Timetraveller007
Mechanical
We are running a compressor station design in Canada:
Per one of our purchase requirements:
CWB certification is required for structural skid, module, and building fabricators. However, equipment supports (vessels/compressors/pumps etc.) can be exempted from qualifying the welding of the structural component under the structural codes through the following clause from CSA W59-13:
1.2
This Standard is not intended to apply to pressure vessels or to structures governed by special codes such as those of the American Petroleum Institute, the American Society of Mechanical Engineers, or the American Water Works Association.
This is the typical method of exemption from CWB certification for most mechanical equipment baseplates/structural frames. In this case, the structural frame is similar to saddles for a horizontal vessel, where structural codes are not typically used. These are considered special applications.
API 661 section 7.3 for coolers states:
7.3.1.1. The structural code shall be specified or agreed by the purchaser .Structural steel design , fabrication and erection shall be in accordance with the structural code.
Our default here is to reference the Canadian structural codes to guide the application of seismic, wind, and other parameters required for the structural design under Section 7.3. API 661 relies on these codes for more general requirements, but still provides additional guidance in 7.3 which is specific to this application.
We request CWB certification and the application of the full structural codes in our scope of work wherever possible, but because this is a special API application and an elective application of the structural codes, we prioritize Vendor familiarity with the equipment type and allow some leniency with respect to welding certification where necessary. This is due to the similarities in the CWB and AWS welding codes and limited benefits of CWB certification. Cooler units specifically are often purchased from outside of Canada, where CWB certification is much less likely to be held.
We did not review both AWS and CWB requirements for this specific application, however we have compared them in the past. The primary difference in CWB certification is the oversight, inspection, and quality audits it mandates. This is something we typically see also being performed by the project/client, so the benefits of CWB certification on our projects are minimal.
With respect to the integrity of the weld itself, we have confidence that welds conducted to AWS requirements will perform sufficiently in the field and meet the requirements of equipment for our typical applications due to the near-equivalency of the two codes.
We do not anticipated any shortcomings. Do you think following AWS is enough for us ?
Please let me know if you have any comments.
Per one of our purchase requirements:
CWB certification is required for structural skid, module, and building fabricators. However, equipment supports (vessels/compressors/pumps etc.) can be exempted from qualifying the welding of the structural component under the structural codes through the following clause from CSA W59-13:
1.2
This Standard is not intended to apply to pressure vessels or to structures governed by special codes such as those of the American Petroleum Institute, the American Society of Mechanical Engineers, or the American Water Works Association.
This is the typical method of exemption from CWB certification for most mechanical equipment baseplates/structural frames. In this case, the structural frame is similar to saddles for a horizontal vessel, where structural codes are not typically used. These are considered special applications.
API 661 section 7.3 for coolers states:
7.3.1.1. The structural code shall be specified or agreed by the purchaser .Structural steel design , fabrication and erection shall be in accordance with the structural code.
Our default here is to reference the Canadian structural codes to guide the application of seismic, wind, and other parameters required for the structural design under Section 7.3. API 661 relies on these codes for more general requirements, but still provides additional guidance in 7.3 which is specific to this application.
We request CWB certification and the application of the full structural codes in our scope of work wherever possible, but because this is a special API application and an elective application of the structural codes, we prioritize Vendor familiarity with the equipment type and allow some leniency with respect to welding certification where necessary. This is due to the similarities in the CWB and AWS welding codes and limited benefits of CWB certification. Cooler units specifically are often purchased from outside of Canada, where CWB certification is much less likely to be held.
We did not review both AWS and CWB requirements for this specific application, however we have compared them in the past. The primary difference in CWB certification is the oversight, inspection, and quality audits it mandates. This is something we typically see also being performed by the project/client, so the benefits of CWB certification on our projects are minimal.
With respect to the integrity of the weld itself, we have confidence that welds conducted to AWS requirements will perform sufficiently in the field and meet the requirements of equipment for our typical applications due to the near-equivalency of the two codes.
We do not anticipated any shortcomings. Do you think following AWS is enough for us ?
Please let me know if you have any comments.
