1.1 本规范涵盖了一般应用的直接和间接读数目测液位指示器的要求。间接阅读观察镜的一般应用是工作压力为2.07 MPa（300 lb/in）的水和燃料服务。 2. )温度在149°C（300°F）及以下。直读式视镜的一般应用是温度不超过66°C（150°F）的应用。 1.2 直读式视镜指示器可能由玻璃管或塑料管组成，带有包括截止阀在内的配件。 玻璃管可用于液体与塑料不兼容的低冲击直读观察镜指示器。 1.3 间接读数指示器可能由带有磁性浮子或标志指示器的密封室组成。 1.4 本标准的补充文件中包含了海军舰船应用的特殊要求。 1.5 以国际单位制表示的数值应视为标准值。括号中给出的值是英寸-磅单位的数学转换，仅供参考，不被视为标准值。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。

1.1 This specification covers the requirements for direct and indirect reading sight liquid level indicators for general applications. General applications for indirect reading sight glasses are water and fuel service at working pressures 2.07 MPa (300 lb/in. 2 ) and below, temperatures of 149°C (300°F) and below. General applications for direct reading sight glasses are applications in which the temperature does not exceed 66°C (150°F). 1.2 Direct reading sight glass indicators may consist of glass or plastic tubes with fittings including shutoff valves. Glass tubes may be used for low shock direct reading sight glass indicators in which the fluid is not compatible with plastic. 1.3 Indirect reading indicators may consist of a sealed chamber with a magnetic float or flag indicator. 1.4 Special requirements for naval shipboard applications are included in the supplement to this standard. 1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.