CRN 1

[valvespro]

Does anyone have experience at applying for a CRN (Canadian Registration Number) for Cat C valves that are B16.34 design but are made from a material that is not listed in B16.34?
I know that there are two options:
1) Burst Proof Test witness by Third Party
2) Detailed engineering Calculations

Question: What exactly do they mean by Detailed Engineering Calculations?

Thanks,

 

[rneill]

I'm assuming that these are flanged valves?

I don't think I would want to do burst testing so I think you have two options.

1. Compare your material to an existing code listed material similar but lower yield and tensile strength and then apply the ratings for that weaker material to your valve (in other words, assign it to the lower materials group). Note: you would need to consider the material properties at the required design temperature.

2. Complete detailed calculations on the pressure capacity of the valve body (based on body wall thickness), and any other aspects of the valve (including bolted bonnets and flanges) using appropriate design rules or FEA. Appendix B of ASME B16.34 would provide some guidance on how the ratings in the Standard were derived for the listed materials if you want to do calculations.

 

[valvit]

My guess is that you are dealing with ABSA, which can be quite a challenge.

ABSA is responsible for the administration and delivery of safety programs related to boilers, pressure vessels and pressure piping systems in the province of Alberta, Canada. In that ABSA's requirements are the most stringent in Canada, seeking a CRN issued through ABSA is often the best choice, because once you have an ABSA issued CRN, the submission to the remaining provinces can refer to the ABSA CRN. While the other provinces are not required to issue a CRN on this basis (because they have their own law) they often will defer to ABSA's rigorous requrements.

I've not personally submitted a valve design package that included materials that were not shown in ASME B16.34, but I did discuss the issue with them, and the outlook is not too promising. The issue at its core is that ABSA will not look past recognized codes when performing their survey of a design. It's important to note that "recognized code" are codes recognized by ABSA, no one else. For example, ASBA do not recognize ASME VIII Division 2, because it is alternate rules for pressure vessel design. I’ve submitted flange design calculations in accordance to 2007 ASME VIII D2 paragraph 4.16, only to have them rejected on the basis that D2 provides alternate rules which are not recognized by ABSA.

This being said, my advice to you, for you material selection, is to find an internationally recognized design code (that ABSA recognizes) that provides pressure and temperature ratings for your material selection. If such a design code does not exist, you will have to make a selection from ASME B16.34. If you do not, ABSA will continue to reject your design.

To your question regarding what is meant by “detailed engineering calculations”. In my experience with ABSA, since their charter is essentially to provide engineering survey of pressure vessels and piping systems, for the purpose of public safety, they are only concerned with pressure containment. They do not care a bit about valve performance, or leakage rates, or stem thrust/torsion, only pressure containment. So, the detailed engineering calculations you should provide are only those related to pressure containment. Wall thickness, bolting end-load, bonnet bolting, weldment design for fabricated products, etc. If your stat dec does not state full compliance to ASME B16.34, which yours may or may not, depending on your final material selection and the rest of your valve design, ABSA will require you to provide Finite Element Analysis of the pressure boundary (to prove your proprietary design), including all welded or bolted joints. If your design has a flanged connection, as in a bonnet flange, and that flange is not in compliance with ASME B16.5 or ASME B16.47, then the FEA will have to include the flange design as well. (Yes, this implies that ABSA expects bonnet flanges to meet ASME B16.5/16.47 because these are known and proven designs.) ABSA provides details on their requirements for FEA at the link provided below.

Good luck...

http://www.absa.ca/IBIndex/ib09-009.pdf

 

[ghillis]

May I ask what material you are working with? B16.34 is not the only code of construction that may be appropriate.

 

[valvespro]

Examples of materials would be:
A990-CN3MCu
B367-TITANIUM GR 2 , GR 3, GR 7B, GR 12
B752-ZIRCONIUM GR 702C, 705C

 

[hsbcn]

The alloys you mention are very rarely used, for example Titanium-Palladium 7, and if you go for 7B even less, or Zirconium. So, there's a cost factor which you will also have to bear in mind as you get your application processed, unless you're dealing with very high and regular volumes of valves in these exceptionally rare alloys.

Please share your findings.

My focus: Alloy Valves Duplex Valves Super Duplex Valves Monel Valves Inconel Valves [link titanium-valves.com]Titanium Valves[/url]

http://www.6-moly-valves.com

 

[mrpsi]

Valvespro,

For Detailed engineering calculations, you can either try to apply classical pipe-shell and nozzle area replacement calculations or the most robust method is FEA. One advantage that FEA has over burst testing is that you can cover multiple materials by running the weakest material in the analysis.

What is your Code of Construction? I assume you'll need to use B31.3 as an umbrella Code, which allows use of FEA per ASME VIII-2, and is acceptable by ABSA.

Can you get room temp and elevated temperature mechanical properties for these materials? You'll need to convert them to B31.3 material allowable stresses. If you can, then you're golden. Otherwise, as noted by others above, it will be a long and difficult battle.

Lot's more could be touched on, but basically once the materials are acceptable, FEA is used if needed to fill in the gaps in the Classical Code rules (when the configuration doesn't exactly correspond to the standard configurations). ABSA and TSSA will accept this approach.

 

[reichertc]

Sorry, late to the game here.

In order to entirely bypass ABSA approval, you may want to simply get the material added to B16.34/B16.5. I've done this in the past when I knew that an unlisted material was going to be needed on a regular basis. It can take a little while, I think it took me about 18 months, but in the end it will make life easier.

As a designer, this is my preferred option. A manufacturer may want to keep a material unlisted and qualify the valve for a CRN to retain a competitive advantage over competitors.

 

[mrpsi]

Hello Reichertc,

Wow, adding to B16.34/B16.5 sounds like a major undertaking and something that I've never envisioned.

However "in order to entirely bypass ABSA..." is not entirely correct. For a fitting complying with B16.34, ABSA will still want to verify that the manufacturer's quality system is suitable. Thus, it still needs to be registered with them, although their review would be very simple, and it would mostly be a paper exercise. Also, a large number of fittings can be registered simultaneously if set up properly.