Flexible Nozzles and Special Training
The Technical Committee on Aircraft Rescue and Firefighting considered two other issues to be important—flexible nozzles for extinguishers and special training for the use of Halon—but they acted in a markedly less decisive manner on both. On flexible nozzles, the fire protection engineer from a major airline made a convincing case that extinguishers would be much more effective with this design change. He conducted tests that indicated that models with a flexible hose could be almost ten times more effective than current models in aviation use. The committee was largely unmoved, however, and simply changed the standard to permit flexible hoses but not require them. An appendix section advises that "for access to underseat, overhead, and other difficult to reach locations consideration should be given to using extinguishers with a discharge hose."
This seemingly timid approach is a product of the tangled web between installation standards (such as NFPA 408) and product standards (such as UL's). NFPA does not write product standards per se. It does, however, specify some performance characteristics for products. This creates an awkward relationship with the product standards written by such organizations as UL. Sometimes performance characteristics are closely linked to basic product specifications. For example, requiring high enough temperature tolerances for a chimney necessitates that it be made of metal, not masonry. In some instances, NFPA's requirements seem to drive UL's standards; in others, the UL standard appears to control the NFPA standard. The situation is often compared to the proverbial chicken-and-egg problem. In the case of fire extinguishers, however, it is clear which came first: UL did.
Realistically, NFPA can require something different from UL only when it is sure that UL will change accordingly. This is practically assured when the NFPA standard affects a substantial share of the certification market. But in the case of aircraft fire extinguishers, the NFPA standard affects a minuscule portion of the market regulated by UL. Not only does UL feel little pressure to change its fire extinguisher standard to satisfy the special concerns of aviation use; it foresees a
limited reward for the effort as well. The market for aviation fire extinguishers is too small.
The generic UL standard for fire extinguishers continues to take precedence over any NFPA requirements in 408. UL tests extinguishers under specific conditions and certifies them with different ratings. NFPA 408 depends on these standards to define the capabilities of the fire extinguishers required by NFPA standards. What UL requires is not necessarily what NFPA would choose for aviation use. UL does not require a flexible hose on small hand-held extinguishers, for example. Nor does it require a discharge time of more than eight seconds for the typical small Halon extinguisher. A United Airlines engineer thinks that twelve to fourteen seconds would be much more desirable. And flexible nozzles are clearly a major improvement over fixed nozzles for aviation use.
The other technical issue considered, but skirted, by NFPA involved the training requirements for using Halon extinguishers. The committee settled on a vague requirement that "training shall provide classroom instruction and manipulative skills training." The appendix removes the teeth from this provision, however, by adding that "it is highly recommended that live fire training on representative aircraft fires be conducted … [but this is] not required by this standard."
The mild-mannered approach to this provision also stands in contrast to the other more stringent provisions of 408. It reflects in part NFPA's reluctance to specify training requirements and in part the resistance of the airlines to a significant and recurring expense. The representative of Factory Mutual, who had recently conducted a study of hand-held fire extinguishers under contract to the FAA, recalls that the importance of training costs was repeatedly mentioned by those he surveyed. Fire safety experts agreed that training in realistic test situations would be costly. NFPA has a general position against addressing training or other seemingly managerial tasks. The Aircraft Rescue and Firefighting Committee managed to include more specific statements about the nature of recommended training procedures than are contained in most NFPA standards. But even that language is weak.
The committee members approved the proposed changes in May 1983, a full year before the FAA proposed its own rule. A public comment period followed release of the document to the NFPA membership, and when the committee met the following November it was faced with a total of fourteen comments from only four individuals. UL submitted the most detailed comments, most of them definitional, demon-
strating a better understanding of fire extinguishers than the committee as a whole. There was a minor spat about whether a competing Halon agent—lower in toxicity, but also less effective—should be permitted. The committee rejected those proposals on the grounds that they were not supported by accompanying technical data. NFPA 408 was approved without comment or question by the general membership at the organization's 1984 annual meeting. It became effective on July 5, 1984, a little more than two years after the Standards Council instructed the committee to expedite the revision process.