UL 793-2020 pdf free download

UL 793-2020 pdf free download.Automatically Operated Roof Vents for Smoke and Heat.
a) A coating of hot-dipped mill galvanized sheet steel complying with the coating Designation G60 (G90 for an enclosure that houses live parts) or A60 in Table I of ASTM A653/A653M, with not less than 40 percent of the zinc on any side, based on the minimum single spot test requirement in the ASTM Designation. The weight of the zinc coating may be determined by any method, but in case of question shall be established In accordance with the test method in ASTM A90. An A60 (alloyed) coating shall also comply with the requirements in 94.
b) A zinc coating. other than that provided on hot-dipped mill galvanized sheet steel, uniformly applied to an average thickness of not less than 0.0104 mm (000041 in) on each surface with a minimum thickness of 0.00864 mm (0.00034) The thickness of the coating is to be established in accordance with the test method in ASTM B555. An annealed coating shall also comply with the requirements in 9.4.
c) A cadmium coating not less than 0.0127 mm (0.0005 in) thick on both surfaces. The thickness of coating is to be established in accordance with ASTM B555.
d) Two coats of an organic finish of the epoxy or alkyd-resin type or other outdoor paint on each surface. The acceptability of the paint may be determined by its composition or by corrosion tests as specified in UL 1332.
9.2 Coated oi- uncoated metals used in the assembly of vents shall be galvanically compatible.
9.3 Component springs and bearings used in the assembly of vents shall be of material having resistance to atmospheric corrosion.
9.4 A hot-dipped mill galvanized A60 (alloyed) coating or an annealed zinc coating that is bent or similaily formed after annealing and that is not otherwise required to be painted shall be painted in the bent or formed area as specified in 9.1(d) if the bending or forming process damages the zinc coating as described in 9.5.
9.5 II flaking or cracking of the zinc coating at the outside radius of the bent or formed section is visible at
25 power magnification, the zinc coating is to be considered damaged. Simple sheared or cut edges and
punched holes are not considered to be formed, but rolled edges shall comply with the requirements in
9.4.
10 Heat Responsive Devices
10.1 A heat responsive device shall comply with UL 33, and shall be used in a manner such that It Is not subjected to loads that exceed its rating.
10.2 The temperature rating of the fusible link or other heat responsive devices shall be a minimum of
71°C(160°F) and shall not exceed 271°C(520°F).UL 793-2020 pdf free download.