1.1 This specification covers black and hot-dipped galvanized hot-formed welded and seamless carbon steel square, round, rectangular, or special shape structural tubing for welded, riveted, or bolted construction of bridges and buildings, and for general structural purposes. 1.2 Square and rectangular tubing is furnished in sizes 1 to 32 in. (25.4 to 813 mm) across flat sides with wall thicknesses 0.095 to 3.00 in. (2.41 to 76 mm), dependent upon size; round tubing is furnished in NPS 1/2 to NPS 24 (see Note 1) inclusive, with nominal (average) wall thicknesses 0.109 to 1.000 in. (2.77 to 25.40 mm), dependent upon size. Special shape tubing and tubing with other dimensions is permitted to be furnished, provided that such tubing complies with all other requirements of this specification. 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." 1.3 This specification covers the following grades: 1.3.1 Grade A -36000 psi (250 MPa) min yield strength. 1.3.2 Grade B -50000 psi (345 MPa) min yield strength. 1.4 An optional supplementary requirement is provided for Grade B and, when desired, shall be so stated on the order. 1.5 The following precautionary statement pertains only to the test method portion of this specification: This standard does not purport to address all the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.7 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.