WAACNewsletter
Volume 15, Number 2, May 1993, pp.31-33

Fire Suppression and Life without Halon

by Barbara O. Roberts

In 1987, an international agreement known as the Montreal Protocol mandated the phaseout of halons in developed countries by the year 2000 and in less-developed countries by 2010. Du Pont has announced that it will phaseout worldwide sales of Halon 1301 (CF3Br) by December 31, 1993.

Substitutes for Banned Halons

The New York Times, in an article by Malcolm W. Browne1, stated that the recent agreement of 87 countries to "halt the manufacture of halon fire extinguishers will eventually eliminate a potent threat to the earth's protective ozone layer."

Mr. Browne quotes Dr. William Grosshandler, Director, Building and Fire Research Laboratory, National Institute of Standards and Technology, "Now that halons are to be banned, however, scientists are rushing to gain insights into their chemical properties, with a view to mimicking them in substitutes. The theory is that the bromine in Halon-1301 combines with the hydrogen released in fires by burning oil, gasoline, wood, paper or any other hydrocarbon. By removing the free hydrogen liberated in a hydrocarbon fire, hydrogen is no longer available to combine with oxygen in the air. The burning of hydrogen with oxygen is one of the main producers of heat in a hydrocarbon fire, and when this is stopped, the reaction is cooled, helping to put out the fire."

The National Fire Protection Association (NFPA) published this spring the latest draft of its document known as NFPA 2001, "Standard on Clean Agent Fire Extinguishing Systems"2, to deal with new halon replacement agents. As stated in the preface to NFPA 2001, "This document addresses...total flooding fire extinguishing systems that use clean agents. It does not cover fire extinguishing systems that use carbon dioxide, Halon 1301, Halon 1211, Halon 2402, or water, [which] are addressed by other NFPA documents." Clean agent is defined as "electrically nonconducting, volatile, or gaseous fire extinguishant that does not leave a residue upon evaporation." The following substances are listed in the standard as "clean agents," with the note that other agents may become available at later dates:

FC-3-1-10

(chemical name: perfluorobutane (C4F10); trade name PFC-410 Clean Extinguishing Agent; contact Joan Leedy of 3M at 612/733-7937)

HFC-227ea

(chemical name: heptafluoropropane (CF3CHFCF3); trade name: FM-200; contact Doug Register of Great Lakes Chemical at 317/497-6382)

HBFC-22B1

(chemical name: bromodifluoromethane (CHF2Br); trade name: FM-100; contact Doug Register of Great Lakes Chemical at 317/497-6382)

R-595 Blend

(blend of hydrochlorofluorocarbons: HCFC-123 (4.75%), HCFC-22 (82%), HCFC-124 (3.75%), Isopropenyl-1-Methylcyclohexane (3.75%); trade name: NAF S-III; contact Elio Guglielmi of North American Fire Guardian at 604/684-7374)

IG-541

(mixture of inert gases: nitrogen (50%), argon (40%), carbon dioxide (10%)--also shown in 52:40:8 ratio; trade name: INERGEN; contact Jack Riley of Ansul Fire Protection at 715/732- 3608)

HFC-23

(chemical name: trifluoromethane (CHF3); trade name: FE-13; contact Dan Moore of Du Pont at 302/992-2177)

HFC-125

(chemical name: pentafluoroethane (CHF2CF3; trade name: FE-25; contact Dan Moore of DuPont at 302/992-2177)

HCFC-124

(chemical name; chlorotetrafluoroethane (CHClFCF3; trade name: FE-241; contact Dan Moore of DuPont at 302/992-2177)

In November 1992, HARC News (Halon Alternatives Research Corporation)3 reported that NFPA's technical committee had received sufficient data on FC-3-1-10, HFC-227ea, and HFC-23 for these agents to be considered as acceptable for use in normally occupied spaces.

Recycling of Halon 1301

HARC News also reported that the board of directors of HARC have approved the formation of the Halon Recycling Corporation (HRC). A recent study by a review panel for HRC points out that the recycling of existing Halon 1301 will probably be managed through local fire equipment companies and recommends the formation of a not-for-profit corporation for larger-scale operations, including refurbishment of more severely contaminated Halon 1301 and 1211 than may be practical at the fire equipment distributor level. For more information on donating or selling halon to essential uses, obtaining halon for essential uses, or becoming a member of HRC, please call 800/258-1283.

The decision to develop a code of practice for the best use of recycled and banked halon has been applauded by both the US Environmental Protection Agency and Environment Canada, and voluntary guidelines are being written by the Fire Suppression Systems Association (FSSA), National Association of Fire Equipment Distributors (NAFED), Fire Equipment Manufacturers Association (FEMA), and the Fire Equipment Manufacturers Institute of Canada (FEMI).

Costs to Keep or Modify a Halon System

Awareness of the cost of replacing halon once it has been discharged may be the incentive for you and your institution to think through what you are going to do about your existing halon system.

As part of the 1992 National Energy Policy Act, The US Congress increased the tax on substances controlled by the Montreal Protocol. The tax is applied to newly produced Halons 1211, 1301, and 2402 and will increase according to the following schedule3:

EXCISE TAX ON NEWLY PRODUCED HALONS (dollars/pound)


    YEAR   HALON 1211  HALON 1301  HALON 2402

    1993   0.2502      0.2512      0.2492

    1994   13.05       43.50       26.10

    1995   16.05       53.50       32.10

    1996   17.40       58.00       34.80

    1997   18.75       62.50       37.50

In other words, a surcharge tax of about $44 will be levied on each pound of newly produced Halon 1301 sold in the US after January 1, 1994. Look at the capacity of the tanks in your institution and work out the cost of halon replacement.

The extremely high future cost of halon may motivate you to consider using one of the new clean-agent extinguishant gases in your present system. But there are a few more wrinkles: first, your hardware will need modification. For example, Du Pont's FE- 13 (the substance used most widely in museums and archives) also known as HFC-23 , "is not as efficient as Halon 1301 because it does not contain ozone-impacting bromine. Therefore, a fire that is extinguished with one pound of Halon 1301 would require 1.75 lb of FE-13. This need for an increased quantity of agent leads to an obvious fact--FE-13 requires more storage volume."4 In addition to needing a new tank(s), you will need new piping because FE-13 also has a much higher vapor pressure than Halon 1301. "Hardware used for carbon dioxide systems could be the likely choice."4

Furthermore, from discussions with Dan Moore of Du Pont, it is clear that the availability of the new products is not necessarily a long-term given. "Under ideal conditions, there would be an orderly transition to zero ozone-depleting substitutes. However, appropriate substitutes for many applications have not yet been developed. Taking these factors into consideration, authorities recognize that hydrochlorofluorocarbons (HCFCs), which have measurable, but comparatively low ozone depletion potential (ODP), could serve as transitional compounds for a reasonable length of time, perhaps for the normal lifetime of the equipment."4 (emphasis added)

So! If you do decide to switch to the new products, tanks, and piping, you may well have to repeat the process in, say, 15 or 20 years (give or take a few)--and please note that the recycling program for the present products is still only in the discussion phase.

More About Du Pont'S FE-13 (CHF3--Trifluoromethane; HFC-23)

The Du Pont company has written, "Prior to the completion of the cardiac sensitization study, we thought that FE-25 (HFC-125) would be the best alternative agent since it had all the required attributes and could be used in existing high- and low-pressure Halon 1301 hardware. [However,] the higher concentrations required to effectively extinguish fires can, based on our recently completed testing, lead to cardiac sensitization problems. Therefore, FE-25 is no longer considered a viable alternative for Halon 1301 in occupied spaces..."4

"Du Pont is now offering FE-13 ... for applications requiring immediate availability of a clean, environmentally acceptable, and humanly compatible fire extinguishing agent. ...Its ozone depletion potential is zero....

"FE-13 extinguishes fire by both physical and chemical means. Primarily it raises the total heat capacity of the environment to the point that the atmosphere will not support combustion. In practice, however, extinguishment occurs at concentrations less than the theoretical heat capacity value...

"When exposed to open flames, FE-13 will decompose and produce hydrofluoric acid (HF). The amount of HF will depend upon the size of the fire and the speed of extinguishment. Even at low levels, these decomposition products have a very acrid odor and are easily detected by the human senses. The natural tendency to escape exposure should be heeded."5

The toxicity profile for FE-13 is as follows5:


    TEST                                    VALUE

    Approx. lethal concentration            >663,000 ppm
         (rats, 4 hrs)

    Cardiac Sensitization                   50% with added oxygen
         Threshold Level                    30% without added oxygen

    No Observable Adverse Effect Level
         90-day study--rats                 10,000 ppm
         90-day study--dogs                  5,000 ppm

    Ames Assay                              not mutagenic

What To Do?

I advocate a well-installed, well-maintained sprinkler system for fire suppression. I am convinced that they put out a fire quickly and effectively. Conservators can usually deal with the wet or damp collections material that might be below the limited number of sprinkler heads that may discharge water. I want the fire out quickly with minimal impact on the objects and building as a whole.

The argument that sprinkler heads are unsightly is outdated. The only reported incident of a sprinkler system activating inadvertently in a museum was traced to a sprinkler head that was taken off the market in the 1970s because of leaking problems.

There may be problems with introducing sprinklers into some historic structures, but I would still prefer to take the decision to save the structure in the event of fire than to opt for luck and a prayer.

In recent correspondence with Andrew Wilson (Chief, Fire Protection Division, Smithsonian Institution), he informed me that the present Smithsonian position on halon and sprinklers is as follows: "It is the policy of the Smithsonian Institution to install automatic sprinklers and standpipe systems in appropriate areas ... We have stopped allowing halon systems, but much of the policy will probably hold true for whatever replacement gases are developed. ...As far as types of sprinkler systems and/or heads I recommend or advocate, it all depends on the circumstances. ... It should be noted that a few institutions do have a written policy prohibiting the loan of collections to facilities that have automatic sprinklers."6

Additionally, very early smoke detection devices are now on the market. These can often provide sufficient early warning of a fire to allow human intervention before the activation of sprinklers or the release of gaseous suppressants.7

Protect collections that are particularly vulnerable to water by good cases, frames, fireproof cabinets, boxing, polyethylene bags, or whatever secondary protection makes sense.

Ensure that the sources of fires are kept to a minimum.

Maintain and inspect electrical wiring on a regular basis. Place combustible materials in fireproof/waterproof cabinets that are properly vented. Maintain a high standard of housekeeping. Monitor contractors, especially when they are using equipment that can cause fires.

Install lightning rods if appropriate. Ban smoking and use of matches and cigarette lighters or curtail their use to specific areas. Write and practice an emergency plan.

Keep hand-held fire extinguishers serviced and in all appropriate areas, and train everyone concerned how to use them. (Remember that the object or specimen itself is rarely the cause of the fire, and if there is time to use the extinguisher, you should be directing the flow at the fire source itself not the artifact.)

Extinguishers should be carefully chosen for the type of fire that you expect: Class A: paper, wood, textiles, and ordinary combustibles; Class B: flammable liquids and grease; Class C: electrical equipment.

The A-B-C type extinguishers (containing ammonium phosphate) are effective in labs or where flammable and combustible materials are found. Carbon dioxide extinguishers leave no residue after use and are effective for electrical equipment but not for organic materials. Water type extinguishers are effective for collections areas and storage (they contain about 2-1/2 gallons of water and are probably the easiest to use). I, for one, do not wish to spend vital seconds deciding on the type of fire I am trying to suppress, and if you do have to go with one type, the A-B-C has the widest variety of applications--but note that if objects are sprayed the residue is difficult to remove.

Paul Baril has a compilation of papers entitled Museum Fire Protection Technical Papers8 that I strongly recommend to anyone who is grappling with this subject. Paul is an advocate of wet-pipe sprinklers, and when all is said and done--and the fire is out--I am too.

References

1. Browne, Malcolm W.: "As Halon Ban Nears, Researchers Seek a New Miracle Firefighter," New York Times, December 15, 1992.

2. 1993 Fall Meeting Technical Committee Reports (Proposals), 1993, National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy, Massachusetts 02269-9101.

3. HARC News, Volume 2, No. 2, November 1992. Published by the Halon Alternatives Research Corporation (HARC), 1025 Connecticut Avenue NW-Suite 712, Washington, DC 20036.

4. DuPont Fire Extinguishants News, Volume 1, No. 3, Fall 1992.

5. Du Pont Alternative Fire Extinguishants: FE-13 for Total Flooding Agent Applications, (H-27337-2, Revised 5-92), Du Pont Chemicals, Barley Mill Plaza 13-2150, P. O. Box 80013, Wilmington, Delaware 19880. For more information also contact DuPont Chemicals, Customer Service Center, 800/441-9442 and in Canada DuPont Canada, Inc., P.O. Box 2200, Streetsville, Mississauga, Ontario L5M 2H3. 416/821-3300.

6. Wilson, J. Andrew: "Fire Fighters: An Automatic Fire Suppression System Is among Your Museum's Best and Safest Forms of Insurance," Museum News, November/December 1989, pages 68-72. I urge everyone to read this article and to learn the difference between "wet-pipe," "pre-action system," and "dry-pipe systems."

7. More information is available from I.E.I (North America) Inc., 35 Pond Park Road, Hingham, MA 02043 Tel: 800/229-4434.

8. Baril, Paul: Museum Fire Protection Technical Papers, Museums Assistance Program, 300 Slater Street, Ottawa, Ontario, K1A OC8, Canada, (613/991-1701).

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