What is MAWP?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.“
What is design pressure?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.”
What is a generic design?A generic design describes variable dimensions and feature locations of pressure equipment. For example, a generic vessel design can 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. Other restrictions may apply subject to regulator acceptance.
What is a boiler?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.
What is a pressure vessel?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.
What is a CRN?CRN stands for Canadian Registration Number. It is assigned to pressure equipment in Canada by provincial regulatory jurisdictions. Unless exempt from 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.
What is B31.3?B31.3 is the ASME (American Society of Mechanical Engineers) code for process piping. This code outlines the requirements for materials, design, fabrication, assembly and erection of piping systems. The proper examination, inspection, and testing of piping is also covered by B31.3. The piping systems governed by this code include those that contain fluids. Typically, these piping systems are found in:
- • Petroleum refineries
- • Chemical plants - applies to the piping of raw, intermediate, and finished chemicals
- • Pharmaceutical plants
- • Textile plants
- • Paper plants
- • Semiconductor plans
- • Cryogenic plants
- • Processing plants, etc.
What is B31.1 piping?B31.1 is the ASME code for power piping. B31.1 was developed by the American Society of Mechanical Engineers (ASME) and is used worldwide. This code outlines proper methods for the installation, inspection, and maintenance of power piping systems. ASME B31.1 also provides requirements for the operation, design, materials, fabrication, erection, and testing of piping systems. The piping systems governed by this code are commonly found in:
- • Stations generating electric power
- • Industrial plants
- • Geothermal heating systems
- • Other heating and cooling systems
- • Manufacturers
- • Mechanical Engineers and Designers
- • Operators
- • Owners of piping systems, etc.
What is the difference between ASME B31.1 and B31.3?The biggest difference between ASME B31.1 and B31.3 is their requirements. In fact, although these codes are often used in conjunction, they vary significantly in their CRN registration requirements.
Some of the most common differences between ASME B31.1 and B31.3 include scope, allowable strengths, unlisted material specification, non-service hydro pressure testing, pneumatic pressure testing, service testing, alternatives to pressure testing, radiography and ultrasonic testing, minimum design metal temperature (MDMT) and impact testing requirements.
Although these codes differ extensively, equipment that meets ASME B31.1 and B31.3 requirements is possible to design and develop. Products that meet both standards can also receive CRN registration. The benefit of designing and registering equipment that meets all requirements is that it can be sold to a larger number of buyers.
What is the difference between ASME vs API?The difference between ASME vs API is that ASME standards hold more weight than API standards. That is, adherence to ASME standards is required for CRN registration. On the other hand, API specifications are only recommended practices. The ASME, or the American Society of Mechanical Engineers, provides codes that govern the safety of mechanical equipment. These codes are meant to provide overarching specifications for mechanical engineering applications. The API, or the American Petroleum Institute, on the other hand, produces recommended guidelines. In most cases, these standards are simply intended to encourage safety. Most commonly, these guidelines are directed at offshore structures that are used by oil and gas companies.
About Cammar Corporation
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, & Ontario.
- CRN Reconciliation, Harmonization, History, and Public Safety July 20, 2021
- Generic Designs Revisited March 17, 2021
- Revisiting Maximum Allowable Working Pressure & Design Pressure February 8, 2021
- API 6A Is Not The Same as ASME B31 January 6, 2021
- Valid Canadian Registration Number (CRN) Database and Directory Information June 8, 2020