



Additional Notes & Exemptions:
Please remember that this has been supplied for information purposes only. Only ASME can interpret the Code rules, and each Canadian Jurisdiction has their own requirements.



The data presented in the following flowcharts is published in the B51 Code and serves as a general guide for fluids categorized as either "not more hazardous than water", "non-lethal", or "lethal". When dealing with a specific case, there may be additional factors to consider.

TABLE 1 CATEGORIES OF FITTINGS
Category
Type of fitting
A
Pipe fittings : including couplings, tees, elbows, wyes, plugs, unions, nipples, pipe caps or reducers
B
Flanges : all flanges
C
Valves : all line valves
D
Expansion joints, flexible connections, and hose assemblies : all types
E
Strainers, filters, separators and steam traps
F
Measuring devices : including pressure gauges, level gauges, sight glasses, level and pressure transmitters
G
Certified capacity-rated pressure-relief devices acceptable as primary overpressure protection on boilers, pressure vessels and pressure piping, and fusible plugs
H
Pressure-retaining components that do not fall into any of the above categories.

Additional notes:
Position 1:
-For Fittings, this position has a zero placeholder.
-For Pressure Vessels, this position is blank.
-For Pressure Piping, both positions 1 & 2 have a "P", such as PP2785.7
Position 2:
-For Fittings, this position holds the category of the fitting.
-For Pressure Vessels, it holds an assigned letter.
-For Power Piping, it holds a 'P', as noted above.
Position 8:
-See table below for each Jurisdiction's identification number/letter.
-For a Canada-wide registration, the user can place a 'C' here instead of listing all of the other jurisdictions. For example, for a fitting: 0A2548.2C.
-For certain categories of fittings, see comments entitled “Limited CRN Registration” relating to how to handle the fact that BCSA & Saskatchewan will not register these categories of fittings.

The acronym 'CRN' stands for: Canadian Registration Number. This number is issued by a Canadian Jurisdiction and covers either pressure vessels, fittings, or pressure piping. It is a necessary authorization allowing these components to be in operation in Canada. The Canadian standard B51 defines it as having the following features:

