NFPA 268-2001 Standard Test Method for Determining Ignitability of Exterior Wall Assemblies Using a Radiant Heat Energy Source.
5.1* Radiant Panel. 5.1.1 Panel. The radiant panel shall have minimum face di- mensions of0.91 m × 0.91 m (3 ft × 3 ft) and shall consist ofan arrayofindividual burner heads, each measuring notless than 152.4 mm × 152.4 mm (6 in. × 6 in.). 5.1.2 Burner Heads. The individual burner heads shall consist ofa porous ceramic plate covered by an Inconel™ mesh, or equivalent radiant panel burners. The burner heads shall be fired by a premixed propane–air fuel mixture. 5.1.3 Zones. The gas supply to the burner heads shall be sepa- rated into three zones. Each zone shall consist of two horizontal rows of six burner heads. The zone arrangement shall allow the surface of the 0.91-m × 0.91-m (3-ft × 3-ft) radiator to be controlled to pro- duce a relatively uniform temperature. The temperature of each zone of burner heads shall be established by controlling the propane–air fuel mixture pressure supplied to each zone. 5.1.4 Control Equipment. Automatic controls shall be pro- vided to ignite the radiant panel and to shut off the propane gas fuel flow in the event ofa misfire. 5.1.5 Mounting. The burner heads and the associated pro- pane and air plumbing and control equipment shall be mounted on a steel platform as shown in Figure 5.1.5(a) and Figure 5.1.5(b). Exception: Alternate radiant panels shallbe permitted, provided the calibration criteria ofSections 8.3(1) and8.3(2) aremet. 5.2 Test Specimen. A minimum 1.22-m (4-ft) wide × 2.44-m (8-ft) high test specimen shall be mounted on a steel frame trolley assembly as shown in Figure 5.2 or equivalent support system. 5.2.1 Mounting Frame. The mounting frame shall hold the test specimen securely in a vertical orientation and shall allow for the spacing between the test specimen and the radiant panel to be adjusted. The V-groove wheels shall travel on angle-iron tracks that are mounted securely to the laboratory floor and that incorporate leveling adjusters. Ameans shall be provided to prevent the trolley from overturning. 5.3 Radiation Shield. 5.3.1* General. Aradiation shield shall be used to isolate the test specimen from the radiant panel both before and after the test period. The radiation shield shall consist of a water- cooled panel or other construction that has been shown to have no effect on the specimen or radiator. 5.3.2 Water Coolant. Where a water-cooled shield is used, dual waterflow connections shall supply coolant water to the bottom ofthe radiation shield.
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