How do I get a CRN number?

It Can Be Challenging. We Can Help.

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.

Crucial Steps

1 – Decide on the Code of Construction

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,

• Though a valve can have ASME B16.5 flanges, ASME B16.5 does not cover all aspects of valve design and so another more encompassing standard of construction like ASME B16.34 needs to be referenced for valves.
• If your valve uses materials that are not listed in ASME B16.34 or somehow does not otherwise meet ASME B16.34 requirements, then a more encompassing code of construction such as ASME B31.3 should be referenced instead of ASME B16.34.

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.

2 – Specify the Design Pressure and Temperature

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.

3 – Determine the MDMT (Minimum Design Metal Temperature) Required

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.

4 – Determine Material Selection

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.

5 – Decide What Connections to Use

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.

6 – Use Impact Testing When Necessary

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.

7 – Non Destructive Examination

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.

8 –Weld Heat Treatment

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.

9 – Pressure Boundary Justification

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.

And then, finally....

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.