[Home](/)/[Resources](/resources)/Pressure Equipment Directive (PED) EUDirective guide # Pressure Equipment Directive (PED) 2014/68/EU The PED determines the CE conformity route for pressure vessels, piping, safety accessories, and assemblies. The key insight is that the category — and therefore the conformity module — is not chosen by the manufacturer. It is calculated from a matrix of pressure, volume or diameter, and fluid hazard group in Annex II. Copy Link[Share on WhatsApp](https://wa.me/?text=https%3A%2F%2Fkrono-labs.com%2Fguides%2Fpressure-equipment-directive-ped) At a glance PED categories 4 Key standards 6 FAQs 4 ## How PED scope and categories work PED 2014/68/EU covers pressure equipment and assemblies with a maximum allowable pressure (PS) greater than 0.5 bar. This includes pressure vessels, piping, safety devices, and pressure accessories. The directive does not apply to certain excluded categories: pipelines for the supply of gas, water, or steam; rotating machinery; nuclear pressure equipment; and several others listed in Article 1(3). The most important concept in PED compliance is fluid group. Group 1 fluids are dangerous — flammable, toxic, oxidising, or explosive. Group 2 is everything else (water, steam, compressed air, nitrogen). The same pressure vessel at the same pressure reaches a higher PED category when handling Group 1 fluid. This determines how much independent third-party verification you need. Once you determine the category from Annex II, the directive specifies which conformity assessment modules are available. You do not have full freedom to choose — the directive restricts which modules can be applied at each category level. Higher categories mean fewer options, and those options all involve Notified Bodies. ## PED categories and conformity routes Category I ### Lowest risk — simple vessels, lowest PS×DN combinations **Modules:** Module A (internal production control). No Notified Body required. Simple pressure vessels, hydraulic accumulators at low pressure, low-risk piping. Category II ### Moderate risk — medium PS×DN or medium-hazard fluids **Modules:** Module A2, D1, or E1 (involving Notified Body for production surveillance or product verification). Steam generators for certain flow ranges, pressure piping for Group 2 gases at medium parameters. Category III ### Higher risk — high-pressure vessels, Group 1 (hazardous) fluids **Modules:** Module B+C2, B+D, B+E, B+F, or G. Notified Body involvement mandatory. High-pressure steam drums, vessels containing flammable or toxic Group 1 fluids. Category IV ### Highest risk — very high pressure or the most hazardous fluid combinations **Modules:** Module B+D, B+F, G, or H1. Only the highest-scrutiny modules. NB required. Reactors, very high-pressure autoclaves, pipelines transporting high-hazard fluids at extreme pressure. ## Key harmonised standards EN 13445 Unfired pressure vessels — design, materials, fabrication, inspection, testing EN 13480 Metallic industrial piping — design, fabrication, and installation EN 13458 Cryogenic vessels — static vacuum insulated vessels EN 286-1 Simple unfired pressure vessels for air or nitrogen (lower-risk category) EN 764-1 Pressure equipment terminology — definitions used across the directive EN 13709 Industrial valves — steel globe and globe stop-check valves for general use ## Frequently asked questions ### How is the PED category determined for a pressure vessel? Category is determined by a combination of maximum allowable pressure (PS, in bar), volume (V, in litres) or nominal size (DN), and fluid group. Table 1 in Annex II provides the classification matrices. Higher PS×V products with Group 1 (hazardous) fluids reach Category III or IV quickly; Group 2 (non-hazardous) fluids reach lower categories at the same pressure and volume. ### What is 'sound engineering practice' and when does it apply? Equipment below the PED category thresholds entirely — falling under Article 4(3) — must still be designed and manufactured according to sound engineering practice. It cannot bear the CE mark for PED purposes, but it must meet basic safety objectives. This equipment typically includes small accumulator vessels, cylinders, and fittings at low pressure. ### Does PED apply to pressure equipment inside other CE-marked machinery? Pressure equipment that is an integral part of a machine and fulfils a specific function (e.g., a hydraulic cylinder that is part of a press) is generally covered by the Machinery Directive as part of the machine. PED only applies to the pressure component separately if it is placed on the market independently and falls within PED scope. ### What is the difference between PED and PSSR (UK)? PED is the EU CE marking directive for the design and manufacture of pressure equipment. PSSR 2000 (UK) is a workplace safety regulation covering the safe use and maintenance of pressure systems already in service. Post-Brexit, the UK has UKCA-based pressure equipment regulations that mirror PED, while PSSR remains a workplace requirement. These are parallel frameworks covering different lifecycle stages. **Disclaimer:** Educational resource only. PED category classification requires careful review of Annex II matrices for your specific fluid group, pressure, and volume. Always verify with a qualified pressure equipment engineer or Notified Body. 🇪🇺 CE Marking roadmap for your product Every standard, document, and test that applies — free, no account required. See your free roadmap[ Want an expert to take your product through 🇪🇺 CE Marking compliance for you? One consultant from Krono's compliance team takes your product from requirements to legal sale, with a fixed quote before any work starts. See compliance services](/services) Learn this properly In-depth course that teaches the full process, not just this one answer. [Start the course — $199](/courses/53-eu-ce-marking-pressure-equipment-simple-pressure-vessels)[Prefer to read? Get the book — $24.99](/books/53-eu-ce-marking-pressure-equipment-simple-pressure-vessels) Related guides * [PED Category Classification Deep DiveA deep dive into how PED 2014/68/EU categories are actually calculated: the Annex II pressure/volume/DN matrices, Group 1 vs Group 2 fluids, Article 4(3) sound engineering practice, module selection logic, and how PED interacts with SPVD and TPED.](/guides/pressure-equipment-directive-ped-deep-dive) * [CE conformity assessment modules explainedThe CE conformity assessment modules A to H from Decision 768/2008 in plain English: what each one involves, when a…](/guides/ce-conformity-assessment-modules) * [EU type-examination (Module B)Complete guide to EU type-examination (Module B): what it covers, when it is required, how to select a Notified Body, what the …](/guides/eu-type-examination-module-b) * [ATEX Directive CE markingPractical guide to ATEX CE marking: equipment groups, categories, zone classification, ATEX marking format, Notified Body requi…](/guides/atex-directive-ce-marking) * [CE marking for industrial equipmentComplete guide to CE marking for industrial equipment: Machinery Regulation, EMC, LVD, safety requirements, and conformity asse…](/guides/ce-marking-for-industrial-equipment) * [PED Pressure Categories and Fluid GroupsPED fluid group 1 or 2, gas or liquid, and which of the 9 Annex II tables applies: PS, V and DN thresholds, categories…](/guides/eu-ped-pressure-categories-fluid-groups)