With the adoption of the International Conference of Building Officials (ICBO) Uniform Building Code (UBC) 7-2 1997, fire testing standards for swinging fire doors have changed.

Positive pressure testing more closely simulates real fire conditions. As heat develops within the source area, pressure within an enclosed room begins to build relative to the pressure outside the room. The pressure continues to increase until the availability of oxygen relative to fuel causes the fire to reach equilibrium. This typically will occur when the pressure of the top 2/3 of the room is greater than the outside pressure, and the pressure of the bottom 1/3 of the room is less than the outside pressure. The transition area between the higher and lower pressure is referred to as the neutral pressure plane. In the positive pressure zone smoke, hot gases, and flames are forced through any openings in the door assembly. The new positive pressure test methods more closely reflect these real fire conditions.

The UL10C and UBC 7-2 Part I fire test methods for swinging doors, referenced under the new UBC 7-2-1997, requires a change in the location of the Neutral pressure plane. These test methods also use more stringent acceptance criteria during the fire test.

The neutral pressure plane is now established at 40" from the sill. Cotton pads are used to assess the reduction of airflow from within the furnace and past the vertical and horizontal door edges. Fire tests are still followed up with rigorous hose stream testing.

To pass these new test methods, many swinging fire doors need to be installed using intumescent materials. These may be applied between door and frame edges, or built into a door's stile/rail edges.

The UBC 7-2-97 code also has requirements for the certification of a swinging fire door assemblies ability to retard the flow of both cold and hot smoke through the opening. Swinging fire doors must be evaluated under Part II of the UBC 7-2 Fire Tests of Door Assemblies. This method of test measures air leakage through door assemblies to determine the resistance of the door assembly to the passage of smoke.

Swinging door assemblies that pass Part I and Part II of the UBC are marked with the hourly rating followed by the letter "S". The letter "S" indicates air leakage resistance testing conformance.

Marshfield DoorSystems has been very active in product testing and development in response to these changes in test methods. Please call your inside sales representative (800-869-3667) for details on specific application conditions.