment. Therefore, persons respon-
sible for selecting foam concentrates should review the following subsection.
3.2 Foam Quality
Two important indicators of foam quality in relation to vapor control
are the "expansion ratio" and the "quarter drainage time". The expansion
ratio is a dimensionless number that expresses the ratio of the volume of
foam to the volume of foam concentrate that produced the foam. Since the
technology for foams is rapidly changing and values for expansion ratio are
somewhat controversial, expansion ratios will be defined as follows:
o High-expansion: greater than 250:1
o Medium-expansion: between 20-250:1
o Low-expansion: less than 20:1
High-expansion foams can only be generated using high-expansion sur-
factant foam concentrates in combination with special foam-generating equip-
ment. However, low- and medium-expansion foams can be generated using various
combinations of foam types and foam nozzles. For example, a given brand of
alcohol type foam concentrate may produce a medium-expansion foam with one
nozzle and a low-expansion foam using a different nozzle. Another brand of
alcohol type foam may produce a medium-expansion foam with both nozzles.
In general, medium-expansion foams are the most effective foams for
controlling vapors from spilled chemicals (4,6,10, 27). They are more easily
applied to spills than high-expansion foams, and are not as easily displaced
by wind. Furthermore, they generally have longer quarter drainage times than
low-expansion foams and do not need to be reapplied as often.
The term "quarter drainage time" refers to the time it takes for a foam
to release 25 percent of the total liquid incorporated into the foam. Long
quarter drainage times are indicative of stable foams, which are capable of
16
-------
supressing vapors from spilled chemicals for long time periods before re-
application is necessary (assuming the foam is compatible with the spilled
chemical). High-expansion foams exhibit the longest quarter drainage times,
often exceeding one hour. However, these foams are not always recommended
because they may be either incompatible with the spilled material (See Table
1) or they may be easily blown away in windy conditions. Medium-expansion
foams exhibit quarter drainage times exceeding 15 minutes, but usually less
than 30 minutes. Quarter drainage times for low-expansion foams, except AFFF
foams, generally range between 3 and 12 minutes. Quarter drainage times for
AFFF foams are also between 3 and 12 minutes, but the test procedures for
AFFF foams are different than those used for the other foam types (28).
Expansion ratio and quarter drainage time are determined by standard
tests described in the National Fire Codes (NFPA Standards 11 and 11A) and in
Underwriters Laboratories' UL 162 (2,28,29). The tests for both of these
parameters begin when foam is discharged from a standard distance onto a
sloped backboard structure which drains into either a pan or a graduated
cylinder (Figure 1). The graduated cylinder, shown in the top half of Figure
1, was incorporated into the standard expansion and drainage tests for exclu-
sive use on AFFF foams due to their rapid drainage rates. Quarter drainage
times for the other foam types are measured using a pan, as shown in the
bottom half of Figure 1 (28).
Quarter drainage time is determined by plotting on a graph the volume of
water drainage over time, and then interpolating the time when one-quarter of
the water has been lost from the foam. Expansion ratio is determined by
weighing the foam in the collection container and dividing this weight into
the weight of an equivalent volume of water (23).
In determining quarter drainage times and expansion ratios of foams, it
is important to consider the type of foam nozzle used to conduct the tests
(4). The same batch of a given foam concentrate may display widely differing
test results when different nozzles are used. Therefore, it is important to
determine whether the nozzle used to produce the desired foam quality is
available to the person applying the foam in the field.
One method of ensuring the selection of a reasonably high-quality foam
without comparing expansion ratios and drainage times is to check the Under-
writers Laboratories (UL) listings in the book entitled "Fire Protection
Equipment Directory" (5). Although the book does not address vapor control,
it lists all foams that passed the UL 162 tests for fire knockdown and burn-
back resistance. It also lists the specific combinations of liquid concen-
trates and equipment that have been tested and gives UL minimum performance
standards for the tests. UL has also reviewed manufacturer's test reports
and can recommend test procedures for a particular foam (28).
In the UL 162 tests, a 50-sq. ft. pan containing a specified test mate-
rial is ignited and allowed to burn for 1 minute. Next, the fire is extin-
guished with foam and a lighted torch is moved over the entire foam blanket,
17
-------
26"
1660mm)
1 Litre
Graduated^
Cylinder
Nalgene TPX
Plastic
Aluminum Sheet
Pan
Figure 1: Typical standard backboard structures for collection of foams
prior to testing for quarter drainage time and expansion ratio (according to
Underwriters Laboratories, 1983).
18
-------
approximately 1 inch above the foam, for either 9 minutes (AFFF foams only)
or 15 minutes (all other foam types). To pass the torch portion of the test,
there must be no candling, flaming, or flashing in excess of 30 seconds
duration. This handbook provides a description of only part of the UL 160
test procedure. A full description of this procedure is available from
Underwriters Laboratories, Northbrook, Illinois (28). All foams that pass
the torch portion of this test would be beneficial in controlling vapors from
the chemicals that were successfully tested. However, the best brand of foam
for a given chemical can be identified only by comparing quarter drainage
times and expansion ratios of representative foams from the foam types that
are recommended in Table 1.
Comparisons of drainage times and expansion ratios between recommended
types of foam are valid only when high-expansion foam is not involved in the
comparison. High-expansion foams do not have the same flow characteristics
and physical properties as low-expansion foams; therefore, without knowing
site conditions, it is difficult to predict when they would be superior or
inferior to low-expansion foams. It is recommended that a responder to a
spill use proportioners, foam concentrates, and nozzles that are listed and
approved by Underwriters Laboratories or Factory Mutual Research Corporation
(5,30).
The importance of using quarter drainage time and expansion ratio to
select a foam should be emphasized. Manufacturers do not always put these
specifications on their labels, so responders should evaluate foams through
inexpensive and easy-to-conduct tests for quarter drainage time and expansion
ratio.
19
-------
4. SUGGESTIONS FOR APPLYING FOAMS FOR VAPOR CONTROL
This section is a compendium of suggestions on when, where, and how to
apply foams for vapor control.
4.1 Equipment
Fog nozzles should not be used to apply foams for vapor control. Fog
nozzles typically reduce the expansion ratio of the foam by at least 50
percent, which also reduces its drainage time (6). Use foam nozzles that
minimize drainage and maximize expansion of the foam. These can be either
straight stream or spray nozzles, and either turret-mounted or hand-held.
All nozzles are air aspirating (6).
Because medium-expansion foams are becoming available, there are fewer
hard and fast rules regarding the size of nozzles to use for producing foam.
Therefore, quarter drainage time becomes an increasingly important criterion
for selecting a particular brand of foam. Nozzles may vary; thus foams
should be tested with particular nozzles to produce the desired effects. The
nozzle must match the eductor for proper foaming to occur (4).
4.2 Application of Medium-Expansion and High-Expansion Foams
High-expansion foams cannot be emplaced by a nozzle. They must be
directed onto the spill using a foam chute or other conveying device. Winds
over 10 miles per hour preclude their use unless a foam fence is available
for corralling the foam over the spilled material. Even when a fence is
used, these foams should not be considered for use when wind velocities
exceed 20 miles per hour.
The application rate for high-expansion foams should be maximized and
should exceed 0.5 cubic feet per minute for every square foot of spill area.
The depth of high-expansion foams over flammable liquid spills should be
greater than or equal to 18 inches. This depth is sufficient to keep the
concentration of most vapors beneath or within the Lower Explosive Limit
(LEL)(6).
4.3 Application of Low-Expansion Foams
When using a foam pumper, low-expansion foams can be discharged for
maximum distances between 30 and 200 feet, depending on the nozzle size and
20
-------
the water pressure used (31). These distances can also be achieved by using
an eductor; however, water pressure must remain constant at the junction to
the eductor. In general, foams should be directed to a point just in front
of the spilled chemical, or to a wall behind the spilled chemical. This
ensures that the foam will flow across the surface of the chemical and main-
tain its structural integrity (9). Careful application is especially impor-
tant when using alcohol type foams, which separate into phases upon contact
with polar solvents. Plunging these foams into a spill could result in
little or no vapor mitigation due to multiple breaks in the lower foam
layer (6).
The application rate of low-expansion foams for vapor control is not as
critical as that for high-expansion foams because low-expansion foams can be
applied rapidly with respect to mass/time (6). Assuming there is no fire and
that the foam type is compatible with the spilled material , the foam will be
destroyed only at a low rate, thus making the application rate even less
critical. However, response organizations should attempt to cover a spill as
gently and as rapidly as their equipment will allow without creating turbu-
lence because the release of toxic and/or flammable gases will continue until
the entire spill area is covered. The capabilities of equipment and foam can
be determined by using the following formula:
_ 0.748DA _
RE
Where:
T = Desired time of coverage in minutes
D = Desired foam depth in feet
A = Area of the spill in square feet
R = Discharge capacity of existing equipment in gallons per minute of
foam concentrate/water mixture
E = Expansion of foam (e.g., 6,7,7.5,8,...).
For example, this formula estimates that one 65 gpm nozzle could cover a
1,330-sq. ft. spill area in under 1 minute, assuming a foam expansion ratio
of 8:1 and a desired foam depth of 6 inches.
In addition to determining the amount of time for covering different
size spills, it is important to estimate the spill sizes that can be miti-
gated by each type of foam to be carried on a response vehicle. To estimate
this amount , decide how much of each foam type will be carried on the re-
sponse vehicle. Next, calculate the maximum area to be mitigated by each
foam by the following formula:
A = 100 EC 4_2
7.48 DP
21
-------
Where:
A = Area of spill in square feet
E = Expansion ratio of the foam used
C = Gallons of foam concentrate in response vehicle
D = Desired foam depth in feet
P = Percentage shown on container of foam concentrate (a concentration).
For example, if a response vehicle could carry 25 gallons of 3 percent
alcohol foam, it would be capable of covering a 2,670-sq. ft. acetone spill,
assuming a foam expansion ratio of 8 and a desired foam depth of 4 inches.
According to Table 1, the foam blanket on acetone would need to be reapplied
after one hour. Therefore, more than 25 gallons of foam concentrate would be
needed for a spill of this size lasting over 1 hour.
4.4 Special Considerations
Foams should never be applied for vapor control on materials that have
not been tested. In general, they should not be used on liquefied gases
(except chlorine and bromine) that are heavier than air (e.g., butane, pro-
pane, butadiene) because they may cause accelerated formation of vapor clouds
that stay close to the ground and flow to low-lying areas (6).
Foam life is finite; thus, with spills that require a long cleanup
period, foams must be reapplied in order to maintain their desired thick-
nesses. Therefore, it is important to have enough foam on hand to complete
the foam layer and to reapply the foam as necessary.
Foams covering flammable liquids can develop gas mixtures within the
bubbles within flammable/explosive range and such foams can rapidly deflagrate
if presented with an ignition source. This will usually result in ignition
and fire of the liquid pool covered by the foam.
The control of vapors by the use of foams should not be undertaken
without proper protective gear. Similarly, protective gear, such as a self-
contained breathing apparatus, should never be removed after foam application
because it is impossible to predict the degree of vapor mitigation at a site
in terms of human toxicity. It is also impossible to precisely predict the
foam effectiveness time. Therefore, reapplication times of foams must be
established on-scene through periodic visual inspections of the foam blanket
(6). For flammable vapors, protective clothing is necessary, and one can
determine when to reapply the foam by monitoring the spill continuously with
an explosimeter.
22
-------
REFERENCES
1. Gross, S.S., and R.H. Hiltz. "Evaluation of Foams for Mitigating Air
Pollution from Hazardous Spills". Prepared for the U.S. Environmental
Protection Agency Report EPA-600/52-82-029. July 1982.
2. National Fire Codes. Foam Extinguishing Systems, Volume 1, Number 11.
1983.
3. O'Brien, Pat, and Joyce Seawell. Angus Fire Armour Corporation, Angier,
North Carolina. Personal communications with M. Evans, JRB/SAIC. June
1984.
4. Eversole, J., Chicago Fire Academy, Chicago, Illinois. Personal
communications with M. Evans. JRB/SAIC. May 1985.
5. Underwriters Laboratories. Foam Protection Equipment Directory.
January 1984.
6. Hiltz, Ralph H., MSA Research Corporation, Evans City, Pennsylvania.
Personal communications with M. Evans. JRB/SAIC. April 1984 through
May 1985.
7. Lockwood, Norman. Chairman of the NFPA Foams Committee. Personal com-
munications with M. Evans and H. Carroll. JRB/SAIC. June 1984, May
1985.
8. 3M Corporation. "Light Water AFFF/ATC", Product Information Bulletin.
3M Corporation. 1981.
9. National Foam. "Controlling Hazardous Vapors", Advertising literature,
Section XIV. Enterra Corporation. 1982.
10. Norman, E. National Foam, Lionville, Pennsylvania. Personal communi-
cations with M. Evans. JRB/SAIC. May through July 1984.
11. Hiltz, Ralph H. "The Use of Foam in Fire and Spill Control of Hydro-
carbon and Petrochemical Materials". Unpublished. June 1980.
12. Brown, L.E. and L.M. Romine. "Liquefied Gas Fires: Which Foam?",
Hydrocarbon Processing. September 1979.
13. Clark, W.C. "Use of Fire-Fighting Foam on Ammonia Spills", American
Institute of Chemical Engineers, 80th National Meeting, Boston. 1975.
23
-------
14. Gross, S.S. "Evaluation of Foams for Mitigating Air Pollution From
Hazardous Materials Spills", Proceedings of the 1978 National Conference
on Control of Hazardous Materials Spills. 1978.
15. Gross, S.S. "Application of Foams to Hazardous Chemical Spills",
Proceedings of the 1980 National Conference on Control of Hazardous
Materials Spills. 1980.
16. Greer, J.S. "Feasibility Study of Response Techniques for Discharges of
Hazardous Chemicals that Float on Water", U.S. Coast Guard Report CG-D-
56-77. October 1976.
17. Hiltz, Ralph H. "Control of the Vapor Hazard from Water Reactive
Volatile Hazardous Materials by Foam", presented at EnviroCanada Spill
Symposium. Toronto. October 1983.
18. Hiltz, Ralph H. "Vapor/Hazard Control Mechanisms for Spilled Volatile
Chemicals", presented at the 1983 Meeting of the Ohio Environmental Pro-
tection Agency. May 1983.
19. Hiltz, R., and S. Gross. "The Use of Foams to Control the Vapor Hazard
from Liquefied Gas Spills", Proceedings from the 1980 National Conference
on Control of Hazardous Materials Spills. 1980.
20. Hiltz, R.H. and Friel, J.V. "Application of Foams to the Control of Haz-
ardous Chemical Spills", Proceedings of the 1976 National Conference on
Control of Hazardous Materials Spills. April 1976.
21. Meldrum, D.N. "Aqueous Film-Forming Foams: Facts and Fallacies." Fire
Journal. 66(1). January 1972.
22. MSA Research Corporation. "Summary Engineering Report on Foam Develop-
ment for Hypergolic Propellant Spill Control", Contract F42600-83-C-0615
to Air Force. Evans City, Pennsylvania, 73 p. 1985.
23. Norman, E., and H. Dowell. "Using Aqueous Foams to Lessen Vaporization
from Hazardous Chemical Spills". American Institute of Chemical
Engineers. 13th Loss Prevention Symposium. 1979.
24. Norman, E. "Vapor Mitigation by the Use of Foam: Case History
and Large Scale Outdoor Tests", Proceedings from the 1978 National
Conference on Control of Hazardous Materials Spills. 1982.
25. Pignato, J., J., Huber, J. Hottinger, and M. Sierakowski. "Foam Agent to
Mitigate the Vapors from Hazardous Material Spills", Proceedings from the
1982 National Conference on Control of Hazardous Materials Spills.
November 1982.
26. Welker, J., H. Wesson, and L. Brown. "Use Foam to Disperse Vapors?",
Hydrocarbon Processing. February 1974.
24
-------
27. McRae, M., District Chief, Hazardous Materials Response Team, City of
Houston. Personal communications with M. Evans. JRB/SAIC. May 1985.
28. Underwriters Laboratories, Inc. Standards for Foam Equipment and Liquid
Concentrates, UL 162, Fifth Edition. June 1983.
29. NFPA. Medium and High Expansion Foam Systems NFPA 11A. Fire Protection
Handbook. 1983.
30. Factory Mutual Research Corporation. Approval Guide. 1985.
31. Parker, Thomas. Rockwood Systems Corporation, Lancaster, Texas.
Personal communications with M. Evans. JRB/SAIC. July 1984.
25
-------
APPENDIX
FACTORS FOR UNIT CONVERSION
Unit Multiply by To find
inch 2.54 centimeters
foot 30.48 centimeters
foot 0.30 meters
yard 0.90 meters
cubic foot per second 448.8 gallons per minute
square foot 0.09 square meters
26
•&U. S. GOVERNMENT PRINTING OFFICE: 1986/646-117/40645
------- |