UL 404-1997 用于压缩气体服务的安全仪表 UL 标准 指示压力 （第六版；1999年12月21日（包括 12 月 21 日）重印修订版）
UL Standard for Safety Gauges@ Indicating Pressure@ for Compressed Gas Service (Sixth Edition; Reprint with Revisions Through and Including December 21@ 1999)
These requirements cover indicating pressure gauges of the elastic element type usually 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. Such gauges usually have pressure ranges of 0 - 1500@ 0 - 2000@ 0 - 3000@ or 0 - 4000 pounds per square inch (psi) (0 - 10.34@ 0 - 13.78@ 0 - 20.68@ or 0 - 27.56 MPa). A product that contains features@ characteristics@ components@ materials@ or systems new or different from those covered by the requirements in this Standard@ and that involves a risk of fire@ electric shock@ or injury to persons shall be evaluated using the appropriate additional component and end-product requirements to determine that the level of safety as originally anticipated by the intent of this Standard is maintained. A product whose features@ characteristics@ components@ materials@ or systems conflict with specific requirements or provisions of this Standard shall not be judged to comply with this Standard. Where appropriate@ revision of requirements shall be proposed and adopted in conformance with the methods employed for development@ revision@ and implementation of this Standard.