46 C.F.R. Subpart 56.25—Pipe Flanges, Blanks, Flange Facings, Gaskets, and Bolting
Title 46 - Shipping
Flanges must conform to the design requirements of the applicable standards of Table 56.60–1(b) of this part or Appendix 2 of section VIII of the ASME Code. Plate flanges must meet the requirements of §56.30–10(b)(5) of this part and the material requirements of §56.60–1(a) of this part. Flanges may be integral or may be attached to pipe by threading, welding, brazing, or other means within the applicable standards specified in Table 56.60–1(b) of this part and the requirements of this subpart. For flange facing gasket combinations other than those specified above, calculations must be submitted indicating that the gaskets will not result in a higher bolt loading or flange moment than for the acceptable configurations. [CGD 77–140, 54 FR 40605, Oct. 2, 1989, as amended by USCG–2002–13058, 67 FR 61278, Sept. 30, 2002] (a) Blanks shall conform to the design requirements of 104.5.3 of ANSI-B31.1. [CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9978, June 17, 1970] (a) Flange facings shall be in accordance with the applicable standards listed in Table 56.60–1(b) and MSS-SP-6. (b) When bolting class 150 standard steel flanges to flat face cast iron flanges, the steel flange must be furnished with a flat face, and bolting must be in accordance with §56.25–20 of this part. Class 300 raised face steel flanges may be bolted to class 250 raised face cast iron flanges with bolting in accordance with §56.25–20(b) of this part. [CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 77–140, 54 FR 40605, Oct. 2, 1989] (a) Gaskets shall be made of materials which are not injuriously affected by the fluid or by temperature. (b) Only metallic and suitable asbestos-free nonmetallic gaskets may be used on flat or raised face flanges if the expected normal operating pressure exceeds 720 pounds per square inch or the operating temperature exceeds 750 °F. (c) The use of metal and nonmetallic gaskets is not limited as to pressure provided the gasket materials are suitable for the maximum fluid temperatures. [CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 86–035, 54 FR 36316, Sept. 1, 1989] (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
§ 56.25-5 Flanges.
§ 56.25-7 Blanks.
§ 56.25-10 Flange facings.
§ 56.25-15 Gaskets (reproduces 108.4).
§ 56.25-20 Bolting.
