ULC 404

1 Scope

1.1 This Standard covers minimum requirements for indicating pressure gauges of the elastic element type.

1.2 Indicating pressure gauges include:

1. a) High pressure gauges employed in the high-pressure side of regulators or reducing valves used on compressed gas containers or cylinders of oxygen, hydrogen, nitrogen, and other gases usually have pressure ranges of 0 – 500, 0 – 1 000, 0 – 1 500, 0 – 2 000, 0 – 3 000, 0 – 4 000, 0 – 5 000, or 0 – 6 000 pounds per square inch (psi) (The related metric gauge ranges are approximately 0 – 3.4, 0 – 6.89, 0 – 10.34, 0 – 13.78, 0 – 20.68, 0 – 27.56, 0 – 34.47, or 0 – 41.36 MPa); and
2. b) Differential pressure gauges employed to measure the difference between two pressures with a maximum inlet pressure of 1 000 psig (6.89 MPa).

1.3 For requirements for gauges employed in the low side of regulators with ranges of 1 000 psig (6.89 MPa) or less, refer to the Standard for Compressed Gas Regulator Accessories, ANSI/CAN/UL/ULC 252A.