There are several different documents available on the details of pressure vessel design. However, the basis of the design of pressure vessels is the use of appropriate formulae for vessel dimensions in conjunction with suitable values of design strength.

Pressure vessels can be divided into `simple vessels' and those that have more complex features. The relevant standards and codes specify information about the design and manufacture of vessels and vessel design and fabrication is an area well covered by standards and codes.

As a result of this standardization, the outright failure of a properly designed, constructed, operated, and maintained pressure vessel is rare.

What is the Difference Between ASME BPVC, PD 5500, and BS EN 13445?

The design and manufacture of boilers and pressure vessels are normally carried out to meet the requirements of national and international standards with one of the earliest being the AOTC 1939/48/58 `Rules for the construction, testing, and scantlings of metal arc welded steel boilers and other pressure vessels’.

The other principal standards in the UK were BS 1500 and BS 1515, both of which are now withdrawn and superseded by PD 5500, whereas the BS EN 13445 series of standards deals with the design unfired pressure vessels. The other most used design code is the ASME (American Society of Mechanical Engineering) Boiler & Pressure Vessel Code (BPVC).

In the 1950s, ASME Boiler & Pressure Vessel Code was dominant across most of the world. 

Over time, PD 5500 and BS EN 13445 series became more competitive in designing lighter and more efficient vessels.

Now as it stands, all three are used and recognized globally, though with the ASME BPVC being more prominent in America, PD 5500 more prominent in the UK, and the BS EN 13445 series more widely used in Europe.

There are several main points of difference between them, which include; material selection restrictions, allowable stresses, and joint efficiencies.

What is the ASME BPVC?

ASME Boiler & Pressure Vessel Code establishes the rules of safety – in relation to pressure integrity only – governing the design, fabrication, and inspection of boilers and pressure vessels and of nuclear power plant components during construction. The aim of the rules is to provide a margin for deterioration in service. It is suitable for those who’ve purchased it in the past, as well as users of PD 5500 and the BS EN 13445 series.

ASME BPVC is international in scope, with more than 100,000 copies in use in 100 countries. In particular, the boiler and pressure-vessel sections are considered essential within such industries as electric power generation, petrochemicals, transportation, and many others.

Currently, half of the world’s nuclear power plants incorporate all or portions of ASME nuclear codes and standards in their construction, operation, and/or maintenance. Sixty nations generally recognize and apply the BPVC, while 30 of the 44 nuclear nations purchase their nuclear components to specifications contained within ASME’s nuclear codes and standards. 

The nuclear sections of the BPVC reflect the best practices of the industry while contributing to more than a half-century of safety for the general public.

ASME BPVC in its entirety includes 31 books and 17,000 pages covering industrial and residential boilers as well as nuclear reactor components, transport tanks, and other forms of pressure vessels. The requirements cover:

• power boilers,

• heating boilers,

• pressure vessels,

• fiber-reinforced plastic pressure vessels,

• construction of nuclear facility components,

• rules of in-service inspection of nuclear power plant components.

Pressure vessels are covered in section VIII of the document. This section, in turn, is divided into three parts, each of which covers different vessel specifications. Division 1 addresses the requirements for design, fabrication, inspection, testing, and certification. Division 2 provides requirements on materials, design, and non-destructive examination standards. Division 3 provides guidelines for pressure vessels operating at internal or external pressures above 10,000 psi.

ASME BPVC is also continually kept current by committees comprising more than 1,000 technical experts. This ensures that the Code is always being developed to reflect advancements in design, in materials, and from the evidence of experience.

To learn about the energy storage market and its contribution to net zero targets, click here.

What is PD 5500?

PD 5500:2024+A2:2025 Specification for unfired fusion welded pressure vessels is the UK’s national pressure vessels code. It specifies requirements for the design, construction, inspection, testing, and compliance verification of new unfired pressure vessels made from carbon, ferritic alloy, and austenitic steels. It also includes material supplements containing requirements for vessels made from aluminum, copper, nickel, titanium, and duplex.

It is an invaluable reference tool for the safe and cost-effective design and assessment of pressure vessels. PD 5500 also helps users enter new markets, trade more seamlessly, increase trust in their products, and manage risk more efficiently. It also contributes to UN Sustainable Development Goal 9 on building resilient infrastructure because its use leads to safer and more robust pressure vessels.

To learn more about PD 5500:2024+A2:2025, click here.

What is the BS EN 13445 Series of Standards?

The BS EN 13445 series of standards applies to unfired pressure vessels subject to a pressure greater than 0,5 bar gauge but may be used for vessels operating at lower pressures, including vacuum.

It specifies the requirements for the design, construction, inspection, and testing of unfired pressure vessels. It defines terms, definitions, and symbols applicable to unfired pressure vessels. As a result, this standard will be used by those involved in commissioning, designing, building, or maintaining pressure vessels.

The BS EN 13445 series is also invaluable to anyone wanting to demonstrate compliance with the EU Pressure Equipment Directive (97/23/EC). It also helps with entry to new markets, facilitates trade, and increases customer trust.

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