CRN 101


CRN stands for Canadian Registration Number and is issued by one of the provincial jurisdictions for a design that is submitted along with all the required proof of design and documentation according to their regulations and CSA B51 (Boiler, pressure vessel and pressure piping code).You can buy CSA B51 straight from CSA.

Pressure Vessel Engineering (PVEng) is an engineering firm that specializes in helping customers navigate the requirements for each province and type of submission. We ensure that the correct information is submitted to the required jurisdiction for the successful application and acceptance of your design and that you receive your CRN.

The information provided on our website is for reference only. Due to changes in interpretations some information may be out of date. Current jurisdiction rules and requirements should always be checked before submitting your application for CRN Registration.

Items that apply to all types of registrations

  • Harmonized CRN program is a work in process and has not been fully implemented. More Information on Harmonization.
  • All designs must be proven to one of the ASME codes regardless of the original code of design No other codes (EN, PED etc.) are accepted in Canada. (see note in fittings for one exception).
  • Every province has regulations that use their own interpretation of CSA B51 and may override the CSA code. It is critical that the provincial regulations are reviewed for the system and/or vessels to determine registration requirements.
  • Every submission must include proof of a quality control program. These are explained further in each of the categories below, but this is a critical part of the submission process.
  • There are three types of CRN available: Vessels, Piping and Fittings. These are explained in detail below.
  • CRN approval is completed in one province first. If additional provinces are required, then the initial acceptance can be sent to all additional provinces simultaneously and they will review and add their provincial number to the CRN number as acceptance. This would be a reciprocal CRN. Guide to CRN Numbers.


  • Vessels classified as ASME pressure vessels must be designed and calculated to the ASME code. Vessel or Fitting?
  • All ASME pressure vessels must be stamped with the appropriate ASME code mark and be registered with the National Board. CSA B51
  • Most provinces require a Professional Engineers (P. Eng) stamp on vessel drawings and calculations. A Professional Engineers stamp from anywhere in North America is accepted in most provinces. Ontario is the only province that states it must be an Ontario P. Eng.
  • Once a vessel is registered it can be built as many times as required in the registered province until the design is changed or an ASME code change makes the design invalid. There is no specific expiration date. CSA B51 4.1.2


  • There are multiple categories of fittings and each must be registered separately. CSA B51 4.2.7
  • Here is the list with the fitting categories explained. Fitting Categories Explained.
  • Category H can also be a small pressure vessel under some circumstances or a collection of piping components provided none are greater than 6” and the total volume is less than 1.5 cubic feet. Fitting Categories Explained.
  • All fittings purchased to assemble Category H fittings must have valid CRN’s for the province of registration regardless of the design, manufacturer, or code. This is critical for pipe fitting registrations.
  • Fittings can be registered with an ASME or an ISO certificate. The QC must cover the scope of the registration. For example, the QC certificate must include fabrication if that is required to produce the component. A QC certificate that includes strictly design would not cover welding or assembly.
  • Fitting registrations include a notarized statutory declaration. This includes the drawing number, what is being provided for proof of design (calculations, burst test, etc.), as well as the manufacturers QC certification and the logo or icon that will be used to signify the CRN on the fitting.
  • There is a stipulation for someone other than the manufacturer to accept responsibility for the design. However, the following must be observed “The organization responsible shall provide a statutory declaration form and evidence of a valid quality control program acceptable to the regulatory authority in the province where the registration is sought. The manufacturer(s) shall be identified, and proof of their quality control program(s) shall also be provided.” CSA B51 4.2.
  • In some very specific cases UL certification may be used for fitting registrations. However, specific requirements must be met and testing procedures followed. These are not as straightforward as standard fitting registrations.
  • Fitting CRN’s are valid for 10 years from the original acceptance date provided the design does not change and the quality program used to register the design is kept current. When the expiry date is approaching the manufacturer can apply for a renewal.
  • There are some provinces that exempt certain categories of standard ASME fittings, but this must be determined on a case-by-case basis. “British Columbia, Manitoba and Saskatchewan have declared categories A, B, C exempt from registration provided they are designed to standards listed in Table 126.1 (B31.1), Table 326.1 (B31.3), Table 526.1 (B31.5) or Table 926.1 (B31.9). Category G is also exempt from registration if designed to ASME or National Board. Quebec has exempted Category A, B and C from registration when used in piping systems. Other provinces still require these items to be registered. See provincial regulations for more details” Provincial Contacts and Requirements.
  • SUBSECTION under fittings “notes about standard fitting registrations”
  • Standard ASME fittings such as B16.34 valves and B16.5 flanges do not have to be “proven” but they do need drawings that show all critical dimensions as well as having the materials listed. This will verify that all aspects of the design are in compliance with the code of construction. CSA B51 4.2.8 (a)
  • PVEng’s role in fitting registrations includes consultation, design review, and submission. The provincial jurisdictions require all submissions to be compliant with the applicable codes and we perform a review to confirm this. The amount of time required for our review depends entirely on the scope of products being registered.


  • It is important to review the provincial regulations for piping as the differences can be substantial. Piping Registration Requirements.
  • CRITICAL – All purchased fittings used in piping systems must have valid CRN’s from the manufacturer for the province of registration regardless of the design, manufacturer or code. CSA B51 8.2. This is crucial for pipe fitting registrations and is often the most difficult part of a piping registration. Canada registers all fittings used in pressure systems including small pipe fittings (elbows, tees reducers etc.) as well the standard ASME flanges, valves, filters etc. (see fitting section above for more information and possible exemptions)
  • There are two types of piping registrations. Category H for assemblies less than 1.5 cubic feet (see fitting description above) and piping registrations for system larger than 1.5 cubic feet.
  • Piping registrations are tied to an actual address and cannot be built multiple times like vessels or fitting CRN’s allow.
  • There are very specific PRV requirements in many provinces, specifically Alberta.
  • Pressure vessels and heat exchangers are not considered as part of the piping system and must be registered separately by the manufacturer and have their own CRN numbers. They are not included as part of the calculation of volume for the piping system.
  • Sample and explanation of various documents included with piping submissions.

Used Vessels

Used vessels present unique challenges as we are tasked with proving that the vessel condition is still sufficient to pass the code requirements for the original pressure and temperature ratings.

The first determination is whether the vessel requires Ultrasonic Testing (UT) to determine the level of corrosion. This is not typically required for stainless steel vessels but the final decision would be made by an Authorized Inspector (AI). This Authorized Inspector must be from one of the Canadian provincial jurisdictions or be registered with the National Board. If the vessel is not able to be inspected the UT testing may be done as a precaution. If we run ASME calculations based on the original drawing and then the AI decides it needs to have UT at time of inspection, then the calculations will have to be updated based on the test results.

The documentation required for used vessel registration is as follows:

  • The original U1-A form that was completed and signed by the National Board (NB) inspector at the time of fabrication. This form is often available from the national board if you have the original NB number from the nameplate.
  • Ideally the original drawing of the vessel if available. If not available, a drawing will need to be created. This will include using the U1 for reference and additional inspection. For example, radiography and physical measuring and inspection to verify the weld sizes, nozzle thickness and elevations/orientations etc.
  • If the original calculations are available, they can be reviewed and used as reference for the CRN registration.
  • If the original calculations are not available, new calculations done to the original code of design can be run. This would also reflect the minimum wall thickness from an ultrasonic test report if applicable due to corrosion.
  • If the nameplate is missing from the vessel then it is very difficult to register even with the U1 and the original drawing. Without the nameplate it must be proven that the drawing and the U1 match the vessel. This involves much more testing (i.e., Radiography, PMI (Positive Material Identification), Magnetic Particle Inspection etc.). Often the cost and time to prove a design without a nameplate negate the value of registration except on very valuable designs.

In Canada vessel registrations require an ASME U stamp as well as NB registration for acceptance. These requirements are the same for used vessel registrations.

Required submission documents for each type of registration


  • Copy of ASME U Stamp certificate
  • Drawings showing design, materials, weld details, design code, etc.
  • Proof of design as required i.e., calculations, FEA, proof test etc.


  • Valid QC certificate (typically ISO or ASME)
  • Statutory Declarations
  • Drawings showing design, materials, code of construction, etc.
  • Proof of design as required i.e., calculations, FEA, proof test etc.


  • Valid QC certificate
  • P&ID
  • Line List including media and pressure and temperature etc.
  • List of fitting CRN’s used in piping system
  • Address of installation