46 C.F.R. § 56.25-20 Bolting.
Title 46 - Shipping
(a) General. (1) Bolts, studs, nuts, and washers must comply with applicable standards and specifications listed in §56.60–1 of this part. Unless otherwise specified, bolting must be in accordance with ANSI B16.5. (2) Bolts and studs must extend completely through the nuts. (3) See §58.30–15(c) of this chapter for exceptions on bolting used in fluid power and control systems. (b) Carbon steel bolts or bolt studs may be used if expected normal operating pressure does not exceed 300 pounds per square inch gage and the expected normal operating temperature does not exceed 400 °F. Carbon steel bolts must have heavy hexagon heads in accordance with ANSI B18.2.1 and must have heavy semifinished hexagonal nuts in accordance with ANSI B18.2.2, unless the bolts are tightly fitted to the holes and flange stress calculations taking the bolt bending stresses into account are submitted. When class 250 cast iron flanges are used or when class 125 cast iron flanges are used with ring gaskets, the bolting material must be carbon steel conforming to ASTM Specification A 307 (incorporated by reference, see §56.01–2), Grade B. (c) Alloy steel stud bolts must be threaded full length or, if desired, may have reduced shanks of a diameter not less than that at the root of the threads. They must have heavy semifinished hexagonal nuts in accordance with ANSI B18.2.2. (d) All alloy bolts or bolt studs and accompanying nuts are recommended to be threaded in accordance with ANSI B1.1, Class 2A external threads, and Class 2B internal threads (8-thread series 8UN for 1 inch and larger). (e) (Reproduces 108.5.6.) Washers, when used under nuts, shall be of forged or rolled steel. [CGFR 68–82, 33 FR 18843, Dec.18, 1968, as amended by CGD 77–140, 54 FR 40605, Oct. 2, 1989; USCG–2000–7790, 65 FR 58460, Sept. 29, 2000]
Title 46: Shipping
PART 56—PIPING SYSTEMS AND APPURTENANCES
Subpart 56.25—Pipe Flanges, Blanks, Flange Facings, Gaskets, and Bolting
§ 56.25-20 Bolting.
