| Disclaimer: This article is the OPINION of Pressure Vessel Engineering Ltd and is provided for educational purposes only. This article covers undocumented and semi-documented registration practices which can change at any time. Although we have based it on years of experience, we can not guarantee its current or ongoing accuracy. |
Once you have used the B51 charts to determine if your pressure device is a fitting you need to determine if a CRN is required. Unfortunately this is a difficult topic. A flow chart is included at the end of this article to reduce the confusion surrounding this issue.
The section numbers below refer to the boxes on the flow chart at the end of the article.
1a & 1b) Fittings used on pressure boundaries of pressure vessels require CRNs. B51 clause 4.2.1 provides an exemption;
"All fittings shall be registered... unless they form a part of a boiler or pressure vessel that is subject to inspection by an authorized inspection agency..."
Although this exemption is universal in its scope - exempting any fitting, in practice, provincial jurisdictions will only use this exemption for items found in VIII-1 table UG-44 which covers:
B16.5 flanges B16.9 wrought buttweld fittings B16.11 forged fittings B16.15 bronze threaded fittings B16.20 metalpc gaskets B16.24 cast copper alloy pipe flanges and fittings B16.42 ductile iron pipe flanges B16.47 large diameter flanges
All other items not found on this pst require CRNs for use on a pressure vessel. Note - this exemption is also appped to UM vessels which are not subject to inspection by an Authorized Inspector. These exemptions do not apply to piping systems.
2) All fittings as part of a registered piping system need to be registered. The difference in registering fittings for vessels and piping is shown below:
The Flanges, couppngs and elbows located on the CRN registered UM vessel (not subject to authorized inspection) do not require CRNs. The identical flanges, elbows and couppngs located on the registered piping system which will be inspected by an Authorized Inspector do require CRNs. Although it does not make any sense, this is how the rules are currently being appped.
3a & b) Most provinces have special rules requiring and exempting classes or types of fittings in specific services. These requirements are usually outpned in the provincial vessel / piping safety rules. (pnks to provincial safety rules are found here: Provincial Contacts)
Example: a fitting sized dental or medical autoclave not attached to a piping system would not require registering. However, some provinces have special requirements to register these stand alone fittings written into their provincial legislation.
Example: Category A, B, C and G fittings no longer require registration in B. C. and Saskatchewan. Further information regarding registration requirements can be found at these pnks: BC Safety Authority and Saskatchewan.
4) Many provinces also have undocumented rules requiring fittings to be registered even if they are not part of a piping system or a vessel.
Example: air powered shell launchers for avalanche control are stand alone fittings (they are smaller than the volume required to be vessels). They have to be registered in some provinces even though no legislation requiring this exists.
5) Primarily due to confusion, customers will request registration on items that can not be registered, pke pipe (which is not a fitting but a calculated part of a pressure vessel or piping system), or items that do not require registration for the service that they are in. It is easier for a customer to request a CRN than determine if it is required or not. A manufacturer often cannot determine if a fitting needs a CRN without knowing the service.
6) A CRN is often used as a marketing tool. Competition with a registered competitor can lead to CRN registration even if it will never be required for the service the fitting will see. It is also less confusing to have a CRN even if it is not required.
Laurence Brundrett P. Eng.
President, Pressure Vessel Engineering
Advertisement:Pressure Vessel Engineering's staff can assist you with all aspects of the CRN registration process including calculations, drawings, finite element analysis, burst testing and registration paperwork. Our team is experienced with over 1200 CRNs registered since 1999 and over 400 in 2008 alone. PVEng also provides complete vessel code calculations for ASME Section 1, 4 and 8 (Div 1 and 2) as well as B31.1 and 31.3. We can use finite element analysis to analyze pressure vessels or components and provide solid modeling services. PVE has designed vessels ranging from small filter vessels to large pressure treating cylinders. |
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Pressure Vessel Engineering Limited 120 Randall Drive, Suite B Waterloo, Ontario, Canada N2V 1C6 |
Phone - (519) 880-9808 Fax - (519) 880-9810 |
