ASME vs EN 13445: Two Approaches to Pressure Vessel Design

In the field of mechanical design, pressure vessels occupy a critical position: they are essential for industrial processes in sectors such as energy, chemicals, petrochemicals, and food.

To ensure their safety and performance, different regions around the world have developed their own technical codes. Two of the most widely used and influential standards are the ASME Boiler and Pressure Vessel Code (BPVC) of the United States and the European standard EN 13445.

Approach and Scope

The ASME Code, especially its Section VIII Division 1, is a comprehensive framework that is widely used internationally. It establishes the rules for the design, manufacture, inspection, and certification of pressure vessels, including both boilers and non-fire-exposed vessels. It is recognized for its technical rigor and level of regulatory detail, with precise specifications for each component, material, and process.

For its part, the EN 13445 standard was created to harmonize the design of pressure vessels within the European Union, in accordance with the European Pressure Equipment Directive (PED). It applies exclusively to vessels not exposed to flame and covers a wide variety of materials, such as steels, alloys, and cast irons. Its structure facilitates CE marking, a key requirement for marketing within the European market.

In the last year, we have executed various projects under the ASME code in locations as diverse as Finland, Poland, Saint Lawrence, Iraq, and Kyiv, and under the EN 13445 standard in different parts of Europe, such as the Iberian Peninsula and Switzerland, serving a wide variety of sectors, from chemicals to food.

Welded Joint Efficiency: A Key Factor

One of the factors that most influences the calculation of minimum thickness is the value assigned to the welded joint efficiency (E). This efficiency reflects the degree of confidence that can be placed in the quality of the welds with respect to the structural behavior of the assembly.

• In the ASME code, this value can vary considerably depending on the type of weld and the inspection procedures used. If radiographic testing is not performed, the efficiency can be significantly reduced.
• The EN 13445 standard, on the other hand, adopts a more modern approach: it assumes that welds are reliable if certain quality and traceability requirements are met, thus assigning an efficiency value close to 1. This allows for lighter designs while maintaining an equivalent level of safety, reducing material costs.

This contrast represents a difference in philosophy: while ASME opts to be more conservative by default, EN 13445 assumes that the quality of modern processes allows for better optimization of resources without compromising safety.

Compatibility with the PED Directive and CE Marking

Another major practical difference lies in compatibility with the European Pressure Equipment Directive (PED). While EN 13445 is specifically designed to comply with the PED—and is therefore the natural tool for projects within the European market—the ASME code is not by default.

This does not mean that ASME cannot be used in European projects, but it does mean that additional verifications, supplementary documentation, or equivalency processes will often be required, especially if CE marking is desired.

This distinction can be critical for manufacturers or engineering firms wishing to operate internationally: while ASME has a strong presence in the Americas and Asian markets, EN 13445 is essential for operating in Europe.

Conclusion: Which code is best?

The answer is not unique; it depends on the context. Both codes offer a high level of security and technical detail, but have different advantages depending on the project:

• ASME is ideal for international or non-European projects due to its robustness, global recognition, and cross-application to all types of vessels, including boilers.
• EN 13445 is the natural choice for projects within the European Union or those requiring CE marking. Furthermore, its more analytical approach can offer advantages in optimized design and cost control.

Whether prioritizing regulatory compliance or seeking structural efficiency, the most important thing is to understand the differences and choose the code that best suits the application, market, and project requirements.

At IES Soler, we know that every industrial project has specific needs. That’s why we offer technical advice to help you find the right heating solution most suitable electrical, compatible with both the ASME code and the EN 13445 standard. This way we guarantee safety, efficiency and legal compliance in any market.