Fusible Link LouverWhen I started working in the door and hardware industry, we regularly installed fusible link louvers in fire-rated doors, as allowed by various door manufacturers’ listings.  Although fusible link louvers are still available, their use is limited by current codes:

The IBC – 2009 does not allow louvers in smoke barrier doors in I-2 occupancies (710.5, Exception 1), smoke partitions (711.5.1), or door assemblies in corridors or smoke barriers (715.4.3.1). [Previous editions of the IBC contain the same requirements but the reference numbers are slightly different.]

NFPA 101 – 2009 does not allow louvers in smoke partitions ( or smoke barriers (8.5.4), and various occupancy chapters contain further limitations on their use.

Fusible link louvers rely on a fusible link which melts at elevated temperatures, allowing the blades of the louver to close.  These louvers have been tested and certified to maintain the fire resistance of the door assembly, but smoke may pass through the louver before the link melts.

There are two additional types of louvers available for use on fire-rated doors, but they would require a variance from the local code official since they are not specifically allowed by the codes.  One type is the Advantage Intumescent Louver by Zero International (Zero also offers the FB Intumescent Block).  This louver design incorporates intumescent material which expands when heated to seal the openings in the louver.  Smoke would also be a concern with this type of louver.

The second type is a smoke-actuated damper/shutter assembly by the Lorient Group.  Although I have seen a sample of this system, I have not seen it in use in the U.S.  If it reliably prevents the passage of smoke through the louver, we could eventually see the use of this type of product allowed by the codes.

If you have any information to add about the use of louvers in fire-rated doors, please leave a comment (click and scroll down).

Graphic courtesy of National Guard Products, Inc.

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