UL-1990:2013 pdf free download – STANDARD FOR SAFETY Nonmetallic Underground Conduit with Conductors.
9 Identification of Compounds
9.1 An HDPE material used in conduit shall be subjected to the Infrared Spectroscopy (IR), Thermogravimetry (TGA), and Differential Scanning Calorimetry (DSC) Tests specified in the Standard for Polymeric Materials — Short Term Property Evaluations, UL 746A.
10 Water Absorption Test
10.1 Finished conduit shall have a maximum ratio, W2/W1, of 1.0015 after immersion in distilled water for 24 hours (see 10.3). The test is to be as indicated in 10.2 — 10.4 (similar to the method described as Procedure A in the Standard Test Method for Water Absorption of Plastics, ASTM D 570).
10.2 Specimens are to be preconditioned by drying in a full-draft, circulating-air oven at a temperature of 50.0 ±3.0°C (122.0 ±5.4°F) for 24 hours, after which they are to remain in still air at room temperature for 24 hours.
10.3 A clean, dry specimen of finished conduit at least 6 inches (152 mm) long is to be preconditioned as indicated in 10.2, weighed, W1, to within 5 mg of balance, and immersed for 24 hours in distilled water that is at room temperature. The specimen is then to be removed from the water, dried quickly inside and out with a clean piece of soft lintless cloth, and immediately reweighed, W2, to within 5 mg of balance. W2/W1 shall not be larger than indicated in 10.1.
10.4 When a specimen is known or suspected to contain appreciable amounts of water-soluble material, two specimens are to be preconditioned by drying in a full-draft circulating-air oven at a temperature of 50.0 ±3.0°C (122.0 ±5.4°F) for 24 hours, cooled in a desiccator for 24 hours, and immediately weighed, W1. The specimens are then to be immersed in distilled water for 24 hours with the water at room temperature. Immediately following this immersion, the specimens are to be reconditioned for 24 hours in the oven at 50.0 ±3.0°C, cooled in a desiccator for 24 hours, immediately reweighed, W2, and the criteria in 10.1 applied.
11 Low Temperature Handling Test
11 .1 The conduit shall not shatter, chip, or crack when tested in accordance with 11 .2.
11 .2 One 30-inch (760-mm) specimen is to be cut from lengths of each size of finished conduit. The ends of each specimen are to be smooth and perpendicular to the longitudinal axis of the conduit. The specimens are to be cooled in circulating air for five hours to a temperature of minus 20.0 ±1.0°C (minus 4.0 ±1 .8°F). Within 15 seconds of removal from the low temperature, each specimen is to be dropped onto a concrete floor twice in quick succession from a height of 60 inches (1.53 m). The specimen is to be dropped at an angle of approximately 45 degrees to the floor so that one end of it hits the floor first. For the second drop, the specimen is to fall parallel to the floor.
12 Tensile Strength
12.1 General
12.1.1 The average tensile strength of three aged specimens of finished conduit shall equal or exceed 95 percent of the average tensile strength of three unaged specimens of conduit. The average tensile strength of the unaged specimens shall comply with the limit established for the compound used but, in any case, shall not be less than 2700 lbf/in2 (18.6 MPa). The procedures (similar to those described in the Standard Test Method for Tensile Properties of Plastics, ASTM D 638) for preparing and conditioning the specimens, for making the measurements, and for calculating the average tensile strengths are indicated in 12.2.1一12.4.1.