January/February 2023 - 28

DIREC TOR OF MA INTENANCE DISCUSSION
Facility personnel should understand how the system
operates and how to shut it down in the case
of an inadvertent discharge. Check with your local
fire marshal to ensure you are permitted to shut the
system down in the case of an inadvertent discharge
prior to fire department arrival.
AMT: Broadly, what is National Fire Protection
Association (NFPA) 409, what is its history and
what are the latest changes to it?
The National Fire Protection Association (NFPA) 409:
Standard on Aircraft Hangars is the primary standard for
hangar fire protection and is referenced by the international
building code (IBC), the international fire code
(IFC), and state and local statutes, ordinances, and
regulations. Historically, NFPA 409 has required most
modern general aviation hangars to have automatic
foam fire suppression systems installed.
The 2022 NFPA 409: Standard on Aircraft Hangars
The 2022
standard
better reflects
the current
operating
environment,
which has
evolved
significantly
since its original
writing in 1966.
incorporates changes proposed and supported by
NATA, providing aviation businesses significant tools to
protect against fire without the use of foam fire suppression
systems. The 2022 edition contains provisions that:
* Create an alternative Performance-Based Design
process allowing modification of any part of the
NFPA 409 standard
* Create a Risk-Assessment process that allows
businesses to propose alternative fire protection
schemes with or without foam
* Exempt Group II hangars that prohibit hazardous
activities from foam requirements
* Approve the use of ignitable liquid floor drainage
systems in lieu of foam systems
AMT: Why were the changes made to NFPA 409?
NATA and its members have long advocated that
aircraft hangar foam fire suppression requirements
within the previous versions of the standard do not
reflect the reality of the current risk of fuel fires, nor
do they consider the public and private liability and
expense of environmentally hazardous clean up after
accidental system discharges.
The 2022 standard better reflects the current operating
environment, which has evolved significantly
since its original writing in 1966.
AMT: Given the changes, what should our audiences'
main takeaways be for their own hangar
fire suppression systems?
Determine if hazardous operations, as defined in
NFPA 409, are being performed in the hangar. If not,
look at possibly removing foam from the hangar as
28 JANUARY/FEBRUARY 2023
permitted by NFPA 409, 2022 edition. The NATA
Aircraft Hangar Fire Protection Guidance provides
additional information and resources to assist with
this review. Most importantly, engage the services
of a qualified professional, fire protection engineer
or architect, with experience in working with the
AHJ [Authority Having Jurisdictions] to permit the
removal of foam from the hangar.
AMT: Should people be thinking of upgrading
or replacing their fire suppression systems in
light of the updates to NFPA 409?
There are a variety of design options, already permitted
by the codes, and equivalency approaches that
may allow for the removal of a foam fire suppression
system. It is strongly recommended to utilize the
services of a licensed design professional, typically
a fire protection engineer or architect, to assist you
in working with your local code authorities when
discussing the need for a foam fire suppression system
in your hangar. Experienced design professionals
can help bridge the knowledge gap between the
operations being performed in the hangar and the
requirements for a foam fire suppression system.
AMT: When evaluating their current fire suppression
system, what should a hangar operator
be aware of and what are the key points they
should have in mind?
Determine if the operations being performed in the hangar
meet the definition of hazardous or not, per NFPA
409. From there, determine if your hangar requires foam
or an equivalent protection method (i.e., the ILDFA) or
if foam is not required per NFPA 409, 2022 edition. If
foam is required, have a qualified professional review
the system installation and current inspection, testing
and maintenance practices to determine if there
are options to reduce the potential for an inadvertent
discharge. For example, a typical foam system will discharge
from activation of a single sprinkler water flow
switch. However, the use of optical flame detectors in
lieu of a sprinkler water flow switch can reduce the
potential for an inadvertent discharge. Further, the
system can be sequenced to require two flame detectors
to go into alarm rather than one. Finally, the flame
detector can be multi-spectrum (vs. UV), which will
further reduce the potential for false activation.
AMT: Are there any other changes to NFPA 409
on the horizon and/or new fire suppression
technology/methods our audience should keep
an eye out for?
AIRCRAFT MAINTENANCE TECHNOLOGY
January/February 2023

Table of Contents for the Digital Edition of January/February 2023
