There is a great deal of confusion in Australia regarding the requirements for smoke doors and smoke gasketing for these doors. This article has been written to provide the reader with a brief overview on the performance testing of smoke doors and internationally accepted smoke leakage ratings and test conditions.
AIR (SMOKE) LEAKAGE TESTING OF DOORS
Like fire resistance testing, there are also International documented and applied air (smoke) leakage testing protocols for smoke resistance of doors.
The International Standard, ISO5925-1 Fire tests — Evaluation of performance of smoke control door assemblies — Part 1: Ambient temperature test is the basis for most national air (smoke) leakage standards for door assemblies.
As smoke is simply particles of incomplete combustion suspended in air, smoke leakage rates are determined from air leakage rates. There is no real smoke introduced into the test apparatus and no recording for toxic species concentrations or visibility is taken during these tests.
Air (smoke) leakage, or smoke leakage resistance testing involves subjecting door assemblies to full size (scale) fire tests in an air (smoke) leakage test apparatus. A prototype assembly consisting of a section of surrounding construction (wall) containing a door assembly is built into a test frame and then mounted onto the full size (scale) apparatus.
Measurement are taken for air (smoke) leakage at different pressure differentials for both in-swing and out- swing orientations of the door assembly. The measurements are taken at ambient temperature and typically at medium temperature, defined as 200ºC for 30 minutes exposure by the test standard.
Typically measurements are taken for both the perimeter of the door assembly including the door bottom (threshold) and for the perimeter of the door assembly excluding the door bottom (threshold). In the latter case, the door bottom (threshold) is taped up so the perimeter leakage can be isolated. Using both results the perimeter leakage and the door bottom (threshold) leakage can be calculated separately. This allows for subsequent interchange of different perimeter and door bottom sealing options.
Like fire resistance testing, results from air (smoke) leakage standard fire resistance testing are simply a record of the observed facts and observations and of course the respective leakage rates for the door assembly for the temperatures, pressure and orientations during testing.
Air (smoke) leakage rates for a door assembly are usually defined in m3/hour per lineal metre of door perimeter. This allows for subsequent extrapolation of leakage rates for different size doors. As discussed above, separate results are obtained for the perimeter of the doors and the door bottom, as typically the clearances and seals used at these locations are different sizes and types.
The standard air (smoke) leakage test methodology in Australia is AS/NZS1530.7: 1998 Smoke control door and shutter assemblies-Ambient and medium temperature leakage test procedure.
REQUIREMENTS FOR SMOKE DOORS
National Building Codes and/or Codes of practices usually dictate what the exposure conditions (temperatures and pressures) and what the acceptable air (smoke) leakage rates are for smoke door assemblies. Again, like fire resistance ratings, these rating typically vary according to the type or class of building and the location of the door itself within the building.
In Australia, all the states and territories through their respective Building Control legislation and regulations have called up the Building Code of Australia, commonly referred to as the BCA, for all technical provision related to Buildings.
The BCA, in Section C, Fire Resistance, does require the use of smoke doors. All smoke doors are required to comply with Specification C3.4 of the BCA.
Unlike fire doors, Section C of the BCA does NOT nominate air (smoke) leakage rates for smoke doors NOR does Specification C3.4 provide adequately for the performance testing of smoke doors by way of a reference to AS/NZS1530.7 for example. Specification C3.4 Section 3 (Smoke Doors) does require in the General Section that doors to be constructed so that smoke will not pass (should really be so that smoke leakage will be limited) from one side of the doorway to the other. The Construction Deemed to Satisfy section does require exposure conditions of 200ºC for 30 minutes and also has a requirement for smoke seals, but it does NOT provide a nominated air (smoke) leakage test method for which to prove performance of the door leaf and door seals.
AS/NZS1530.7 was published in November 1998, but to date the BCA has not been changed to nominate this test methodology.
INTERNATIONAL BEST PRACTICE FOR SMOKE DOORS
In the absence of an acceptance criteria, (maximum allowable leakage rate at a nominated exposure temperature and pressure differential) in the current Building Code of Australia for performance testing to AS/NZS1530.7, it is prudent to include some international accepted practice to guide the user.
The BS5588 (Fire precautions in the design and construction of buildings) series of standards nominate an acceptable leakage rates for smoke doors as 3m3/hr per lineal metre of perimeter (excluding the threshold or door bottom) measured at ambient temperature and at 25 Pa pressure differential during testing to BS476/31.1 (air leakage test standard for door assemblies). These codes also require the use of a door bottom seal on all smoke doors.
This result in a total allowable leakage for a standard size unit entry door leading onto a common corridor, being in the order of 15 m3/hr.
There are numerous codes and standards applied in different regions within the USA.
The Uniform Building Code, 1997, by way of standard UBC 7-2 requires smoke and draft control doors to have leakage rates less than 3cfm/ft2 of opening, measured at a temperature of 400 ºF (200ºC) and at a pressure differential of 0.10-inch water (25Pa), as determined by testing to the requirement of the standard which are based on UL1784 (Air leakage test for door assemblies).
NFPA 105 (Installation of Smoke-Control Door Assemblies) is a good reference document and it also nominates some acceptance criteria for smoke doors.
DESIGN, INSTALLATION AND LABELING
FOR SMOKE DOORS
Unlike fire doors, there is no current Australian product standard for smoke doors analogous to AS/NZS1905.1: 1997 Fire resistant door sets.
Therefore, no guidance is provided to industry at large for the design, installation and labeling of smoke doors.
It is recommended that the marking or tagging requirements for fire doors be also used for smoke doors.
MAINTENANCE OF SMOKE DOORS
All essential services, including smoke doors require on going maintenance to ensure their performance in case of a fire will be as intended.
Unlike fire doors, there is NO non- mandatory standard for the maintenance of smoke doors analogous to AS1851.7.
Unlike fire doors, there is No standard for the maintenance of smoke doors analogous to AS1851.7. (Maintenance of Fire Protection Equipment, part 7, Fire Resistant Doorsets)