UL 429-2020 pdf free download

UL 429-2020 pdf free download.Electrically Operated Valves.
6.3.2 With reference to the requirements in 6.3.1. the change in volume shall not be more than 25 percent swelling (40 percent in Reference Fuel C or H) or 1 percent shrinkage, and the weight loss (extraction) shall not be more than 10 percent.
6.3.3 If the limits for volume change or weight loss in 631 are exceeded, a complete valve assembly is to be filled with the appropriate test liquid for 70 hours. Following the conditioning the liquid shall be drained and the valve assembly permitted to dry in free air for 70 hours at any ambient temperature in the range of 10 — 40 C (50 — 104 F). The valve shall then comply with the requirements for the External Leakage Test. Section 29, the Seat Leakage Test, Section 30. and the Hydrostatic Strength Test, Section 34 as appropriate for the type of seal and valve.
6.3.4 External seal parts, and operating parts of safety valves affecting the closing of the valve and made of synthetic rubber shall not crack or show visible evidence of deterioration after being subjected to hand flexing following exposure as specified in the accelerated air-oven aging test in the Standard for Gaskets and Seals. UL 157. The oven temperature is based on the maximum normal operating (service) temperature of the seal or operating part. The oven temperature shall not be less than 609C (140F).
Exception No. 1: Oxygen bomb test for valves rated for oxygen seniice.
Exception No. 2: When a synthetic rubber material only used as a static seal cracks or shows visible evidence of deterioration following exposure as specified in the accelerated air-oven aging test, new samples of the synthetic rubber material are to be tested in the complete valve assembly, or as an alternative, new samples of the synthetic rubber material are to be tested in a test setup, which simulates the seal or gasket in the valve. After the accelerated air-oven aging testing, the samples shall comply with the requirements for the External Leakage Test. Section 29 and the Hydrostatic Strength Test, Section .4. For accelerated air-oven aging testing on the valve assembly, other seals or gaskets for which the valve assembly oven aging test is not intended, may be removed from the valve assembly before the accelerated air-oven aging test and then installed prior to the External Leakage Test and the Hydrostatic Strength Test.
6.3.5 External seal parts, and operating parts of safety valves affecting the closing of the valve made of a thermoplastic material in contact with one of the fluids listed in Table 6.1 shall be subjected to the Dimensional Stability Test in Section i.
6.3.6 External seal parts, and operating parts of safety valves affecting the closing of the valve made of elastomenc arid synthetic rubber material in contact with Hydrogen gas at pressures greater than 75 psig shall be subjected to the Accelerated Hydrogen-Pressure Aging Test. Section M.UL 429-2020 pdf free download.