46 C.F.R. § 56.30-20 Threaded joints.
Title 46 - Shipping
(a) Threaded joints may be used within the limitations specified in subpart 56.15 of this chapter and within other limitations specified in this section. (b) (Reproduces 114.1.) All threads on piping components must be taper pipe threads in accordance with the applicable standard listed in Table 56.60–1(b). Threads other than taper pipe threads may be used for piping components where tightness of the joint depends on a seal weld or a seating surface other than the threads, and where experience or test has demonstrated that such threads are suitable. (c) Threaded joints may not be used where severe erosion, crevice corrosion, shock, or vibration is expected to occur; or at temperatures over 925°F. Size limitations are given in Table 56.30–20(c) of this section. (d) Pipe with a wall thickness less than that of standard weight of ANSI B36.10 steel pipe must not be threaded regardless of service. For additional threading limitations for pipe used in steam service over 250 pounds per square inch or water service over 100 pounds per square inch and 200°F, see part 104.1.2(c)(1) of ANSI B31.1. Restrictions as to the use of threaded joints appear for low temperature piping and should be checked when designing for these systems. [CGFR 68–82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69–127, 35 FR 9978, June 17, 1970; CGD 73–254, 40 FR 40164, Sept. 2, 1975; CGD 77–140, 54 FR 40606, Oct. 2, 1989]
Title 46: Shipping
PART 56—PIPING SYSTEMS AND APPURTENANCES
Subpart 56.30—Selection and Limitations of Piping Joints
§ 56.30-20 Threaded joints.
Table 56.30-20(c)_Threaded Joints \1,2\------------------------------------------------------------------------ Maximum nominal size, inches Maximum pressure, p.s.i.g.------------------------------------------------------------------------Above 2[inch]............................. (Not permitted in Class I piping service.)Above 1[inch] up to 2[inch]............... 600.Above \3/4\[inch] up to 1[inch]........... 1,200.\3/4\[inch] and below..................... 1,500.------------------------------------------------------------------------\1\ Further restrictions on the use of threaded joints appear in the low temperature piping section.\2\ Threaded joints in hydraulic systems are permitted above the pressures indicated for the nominal sizes shown when commercially available components such as pumps, valves and strainers may only be obtained with threaded connections.
