Pressure Equipment Directive (PED 2014/68/EU): Category Tables I to IV, Fluid Groups and Modules
How is pressure equipment classified into Categories I to IV under PED 2014/68/EU? Pressure Equipment Directive (PED 2014/68/EU) classifies pressure vessels, steam generators, piping, and safety accessories into Sound Engineering Practice (SEP) and Hazard Categories I, II, III, or IV based on five parameters: equipment type (vessel, steam generator, or piping), physical state of fluid (gas or liquid), fluid hazard group (Group 1 dangerous vs Group 2 non-dangerous), maximum allowable pressure (PS in bar), and internal volume (V in litres) or nominal size (DN in mm). Categories I through IV require progressive conformity assessment modules from self-certification (Module A for Category I) up to full quality assurance with design examination by a Notified Body (Module H1 or G for Category IV).
Engineering guide to PED 2014/68/EU classification: Category Tables 1 to 9, PS·V thresholds, Fluid Group 1 vs 2, and Module A to H1 conformity routes.
Technical Specifications & Regulatory Comparison Matrix
| PED Category | Equipment Examples | Conformity Modules Allowed | Notified Body Involvement |
|---|---|---|---|
| SEP (Sound Engineering Practice) | Small compressed air tanks (PS·V < 50 bar·L), water pipes | Sound Engineering Practice (Article 4(3)) | NO (No CE mark permitted) |
| Category I | Standard industrial air tanks (PS·V = 50 to 200 bar·L) | Module A (Internal production control) | NO (Manufacturer self-declaration) |
| Category II | Medium air receivers, industrial chillers, refrigerant piping | Module A2, D1, E1 | YES (Unannounced inspections or QM audit) |
| Category III | Steam boilers, large pressure reactors, toxic chemical piping | Module B (design type) + D or F, Module H | YES (Full type examination & production surveillance) |
| Category IV | High-pressure fire-tube boilers, dangerous gas vessels (PS > 500 bar) | Module B (production type) + D or F, Module G, Module H1 | YES (Design examination + individual testing) |
1. Fluid Group Classification (Article 13)
Fluid Group 1 comprises dangerous substances defined under CLP Regulation (EC) 1272/2008 (explosives, extremely/highly flammable gases, flammable liquids, acute toxic categories 1 to 3, and oxidizing agents). Fluid Group 2 comprises all other fluids, including steam, compressed air, nitrogen, and non-toxic water. Classifying a fluid into Group 1 substantially shifts equipment into higher regulatory categories.