United States
Environmental Protection
Agency
Office of Solid Waste
and Emergency Response
(5104)
EPA 55Q-F-9?-QQ2e
May 199?
f/EPA
FIRE HAZARD FROM CARBON
ADSORPTION DEODORIZING
SYSTEMS
The Environmental Protection Agency (EPA) is issuing this Alert as part of its ongoing effort to
protect human health and the environment by preventing chemical accidents. Under CERCLA,
section 104(e) and Clean Air Act CCAA), EPA has authority to conduct chemical accident
investigations. Additionally, in January 1995, the Administration asked the Occupational Safety
and Health Administration fOSHA) and EPA to jointly undertake investigations to determine
the root causefs) of chemical accidents and to issue public reports containing recommendations
to prevent similar accidents. EPA has created a chemical accident investigation team to work
jointly with OSHA in these efforts. Prior to the release of a full report, EPA intends to publish
Alerts as promptly as possible to increase awareness of possible hazards. Alerts may also be
issued when EPA becomes aware of a significant hazard. It is important that facilities, SERCs,
LEPCs, emergency responders and others review this information and take appropriate steps
to minimize risk.
PROBLEM
Activated carbon systems used to
adsorb vapors for control of
offensive odors may pose a fire
hazard when used for certain types of
substances, if proper procedures are not
followed. In particular, crude sulfate
turpentine, commonly produced in the
pulp and paper industry, can pose a fire
hazard if the adsorption system is not
properly designed and proper
procedures are not implemented.
Facilities should take precautions to
avoid or mitigate these fire hazards.
ACCIDENTS
In a 1995 accident at a chemical
terminal facility, a fire and explosion
occurred involving three tanks of
crude sulfate turpentine. The tanks
were connected to drums of activated
carbon for deodorizing. The fire and
explosion damaged other storage tanks,
resulting in the release of toxic gases and
forcing a large-scale evacuation of area
residents.
Fires have occurred in the past in
activated carbon systems used for
deodorizing crude sulfate turpentine. In
general, such fires have not had effects
as serious as those reported in the 1995
fire. Serious effects would not be
expected if fires are confined to the
activated carbon containers and do not
spread to tanks containing flammable or
combustible substances.
Activated carbon is widely used to
adsorb vapors to prevent their
release to the air. For certain
classes of chemicals, reaction or
adsorption on the carbon surface is
accompanied by release of a large
amount of heat that may cause hot spots
in the carbon bed. Such chemicals
include organic sulfur compounds (e.g.,
mercaptans), which may be found as
impurities in crude sulfate turpentine
and other materials. Other classes of
chemicals that may cause large thermal
releases are ketones, aldehydes, and
some organic acids. Adsorption of high
vapor concentrations of organic
compounds also can create hot spots. If
flammable vapors are present, the heat
released by adsorption or reaction on the
surface of the carbon may create a fire
hazard (e.g., a fire may start if the
temperature reaches the autoignition
temperature of the vapor and oxygen is
present to support ignition).
Chemical Emergency Preparedness and Prevention Office
i Printed on recycled paper
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Fire Hazard from Carbon Adsorption Deodorizing Systems
May 1997
The fire hazards of carbon adsorption
deodorizing systems may increase at night. At
certain times (typically during the day), high
temperatures may lead to the expansion of vapor
in the system, and vapor is likely to exit to the
atmosphere. When temperatures drop (typically
at night), a slight vacuum may be created",
causing air to be drawn into the system. If the
carbon surface is very hot, because of the heat
generated by adsorption, air drawn in over the
carbon may provide the oxygen to start a fire.
4 If the potential exists for fires in the acti-
vated carbon system, be sure the carbon
containers are separated from containers of
flammable or combustible substances and
can be easily and rapidly removed in case
the container becomes hot or catches fire.
4 If high concentrations of organic com-
pounds may cause development of high
temperatures, take steps to control the
heating. Such steps may include diluting
inlet air, time weighting the inlet concentra-
tion to allow heat to dissipate, and pre-
wetting the carbon.
Facilities should be aware of the potential
fire hazards of activated carbon systems for
absorbing flammable vapors and take
steps to minimize these hazards. Actions that
may help to prevent fires include:
4- Follow the manufacturer's instructions for
design and operation of activated carbon
adsorption systems.
4 Ensure that a qualified engineer or technician
supervises the design, construction, and
operation of the carbon adsorption system.
4 Evaluate the composition of the vapors that
will contact the carbon and heed the
manufacturer's warnings about potential
hazardous interactions with the carbon. If
the vapor may contain organic sulfur
compounds (e.g., vapor from crude sulfate
turpentine), ketones, aldehydes, or organic
acids, or if the vapor contains high concen-
trations of organic compounds, consider the
potential for development of hot spots on
the carbon.
4 Test the action of the vapors on carbon for
potential heat release before putting the
carbon adsorption system into service, if
possible reactions are not known.
4- If test results or known reactions with
carbon indicate the potential for fires in the
activated carbon system, design the system
so that air does not enter the system over
the carbon bed (e.g., install vacuum break-
ers on the storage tanks).
4 Visually inspect activated carbon adsorp-
tion systems frequently for hot spots and
fires.
4 Before using an activated carbon adsorption
system, ensure that safety systems are in
place for fire prevention and mitigation,
including flame arrestors to prevent the
spread of fire from the carbon containers to
the flammable chemical containers.
4 Ensure that flammable and combustible
chemicals connected to activated carbon
adsorption systems are handled in accor-
dance with applicable regulations, codes,
and standards.
Some references that may contain
information about the fire hazards of
activated carbon adsorption systems and
methods of minimizing them are listed below.
Regulations applicable to such systems, and
codes and standards that may be relevant, are
also listed.
For more information consult the following:
Information on carbon adsorption systems for
crude sulfate turpentine can be found in W.A.
Harrell, J.O. Sewall, and T.J. Walsh, "Control of
Malodorous Compounds by Carbon Adsorption,"
American Institute of Chemical Engineers, Loss
Prevention, Volume 12,1979, pp 124-127.
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Fire Hazard from Carbon Adsorption Deodorizing Systems
May 1997
Manufacturers of activated carbon can provide
product literature until information on properties, safe
handling, and use.
flammable and combustible substances are included,
in DOT's Hazardous Materials Table [49 CFR
172.102].
Section 112(r) of the Clean Air Act focuses on
prevention of chemical accidents. It imposes on
facilities with regulated substances or other extremely
hazardous substances a general duty to prevent and
mitigate accidental releases. Accident prevention
activities include identifying hazards and operating
a safe facility.
EPA's Risk Management Program (RMP) Rule [40
CFR 68] is intended to prevent and mitigate
accidental releases of listed toxic and flammable
substances. Requirements under the RMP rule
include development of a hazard assessment, a
prevention program, and an emergency response
program.
Processes containing flammable gases and liquids
may be covered under the Occupational Safety and
Health Administration's (OSHA) Process Safety
Management Standard, which establishes procedures
intended to protect employees by preventing or
minimizing the consequences of chemical accidents
involving highly hazardous chemicals [29 CFR
1910.119].
OSHA also has a Standard for Flammable and
Combustible Liquids [29 CFR 1910.106].
Occupational Safety and Health Administration
Phone: (202) 219-8151 - Public Information
Web site: http://www.osha.gov
The Department of Transportation (DOT) regulates
transportation of activated carbon and other
flammable and combustible substances under its
Hazardous Materials Regulations. Activated carbon
and many combustible and flammable substances are
listed individually, and several categories of
Department of Transportation
Phone: (202) 366-5580 - Public Information
Website: http://www.dot.gov
The National Fire Protection Association (NFPA) has
a code for flammable and combustible liquids that may
be adopted into law at the state or local level. NFPA
30 — Flammable and Combustible Liquids Code,
1996.
National Fire Protection Association
1 Batterymarch Park
P.O. Box 9101
Quincy, MA 02269-9101
Phone: (617)770-3000
Customer Sendee: 1 (800) 344-3555
Web site: http://www.nfpa.org
FOR MORE INFORMATION...
CONTACT THE EMERGENCY PLANNING AND
COMMUNITY RTGHT-TO-KNOW HOTLINE
(800) 424-9346 OR (703) 412-9810
TDD (800) 553-7672
MONDAY-FRIDAY, 9 AM TO 6 PM, EASTERN TIME
VISIT THE CEPPO HOME PAGE ON THE WORLD
WIDE WEB AT:
http://www.epa.gov/swercepp/
NOTICE
The statements in this document are intended solely as guidance. This document does not substitute for EPA's or other
agency regulations, nor is it a regulation itself. Site-specific application of the guidance may vary depending on process
aetiwities, and may not apply to a given situation, EPA may revoke, modify, or suspend this guidance in the future, as
appropriate.
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