Position:Home>UL Standards>UL 790-2018 pdf free download

UL 790-2018 pdf free download

UL 790-2018 pdf free download.Standard for Electrochemical Capacitors.Standard Test Methods for Fire Tests of
Roof Coverings.
e) Adjustable fins mounted inside the air duct to straighten the air stream and reduce turbulence,
f) A baffle mounted on the back edge of the test deck to prevent backfiring under the deck.
g) Noncombustible boards extending from the sides and bottom of the air duct to the simulatedeaves-and-cornice construction mentioned in (b) (not used during burning brand test).
5.2 The tests are to be conducted in a room vented to relieve the air pressure created by the blower. During these tests, all doors and windows in the room are to be closed, and the room otherwise controlled as necessary to prevent outside wind and weather conditions from affecting the test results. Calibration of the air current described is to be conducted with all vent and exhaust fan settings adjusted to that used during the conduct of the tests. Tests are not to be conducted if the room temperature is less than 500 F (10°C) or more than 90° F (32°C).
5.3 For these tests, mortar (cementitious mixture, lime, and water) is to be troweled into the joint formed by the leading edge of the roof covering material and the framework of the carriage, to prevent air or the test flame from traveling under the material being tested.
5.4 During the tests, the test decks are to be subjected to an air current that flows uniformly over the top surface of the roof covering material, as determined by a pretest calibration of the equipment using a bare 3-1/3 by 4-1/3 foot (1 by 1.3 m) plywood, gypsum- or cement-board deck. At points midway up the incline of the bare deck, with the deck positioned at an incline of 5 inches (127 mm) to the horizontal foot (0.3 m), the velocity of the air current is to be 12 ±1/2 miles per hour (19 ±0.8 km/h), as measureda at the center and at each of two locations measured 3 inches (76 mm) from each edge of the deck, with each measurement being 3-11/16 inches (94 mm) above the surface of the deck. Adjusting the time averaged air current velocity at each location by up to 5 percent from the initial measurements is not prohibited in order to comply with the flame pattern description (see 5.5) so long as the average velocity of all three locations is 12 ±0.5 mph (5.3 ±0.2 m/s).
8Any direct reading instrument with scale graduated in increments of not more than 20 feet per minute (6 rn/mm) or any timed instrument with scale graduated (for a 1-minute timed reading) in increments of not more than 5 feet per minute (1.5 rn/mm) is acceptable.
5.5 Calibration of the flame is to be conducted using a bare 3-1/3 by 4-1/3 foot (1 by 1.3 m) cement board deck positioned at an incline of 5 inches (127 mm) to the horizontal foot (0.3 m). The test deck is to be subjected to a luminous gas flame approximately triangular in shape, approximately 3 feet (0.9 m) wide at the leading edge of the deck, and gradually narrowing to a width of approximately 6 inches (152 mm) at the top of the deck. Licks of flame that extend approximately an additional 1 to 2 feet (0.3 to 0.6 m) are not prohibited. The gas supply is to be regulated so that the flame develops a temperature of 1400 ±50°F (760 ±28°C) for a Class A or B test, and 1300 ±50°F (704 ±28°C) for a Class C test. The temperature is to be determined by a No. 14 B&S gage (2.1 mm2) chromel-alumel wire thermocouple located 1 inch (25.4 mm) above the surface and 1/2 inch (12.7 mm) toward the source of flame from the lower edge the deck.UL 790-2018 pdf free download.

Download Information
Go To Download

All resources on this website are from the Internet. It is only for personal study and research. No one is allowed to use it for any commercial purpose. If you need, please buy the genuine standard. If there is any infringement of your copyright, please contact the webmaster in time, and I will correct it immediately.