本标准包括用于地下消防干管的NPS（标称管道尺寸）4英寸至36英寸标称尺寸FRC管道和配件的设计和性能要求，其他尺寸可根据具体情况进行评估。

This standard encompasses the design and performance requirements for NPS (Nominal Pipe Size) 4 inch through 36 inch nominal size FRC pipe and fittings for use in underground fire service mains, other sizes may be evaluated on a case-by-case basis.