Proposed Task Groups: – Creep Design Rules – Additive Manufacturing – Pressure Equipment Recertification

Proposed ‘Technical Task Group’
IN SERIES Produced VESSELS, Heat Exchangers and other pressure EQUIPMENT


Proposed Task Groups:
– Creep Design Rules
– Additive Manufacturing
– Pressure Equipment Recertification

Most construction codes used in the industrialized countries give reductions on inspection and testing requirements of in-series produced vessels, heat exchangers and other pressure equipment considering the repetitive character of the manufacturing and inspection operations and the acquired skill of the personnel. A reduction in inspection requirements of in series produced pressure equipment is allowable without lowering safety providing some precautions are observed in design and fabrication, depending on the construction code.

  • It is proposed to form an EPERC Task Group to consider these precautions within a practical context for different types of pressure equipment.
  • The Task Group should also consider new possibilities offered by Additive Manufacturing in the creation of prototype and the fabrication in series of pressure equipment. The Task Group will pay attention to the new standards related to Additive Manufacturing and connected topics edited by ISO, CEN and/or ASTM and propose a new philosophy in this domain to meet the Essential Safety Requirements of the Pressure Equipment Directive.

In-series produced pressure vessels may be simpler and more economical to produce, than their unit produced counterparts, particularly when the volume is rather small and the operating conditions are moderate. The harmonized European standard for pressure vessels, EN 13445, has recognised this through having particular requirements for these vessels (reduced nominal stress and higher test pressure). These requirements should be re-examined in the present context.

Unfired pressure vessels in small series productions mostly follow the specifications of large manufacturers, based on economics, as agreed with the customer/ user. The overwhelming variety of possible constructions and complexity allowed under the European standards creates a restricted market that is out of reach for SMEs (Small and Medium Sized Companies), which the EU promotes as the backbone of our welfare in a free Economic Market.

  • The Task Group will consider ways in which simplified standards for restricted designs and constructions of in-series produced pressure vessels can be developed that will widen the market to be accessible to all competent manufacturers.
  • The Task group should also consider the use of non-ferrous materials for pressure equipment where factors other than the economic targets dictate the specifications (like lightness, very high corrosion resistance, extreme or full recycling, extremely high or low temperature etc.) to give a single set of recommendations. This may lead to the concept of single or multi-level standards for such series of produced pressure vessels or pressure parts.
  • The Task Group should also consider limits of application of Non-Destructive Testing inspection, other than visual, for developing rules for designing and fabricating visually inspected vessels and equipment beyond their allowed maximum pressure cycles according to prescribed standards or regulations. Indeed, there are thousands of pressure vessels in the field, only visually inspected, under cyclic pressure load, giving satisfactory service with very little problems due to the cyclic nature of their

The scope of the Task Group should also include in-series produced heat exchangers, where design standards allow many possibilities for construction often resulting in diverse non-standardized products being produced.