1.1 本规范涵盖电熔（电弧）焊接直缝或螺旋缝钢套管NPS 10( 注释1 )直径较大（外径由买方规定），壁厚0.200英寸。[5.1 mm]或更大。如果管道符合本规范的所有其他要求，则允许指定和提供具有其他尺寸的管道。该管道用于水平地下钻孔、隧道或明沟应用中的套管或外壳。 1.2 本规范以英寸-磅单位和国际单位表示；但是，除非采购订单或合同规定了适用的M规格名称（SI单位），否则应采用英寸-磅单位。 以英寸-磅单位或国际单位表示的数值应单独视为标准值。在文本中，SI单位显示在括号中。每个系统中规定的值可能不完全相等；因此，每个系统应独立于其他系统使用。结合两个系统的值可能会导致不符合标准。 1.3 本规范的文本包含注释和脚注，提供解释性材料。此类注释和脚注（表和图中的注释除外）不包含任何强制性要求。 1.4 以下预防性警告仅适用于试验方法部分，章节 11 , 12 和 13 本规范的要求。 本标准并不旨在解决与其使用相关的所有安全问题（如有）。 本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 注1: 本标准中，无量纲指示符NPS（公称管道尺寸）已取代传统术语，如“公称直径”、“尺寸”和“公称尺寸” 1.5 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 electric-fusion (arc)-welded straight seam or spiral seam steel casing pipe NPS 10 ( Note 1 ) and larger in diameter (outside diameter as specified by purchaser) with wall thickness 0.200 in. [5.1 mm] or greater. It shall be permissible to specify and furnish pipe having other dimensions provided such pipe complies with all other requirements of this specification. The pipe is intended for use as casing or encasement in horizontal underground boring, tunneling, or open trench applications. 1.2 This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies the applicable M specification designation (SI units), the inch-pound units shall apply. The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.3 The text of this specification contains notes and footnotes that provide explanatory material. Such notes and footnotes, excluding those in tables and figures, do not contain any mandatory requirements. 1.4 The following precautionary caveat pertains only to the test method portion, Sections 11 , 12 , and 13 of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Note 1: The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as “nominal diameter,” “size,” and “nominal size.” 1.5 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.