Potential Driver Exposure to Halons and Alternative Agents from On Board Fire Suppression Systems in Stock Cars 2004-01-3551
This paper presents a review of the regulatory, environmental, and health issues surrounding the use of halons as a fire suppressant and a summary of the recently completed Racecar Fire Suppressant Exposure Study by ICF Consulting, Inc., under contract with the U.S. Environmental Protection Agency (EPA) (U.S. EPA, 2004a). In 2003 the EPA learned that the SFI Foundation Inc., the organization responsible for developing safety regulations and testing requirements for numerous Performance Racing Industry (PRI) sanctioning bodies, was revising its Quality Assurance Specification for On Board Fire Suppression Systems (SFI Specification 17.1). The previous Specification 17.1 required either halon 1211 or halon 1301 to be used in these systems. Halons are ozone-depleting substances (ODS) widely used in fire protection applications and whose production and use are controlled under the Montreal Protocol and the Clean Air Act (CAA). Emissions of halons lead to destruction of the earth's protective stratospheric ozone layer. Because halons are the most potent ozone depletors of the controlled ODS, the production and import of virgin halons1 was banned in the U.S. beginning in 1994. Since then, EPA has worked with industry and other affected organizations to develop, evaluate, and support adoption of alternatives to halons through EPA's Significant New Alternatives Policy (SNAP) program. Alternatives to halons are now available and used in many new applications that formerly depended on halons. With the availability of approved alternatives, EPA was concerned that the draft of the new SFI specification still allowed for the use of halons 1211 and 1301 and that the potential risk to the driver from exposure during a discharge directly into the driver's compartment had not been fully considered. To address these concerns, EPA prepared a scoping analysis of possible fire suppressant agent concentrations that could be reached in a typical stock car due to the release under various scenarios. The study was not meant to determine acceptable quantities of an agent to be used, but to serve as an example of the type of analysis EPA believes should be considered to minimize driver exposure to potentially high concentrations of the agent.
The stock car scenario was modeled after what EPA understood to be reasonable race car metrics for the National Association for Stock Car Auto Racing (NASCAR) circuits and the agents included halons 1211 and 1301 as well as SNAP approved alternatives. This application was chosen because of the similarity in the dimensions of the driver's compartments of the stock car and truck body models to those of many other sanctioning bodies. From our model, the results of the study indicated that an “as designed” release of 5 lbs. of halon 1211 or 1301 into the driver's compartment could potentially create concentrations that would kill the driver. For the alternatives, at least one agent could reach the necessary concentration for fire extinguishment within the driver compartment while not posing a risk to the driver in both the car and truck body types. In the event of a catastrophic release of all agent from the system into the driver compartment, every agent reviewed would produce a potentially lethal concentration for the driver under the conditions modeled.
The finished analysis was reviewed by experts at the National Institute of Standards and Technology (NIST), Delphi Corporation, DuPont, 3M, and American Pacific, and their comments and the authors' responses are summarized in Appendix A. The results of this research have been presented to SFI as well as sanctioning bodies that use SFI's safety specifications. The goal is to promote the safe application of fire suppression agents, and the use of effective alternatives to halons 1211 and 1301.