ASME Stamp and Its Importance for Pressure Vessels

An ASME stamp or certificate communicates to authorities, customers, and industries that your business is dedicated to quality and safety. It also implies that your items are dependable, safe, and of excellent quality. That’s why pressure vessel products should be registered by a valid authority. Not only pressure vessels, but also pressure vessel accessories can be given ASME stamps. Three mains aspects stand out when we consider their importance for pressure vessels: 

  1. Reducing Risks: An ASME stamp is highly valued by insurance providers. Insurance companies generally refuse a claim if the vessel is not code-stamped. 
  2. Quality: Third-party inspections are performed before a pressure vessel acquires any kind of ASME stamp. Non-stamped vessels are only held to their own quality control requirements. 
  3. Safer Pressure Products: At high pressures, many pressure vessels contain potentially dangerous chemicals. Keeping their contents secure should be a primary priority of everyone who comes into contact with these vessels. An ASME stamp certifies that the tank containing these substances was correctly manufactured. 
Image of ASME stamp
Figure 1. Image of ASME stamp

Although there are many subcategories of ASME stamps, in this article, the three most commonly encountered ones will be explained. Also, additional information about U-Stamp will be given for further understanding. A person who is going to work with pressure vessels should have adequate knowledge about these certifications. Three pressure vessel certifications that are commonly used can be listed as follows:

1) ASME R Stamp

After an onsite assessment, the National Board of Boiler and Pressure Vessel Inspectors issues the R symbol stamp for the alteration and/or repair of pressure vessels, boilers, and other pressure-retaining equipment. The inspection may be done by a member of the National Board or a representative, depending on the jurisdictional requirements.

2) ASME S Stamp

ASME S is another significant ASME stamp that allows firms to build power boilers, power pipelines, and ASME Pressure Retaining Parts in accordance with Section I of the most recent copy of the ASME Boiler and Pressure Vessel Code.

3) ASME U Stamp:

The ASME U Stamp certifies that the pressure vessels follow ASME requirements for design, construction, inspection, and testing. It is used for pressure vessel certification and acceptance. The presence of the “U” sign on a product indicates that it complies with the most recent edition of the Code. It also confirms that the vessel was designed and constructed in under ASME specifications.

As said earlier, additional information about ASME U stamp will be given due to many reasons such as being a mandatory requirement in many countries and of most insurance companies dealing with this kind of pressurized equipment. ASME establishes stringent standards for pressure vessels to provide the utmost safety of life and property.

Stainless steel nitrogen tank, ASME U stamp is required for products like this tank
Figure 2. Stainless steel nitrogen tank, ASME U stamp is required for products like this tank

Manufacturers must comply with some strict rules in order to acquire this ASME stamp. Pressure vessels subject to ASME U stamp standards are especially examined by a third-party authorized inspector. The inspector must examine and approve the calculations. The National Board of Boiler and Pressure Vessel Inspectors appoints these inspectors. For the fabrication of ASME U stamped pressure vessels, such pressure vessel manufacturers must be registered with the National Board.

Here, an important question may arise. This question could be “Is ASME U stamping a compulsory requirement?”. The answer to this question is not so straightforward. In short, it is not mandatory in every case just like other ASME stamp categories. A particular company states if a pressure vessel it purchases must possess an ASME U stamp. On the other hand, because pressure vessels are used in a broad range of processes and conditions, it is critical to design and construct vessels of the highest possible level and quality. The ASME U stamp meets this criterion. Failure to get an ASME vessel can occasionally put the firm in jeopardy. In addition to this critical information, it is also crucial to note that any vessel carrying a pressure greater than 15 PSI is subject to the ASME Code and must be stamped or verified by the ASME. However, the type of this ASME stamp depends on multiple factors.

Sample nameplate for ASME certification
Figure 3. Sample nameplate for ASME certification

As it is mentioned later, pressure vessels must meet some items to obtain an ASME stamp. To make matters clearer, requirements that must be met for an ASME U stamp is listed as follows:

  • Before raw material can be used, it must meet detailed specifications
  • Weld materials must meet detailed specifications before they can be used
  • Welders must be ASME certified
  • Material thickness and tank calculations must meet ASME-controlled standards for the specific operating conditions.
  • A re-qualification audit is required every three years by a representative of the national board of pressure vessels.

The list above proves the strict approach for pressure vessel ASME stamp qualification procedure. So, it could be wise to know beforehand if a certain company has ASME stamp products by easily looking at a website that provides such information. One can easily find out whether a certain company is ASME certified or not. Click the link below to access this piece of information:

Read more:
ASME Stamps with Important Examples

For more information about Pressure Vessels, check out :
Pressure Vessels – Everything you need to know
Learn About Pressure Vessels: Production, Types and Uses


©[2019] Yena Engineering

Log in with your credentials

Forgot your details?