UL 495-2016 pdf download

UL 495-2016 pdf download.Power-Operated Dispensing Devices for LP-Gas.
25 Endurance Test
25.1 Mechanical shaft seal
25,1,1 A mechanical-shall seal employed In a pump, meter, or the like shall not seize, leak. or otherwise malfunction during operation when tested as specified in 25.1.2.
25.1.2 The assembly Is to be operated continuously for 300 hours; 50 hours at a pressure just under the maximum operating pressure to which it will be subiected in use, and 250 hours at a pressure of 20 percent of the maximum operating pressure. Operating parts are to be kept wet during the test by maintaining a flow of liquid.
25.2 Retrieving mechanism
25.2.1 A retrieving mechanism provided for an extra-long hose that is supplied entirely outside the housing shall not show evidence of damage when tested as specified in 25.2.2. Any clamp or fitting for attachment to the hose shall not damage the hose during this test.
25.2.2 A retrieving mechanism equipped with the hose is to be operated through 35,000 withdrawal-and-return cycles. The hose need not contain liquid during this test.
26 High-Pressure Leakage Test
26.1 A mechanical-shaft seal and any other liquid-handling part, including any joint made in the assembly of the complete dispensing device, shall not leak when subjected to an aerostatic pressure of 525 psig (3.62 MPa) for 1 minute.
26.2 This test is to be conducted following and using the same samples as used for the Endurance Test. Section 25.
27 Hydrostatic Strength Test
27.1 A liquid-handling part of the dispensing device shall withstand for 1 minute. without rupture, an internal hydrostatic pressure of 1750 psig (12.10 MPa).
Exception: A mechanical shaft seal need not be subjected to this test.
28 Moist Ammonia-Air Stress Cracking Test
28.1 After being subjected to the conditions described in 28.2 — 28,4. a pressure confining brass part containing more than 15 percent zinc shall:
a) Show no evidence of cracking, delamination, or degradation, or
b) Perform as intended when tested as described in 28.4.
28.2 One test sample of each size is to be subjected to the physical stresses normally imposed on or within a part as the result of assembly with other components. Samples with female threads, intended to be used for installing the product in the field, are to have the threads engaged and tightened as specified in Table 34.1. Samples with female threads other than tapered pipe threads shall be torqued as specif led by the manufacturer. Polytetrafluoethylene (PTFE) tape or pipe compound are not to be used on any threads. Samples with male threads are evaluated as received.
28.3 The samples are then to be tested in accordance with Apparatus. Section 6, Reagents and
Materials, Section 7, Test Media, Section 8, Test Sample Preparation (9.3 – 9,4), Test Procedure (10.1
10.4) of the Standard Test Method for Ammonia Vapor Test for Determining Susceptibility to Stress
Corrosion Cracking in Copper Alloys, ASTM B858-06, except the pH level of the test solution shall be High
10.5 ±0.1 and the exposure temperature shall be 25 ±1CC.
28.4 After the exposure period, the samples are to be examined for cracks or other signs of stress corrosion using a microscope having a magnification of 25X. Pressure-confining parts exhibiting degradation as indicated in 28.1 as a result of the test exposure described in 28.2 and 28.3 shall withstand, without rupture. a hydrostatic test pressure of five times the rated pressure of the valve, for I minute.
29 Float Crushing Test
29.1 A hollow float shall not leak when immersed in water as described in 29.2 and shall withstand for 1 minute an external pressure of 750 psig (5.17 MPa) without distortion.
29.2 Two samples of a hollow float are to be subjected to this test. Each float is first to be checked for leakage by being suddenly immersed in water heated to just below the boiling point and observed for 3 minutes for the appearance of bubbles. If no leakage is noted, each float is then to be placed in a container of appropriate size and strength. The container is to be connected to a source of hydrostatic pressure, and a calibrated pressure gauge is to be installed in the pressure-supply plping. Care is to be taken to completely fill the container with liquid to expel all air. The pressure is then to be increased slowly to 750 psig (5.17 MPa) and held for 1 minute, The floats are then to be removed from the container and examined for distortion.