When Is a CRN Required in Canada?

Reviewed by CRN expert team · Last updated: October 2, 2026

CRN registration is required whenever a pressure-containing component exceeds the pressure and volume thresholds defined in CSA B51 and provincial regulations. Kopfkino Consulting provides compliance reviews to determine whether your specific equipment requires registration.

Equipment Categories Requiring CRN

• Pressure Vessels: tanks, separators, heat exchangers, reactors
• Fittings: valves, flanges, pipe fittings, expansion joints, strainers, filters
• Piping Systems: interconnected piping assemblies above thresholds
• Boilers: steam generators and hot water generators above threshold conditions

The four categories share one test: whether the component contains pressure above the applicable threshold. A tank, a valve, a piping assembly, and a boiler look nothing alike in a plant, but each is assessed the same way, by its design conditions and the rules of the jurisdiction where it will be installed.

Pressure and Volume Thresholds

Registration thresholds are set by each jurisdiction. In Ontario, for example, O. Reg. 220/01 s. 2(2)(d) excludes a pressure vessel, fitting or piping containing a gas, vapour or liquid at a maximum allowable working pressure of 15 psi (103 kPa) or less. Other provinces add volume or diameter limits, so check the rules where the equipment will be installed.

Because thresholds are set by each jurisdiction, the answer for identical equipment can differ between provinces. The practical approach is to fix the installation list first, then test the design conditions against the rules of each destination, recording the basis for every conclusion reached.

Common CRN Exemptions

• Small bore piping: NPS 3/4 or less is generally exempt in most provinces
• Low-pressure storage tanks: atmospheric or low-pressure tanks below threshold
• Portable fire extinguishers
• Equipment designed for private residential non-commercial use

An exemption is a conclusion to confirm, not an assumption to make. The exemptions in this list apply generally rather than everywhere, and some provinces apply stricter rules for certain fluid services, so each conclusion is confirmed for the jurisdiction where the equipment will be installed and its basis is recorded.

Related In-Depth Guides

• What Needs a CRN in Canada? Boilers, Pressure Vessels, Fittings and Piping Above 15 psi
• Fitting CRN Registration in Canada: CSA B51 Categories A-H and Provincial Exemptions
• Does My Skid Need a CRN? Pressure Equipment Skids in Canada

Frequently Asked Questions

Does small bore piping always avoid CRN?

In most provinces, NPS 3/4 and under piping is exempt. Alberta (ABSA) has stricter rules for certain fluid services. Always confirm with a P.Eng. review.

"The threshold question sounds simple, but provincial exemptions do not line up neatly. We have seen manufacturers register equipment they did not need to, and far worse, skip registration on piping assemblies that clearly qualified."