Last Updated: Mar 27 2018, By: LB

Fittings on pressure vessels can be exempt from registration even when the same fittings used on piping attached to the vessel are not.

FlangeUnder the B51 program, fittings need to be registered before they can be used on pressure devices. However, fittings on pressure vessels are exempted from requiring registration by B51-09 clause 4.2.1:

Fittings shall be registered in accordance with Clauses 4.2.2 to 4.2.9 unless they form a part of a boiler or pressure vessel that is subject to inspection by an authorized inspection agency. Registrations of fittings shall be resubmitted for validation not more than ten years after the date of acceptance by the regulatory authority in the original registering province or by a nationally recognized organization as specified in Clause 4.2.3.

In practice, this exemption from registration is only applied to standard fittings – those listed in VIII-1 UG-44:

UG-44(a) ASME B16.5, Pipe Flanges and Flanged Fittings [see UG-ll(a)(2)]

UG-44(b) ASME B16.9, Factory-Made Wrought Butt welding Fittings

UG-44(c) ASME B16.11, Forged Fittings, Socket Welding and Threaded

UG-44(d) ASME B16.15, Cast Bronze Threaded Fittings, Classes 125 and 250

UG-44(e) ASME B16.20, Metallic Gaskets for Pipe Flanges – Ring-Joint, Spiral-Wound, and Jacketed

UG-44(f) ASME B16.24, Cast Copper Alloy Pipe Flanges and Flanged Fittings, Class 150, 300, 400, 600, 900, 1500, and 2500

UG-44( g) ASME B16.42, Ductile Iron Pipe Flanges and Flanged Fittings, Class 150 and 300

UG-44(h) ASME B16.47, Large Diameter Steel Flanges, NPS 26 Through NPS 60

This exemption is also applied to ASME “UM” vessels which are shop, but not authorized inspector inspected. All other non-standard fittings will need registering for pressure vessel use. 

In contrast B51-09 clause 8.2 requires the registration of fittings on piping systems:

“Fittings used in piping systems shall be registered in accordance with Clause 4.2.”

We made up a diagram to help illustrate:

The attached piping system and vessel are under identical operating conditions. The red items need registration, the green items do not. The non-standard elliptical manway cover always needs registering – on vessels or piping. The standard flanges, elbows and couplings need registration for use on the piping system but not the vessel.

Some fittings are always exempt in some provinces (latest here: Fittings).