Materials: NexGen Burner
A new and improved burner was developed to test the fire penetration resistance of thermal acoustic insulation in accordance with Title 14 Code of Federal Regulations (CFR) Part 25.856 (b). This next-generation (NexGen) burner was developed mainly to provide industry with an alternative to the currently accepted burner apparatus manufactured by Park Electric Motors of Atlantic City, NJ. Title 14 CFR 25.856 was written based on the use of the Park DPL 3400 burner; however, the company stopped production of this apparatus shortly after the new test method became final in 2003. The NexGen burner can be considered a direct replacement to the Park-manufactured burner, with several key improvements.
The NexGen burner is based on the same operating principle as the Park DPL 3400, using the same, or very similar, internal components to avoid drastically changing the overall character of the flame. The main difference is the elimination of the electric motor, which provided power to the fuel pump and blower fan in the Park-manufactured burner. In the NexGen burner, these functions have been replaced with regulated and conditioned compressed air and a pressurized fuel delivery system. Compressed air, when metered with a sonic orifice and conditioned to remove heat and moisture, proves to be more consistent over extended periods of time than to using a shaft-driven blower and laboratory air for the burner, thus increasing the repeatability of the NexGen burner. NexGen fuel delivery is provided by applying a head pressure of nitrogen gas on liquid fuel contained in a pressure vessel. This new method eliminates any fluctuations that were previously experienced with the electric motor and shaft-driven fuel pump typical of the Park-manufactured burner.
The exit air velocity and the fuel flow rate of the NexGen burner were matched to that of the Park DPL 3400 burner specifications to produce a flame of similar temperature and heat flux. Initial comparison tests indicated that the NexGen burner provides burnthrough results similar to that of the Park burner when comparing identical materials. Multiple NexGen burners were produced, and all were proven to provide the same results. NexGen burners were shipped to participating laboratories, tested with identical materials, and proven to be reproducible at different locations. This work has shown that an equivalent burner can be fabricated from readily available materials and can be used to test materials according 14 CFR 25.856 (b).