UL-157:2015 pdf free download – STANDARD FOR SAFETY Gaskets and Seals.
10.2 Apparatus
10.2.1 The apparatus is to include a cold chest capable of maintaining temperatures of minus 40 ±2°C (minus 40±3.6° F) and minus 54±2°C (minus 65 ±3.6°F) and a metal mandrel having a 0.25 inch (6.4 mm) diameter.
10.3 Specimens
10.3.1 The specimens are to be 5 inches (127 mm) long, 0.25 to 0.50 inches (6.4 to 12.7 mm) wide, and 0.125 to 0.150 inches (3.2 to 3.8 mm) thick. Specimens of “0” ring segments are to be of solid elastomer material, having an inside diameter of 1-1/4 inches (31.8 mm), and a cross-sectional thickness of 0.139 inch (3.5 mm). Three specimens are to be used for each test.
10.4 Method
10.4.1 The specimens or “0” ring segments and mandrel are to be subjected to 24 ±1/2 hours at minus 40 ±2°C (minus 40 ±3.6°F) or minus 54 ±2°C (minus 65 ±3.6°F), or any other temperatures as requested by the manufacturer, depending on the intended use. While at the test temperature, each specimen or “0” ring is to be bent within 5 seconds around the 0.25 inch (6.4 mm) mandrel to form a “U” bend. To minimize heat transfer to the specimen or “0” ring segment, gloves are to be worn. Each specimen or “0” ring segment is to be examined for evidence of cracking.
11 Immersion Test
11.1 General
11.1.1 The immersion test is to be conducted on solid elastomer material, the elastomer portion of coated fabrics, composite material, thermoplastic, and both open and closed flexible cellular material. See Table 4.2 for appropriate tests and requirements.
11.2 Apparatus
11.2.1 Apparatus for tensile strength and ultimate elongation determinations is to be as specified in 5.2.1 — 5.2.8.
11.2.2 Apparatus for the volume change test is to consist of an analytical balance with a bridge for the support of a vessel of distilled water, a small diameter wire hook, alcohol, and a metal die or other equipment for cutting 1 by 1 inch (25.4 by 25.4 mm) specimens. For open flexible cellular material and other absorbing materials, a scale in 1/100 inch (0.25 mm) divisions and a micrometer as specified in 5.2.4 are to be provided.
11 .3.2 Volume change and extraction test specimens may be obtained from parts such as an “0” ring or cut from smooth and uniform slab or sheet material. In order to provide for smooth and uniform material, the sample may be buffed or skived as specified in Table 5.1. Cutting with a die or other equipment specified in 11.2.2 is to be followed for slab or sheet material.
11.4 Method
11 .4.1 Tensile Strength and Elongation Tests
11 .4.1.1 A set of three specimens is to be prepared as specified for Tensile Strength and Ultimate Elongation Test, Section 5, except the 1 inch (25.4 mm) bench marks, if required, are to be placed on the specimens after the immersion period (see 5.4.2). The specimens are to be immersed so that they do not touch each other or the sides of the container. The specimens are to be immersed in the applicable test liquids tabulated in Table 4.2 for 70 ±1/2 hours at 23 ±2°C (73.4 ±3.6°F) unless otherwise specified.