Floor doors with a fire-resistant rating are generally available in larger sizes as they do not meet ASTM or UL heat transfer test requirements for a fire protection rating. While these larger access sizes may seem appealing to design professionals, the tradeoff is the reduced fire protection performance and the limited use in non-fire-rated floor/ceiling applications.
Conversely, fire-rated access doors, with the intumescent coating and ability to limit heat transfer, can be installed in both rated and non-rated floor/ceiling and roof/ceiling applications to maintain fire protection code compliance.
Due to heavy intumescent fireproof coating required to block heat transfer, these doors are commonly available in smaller sizes to ensure safe and easy operation. Products are available in sizes up to 1.06 x 1.06 m (3.5 x 3.5 ft), which generally meets most personnel and equipment access requirements inside of commercial buildings.
Code clarification
The difference between fire-resistant floor doors and fire-protective floor doors is addressed in several building codes.
International Building Code (IBC) 712.1.13.1 states horizontal fire door assemblies used to protect openings in fire-resistance-rated horizontal assemblies shall be tested in accordance with NFPA 288 and achieve a fire-resistance rating no less than the assembly being penetrated.
IBC 712.1.13.2 states access doors shall be permitted in ceilings of fire-resistance-rated floor/ceiling and roof/ceiling assemblies, provided that such doors are tested in accordance with ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials or UL 263, Fire Tests of Building Construction and Material, as horizontal assemblies and labelled by an approved agency for such purpose.
Commentary for this code states “Access doors are often necessary to service mechanical and plumbing systems above the ceiling. This section states that if such doors are used where the ceiling provides part of the protection, they must be tested in accordance with ASTM E119 or UL 263 as a horizontal assembly. This makes it clear that the standard fire test for doors (NFPA 80 or 257) is not acceptable. This ensures the thermal transmission through the access door and its effect on the assembly is considered. The provisions of this section are not applicable if the ceiling membrane does not provide any portion of the fire-resistive protection. Therefore, in a non-rated ceiling, this access door requirement would not apply.”
It is important to note that floor doors with a fire-resistant rating cannot be installed in fire-rated floor/ceiling assemblies. Doors carrying the more stringent fire protective rating can be installed in both fire-rated floor and floor/ceiling applications to meet fire protection code requirements.
Several other codes are also important. For North American building codes, ANSI/UL 263 is the default standard for evaluating fire protection of structural steelwork.
ANSI/UL 263 and ASTM E119 were developed to simulate a building fire. The CAN/ULC-S101, Standard Methods of Fire Endurance Tests of Building Construction and Materials, provides equivalent test requirements for the testing of building materials to ensure market access across North America.
