Membrane Process & Controls proudly announces the successful completion of its ASME “U” and National Board “R” stamp recertification, demonstrating its continued commitment to excellence, quality, and compliance with industry standards. The audit concluded with no findings or deficiencies, and the auditor expressed high satisfaction with the effective implementation of MP&C’s Quality System.
As an ASME authorized designer and fabricator of pressure vessels, MP&C follows a strict set of requirements as documented in various sections of the ASME Code. MP&C is audited every three years by The National Board on behalf of ASME (American Society of Mechanical Engineers).
The ASME Boiler and Pressure Vessel Code was originally released in 1915 primarily in response to a number of deadly boiler explosions in the years leading up to the Code being issued. MP&C follows ASME Section VIII-1 for design and fabrication, ASME Section IX for welding, ASME Section V for Non-Destructive Examination, and Section II for material selection. MP&C is authorized for ASME “U” stamped vessels as well as National Board “R” stamp repairs.
ASME Code helps ensure pressure vessel safety by closely defining requirements in five key areas:
Design
With 110 years of engineering and experience built into the Code, there are very specific calculations and design requirements that must be followed when designing ASME pressure vessels. In the 2021 edition of the Code, ASME has also added specific qualification level requirements for the personnel who can perform calculations and other critical design functions. The qualifications are based on ASME design experience and technical education levels, with more experienced and more highly educated personnel being authorized to perform more complex vessel design compared to those with less experience and lower education levels. One of the fundamental underpinnings of ASME design is that the calculations and material allowable stress (strength) values used generally result in a design margin of approximately 3.5:1. In other words, while an ASME vessel can never be operated above its Maximum Allowable Working Pressure (aka pressure rating), theoretically, the vessel should be able to withstand a pressure of 3.5 times the rated pressure. This design margin (sometimes called a safety margin) accounts for deviations from perfection in welds, materials, or other factors and still results in a safe pressure vessel.
Materials
ASME has extensive controls over the specific materials that can be used as part of the pressure boundary of ASME-certified pressure vessels. By only allowing certain materials as certified by raw material manufacturers, ASME ensures that the materials have the proper chemical and physical characteristics required for safety. In addition to limiting the materials used in ASME pressure vessels, the Code also has detailed material traceability requirements to ensure that only proper materials end up being incorporated into the finished products.
Welding
The vast majority of pressure vessels are fabricated using a variety of welding processes. ASME Code requires authorized fabricators to have established Weld Procedure Specifications. It is also a requirement to perform and carefully document specific tests to validate weld procedures. Additionally, each person who welds on an ASME pressure vessel must undergo a qualification process, which again needs to be carefully documented and monitored.
Inspection
A variety of inspection methods and levels are used to confirm compliance with ASME Code requirements. Inspections can include basic “VT” or Visual Testing performed by a welder who completed a given weld. MP&C has a Quality Department that also performs inspections. MP&C is also required to have an agreement with an Authorized Inspection Agency (3rd Party), who comes on-site and reviews design, materials, and performs a variety of mandatory inspections. Some pressure vessel designs require welds to be x-rayed to ensure they are defect-free. In general, the more welds are x-rayed and confirmed to be defect-free, the thinner the materials can be on the pressure vessel. One of the most important inspections of an ASME pressure vessel is what is commonly referred to as “hydro-testing” of the completed vessel. During hydro-testing, the vessel is completely flooded with water and then pressurized to 130% of its maximum pressure rating. The vessel is filled with water for safety reasons. Since water does not compress nearly as much as air, there is much less potential energy stored within the vessel during this initial pressure testing. The 130% over-pressurization statically validates the pressure vessel’s ability to withstand its rated pressure. The 3rd Party Authorized Inspector is required to witness the hydro-test.
Record Retention
Like a variety of quality systems, ASME is generally based on following three basic steps:
- Say what you do (as documented in MP&C’s Quality Control Manual).
- Do what you say (follow the Quality Control Manual in your daily operations).
- Have documents to prove it (be able to provide objective evidence that work is being completed in accordance with the Quality Control Manual).
A large part of a successful ASME program is the ability to carefully control and be organized with a wide variety of documents. Drawings, calculations, Purchase Orders, Material Test Reports, Welding Documentation, Inspection Records, and Calibration Certificates are just some of the records that must be meticulously completed and maintained as part of an ASME Quality System. A disciplined approach to completing and maintaining such records is a cornerstone of an effective ASME Quality System.
The final quality record for an ASME pressure vessel is the Manufacturer’s Data Report. Each of MP&C’s ASME vessels is identified with a unique National Board number. This National Board Number is listed on the Manufacturer’s Data Report. This report contains critical technical details about the vessel and is, in some respects, a “birth certificate” for the vessel. This Manufacturer’s Data Report is then registered with the National Board. The National Board is a centralized location where most ASME Manufacturer’s Data Reports are registered by the company that originally fabricated the pressure vessel. The National Board also oversees the repair and alteration of any ASME pressure vessel after the vessel is originally certified by the fabricator. Regardless of where or how long a pressure vessel is operated, the owner of the pressure vessel can contact the National Board with the vessel’s National Board number and receive a copy of the vessel’s original data report.
In closing, ASME Boiler and Pressure Vessel Code is a long-standing technical standard specifically designed to help mitigate the inherent risks associated with pressurized equipment. With over a century of refinement, ASME Code has proven to be highly effective in ensuring pressure vessel safety. While many countries and regions have their own pressure vessel codes, ASME is the most universally recognized pressure vessel code in the world. Many other country-specific codes lean heavily on ASME as the basis for their pressure vessel code.
MP&C fabricates ASME-certified pressure vessels from stainless steel and a variety of higher alloys. We are eager to work with new clients who need ASME-rated pressure vessels.
Questions about ASME? Please reach out to Membrane Process & Control’s Director of ASME Products, Bill Wenzel. Bill can be reached via email at bwenzel@membranepc.com or by cell at 715.966.3430. Bill has nearly 30 years of experience with ASME pressure vessels, including positions as Designer, Quality Manager, Engineering Manager, VP Sales, General Manager, and Director.
