BCAB #1572 - Fire Door Latching Mechanism, Subsection 3.1.8.
October 23, 2002
Re: Fire Door Latching Mechanism, Subsection 3.1.8.
This appeal involves the installation of fire rated exit doors in a new secondary school. The paired doors provide access from the floor area to the exit stair enclosure. In question is the latching device used to restrain the door during a fire. The doors use a two-point latch (centre and top) and a fusible link activated spring-loaded latch at the bottom rather than the common three point latch used on most paired fire doors. To restrain the doors from warping in a fire the spring-loaded latch will protrude from one leaf into the other when activated by the heat of a fire.
Reason for Appeal
Clause 18.104.22.168.(1)(a) requires the fire protection rating of doors used as closures in a fire separation to be determined by testing in accordance with CAN4-S104, "Standard Method For Fire Tests of Door Assemblies." Sentence 22.214.171.124.(2) requires fire doors to be installed in accordance with NFPA 80, "Standard for Fire Doors and Fire Windows." Sentence 126.96.36.199.(1) requires swing-type fire doors to be "equipped with a positive latching mechanism designed to hold the door closed after each use."
The appellant contends that the heat activated bottom latch conforms to code requirements. The doors and hardware have been tested in accordance with CAN4-S104 and have achieved the required 45 minute fire protection rating. They are installed in accordance with the requirements of NFPA 80 and the latching mechanism complies with Sentence 188.8.131.52.(1). Neither the standards nor the code prohibit the use of the heat activated bottom latch.
Building Official's Position
The building official maintains that the heat activated bottom latch does not conform to the requirements of NFPA 80. Although the latch is labeled as required by NFPA 80 the building official is not sure it meets both the life safety requirements and fire protection requirements of the standard. The building official also questions conformance of the latch with the NFPA 80 requirement for "…. an active latch that cannot be held in a retracted position …." Also, all the illustrations in NFPA clearly show a top and bottom latch activated by the door hardware. There is also a concern that fire fighters could be trapped in the fire area by a concealed latch with no manual operation.
Appeal Board Decision #1572
It is the determination of the Board that the heat activated bottom latch conforms to both the requirements of Subsection 3.1.8. and NFPA 80, "Standard for Fire Doors and Fire Windows." Neither the code nor NFPA 80 requires the door to be functional after fire exposure. Testing indicates the device does not operate until well into a fire and human life would already be untenable.
George Humphrey, Chair