Cryogenic Equipment ASME Standards

Some customers request that their equipment meet ASME code or standards, but what does that really mean? ASME defines standards as a set of “technical definitions and guidelines” that can become the ‘how to’ on building something. Standards are considered voluntary; there is not a law that says you must follow the standards. If it is adopted by a government body it can be considered a code according to ASME. Firms and even some states/provinces (like Kentucky and Washington DC) specify ASME codes as a requirement in cryogenic systems.

Two common cryogenic equipment codes are the ASME Boiler and Pressure Vessel Code (BPVC Section VIII) and the Pressure (process) Piping Code (ASME B31.3). Certification stamps are available for some standards like BPVC, they indicate compliance and an acceptable quality program to maintain it. For other codes, like ASME B31.3, certification stamps are not used and it becomes more complex and a little more self-regulated.

Ultimately the owner has the overall responsibility for code compliance per ASME B31 code. Tasks for a piping system may be divided among different parties; for example a designer may specify the piping requirements, the manufacturer may make the pipe, and someone else may install the system. Technifab can follow the standards for the pipe in a system, but if the sections of pipe are welded together onsite then those joints and welds also need to be to be made to ASME standards.

The standards are very long (BPVC is over 700 pages and B31 over 450 pages) and following the process correctly can be arduous. A sampling of requirements:

Design Requirements

  • Designed and signed off by a code compliant pipe designer.
  • Wind and earthquake loading factored into the design.
  • Design uses customer thermal cycles in the product life calculations.

Build Requirements

  • Physical pressure testing of components.
  • All valves meet ASME seal retention requirements.
  • Material traceability for all materials subject to pressure.

Assembly/Inspection Requirements

  • Any welds done by ASME certified welders.
  • System relief valves properly sized and routed.
  • Documentation available for 7 years.

With these and other complex requirements it can be tempting for some manufacturers to not fully comply with all of the requirements. Material traceability is perhaps one of the more challenging aspects: the standard specifies that material composition be known, who produced it, and when the materials used were made for seven years after making it. The process then goes beyond that to include how it is made. Technifab uses ASME certified welders and if it’s made on an automatic weld machine an ASME certified weld operator. Quality and inspection records also have to be recorded and saved.

Technifab is proud to be able to build to ASME standards, have National Board of Boiler and Pressure Vessel Inspectors certification, and now have Canadian Registration Numbers (CRNs) for many of our products. We can also provide installation services if needed.