Halon is a "Clean Agent." The National Fire Protection Association defines, a "Clean Agent" as "an electrically non-conducting, volatile, or gaseous fire extinguishant that does not leave a residue upon evaporation."
Currently, there are two common types of Halon in use; Halon 1211 (a liquid streaming agent) and Halon 1301 (a gaseous flooding agent). Both contain low-toxicity, chemically stable, non-conductive compounds that are easily recyclable.
Halon is an extraordinarily effective fire extinguishing agent, even at low concentrations. According to the Halon Alternative Research Corporation: "Three things must come together at the same time to start a fire. The first ingredient is fuel (anything that can burn), the second is oxygen (normal breathing air is ample) and the last is an ignition source (high heat can cause a fire even without a spark or open flame). Traditionally, to stop a fire you need to remove one side of the triangle - the ignition, the fuel or the oxygen. Halon adds a fourth dimension to fire fighting - breaking the chain reaction. It stops the fuel, the ignition and the oxygen from dancing together by chemically reacting with them."
A key benefit of Halon, as a clean agent, is its ability to extinguish fire without the production of residues that could damage the assets being protected.
HALON AND THE OZONE LAYER
- What Is the Ozone layer?
At the outer edge of the earth's atmosphere there is a thin layer of invisible, naturally occurring gas that is critical to life on earth. It is the stratospheric ozone layer. This layer protects life on earth from the harmful rays of the sun.
- What Causes Reductions Of The Ozone Layer?
When certain chemicals used on earth escape into the atmosphere they are broken down by solar radiation and release chlorine and bromine atoms, which, in a chain reaction, destroy ozone molecules. This reaction occurs more frequently than natural ozone replenishment, resulting in a thinning of the ozone layer.
- Is The Ozone Layer Threatened?
Atmospheric measurements reveal that the ozone layer is getting thinner, and that at certain times of the year a hole in the ozone layer appears over Antarctica. Some people believe this reduction is due to solar or volcanic activity, but most scientists believe that certain man-made chemicals are major contributors to the problem. These chemicals include the chlorofluorocarbons (CFCs) found in refrigerators, solvents and blowing agents for foams, and the Halon used for fire fighting.
- How Damaging Is Halon to the Ozone Layer?
A compound's ability to destroy ozone depends on many factors, including the amount of chlorine and/or bromine that it contains. To aid in comparing compounds, scientists have developed a relative scale called the ozone depletion potential (ODP). Common refrigerants, like those found in refrigerators and in automobile air conditioners, have been assigned the value 1 as a reference. Halon 1301 has the value between 10 and 16, meaning it has 10-16 times the more potential for destroying the ozone layer.
- Halon's Role in Stratospheric Ozone Depletion
The Halon covered by EPA Rule 40 CFR Part 82, Subpart H contains the chemical element bromine (Br) and also, in the case of Halon 1211 specifically, chlorine (Cl). Br and Cl both contribute to stratospheric ozone destruction. The earth's stratosphere is a layer of the atmosphere that begins between 5 and 11 miles above the earth's surface and extends up to about 30 miles above the earth's surface. Ninety percent of the ozone in the earth's atmosphere is found in the stratosphere. The characteristics of Halon and other human-made chemicals that can deplete ozone (e.g., chlorofluorocarbons, or CFCs) enable them to reach the stratosphere, where they break down and the Cl and Br from them can destroy ozone. Halon is a major source of bromine in the stratosphere.
- Stratospheric Ozone Destruction is a Health Risk
Ozone in the earth's stratosphere protects the earth from the penetration of harmful ultraviolet (primarily UV-B) solar radiation by absorbing most of this harmful UV-B, allowing only a small amount to reach the earth's surface.
INDUSTRY SELF REGULATION
What Is Industry Doing About Halon Use?
When the environmental effects of Halon became known, industrial users of Halon and fire protection professionals worked together to limit Halon use and emissions. Through changes in standards and specifications, industry has virtually eliminated its use of Halon for testing and training purposes. Historically, testing and training has been responsible for the majority of Halon emissions. Many organizations that continue to rely on Halon systems for fire protection have instituted programs to identify their most critical needs. Halons that can be removed from non-critical or obsolete facilities are then recovered for use in more critical applications.
- The Halon Alternatives Research Corporation (HARC)
The Halon Alternatives Research Corporation (HARC) is a non-profit trade association formed in 1989 to promote the development and approval of environmentally acceptable Halon alternatives. HARC was formed to focus efforts for finding suitable alternatives for the Halons used in fire fighting and it has developed a unique, cooperative working relationship with government agencies concerned with the Halon/CFC issue. It is also the major industry association providing information to the user community on Halon-related issues. HARC has facilitated and encouraged the involvement of the fire protection community in environmentally responsible activities, including:
Coordinated development of an Industry Code of Practice for the best use of recycled Halon.
Assisted in development of EPA Public Education Brochures.
Sponsored major conferences on aviation fire safety and alternative technologies.
Sponsored workshop on toxicological issues related to halocarbon replacements.
Sponsored research on Halon bank management leading to the formation of the Halon Recycling Corporation (HRC).
- The Halon Recycling Corporation (HRC)
The Halon Recycling Corporation (HRC) is a voluntary, non-profit trade association formed by concerned Halon users and the fire protection industry to support the goals of the environmental community and the United States Environmental Protection Agency (EPA). Its function is to assist users of Halon fire fighting chemicals to redeploy the existing bank of Halons from applications where alternatives are feasible to those unique situations that still require Halons. HRC can assist you in selling your Halons, or help you to find Halons to keep your critical systems functional. HRC will also keep you informed about changes in international and domestic regulations that can impact continued Halon use.
HRC has developed an ethical code of practice for reclaimers of Halon. This Code of Practice has been developed to provide an assurance to the public that HRC Enrolled Sellers engaged in the business of Halon recycling and recovery operate in a manner that promotes safe and environmentally responsible Halon reclamation. HRC has the following missions:
Facilitate Halon Recycling - HRC acts as a facilitating organization for the recycling of Halon 1211 and 1301 by providing information services to match companies that have excess Halons with those companies that need the fire fighting agents for critical uses.
Determine Critical Use - HRC provides guidelines and procedures for a self determination of critical Halon use. HRC also provides an independent review and critical use certification if requested.
Recycling Advocacy Organization - HRC represents the interests of Halon reclaimers and critical users of recycled Halon, including the preparation of comments on proposed recycling and import regulations and support for market-based approaches to controlling emissions.
- HFC Emissions Estimating Program (HEEP)
The HFC Emissions Estimating Program (HEEP) is a vehicle to simply, economically and accurately determine annually the quantities of HFCs (and perfluorocarbons, or PFCs) that are discharged to the atmosphere when used for fire protection purposes. A prime motivation to implement HEEP derives from the fire protection industry's Voluntary Code of Practice (VCOP). The VCOP had its inception in 1999 and was adopted in 2001 by the segment of the fire protection industry that employs HFCs as alternatives to
Halons. HEEP provides a format to help industry minimize emissions by setting benchmarks, by providing the incentives to make improvements to current standards and practices, by documenting the industry's commitment to safety and responsible use, and by providing data to support these substitutes for Halon systems
HANDLING AND DISPOSAL
1What are the requirements for disposing of Halon and Halon-containing equipment?
According to EPA RULE 40 CFR Part 82 Protection of Stratospheric Ozone:
Non-emergency venting of Halon is prohibited.
Halon in equipment must be recovered by a facility that operates in accordance with NFPA standards 10 and 12A (references 23 and 24 in Appendix B, and Appendix C) (82.270(d)).
The EPA regulation further requires that Halon itself can only be disposed of by:
Sending the Halon for recycling to a facility operating in accordance with the NFPA standards mentioned above, or
Arranging for its destruction by a destruction process that meets relevant regulations (82.270(e)).
In the United States, very few destruction facilities for ozone-depleting substances (ODS's) such as Halons currently exist. This is due in part to technical difficulties in destroying Halons and other ODS's, and the costs of doing so. EPA continues to monitor technological developments in the United States and other countries for the destruction of ozone-depleting substances.
DECOMMISSIONING A HALON SYSTEM
- Decommissioning is a Two Step Process
Decommissioning a Halon system from service is usually a two-step process. The first step, field decommissioning, takes place at the site where the fire protection system is located. During this step, the Halon cylinders are disconnected from the system hardware such as manifolds and piping. The second step usually takes place offsite and involves reclaiming the Halon agent from the removed cylinders.
- Purpose of Decommissioning
Decommissioning is undertaken to remove the existing Halon system from service, replace the Halon system with an alternative means of fire protection, and/or recover the Halon from the system so it can be made available for use in other applications. As Halon supplies become increasingly scarce, decommissioned Halon supplies will be an important source to meet the future fire protection needs of critical applications. 3Who Should Perform Decommissioning
Since Halon is stored in cylinders under pressure, they must be handled with great care. If the cylinder is improperly handled and the pressure is released in an uncontrolled manner, the cylinder can act as a projectile potentially causing serious injury or death to people working with the cylinder or bystanders in the vicinity. Uncontrolled pressure release can occur by damaging the cylinder valve or by inadvertently activating the discharge mechanism. In either case, the cylinder contents are discharged in a dangerous and uncontrolled manner that could result in serious injury and death.
The importance of decommissioning Halon systems only by trained and experienced professionals cannot be understated.
In Canada, a service technician was killed while starting to recover Halon from a cylinder. His death was linked to improper safety procedures while performing the recovery operations.
In the United States, the FSSA reports that in all incidents reported to them, the cause of the accidents were attributed to improper handling of the cylinders by untrained and unqualified personnel. In all of these accident incidents, actuating devices had not been removed from the valves and anti-recoil devices and protection caps were not installed prior to removal of the cylinders from service. Therefore, FSSA adamantly recommends the following guidelines(1):
Only qualified and experienced fire suppression system service professionals should perform decommissioning activities.
Decommissioning personnel should be thoroughly trained in safe handling procedures as well as proper procedures related to disabling, removing, transporting, shipping, and emptying Halon cylinders.
Cylinder brackets should NOT be removed and cylinders should NOT be disconnected from system piping, or moved or shipped, without first disabling the actuation devices and providing protective caps and anti-recoil devices.
Halon systems have been manufactured for over 20 years, in many places around the world, and by many different companies.
Even fire protection professionals may not have encountered all possible valve designs and configurations. Ideally, systems should be decommissioned by those who installed and serviced them; however, this is not always possible. In any case, the procedures outlined in the Operations and Maintenance Manuals, Owners Manuals, Service Manuals, etc., provided by the manufacturer for the specific type of equipment installed must be followed. 4Potential Risks Associated with Decommissioning
Despite the different manufacturer types and models of valves and cylinders, the risks associated with decommissioning Halon systems fall into three main categories, independent of the system type or manufacturer: 1) risks due to pressurized cylinders; 2) risks associated with heavy objects; and 3) risks associated with Halon exposure.
1. The most important hazards are the inherent risk of working with pressurized gaseous agents
Since Halon is stored in cylinders under pressure, they must be handled with great care. If the cylinder is improperly handled and the pressure is released in an uncontrolled manner, the cylinder can act as a projectile potentially causing serious injury or death to people working with the cylinder or bystanders in the vicinity. In either case, the cylinder contents are discharged in a dangerous and uncontrolled manner that could result in serious injury and death.
Halon storage cylinders are designed to discharge through system pipework in less than 10 seconds. Obviously, it follows that the discharge rates of unconnected cylinders must be less than 10 seconds. The risk of damage from unimpeded agent discharge in confined or unconfined spaces is high. Mass flows through system pipework are up to 20 kg/sec (44 lbs/sec) for large cylinders˛. In cases of cylinder discharge without pipework, the mass flows are much higher. Once the cylinder valve is open, it generally cannot be closed.
The predominant causes of accidental discharge of Halon systems include (1) accidental automatic firing at the releasing panel/remote, (2) accidental manual activation at the cylinder/remote, (3) accidental operation of the cylinder valve, (4) damage to the discharge head/neck, and (5) high cylinder temperature above the working pressure.
This document is aimed at providing guidance in order to minimize the risks associated with working with gaseous agents. Remaining sections will discuss the failure points as well as suggest practical guidelines for personnel involved in decommissioning Halon systems.
2. Other hazards also exist related to the physical risk of moving or transporting heavy pressurized cylinders.
Risks associated with the Halon storage cylinders themselves can be attributed to their weight (a fully charged Halon storage container may weigh as much as 700 kgs or 1500 lbs). Moving and transporting these large cylinders can prove to be cumbersome and difficult. Accidental dropping or improper lifting can cause injury to handling personnel and could result in an uncontrolled release of the pressure.
- Risks associated with Halon 1301 exposure also exist.
Several other inherent safety issues are associated with Halon system decommissioning activities such as cylinder removal and Halon reclamation. These dangers are caused by the agent itself and completely independent of the system type. The immediate dangers associated with accidental discharge of Halon include dizziness and anesthesia and/or cardiac sensitization. Toxicological risks associated with Halon exposure can be significant and can even cause death, if the exposure is at high concentrations.
IS IT TIME TO SWITCH TO A HALON 1301 ALTERNATIVE SYSTEM?
There are no legal requirements that end users remove Halon 1301 systems from service, and systems can be legally recharged in the event of a discharge.
Since Halon alternatives are generally more costly and require significantly more agent to achieve the same effectiveness as Halon, demand for Halon continues in the home, vehicle, industrial and commercial markets.
A potential drawback of Halon 1301 systems is that the agent, cylinder head rebuild kits and other parts can be difficult to obtain quickly.
- Can Halon Be Recycled?
If Halon is contained in cylinders retired from service or if a container is leaking, the Halon can (and should) be recovered for recycling and reclamation.
Current legislation prohibits the production or importation of new Halon 1211, 1301, or 2402 into the U.S.. Recycled Halon is now the only source of supply.
- Why Recycle?
Conservation of Halon is necessary to preserve existing supplies until alternative products and systems can be implemented. Actual use should be restricted to real incidents requiring fire suppression. Routine testing of systems for proper operation with the Halon product is unlawful. 3How is "Recycling" Distinguished from Recovery and Reclamation?
The term, "recycling" is used in a variety of ways concerning the processing of clean agents. In its broadest usage, it refers to a process that involves recovery, recycling and reclamation. These terms are defined as follows.
Reclamation: The reprocessing and upgrading of a recovered controlled substance through such mechanisms as filtering, drying, distillation and chemical treatment, in order to restore the substance to a specified standard of performance.
Recycling and reclamation, as defined above, are sometimes together referred to as "recycling."
A key objective of GIELLE is to facilitate the redeployment of clean agents that we have recovered and recycled to customers who require them for critical uses, and who commit to using this finite resource responsibly.
- Components Required to Recycle Halon
In order to recycle Halon, certain components are required. The pumping system must be able to quickly and efficiently (99 percent efficiency to prevent the escape of Halon into the atmosphere) move the Halon liquid and vapor from the storage tank to processing equipment. Operating pressures range from 360 to 600 psig for pressurized cylinders down to a vacuum of 10 to 20 inches of mercury for cylinders which will be opened to the atmosphere. The recycling system should include modules for 1) removing contaminants by filtration and 2) removing nitrogen by condensing the Halon and venting the nitrogen. Filters should be replaceable without the release of Halon. In general, the two modules can run automatically and are not labor intensive. For a more detailed analysis of Halon 1301 recycling equipment see the Pollution Prevention Opportunity Data Sheet "Halon 1301 Recycler."
- How To Minimize Losses of Halons During Recycling
Operate and maintain recovery and recycling equipment in strict accordance with manufacturer specifications to ensure that it performs as specified
Ensure that cross-contamination does not occur through the mixing of Halons and/or refrigerants that may be contained in similar cylinders.
The principal objective of recycling equipment is to remove contaminants of residue, suspended matter, water, oils, etc., and to return the Halon to one of the purity standards. Either at time of resale, or on a periodic basis, a sample of recycled Halon should be tested by gas chromatography to ensure that the purity standard is being maintained.
- What Halon Alternatives Are There?
In response to the ban on Halon 1301 manufacture, the fire suppression industry has responded with the development of alternative clean agents that pose less of a threat to the ozone layer. Two classes of agents have emerged as suitable replacements: halocarbon-based agents and inert gas agents. The halocarbon-based agents are carbon-based compounds and extinguish fire primarily via the absorption of heat. Inert gas agents are based on the inert gases (i.e., nitrogen, argon, carbon dioxide) and extinguish fire via oxygen depletion.
Under its Significant New Alternatives Policy (SNAP) program, the U.S. Environmental Protection Agency (EPA) is required to evaluate alternative chemicals and processes intended to be used in place of ozone-depleting substances to ensure that they are acceptable from a human health and environmental perspective.
With the advent of the new clean agents, businesses worldwide will continue to have the ability to protect critical equipment and irreplaceable items, despite the ban and inevitable disappearance of Halon 1301 from the marketplace.
- How Do the Alternatives Compare to Halon?
Although the Halon 1301 alternatives are only approximately 70% as effective as Halon 1301 at extinguishing fires, the alternatives have similar characteristics. Like Halon 1301, the new agents are clean (i.e., they leave no residues following extinguishment). As a result, no cleanup is required after discharge of the agents. Because the agents form no corrosive or abrasive residues they are suitable for use on delicate, expensive assets that might otherwise be destroyed by non-clean agents such as foam or water (e.g. books, paintings, cultural heritage items). The clean agents are gases, and can thoroughly flood a protected area, affording rapid extinguishment of even obscured or hard to reach fires. The clean agent systems are applicable to Class A, B and C fires. When coupled with an early detection system, clean agent systems provide rapid extinguishment, reducing equipment damage and ensuring the safety of personnel within the fire area.
Appearance-wise, clean agent systems are similar in many aspects to Halon 1301 systems, although, in general, none of the clean agents can serve as a complete drop-in replacement for Halon 1301: all require modification to the piping systems and or nozzles and system cylinders. Halocarbon agents are stored as compressed liquefied gases, and systems are typically super pressurized to 25 or 40 bar with nitrogen, with the exception of FE-13, which does not require super pressurization. Inert gas agents are supplied in high-pressure gas cylinders, typically pressurized to 200 or 300 bars. For both halocarbon and inert gas systems, additional system components include the usual collection of selector valves, piping, and nozzles.