[Code of Federal Regulations]
[Title 46, Volume 2]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR56.25-20]

[Page 185-186]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 56_PIPING SYSTEMS AND APPURTENANCES--Table of Contents
 
Subpart 56.25_Pipe Flanges, Blanks, Flange Facings, Gaskets, and Bolting
 
Sec. 56.25-20  Bolting.

    (a) General. (1) Bolts, studs, nuts, and washers must comply with 
applicable standards and specifications listed in Sec. 56.60-1 of this 
part. Unless otherwise specified, bolting must be in accordance with 
ANSI B16.5.

[[Page 186]]

    (2) Bolts and studs must extend completely through the nuts.
    (3) See Sec. 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 [deg]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 Sec. 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]