UL 21:2007 pdf download – LP-Gas Hose
UL 21:2007 pdf download – LP-Gas Hose.
72.1 Hydrostatic pressure may be applied by means of a hand- or power-operated pump or an
accumulator system capable of increasing the pressure in the hose at a rate of not less than 300 psig
(2070 kPa) nOr more than 1000 psig (6900 kPa) per minute. All pressures are to be measured with a
calibrated pressure gauge.
7.3.1 Sampfos are to consist of at least one full length [nominally 50 ft (152 m)J of each size of hose,
7.3.2 By means of couplings or temporary test fittings, one end of the hose is to be connected to the source of water or other acceptable test liquid and the other end closed with a fitting provided with a pet cock for the escape of air while the hose is being filled with liquid. The hose Is to be placed on a test surface so as to lie straight and without twisi,
7.33 With the pet cock open, the test liquid is to be admitted through the hose gradually until all of the air has been expelled and the hose is completely filled. The pet cock is then to be closed and the pressure in the hose is to be increased at a rate of not less than 300 psig (2070 kPa) nor more than 1000 psig (6900 kPa) per minute until the required test pressure is reached. While the pressure is being increased, the hose is to be carefully examined for leakage and other defects. When the test pressure has been reached. it is to be held at 5 mEn and the hose checked for leakage or ballooning.
8 Hydrostatic Strength Test
81.1 A hose shall withstand a hydrostatic pressure of 1750 psig (12.100 kPa) without leakage,
ballooning, or rupture.
8.2.1 The apparatus for this test is to be the same as specified for the Proof-Pressure Test. Section 7, except that instead of the test table an enclosure is to be used to protect the operator.
9,3.1 The tests are to be conducted in accordance witti the test methods outlined in the Test Methods for Rubber Hose, ASTM D380. Adhesion tests are to be conducted on only the cover of wire reinforced hose. A hack saw with a sharp, fine (24 teeth/in) blade has been found acceptable for hose having a wire braided reinforcement, but a band saw with a tine blade gives cleaner edges and is preferable for preparing the ring specimens. The adhesion is to be taken as the rate obtained by dividing the total distance separated in inches (mm). to the nearest 1132 in (0.8 mm). by the elapsed time in minutes.
9.3.2 If the adhesion of the reinforcement to the tube or cover is such that the parts cannot be separated sufficiently to permit attachment of the clamp, the adhesion is considered to be in compliance with the requirements.
10 TensIle Strength and Elongation Tests
10.1.1 The tensile strength of a tube shall not be less than 1000 psi (6.9 MPa), and the ultimate elongation of a tube shall not be less than 150 percent [from 1 to 2-1/2 in (25.4 to 63.5 mm)].
10.1.2 The tensife strength of a cover shall not be less than 1000 psi (6.9 MPa), and the ultimate elongation of a cover shall not be less than 250 percent (from 1 to 3-1/2 in (25.4 to 89 mm)].
10.2.1 Tensile strength and elongation tests are to be made on a power•operated machine, as described in the Test Methods for Vulcanized Rubber and Thermoplastic Elastomers-Tenslon, ASTM D412.
10.2.2 The rate of travel of the poweractuated grip is to be 20 ±1 in per minute (8.5 ±04 min/s).
10.2.3 The elongation is to be measured by means of a scale or other device which is to be used in such a way as not to damage the specimen and is to be capable of indicating the elongation with an accuracy of 0.1 In (2.5 mm).
10.2.4 The specimens are to be butted or skived with the equipment specified in 6.2.
10.2.5 Die C or Die D, as described in the Test Methods for Vulcanized Rubber and Thermoplastic Elastomers-Tension, ASTM D41 2, is to be used for cutting the specimens.
10.2.6 A dial micrometer, as described in 6.3, shall be used to measure thickness of specimens.