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: Regulatory Update
HARC NEWS - Regulatory and Standards Update
International
The European Union (EU) has published final regulations that ban sale and use of CFCs, halons, carbon tetrachloride, hydrobromoflurocarbons, and 1,1,1-trichloroethane. The regulations also accelerate controls on the sale and use of HCFCs.
The new regulations, which replace Council Regulation EC 3093/94, go beyond the requirements of the Montreal Protocol. They include a ban on the sale and use of halons after December 31, 2002 (except for critical uses) with mandatory decommissioning of non-critical halon systems required by December 31, 2003. The new regulations make compulsory the recovery and disposal of halons from fire protection equipment. HCFCs can be used to replace halons in existing critical use systems as long as the removed halon is destroyed ad 70% of the destruction costs are covered by the supplier of the HCFCs.
The regulations include the following list of critical halon uses:
Halon 1301:
In aircraft for the protection of crew compartments, engine nacelles, cargo bays and dry bays, in military land vehicles and naval vessels for the protection of spaces occupied by personnel and engine compartments, for the making inert of occupied spaces where flammable liquid and/or gas release could occur in the military and oil, gas, and petrochemical sector, and in existing cargo ships, for the making inert of manned communications and command centers of the armed forces or otherwise essential for national security, for the making inert of spaces where there may be a risk of dispersion of radioactive matter, in the Channel tunnel and associated installations and rolling stock.
Halon 1211:
In hand held fire extinguishers and fixed extinguisher equipment for engines for use on board aircraft, in aircraft for the protection of crew compartments, engine nacelles, cargo bays and dry bays, in fire extinguishers essential to the personal safety for initial extinguishing by fire brigades, in military and police fire extinguishers for use on persons.
The new regulations also restrict the import and export of ozone depleting substances, including halons. The regulation states that exports of halon are prohibited, except for those contained in products and equipment aimed for critical uses.
United States
The National Fire Protection Association (NFPA) has completed revision of its standards document on halon replacement agents, NFPA 2001 – Standard on Clean Agent Extinguishing Systems. The revisions to the standard include changes to the exposure limits for inert gases and halocarbon agents, inclusion of a pharmacokinetic model for determining exposure times for halocarbon agents, and the addition of a marine chapter. The revised standard recommends a design concentration of 30% above cupburner for Class B fuels or any system that is only manually operated.
Inert Gases
The revised 2001 standard allows exposure to inert gas agents in normally occupied areas at a design concentration of between 43 and 52 percent (10-12% oxygen) for 3 minutes and below 43 percent (above 12% oxygen) for 5 minutes. The old standard did not allow inert gas agents to be used in normally occupied areas at a design concentration above 43% (below 12% oxygen). The changes to the exposure limits for inert gas agents were based on the recommendations of a U.S. Environmental Protection Agency (EPA) expert panel on hypoxia, which concluded that “10% oxygen for a 3-minute exposure conferred an adequate margin of safety considering the variability of working populations.
The exact language of the exposure limits for inert gas agents is as follows:
Inert Gas Agents:
Unnecessary exposure to inert gas agent systems resulting in low oxygen atmospheres shall be avoided. The requirement for pre-discharge alarms and time delays is intended to prevent human exposure to agents. The following additional provisions shall apply in order to account for failure of these safeguards:
- Inert gas systems designed to concentrations below 43 percent (corresponding to an oxygen concentration of 12 percent, sea level equivalent of oxygen) shall be permitted given that:
- the space is normally occupied, and
- means shall be provided to limit exposure to no longer than 5 minutes.
- Inert gas systems designed to concentrations between 43 and 52 percent (corresponding to between 12 and 10 percent oxygen, sea level equivalent of oxygen) shall be permitted, given that:
- the space is normally occupied, and
- means shall be provided to limit exposure to no longer than 3 minutes.
- Inert gas systems designed to concentrations between 52 and 62 percent (corresponding to between 10 and 8 percent oxygen, sea level equivalent of oxygen) shall be permitted given that:
- the space is normally unoccupied, and
- where personnel could possibly be exposed, means shall be provided to limit the exposure to less than 30 seconds.
- Inert gas systems designed to concentrations above 62 percent (corresponding to 8 percent oxygen or below, sea level equivalent of oxygen) may only be used in unoccupied areas where personnel shall not be exposed to such oxygen depletion.
Halocarbon Agents
The revised 2001 standard incorporates the use of an EPA-sponsored, physiologically-based pharmacokinetic (PB-PK) model to determine exposure limits for halocarbon agents. The PB-PK model allows inhalation exposures of halocarbon agents to be assessed in terms of the chemical concentrations in blood during exposure. It provides a more accurate assessment of the length of time that a person can be exposed before toxic effects could occur.
The revised 2001 standard allows exposure to halocarbon agents in normally occupied areas at a design concentration up to the LOAEL (lowest observed adverse effect level) for a length of time determined using a PB-PK model, or less than 60 seconds in the absence of PB-PK information. The old standard did not allow use of halocarbon agents in normally occupied areas at a design concentration above the NOAEL (no observed adverse effect level), except for Class B hazards where a predischarge alarm and time delay were provided.
The exact language of he exposure limits for halocarbon agents is as follows:
Unnecessary exposure to all halocarbon agents (even at NOAEL concentrations) and their decomposition products shall be avoided. The requirement for pre-discharge alarms and time delays are intended to prevent human exposure to agents. The following additional provisions shall apply in order to account for failure of these safeguards:
- Halocarbon systems for spaces that are normally occupied, designed to concentrations up to the NOAEL, shall be permitted.
- Halocarbon systems for spaces that are normally occupied, designed to concentrations above the NOAEL up to the LOAEL, shall be permitted, given that means be provided to limit exposure to no longer than X minutes (where X is the time required to achieve the blood concentration of the agent that was attained in the test animal when exposed at the LOAEL agent concentration in air, as estimated by the U.S. EPA approved and peer-reviewed PB-PK model or its equivalent).
- In spaces that are not normally occupied, and are protected by a halocarbon agent system designed to concentrations above the LOAEL, and where personnel could possibly be exposed, means shall be provided to limit specific exposure times using the U.S. EPA approved and peer-reviewed PB-PK model or its equivalent.
- In the absence of the information needed to fulfill the conditions listed above, the following provisions shall apply:
- When egress takes longer than 30 seconds but less than 60 seconds, the halocarbon agent shall not be used at a concentration exceeding the LOAEL;
- Concentrations exceeding the LOAEL are only permitted in areas not normally occupied by personnel provided that any personnel in the area can escape within 30 seconds. No unprotected personnel shall enter the area during agent discharge.
Other Changes
The revised 2001 standard recommends a design concentration of 30% above the extinguishing concentration for Class B hazards and systems that can only be actuated manually. The basis for this change is that a Class B fire is a more demanding fire than a Class A fire and a manually only actuated system could allow for a longer preburn. Both situations offer the potential for reduced predictability in fire development and where the use of elevated agent concentration offers additional offsetting assurance of rapid suppression. The old standard recommended a safety factor of 20% above the extinguishing concentration for Class B hazards.
A marine chapter is in the revised 2001 standard. This chapter outlines the deletions, modifications, and additions to the 2001 standard that are necessary for marine applications of clean agent fire extinguishing systems on commercial and government vessels.
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