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Terminology: Fire Resistance Con’t.
Terminology can be misleading. For
example, we cannot say that a ceiling
system or the FR Series Fire-Resistant
Speaker Assemblies are “fire proof”. That
would imply that the ceiling and loudspeakers
can survive a fire intact, which is definitely
not the case. The term “fire resistance” is
very narrow and only refers to the ability of
the ceiling to keep a fire from reaching, and
adversely affecting, the strength and safety
of the floor or roof structure above.
Terminology: Plenum Rating versus
Fire Resistance Rating
NFPA 90A, “Installation of Air Conditioning
and Ventilating Systems”, defines a “plenum”
as the space between the top of the finished
ceiling and the underside of the floor or roof
above. Plenums may be used to supply or
exhaust air from the room below if materials
in the plenum are non-combustible or of
limited combustibility and “plenum-rated”.
The primary concern for plenum rating is
smoke generation and heat release. UL
Standard 2043 covers these concerns for
loudspeaker systems.
Fire resistance refers to the ability of a
ceiling to keep a fire from reaching, and
adversely affecting, the strength and safety
of the floor or roof structure above. Fire-
resistance requirements are stricter than
plenum ratings. Loudspeakers, and other
devices, which penetrate the ceiling must
maintain the fire-resistance properties of
the ceiling. UL Standard 263 defines the
requirements for these spaces. As mentioned,
the FR Series Fire-Resistant Speaker
Assemblies passed this test and are UL
Classified for use in specified 1-hour, 2-hour
and 3-hour, fire-resistant ceiling systems.
Part 3
(continued)
Page 10
