This specification covers grades of nominal-wallthickness, stainless steel tubing for general corrosion-resisting and low- or high-temperature service, as designated in Table 1. 

The tubing sizes and thicknesses usually furnished to this specification are ¹⁄₄ in. [6.4 mm] in inside diameter and larger and 0.020 in. [0.51 mm] in nominal wall-thickness and heavier. 

Mechanical property requirements do not apply to tubing smaller than ¹⁄₈ in. [3.2 mm] in inside diameter or 0.015 in. [0.38 mm] in thickness. 

NOTE 1—Additional testing requirements may apply for use in ASME B31.3 applications. 

Optional supplementary requirements are provided and, when one or more of these are desired, each shall be so stated in the order 

The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, 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 non-conformance with the standard. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order. 

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.