With a milestone looming in the revision cycle for the National Fire Protection Association’s (NFPA) standard 409, which deals with aircraft hangars, NATA last week held a webinar to answer industry questions on the topic.
According to NFPA’s original five-year revision timeline, the second draft meeting to consider the latest changes to 409 was supposed to have taken place in April of this year, but due to Covid restrictions, it was postponed. The meeting is now scheduled for the week of February 22, with the revised standard taking effect in 2022.
Among the changes NATA is urging is an easing of the requirements for hangar foam dispensing systems for typical business aviation Group II hangars, which can add $1 million on average to the base build cost, in addition to thousands of dollars in annual maintenance expenses. NATA had commissioned a study from the University of Maryland, which indicated that such systems no longer serve the purpose for which they were intended and are subject to costly false discharges.
Those discharges have become an issue, according to Jon Wenrich, director of business development for FBO construction and design firm Centrex, and chairman of NATA’s NFPA 409 subcommittee. “There are more and more Fortune 500 flight departments in particular that are disallowing their aircraft to be housed permanently or overnight in a hangar with foam,” Wenrich said.
Group II hangars are classified as being between 12,000 and 40,000 sq ft in area, with 28-foot-high doors. NATA is also suggesting that the door-height limit be increased to 35 feet under the Group II specification. In addition, the association is advocating for the establishment of a new category of hangar, for those where potentially hazardous operations such as hot work or fuel transfer would take place, and where the optimal levels of fire prevention would be required.
Lastly, NATA is asking for the reinstitution of the “Hangar Building Cluster” exemption, which was accidentally deleted from the standard during its last revision cycle in 2016 and which allows some subdivided hangars to be classified as Group III that otherwise would be considered Group II.
NFPA 409 is generally accepted by local fire marshals as a cornerstone for hangar construction codes, but it is not mandatory and there have been cases where the industry has proven to authorities that the foam systems weren't warranted. For those looking to possibly avoid the current NFPA foam mandates, Wenrich recommends that hangar builders enlist an expert consultant to help plead their case with their local fire marshal. Even if the foam requirement is eventually shelved in the latest revision cycle, Doug Fisher, a principal fire protection engineer for Fisher Engineering, warned hangar keepers not to simply start tearing out their existing systems.
“Just because the 2022 edition says no more foam, you can’t just go and close your valve and remove all your stuff the next day,” he said. “You were permitted as a hangar with foam, and you still need to get that changed.” If the NFPA 409 foam requirement is removed, he added, that will make it easier to have a conversation with the local fire authorities about removing the systems altogether or at least being able to disable and disarm them.