CSA B51 Issues and CRN Registration
September 2, 2025
Cammar Corporation can provide on-site CRN support for both short and long term engagements. Clients choose this option when they require an expert to provide assistance throughout the CRN acquisition process on multiple products and/or pieces of equipment. With our experience on both sides of the CRN process (applicant & regulator), Cammar can give you significant cost savings and higher CRN acceptance than from doing it on your own.
Many times, clients are already using equipment or products within Canada, despite changes in regulation that may or may not have altered the validity of past CRN requirements. Sound confusing? It can be. But with an on-call CRN advisor available to your organization, you prevent potential risk of a costly audit, or fines for using non-approved pressure vessels. Our services are cost effective and convenient. Give us a shout and let us guide you through any CRN pitfalls and regulatory changes.
To get a CRN number registration for pressure equipment, it can be challenging if you haven’t done it before, and the correct steps need to be followed. If you instead just want to do a CRN number lookup or CRN registration search so that you can just buy some equipment without registering any with a CRN, then beware and read this before you do anything else. For this article I’m going to assume that no exemptions to CRN registration requirements apply to your pressure equipment, that your company has an appropriate quality control program in place, and that your company wants to venture into the Canadian market.
Below the term ‘controlled document’ is used frequently, and it means a numbered document with a revision number.
The list below should give you a flavor of what is involved with getting a CRN number. Obviously all details can’t be included here and every situation is slightly different, but this primer is a good start if you haven’t obtained a CRN number registration. And even if you have, you might well pick up some good pointers about how to proceed. How to get a CRN does involve the application of engineering except in the very limited situations where a fully prescriptive standard is used. It’s not a paper pushing exercise.
Select an adopted code or referenced standard of construction for the design you want to get CRN registration for. This is not optional:
Decide on the code of construction or standard that you want your design to follow. As described in CSA B51, ASME codes and standards are the most common ones applicable to, and used by, Canadian regulators. All regulators refer to CSA B51; some adopt it without modification. Others publish documents that adjust its requirements for their jurisdiction.
The importance of properly selecting a code or standard of construction as the first step cannot be over emphasized. There are advantages and disadvantages to each code and standard.
The code or standard that you select is the very first thing that regulators will consider when reviewing your design for CRN registration. It must be stated on a controlled document included with the design. A good place to note the code of construction would be on the general arrangement drawing of interest. The year of the current edition must be noted on a controlled document; referring to the ‘current edition’ in a note is not specific enough.
Not all types of pressure equipment are always registered to the same code or standard. For example: if your equipment is a vessel, then ASME Section VIII-1 or ASME Section VIII-2 are options to consider. ASME Section VIII-1 is easier to use. Small vessels can occasionally be registered to ASME B31.3 requirements in some instances. Valves can be registered to ASME B16.34, and also ASME B31.3 or B31.1. Flanges can be registered to ASME B16.5, ASME B31.3 or Section VIII-1 Appendix 2. If your equipment is a pressure fitting, then common code options are ASME B31.3, ASME B31.1 and even ASME Section VIII-1. Etc. There are numerous possibilities. Referenced standards can also be used for fitting CRN designs and these are listed in Table 326.1 and Table 126.1 of the ASME B31.3 and ASME B31.1 code books. There are many standards to consider in each; some are not published by ASME though many are.
Make sure that the code or standard you choose is appropriate for your design, and that your design meets all of its requirements. Requirements from different codes or standards cannot be cherry picked; all requirements of a single chosen code or standard must be met for a proper CRN registration.
Unlisted standards and codes are often acceptable provided that all adopted codes and referenced standards, like those noted above, do not address your design requirements. If unlisted codes or standards are used, then they must follow the same engineering philosophy as detailed by the adopted codes listed in CSA B51 and the standards they reference.
Please note that whatever code or standard of construction is selected, it must address all aspects of the equipment design, construction, testing and examination else another, more encompassing standard or code must be referenced. For example,
Codes are generally less specific and prescriptive than standards, more inclusive than standards are, and always require the application of engineering judgement for proper use. Many standards are not particularly prescriptive either and thereby also need the application of engineering for proper use.
Select the maximum design pressure and coincident maximum temperature that the design will *ever* operate at, even with an operation excursion. This is not optional:
All design pressures and corresponding temperatures that the design will be subjected to should be noted on a controlled document included with the design.
If you selected a standard of construction that explicitly lists design pressure and design temperature pairs for a particular material, like the tables in ASME B16.5 or B16.34 for instance, then *all* design pressure and design temperature pairs for that pressure class and material should be explicitly noted on a controlled document included with the design. Explicit notes of the specific design pressures and design temperatures included with that standard are required; a reference to a standard alone is insufficient. Regulators do not want anyone that’s reading a drawing to need to go and search for a referenced standard in order to determine what the design temperature and pressure is supposed to be.
If your design is not meant to operate at all applicable pressures and temperatures as listed in the selected referenced standard of construction (see step 1) then, since the requirements of the standard are not met, then go back to step 1 since either another standard or (more likely) a code of construction needs to be selected in place of the standard.
Select the minimum design metal temperature (MDMT) that the design will ever be at when subjected to internal pressure. This is not optional. Canada has a cold climate, and even close to the border with the United States, temperatures of -40C are not uncommon in the winter.
Some codes and or standards require that a minimum design metal temperature be selected. Others, like ASME Section I for power boilers, do not; after all, water boilers don’t operate at temperatures below 0C. Regardless, in Canada where it can easily reach to -40C every year, brittle transition temperatures of metal need to be taken into account. It is good engineering practice to stipulate the minimum design metal temperature of a CRN design, to clarify the design limits and to avoid any misunderstandings. The MDMT should be noted on a controlled document included with the design.
Materials used to contain pressure must be carefully selected, accounting for their strengths at pressure and temperature, together with the requirements of the code or standard of construction that has been chosen.
Ideally, only materials explicitly listed in the chosen adopted code or referenced standard are selected. Allowable strengths are thereby often prescribed by the code or standard or, if not, a reference to another code or standard that includes the allowable strengths is often given.
Unlisted materials must be considered in accordance with each adopted code and referenced standard requirements. Standards often do not allow for unlisted materials to be used. Adopted codes vary in how unlisted materials can be considered.
For example: ASME Section VIII-1 basically only allows materials that it lists to be used and effectively does not allow unlisted materials to be used. ASME B31.3 and B31.1 allow unlisted materials, provided published specifications documenting the chemical and physical properties of the materials are available at ambient and design temperatures. ASME B31.1 requires written permission and acceptance from the end user to use unlisted materials.
Decide on how pressure parts are to be connected, to contain pressure.
Canadian regulators are interested in the details of all pressure parts, and this includes how they are connected together. A pressure part can be thought of as a component that, if removed from the design, will result in a reduction in strength of the pressure boundary. And of course, of interest is how all the pressure parts are connected together.
Are welds to be used? If so, make sure your welding procedure specification (WPS) and procedure qualification records (PQRs) comply with your quality program manual, the code or standard of construction, and with ASME Section IX requirements.
Dimensions of all welds connecting pressure parts need to be clearly noted on a controlled document.
Are threads used to connect the pressure parts? If so, the type of threads must be properly noted on a controlled document.
Various codes and standards have different rules about which threads can be used, when threads can be used, and how they can be used. Most common threads used in Canada will comply with either ASME B1.20.1 or ASME B1.1. If other threads are proposed, then dimensions and detailed drawings of the threads will likely be required.
Straight threads (non-tapered) will obviously need a gasket to effect a seal and, of course, the gasket detail needs to be noted on a controlled document.
Code and standards require that the minimum design metal temperatures proposed for the selected materials and welds are properly considered.
Various codes and standards have different impact testing requirements.
For example, ASME B31.3 and ASME Section VIII-1 set out clear parameters as to when and how materials and welds are to be impact tested, including the number of samples and the energy that must be absorbed at minimum temperature.
Referenced standards usually point to the referring code for guidance on what MDMT (minimum design metal temperature) is permissible beyond those that a standard lists. In some instances, the referring code does not permit the minimum design temperature proposed by the referenced standard, unless impact testing is performed. In other instances, colder temperatures than what is listed in a standard is desired.
If a standard does not include a proposed MDMT, the referring code should be used as the code of construction and the MDMT must be justified using code rules. Occasionally, impact testing should be specified even if codes and standards do not require it. See this for more.
Again, different codes and standards have different requirements. Make sure your design meets the requirements and acceptance criteria of the construction code or standard that your design follows. For example: ASME B31.3 designs require that 5% of circumferential welds are randomly radiographed or ultrasonically tested with satisfactory results meeting the acceptance criteria that the code describes. ASME Section VIII-1 has various options about how much non-destructive testing is required, and required thickness calculations are affected by it. Even some standards require non-destructive examination. For example, to achieve higher design pressures, ASME B16.34 requires radiographic or ultrasonic examination for valves pursuant to special class ratings.
In all cases, the amount of non-destructive examination to be used must be noted on a controlled document describing the design. If the design is exempt from non-destructive testing on the basis of code or standard requirements, then an exemption is to be noted instead.
For designs that use welding, the time and temperature of the pre and post weld heat treatment needs to be noted on a controlled document. Pre and post weld heat treatment is a design condition, and needs to be properly considered.
Code and standard requirements vary somewhat and, if weld heat treatment is not required by the code or standard of construction, then a note explaining what code based or standard based exemption rule that applies needs to be included on a controlled document.
Pressure boundary thickness requirements are governed by the referencing code, and the thickness selected requires justification. There are tpically three ways of design justification, in order of regulator preference: i) code design rules; ii) proof testing; and iii) FEA analyses. Regulators strongly prefer the use of code rules if applicable. There are few situations where code rules are inapplicable and if they truly are inapplicable, then with regulator permission, proof testing may be used. Proof testing is typically done in accordance with ASME Section VIII-1 paragraph UG-101. And as a last alternative, in the event that proof testing is infeasible or impossible for some reason acceptable to the regulator, then the regulator may grant permission to justify a design using an FEA model that is both verified and validated in accordance with CSA B51 Annex J.
Though you can apply to get a CRN number by documenting your CRN design and submitting the appropriate application forms to the regulator in the province or territory where the equipment will be used, regulators can simply reject your CRN design registration application if they are not satisfied that the design meets the requirements of the jurisdictional regulations, adopted codes, and referenced standards.
And, … though regulators must tell you why a design doesn’t meet their requirements, they cannot tell you how to fix a deficient CRN design, since that would put them in a conflicted position. Afterall, they can’t properly accept a CRN design that incorporates their own advice.
But that’s where we can help the most. We can assist you in revising your designs, pursuant to acquiring a CRN.
Though regulators control the CRN registration process, they don’t control your design. As the owner, you care about and control your design.
Each province and territory has rules in its jurisdiction, which must be met. If some jurisdictions have tougher requirements than others, it’s thereby best to apply to the toughest jurisdiction first. For more about how and why to get a CRN, read this.
We’re here to help. Give CAMMAR a call.
If your equipment requires a Canadian Registration Number, you must apply for the CRN before the pressure equipment can be installed and used in Canada. In fact, it is wise to complete your CRN registration before the pressure equipment is in the final stages of design (i.e. before the equipment is built). This will ensure that you follow CSA B51 and other regulations without issue.
In any case, to avoid unnecessary complications, make sure that your CRN registration is completed before any assembled equipment leaves the producer. If the equipment will not be assembled until after it leaves the manufacturer (e.g. the equipment must be assembled in the field), be sure the design has a Canadian Registration Number.
Determining the kind of CRN number you need is not simple!!
There are few underlying questions you’ll need to answer first, including:
Do you have questions? Ask away! We are here to help!
Give us a call.
Pressure equipment, including pressure vessels, boilers, piping and fittings, used in Canada requires a CRN registration. Equipment must be registered with a CRN before it is used.
In general, if pressure equipment operates at a pressure greater than 15 PSIG it will likely require a CRN registration. In fact, unless a particular exemption applies to the equipment, a Canadian Registration Number is needed.
Keep in mind, provincial and territorial governments have the authority to govern equipment safety in their region. Therefore, CRN registration requirements vary by province and territory. As a result, CRN exemptions are set out by provincial and territorial governments.
It’s the law, in Canada.
Canadian Registration Numbers (CRN numbers) identify unique pressure equipment design concepts for use in Canada, and must meet requirements, in accordance with Canadian statutes and regulations. Canadian law references CSA B51.
Each design concept has a unique CRN number. One Canadian Registration Number can represent millions of individual items, each with a different serial number, that all conform to the CRN design.
Though each provincial jurisdiction has responsibility for the safety of pressure equipment within its borders, Canadian provincial regulatory authorities have cooperated to help ensure CRN numbers are tracked nationwide, and identifiable across provincial boundaries. CRN numbers are required to be stamped on equipment or, in the case of very small fittings, trackable with other identification markings.
CSA B51, the Canadian “Boiler, Pressure Vessel, and Pressure Piping Code”, describes the required rules of CRN use in detail. Part 1, Clause 4 specifies that pressure fittings, pressure vessels, and boilers are assigned CRN numbers with the acceptance of regulatory authorities in provinces where the equipment is to be used.
Vessel and boiler CRN numbers never start with a “0”. Fitting CRN numbers always do.
All CRN numbers have a decimal point that follows the prefix assigned by the regulatory authority.
For fittings, the letter following the “0” in the prefix corresponds to CSA B51 Table 1, and is used by regulatory authorities at their discretion to categorize the fitting according to type:
Subsequent characters in the prefix that precede the decimal, are sequentially assigned by the regulatory authority. For some fitting categories, five digits follow the letter noted above that precede the decimal. For vessels, an alphanumeric (unless the registration is really old) and four digital characters precede the decimal. Following the decimal, the geographical region in which the design was first registered (the originating jurisdiction) is identified with a character listed in Clause 4.3.2.:
1 British Columbia
2 Alberta
3 Saskatchewan
4 Manitoba
5 Ontario
6 Quebec
7 New Brunswick
8 Nova Scotia
9 Prince Edward Island
O Newfoundland
Y Yukon
The prefix, decimal, and character after the decimal identifies a unique design.
To indicate all of Canada, the letter “C” is subsequently used. To indicate all regions in Canada which require registration, the “CL” is used.
Subsequent digits identify other regions in which the design has been registered, in no particular order.
Here are some examples of CRN numbers:
Fitting CRN registrations expire 10 years after the originating registration, and can be renewed before expiry. For example, if 0A.12345.132 was first registered in British Columbia on Jan 31, 2018, and then on in Alberta on March 23, 2019 and Saskatchewan on Aug 19, 2024, then the registration for all three jurisdictions will expire on Jan31, 2028 unless it is renewed in British Columbia before then. Renewal would need to occur in the originating jurisdiction (British Columbia) first and prior to February 1, 2028/ Other jurisidctions can renew the CRN after British Columbia, and not before.
Vessel CRN registations never need renewal.
If the code or regulations become more stringent after registration, then those that have care and control of the design and / or related equipment need to ensure that the registration is revised to meet the new requirements in accordance with regulatory requirements.
Give Cammar Corporation a call to discuss any CRN requirement questions that you might have!
Per ASME Section VIII-1 Appendix 3, MAWP (maximum allowable working pressure) is “the maximum gage pressure permissible at the top of a completed vessel in its normal operating position at the designated coincident temperature for that pressure. This pressure is the least of the values for the internal or external pressure to be determined by the rules of Division 1 for any of the pressure boundary parts, including static head thereon, using nominal thicknesses exclusive of allowances for corrosion and considering effects of any combination of loadings listed in the code that are likely to occur at the designated coincident temperature.“
Per ASME Section VIII-1 Appendix 3, design pressure is “the pressure used in the design of a vessel component together with the coincident design metal temperature, for the purpose of determining the minimum permissible thickness or physical characteristics of the different ones of the vessel. When applicable, the static head shall be added to the design pressure to determine the thickness of any specific zone of the vessel.”
A generic CRN design describes variable dimensions, materials, and feature locations of pressure equipment. For example, a generic vessel CRN design can generally describe a variable shell length, all possible nozzle locations and sizes, together with proximities of nozzle groups etc.* For vessels, generic designs cannot vary the head shape, shell diameter, maximum pressure, maximum temperature, or minimum temperature. For generic fittings, many options are allowed, generally enabling you to register a whole series of fittings with one generic drawing specifying a range of dimensions, materials, and even design pressures.*
*Each situation is somewhat unique and requires careful consideration. Other restrictions may apply subject to regulator acceptance.
Alberta Regulation 49/2006 defines it as “a vessel in which steam or other vapour may be generated under pressure or in which a liquid may be put under pressure by the direct application of a heat source.” Other legislation and code define it in similar ways. CSA B51 Boiler, Pressure Vessel and Pressure Piping Code, defines it as “as a vessel under the Act”. By ‘Act’, CSA B51 refers to the governing statute in each provincial or territorial jurisdiction. For all boilers registered with a CRN in Canada, in the absence of a Variance issued by the jurisdictional regulatory authority, the requirements of ASME Section I must be met in its entirety.
Alberta Regulation 49/2006 defines it as “a vessel used for containing, storing, distributing, processing or otherwise handling an expansible fluid under pressure.” Other legislation and code define it in similar ways. CSA B51 defines it as “a closed vessel for containing, storing, distributing, transferring, distilling, processing, or otherwise handling a gas, vapour, or liquid.” In Canada, pressure vessels must be designed in accordance with the ASME Boiler and Pressure Vessel Code. For non-nuclear equipment, the ASME Rules for the Construction of Pressure Vessels must be met in their entirety. For all pressure vessels registered in Canada, in the absence of a Variance issued by the jurisdictional regulatory authority, either ASME Section VIII-1, Section VIII-2, or VIII-3 must be met. Unless explicitly permitted by regulators, mixing code requirements into a single design is not permitted.
CRN stands for Canadian Registration Number. It is assigned to pressure equipment in Canada by provincial regulatory jurisdictions. Unless exempt from CRN registration , all pressure equipment must be registered with a CRN before use in Canada. It is not the same as certification markings such as CSA, UL, FM, Intertek etc.
Cammar Corporation is the combination of engineering experiences extending back to 1989. It’s Director, Cameron Sterling, MSc, PEng, worked on staff at ABSA, the CRN regulatory authority in Alberta, as a Safety Codes Officer evaluating CRN designs. The company has a solid foundation based on honesty, service, unyielding perseverance of quality and safety, proficient regulatory and technical expertise, thoroughness and practical experience. Cammar is licensed to practise professional engineering in Alberta, Saskatchewan, & Ontario.
