UL 21:2007 pdf download.LP-Gas Hose.
3 Tube and Cover
3.1 The tube er lining of a hose shall be made from synthetic rubber of the oil-resistant type. For hose up to and including the 2-in (50.8 mm) size, a rubber cover may be enployed but is not required ii the Outer braid is impregnated with a rubber cement or compound. For hose larger than the 2-in size, a rubber cover shall be employed. A tube or a cover shall be smooth, of uniform thickness, tree from detects in workmanship. and free from pitting, blisters, or other imperfections. Intentional pricking of a cover shall not be considered an imperfection. This requirement Is not intended to exclude the use of a corrugated cover.
4 Reinforcement
4.1 A reinforcement shall be provided and shall be of cotton, synthetic rers. or corrosion•resistant material such as stainless steel, or any combination thereof, evenly and firmly applied over the tube. The ply or plies shall be impregnated wTth a rubber compound which shall cause tile plies to adhere firmly to each other and to the tube and cover.
5 InsIde Diameter
5.1 The internal diameter of a hose shall be equal to the nominal diameter ±1132 in (0.8 mm) for sizes up to and including 3/4 in (19.1 mm), and ±1/16 in (1.6 mm) for larger sizes.
5.2 A tapered plug gauge of wood or metal having a taper of 3/8 in per ft (31.3 mm/rn) marked to indicate variation of 1/64 in (0.4 mm) in diameter, a set of wood or metal plug gauges, straight or ball type, in increments of 0.005 in (0.13 mm). or in some cases, see 5.3, an expanding ball gauge and micrometer or other equivalent means to accurately measure the expanded ball, is to be used.
3.1 The tube er lining of a hose shall be made from synthetic rubber of the oil-resistant type. For hose up to and including the 2-in (50.8 mm) size, a rubber cover may be enployed but is not required ii the Outer braid is impregnated with a rubber cement or compound. For hose larger than the 2-in size, a rubber cover shall be employed. A tube or a cover shall be smooth, of uniform thickness, tree from detects in workmanship. and free from pitting, blisters, or other imperfections. Intentional pricking of a cover shall not be considered an imperfection. This requirement Is not intended to exclude the use of a corrugated cover.
4 Reinforcement
4.1 A reinforcement shall be provided and shall be of cotton, synthetic rers. or corrosion•resistant material such as stainless steel, or any combination thereof, evenly and firmly applied over the tube. The ply or plies shall be impregnated wTth a rubber compound which shall cause tile plies to adhere firmly to each other and to the tube and cover.
5 InsIde Diameter
5.1 The internal diameter of a hose shall be equal to the nominal diameter ±1132 in (0.8 mm) for sizes up to and including 3/4 in (19.1 mm), and ±1/16 in (1.6 mm) for larger sizes.
5.2 A tapered plug gauge of wood or metal having a taper of 3/8 in per ft (31.3 mm/rn) marked to indicate variation of 1/64 in (0.4 mm) in diameter, a set of wood or metal plug gauges, straight or ball type, in increments of 0.005 in (0.13 mm). or in some cases, see 5.3, an expanding ball gauge and micrometer or other equivalent means to accurately measure the expanded ball, is to be used.
