ASME U Stamp: Everything you need to know (2024)

What is ASME U Stamp?

ASME U Stamp is a certification mark from the American Society of Mechanical Engineers (ASME).

A U stamp is applicable for pressure vessels fabricated according to the BPVC ASME Section VII Division 1. Details about ASME stamping method, nameplate information and data reporting are provided in ASME Section VII Division I, clause UG-118 to UG-120.

A U stamp is used to denote that pressure vessels and other products have been manufactured in accordance with ASME’s Boiler and Pressure Vessel Code.

The U Stamp specifically certifies compliance with Section VIII Division 1 (U Stamp) or 2 (U2 stamp) of the ASME Boiler and Pressure Vessel Code.

Those who become certified are required to submit documentation such as drawings, calculations, material test reports, inspection records and welding procedure qualifications so they can be approved for this certification mark.

Scope of U Stamp Certification

The U Stamp certification, which is issued by the American Society of Mechanical Engineers (ASME), sets forth requirements for materials, design and construction for any device or system that holds a pressure greater than 15 psi.

Following are the main scope of ASME U Stamp Certification:

1. Applicable for ASME Section VIII Pressure vessel construction.
2. General limits for design parameters: Internal or external pressure min. 15 psi (=1 bar) max. 3000 psi (=206.8 bar) Inner diameter or width: min. 6 in. (=152 mm) regardless of length.
   • Products:
     a) stationary pressure vessels,
     b) steam generators such as, evaporator–heat exchangers.
   • d) vessels for steam generation in process plants (chemical industry/petroleum industry).
   • e) directly fired vessels not covered by Sect. I, III or IV fall.
   • f) gas-fired jacked steam kettles.
3. Excludes:
   • Containers that fall within the scope of other code sections.
   • Fired process heaters.
   • Pressed parts in machines, as well as pumps, compressors, hydraulic/pneumatic, and Printing cylinders.
   • Piping and equipment. which are primarily intended for the transport of fluids.
   • Hot water tanks are indirectly heated by steam or other fluids if one of the limit values is exceeded: heating input=58.6 KW / temp.=99°C / volume=454 liters.
   • Tanks for water/water mixtures, if one of the following limits is not exceeded: P=20.7 bar / D=99 °C.

What does ASME U Stamp means?

The American Society of Mechanical Engineers (ASME) U Stamp is a certification that is given to companies that produce boilers, pressure vessels, and other types of equipment.

This stamp is an indication that the company has been inspected by ASME (usually by ASME authorized third-party inspector) and meets all safety requirements set forth by the organization.

To obtain an ASME U stamp, manufacturers must submit an application along with comprehensive documentation detailing the design requirements for their product or service.

Upon review, if all of the necessary criteria are met, then they can receive official U Stamp certification from the ASME Board of Boilers and Pressure Vessels.

The certification process includes regular inspections conducted by independent third-party organizations to ensure continued compliance with established standards.

Once these criteria have been met, then the company can receive the U stamp.

ASME U Stamp vs U2 Stamp

U stamp is for pressure vessel fabrication as per BPVC ASME Section VIII Division I while U2 is for BPVC ASME Section VIII Division II.

U stamp is denoted by the letter “U” while the U2 stamp is denoted by the letter “U”.

Both U stamp and U2 stamp marks are issued by the ASME to the vessel manufacturers.

Is ASME U Stamp is mandatory?

The use of the ASME U stamp is largely determined by local regulations and industry requirements.

In some areas, such as the United States and Canada, pressure vessels must be designed in accordance with certain codes and standards in order to comply with safety regulations, including those set forth by ASME.

The U Stamp certification provides assurance to insurance companies and other interested parties that the vessel has been constructed according to the relevant standards, guidelines, and regulations.

In addition to providing peace of mind to those who need it, insurance companies often require U Stamp certification before they will provide coverage for a pressure vessel.

This ensures that all safety requirements have been met before they take on any risk associated with its use.

Why ASME U stamp is required?

The ASME U stamp is a requirement that all pressure vessels in the United States must meet before they can be put into use.

This stamp signifies that the vessel has been constructed and tested in accordance with American Society of Mechanical Engineers (ASME) guidelines, ensuring its safety and reliability.

The ASME Boiler and Pressure Vessel Code, Section VIII Division 1 outline all of the requirements for a pressure vessel to receive an ASME U stamp.

These include a stringent design code, materials certification, weld inspection requirements, hydrostatic and pneumatic testing procedures as well as documentation to confirm compliance with these standards.

The ASME U stamp certification requires companies to establish a quality management system and demonstrate their ability to consistently manufacture products that meet industry-defined standards.

Additionally, any repairs or alterations made to these vessels must also be done in accordance with ASME standards prior to obtaining an updated U-1 form from the National Board of Boiler and Pressure Vessel Inspectors for revalidation.

How to get ASME U Stamp Certification?

In order to obtain this certification, there are several important steps that any company should take in order to meet the necessary qualifications.

Read more: ASME Stamp application process.

First, it is vital to understand what the requirements are for obtaining the U Stamp Certification, which includes having sufficient personnel resources, as well as understanding quality control processes and other safety procedures.

Companies must also be able to document their compliance with these criteria in a comprehensive Quality Control Manual, which must be reviewed by an ASME Authorized Inspector before installation can begin.

The process for obtaining an ASME U Stamp certification involves completing an application form, having the product designed and manufactured to meet certain design standards, obtaining third-party reviews/assessments on the product’s design, quality control, inspection and manufacture, and making sure that all specific requirements have been met before submitting the application.

Successful applications result in the accreditation of ASME certification for the applicant manufacturer.

What are the types of ASME U Stamp?

There are several types of ASME U Stamps available depending on the type of product being made.

The main types of ASME U stamps are:

1. U – For Pressure Vessels (As per ASME Section VIII Div. I).
2. U2 – For Pressure Vessels (Alternative Rules for Pressure Vessels) (As per ASME Section VIII Div. II).
3. U3 – For High-Pressure Vessels (As per ASME Section VIII Div. III).
4. UM – For Miniature Pressure Vessels (As per ASME Section VIII Div. I).
5. UV – For Pressure Vessel Pressure Relief Valves (As per ASME Section XIII).
6. UD – For Pressure Vessel Pressure Relief Devices (As per ASME Section XIII).
7. UV3 – For High-Pressure Vessel Pressure Relief Valves (As per ASME Section XIII).
8. UD3 –For High-Pressure Vessel Pressure Relief Devices (As per ASME Section XIII).