Smoke barriers are also used to compartment underground buildings,
as a part of a smoke control system and to protect the lobbies for fire
service access and occupant evacuation elevators. Smoke barriers
can be either walls or horizontal assemblies depending on which
directions require protection from both fire and smoke spread. In
general, smoke barriers require a minimum 1-hour fire-resistance
rating with very specific continuity requirements. Therefore, the
provisions for both walls (Section 714.3) and horizontal assemblies
(Section 714.4) specify that penetrations must be protected for both
their fire-resistance aspects and their role in limiting the spread of
smoke. This is accomplished by the reference to Section 714.4.4
and the provisions related to penetrations in smoke barriers.
It can be referred from the above IBC text that Penetrations in smoke
barriers must be tested using the UL 1479 test and receive an L
rating, which indicates that the penetration firestop system has been
evaluated for its air leakage performance. The ASTM E 814 standard
currently does not have a test protocol for L ratings. Therefore, the
code specifies compliance with the UL 1479 standard. The L rating
provides a quantitative indication of the penetration system’s ability
to resist the passage of smoke.
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