UL 2518-2016 pdf download

UL 2518-2016 pdf download.Air Dispersion Systems.
9.2.5 The air velocity for purposes of the test is to be measured by a pilot tube. or direct.reading velometer, positioned in the center of the outlet end of the sample. Room air handled by the Ian and ranging in temperature between 15.6 and 37.8°C (60 and 100°F) shall be employed.
9.2.6 The inlet of the air fan used for the test Is to be covered with a double layer of cheesecloth (14 to
15 square yards per pound (0.026 to 0.028 m2/g) and known to the trade as “count of 32 by 28”).
9.2.7 A damper, when employed for regulating velocity In the system, Is to be located between the screen and the fan or between the fan and the inlet of the test sample.
9.2.8 A collecting screen consisting of a double layer of cheesecloth, as specified in 9.2.6, stretched taut on a frame sized to provide tot an area not less than five times the inside cross-sectional area of the test sample, is to be located 1 foot (0.30 m) from the outlet end of the test sample.
9.3 Test method
9.3.1 Air is to be passed through the sample at test velocity with the collecting screen removed for a period of at east 1 hour and not more than 24 hours, The collection screen then is lobe placed in position.
9.3.2 The lest then is to proceed at test velocity and continued for a period of 4 hours. The collecting screen is to be examined for macroscopic parbcles at the end of each hour during the test period by taping the screen with the adhesive side of transparent tape, or tapes, in order to remove and record any eroded particles.
10 Pressure Test
10.1 Air dispersion system materials shall withstand without rupture an internal air pressure of 2-1/2 times the manufacturers rated positive pressure, and not less than 1-114 inch water column (311 Pa). The sample is not to rupture, as evidenced by breaks, tears, rips, or other openings greater than 118 inch (3.2 mm) In length; any joining material is to remain intact to the extent that materials such as tapes do not become displaced more than a total (or both edges of 1/8 inch (3.2 mm) from their initial position. disregarding movement due to slack or stretch which does not produce a separation of materials; and there is to be no evidence of other damage which results in the samples becoming unusable.
10.2 Air dispersion system sections of samples previously untested are to be used for the test. Samples, 8 feel (2.43 m) long, are to be used In accordance with 9.2.1. Air ducts and air connector sections are to be prepared in accordance with 9.2.2. Each end of the sample is to be sealed airtight by any means consistent with the use of the material under test. To permit the dispersion system to be fully extended to its maximum length, the air dispersion system is permitted to be pressurized to 0.25 Inch water column (62.2 Pa). Each end of the sample is to be attached to a stationary fixture.
10.3 A pressure tap consisting of pipe or tubing is to be sealed into one end of the test sample and connected to a water manometer which shall be read directly to 0.05 inch water column (12.4 Pa). The manometer is to be checked for zero reading at the beginning and at the end of each test.
10.4 An air supply tap consisting of pipe or tubing is to be sealed into the same or the other end of the sample and connected to a source of air pressure capable of maintaining the specified air pressure in the sample. The manufacturer’s rated pressure is to be gradually attained in not less than 45 seconds nor more than 60 seconds from the initial application of the test pressure. This pressure is to be held for 1 minute. The pressure then is to be increased to 2-1/2 times the manufacturer’s rated pressure in not less than 45 seconds nor more than 60 seconds.