November/December 2023 - 35

access door height of 28 feet or less, and a single
fire area less than 40,000 square feet based on construction
type (as listed in Table 4.1.2 of NFPA 409).
Group III: The hangar must have an access door
height of 28 feet or less and a single fire area less
than 30,000 square feet (Table 4.1.3 of NFPA 409).
Group IV: The hangar is any membrane-covered,
rigid-steel frame structure used for the storage or
servicing of aircraft.
Once you've determined the classification of your
aircraft hangar, you can determine the specific fire
protection requirements it needs to meet. Group IV
aircraft hangars are generally subject to the least
stringent requirements, while Group I aircraft hangars
are held to the strictest requirements.
In 2021, the NFPA approved some modifications
to NFPA 409 that were released in its 2022
edition. Prior to publication, the NFPA attempted
to impose a new standard requiring the installation
of foam fire suppression systems in Group II
hangars. However, the National Air Transportation
Association (NATA) lobbied against this charge with
the support of airport users and operators, fire protection
experts and aviation insurance providers.
The NATA successfully argued that the risks of
seemingly arbitrary foam fire suppression requirements
in Group II aircraft hangars outweighed the
rewards - in terms of negative economic impacts
and the numerous hazards associated with inadvertent
foam discharge.
Some firefighting foams have links to per- and
polyfluoroalkyl substances (PFAS) that could
increase the risk of cancer and other adverse health
effects. PFAS do not naturally break down and accumulate
in water, soil and the human body.
In addition, aviation insurance industry data
shows it is more likely for an inadvertent foam discharge
to damage property, interrupt businesses
and take aircraft out of service than a hangar fire.
In the rare occurrence of a hangar fire, its origin is
not typically aircraft fuel and it tends to occur in
less sophisticated environments.
This data supports the conclusion that it is difficult,
if not impossible, to reconcile fire loss history with the
implementation of more stringent fire code requirements
for Group II aircraft hangars. It is even more
critical to consider that when foam is inadvertently
discharged, persons occupying the aircraft hangar
have very little time to evacuate and can be instantly
overcome by the volume of foam both ascending from
the floor and descending from the ceiling.
Following numerous risk-analysis studies, the
NFPA determined Group II aircraft hangars do not
require firefighting foam systems and removed the
proposed requirement. This means airport businesses
can use their own discretion to determine
the best fire suppression system, such as a waterbased
sprinkler and drain system. However, the
local authority with jurisdiction must still approve
the chosen method.
In addition to the exemption of Group II aircraft
hangars from foam requirements, NFPA 409
includes other important changes. These include
provisions to create an alternative performancebased
design process and allow modification for
any part of NFPA 409; a provision to create a riskassessment
process that allows users to propose
alternative fire protection methods, with or without
foam; and approval of the use of ignitable liquid
floor drainage systems.
To improve safety, the fire protection industry
is shifting to fluorine-free foam concentrates, but
this may prove cost-prohibitive for many tenant
businesses. On the positive side, changes to NFPA
409 may provide opportunities for more effective
solutions when proven
applicable and safe. While
the historical trend by
NFPA has been to advocate
foam systems, a thorough
risk assessment may prove
the best option is to permit
water-only fire protection.
NATA has a free online
guide for hangar owners
and operators seeking a
general understanding of
hangar foam suppression
system requirements, options and alternatives.
It includes information on hangar classification,
code exceptions, how to determine if foam protection
systems are required and recommendations
on foam systems. Aircraft Hangar Fire Protection
Guidance also features a flow chart on options to
achieve code compliance relative to fire suppression
systems based on the International Building Code,
2021 edition; International Fire Code, 2021 edition;
and 2016 edition of NFPA 409.
Moving forward, it remains important for the
NFPA and local authorities to understand and
accommodate the unique operating environment
of general aviation businesses.
www.AviationPros.com 35
NATA advises the
services of a licensed
and experienced
design professional
be utilized to achieve
code compliance
relative to fire
suppression systems.
AEROPLEX/AEROLEASE
GROUP
http://www.AviationPros.com

November/December 2023

Table of Contents for the Digital Edition of November/December 2023

A Brief Look Back at 2023
Readers Choice
Maintenance Tracking—   e Good, the Bad and the Ugly
The Risks of Engine Neglect
Know Your Aviation Hose Needs
Understanding Aircraft Hangar Fire Suppression Standards
How to Prepare Your Maintenance Operations for New Aircraft
Passing the Test
Harnessing Technological Advancements
November/December 2023 - 1
November/December 2023 - 2
November/December 2023 - 3
November/December 2023 - A Brief Look Back at 2023
November/December 2023 - 5
November/December 2023 - 6
November/December 2023 - 7
November/December 2023 - 8
November/December 2023 - 9
November/December 2023 - Readers Choice
November/December 2023 - 11
November/December 2023 - 12
November/December 2023 - 13
November/December 2023 - 14
November/December 2023 - 15
November/December 2023 - 16
November/December 2023 - 17
November/December 2023 - 18
November/December 2023 - 19
November/December 2023 - 20
November/December 2023 - 21
November/December 2023 - 22
November/December 2023 - 23
November/December 2023 - 24
November/December 2023 - 25
November/December 2023 - 26
November/December 2023 - Maintenance Tracking—   e Good, the Bad and the Ugly
November/December 2023 - The Risks of Engine Neglect
November/December 2023 - 29
November/December 2023 - 30
November/December 2023 - 31
November/December 2023 - Know Your Aviation Hose Needs
November/December 2023 - 33
November/December 2023 - Understanding Aircraft Hangar Fire Suppression Standards
November/December 2023 - 35
November/December 2023 - How to Prepare Your Maintenance Operations for New Aircraft
November/December 2023 - 37
November/December 2023 - 38
November/December 2023 - 39
November/December 2023 - Passing the Test
November/December 2023 - Harnessing Technological Advancements
November/December 2023 - 42
November/December 2023 - 43
November/December 2023 - 44
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