UL 331B:2015 pdf dwonload – Strainers for Diesel Fuel， Biodiesel Fuel, Diesel/Biodiesel Blends with Nominal Biodiesel Concentrations up to 20 Percent (B20), Kerosene,and Fuel Oil.
6,2.2 Nonmetallic materials — material level
6.2.2.1 Seals shall be evaluated in accordance with the Standard for Gaskets and Seals, UL 157, modified as indicated in 6.2.2.2 — 6.2.2.4. If a specific material complies with these requirements, the material can be considered to be qualified for system level testing.
6.2.2.2 A seal shall be constructed of a material that is acceptable in accordance with the scope ol the Standard for Gaskets and Seals. UL 157.
6.2.2.3 Seals shall be subected to the Volume Change and Extraction Test in accordance with the Standard for Gaskets and Seals. UL 157. except foi- the following modifications:
a) The test duration shall be 1000 hours;
b) The applicable test fkiids shall be as described in Supplement SA; and
C) For all materials, the average volume change shall not exceed 40 percent swell (increase in volume) or 1 percent shrinkage (decrease in volume). In addition, the weight loss shall not exceed 10 percent. There shall be no visual evidence of cracking or other degradation as a result of the exposure for any material.
6.2.2.4 Seals shall be subjected to the Compression Set Test In accordance with the Standard for Gaskets and Seals. UL 157. except for the following modifications:
a) The test duration shall be 1000 hours;
b) The samples shall be immersed, at room temperature, in the test fluids [see item (C)) while compressed for the entire test duration. No oven conditioning is required;
C) The applicable test fluids shall be as described in Supplement SA.
d) The recovery period shall consist of removing the sample from the compression device and immersing it in the applicable test fluid for 30 minutes at room temperature. The sample stiall not be allowed to dry out due to exposure to air. The 30 minute Immersion should use the same fluid as the test fluid for each sample.
e) For all materials, the average compression set is calculated and shall not exceed 35 percent.
Exception: This requirement does not apply to composite gasket matenals as defined in accordance with the Standard for Gaskets arid Seals. UL 157.
6.2.3 Nonmetallic materials — system level
6.2.3.1 For all materials used in non-removable strainer assemblies, gaskets, and seals mat have been shown to comply with the applicable requirements fOr static seals in the Standard for Gaskets and Seals, UL 157, or with the requirements under material level tests shall be subjected to the system level tests after the Long Term Exposure Test, Sechon 11. Static seals shall be provided in accordance with 11.2.4.
6.3 CastIng impregnation materIals
6.3.1 Material level
6.3.1.1 Casting impregnation materials shall be evaluated at the material level in accordance with the requirements in the Outline of Investigation for Power-Operated Dispensing Devices for Diesel Fuel, Biodiesel Fuel, DieselBiodiesel Blends with Nominal Biodlesel Concentrations Up to 20 Percent (B20), Kerosene, and Fuel Oil, UL 878.
6.3.2 System level
6.321 For non-removable strainer assemblies utilizing casting impregnation materials, the casting with the material applied as intended shall comply with the Long Term Exposure Test, Section ii. The casting shall not show indications of porosity leakage at any point during or after this test.
7 Bodies and Covers
7.1 An opening threaded for connection of pipe shall be threaded in accordance with the Standard for Pipe Threads, ANSIASME BI.20.1.
Exception: Strainers intended for use in installations where pipe fittings incorporate other than NPT type threads shall be permitted to be provided with pipe threads complying with a national pipe thread standard compatible with those fittings. The pipe thread type shall be identified in accordance with 17.1.
7.2 A strainer for attachment to pipe larger than 3-inch nominal size shall be provided with flanged pipe connections. Flanges shall conform to the appropriate American National Standard for pipe flanges and flanged fittings covering the material from which the flange is made, or shall be of a construction found by investigation to be equivalent for the specific application.