From what pressure does the PED apply?

Directive 2014/68/EU covers equipment with a maximum allowable pressure PS strictly greater than 0.5 bar above atmospheric pressure. Below that threshold, the equipment is outside the PED, although other regimes (Machinery Directive, Low Voltage Directive, sector-specific rules) may still apply. The PED also sets combined PS x V (volume) and PS x DN (nominal diameter, piping) thresholds that then drive classification into categories I to IV via tables 1 to 9 of Annex II.

What is the difference between the PED and Directive 2014/29/EU (SPVD)?

The PED 2014/68/EU is the general pressure equipment directive. The SPVD (Simple Pressure Vessel Directive, 2014/29/EU) covers a strictly defined subset: welded vessels made of non-alloy carbon steel or non-alloy aluminium, intended to contain air or nitrogen, with pressure between 0.5 and 30 bar and a PS x V product between 50 and 10 000 bar.L. A vessel that falls outside this narrow envelope falls back under the PED. The two directives are mutually exclusive on their respective scope.

What is Sound Engineering Practice (SEP)?

SEP is the regime that applies to equipment falling below category I in the Annex II tables. Such equipment must be designed and manufactured in accordance with the sound engineering practice of a Member State, but does not carry CE marking under the PED, does not require an EU declaration of conformity, and does not involve a Notified Body. It remains subject to the general product safety obligations. SEP does not, however, waive CE marking required under other applicable directives (EMC, Machinery, ATEX, etc.).

How is the I, II, III or IV category of equipment determined?

Classification combines four parameters: equipment type (vessel, piping, fired pressure equipment), fluid contained (group 1 dangerous or group 2 other, gas or liquid), maximum allowable pressure PS, and volume V (vessels) or nominal diameter DN (piping). Annex II contains nine separate tables (tables 1 to 9), one per equipment/fluid/physical-state combination. The (PS, V) or (PS, DN) point is plotted on the relevant table and the category is read off directly. Picking the wrong table is a classic pitfall: a gas table applied to a liquid fluid wrongly raises the category.

Which conformity modules apply per PED category?

Article 14 and Annex III list the admissible combinations. In category I, module A (internal production control) is enough, with no Notified Body. In category II, the manufacturer picks among A2, D1, E1. In category III, the options broaden (B + C2, B + D, B + E, B + F, H). In category IV, the highest level, modules B + D, B + F, G, H1 are available, all with Notified Body intervention on design as well as on production. The four-digit Notified Body number is placed next to the CE for categories II and above.

What are the main harmonised standards for the PED?

The PED relies on a harmonised CEN corpus. Unfired pressure vessels fall under the EN 13445 series. Industrial metallic piping falls under the EN 13480 series. Water-tube boilers and shell boilers are covered by the EN 12952 and EN 12953 series respectively. Safety devices against overpressure (relief valves, bursting discs) are covered by the EN ISO 4126 series. Cryogenic equipment uses EN 13458 and EN 1252 for materials. Industrial valves are covered by EN 12266. Presumption of conformity only attaches if the applicable version of each standard is cited on the harmonised list published in the OJEU.

Is a relief valve bought off the shelf automatically PED-compliant?

No. Safety accessories (relief valves, bursting discs, safety pressure switches) are systematically classified in category IV by article 4(1) point d, regardless of size, as long as they protect a PED equipment. A catalogue valve must therefore have its own EU-type examination certificate and bear the CE marking + Notified Body number. The absence of this marking is a common integration pitfall: a category III main equipment fitted with an uncertified relief valve is not compliant.

PED 2014/68/EU: pressure equipment and categories I-IV

Author Hugues Orgitello Last updated 27 May 2026 ~13 min read

Guide - PED 2014/68/EU

Directive 2014/68/EU, known as the PED (Pressure Equipment Directive), governs the placing on the EU market of pressure equipment with a maximum allowable pressure PS above 0.5 bar above atmospheric. It applies to vessels, piping, safety accessories, pressure accessories, and to assemblies. The directive operates in two stages: an initial scoping under Article 4, then a classification into categories I to IV through the nine tables of Annex II, which in turn drives the choice of conformity assessment modules. This page covers the scope, the thresholds, the classification mechanism, the relationship with the SPVD 2014/29/EU for simple vessels, and the classic pitfalls encountered at integration.

Scope of Directive 2014/68/EU

The PED covers the design, manufacture and conformity assessment of equipment whose maximum allowable pressure PS is strictly greater than 0.5 bar. The directive distinguishes several types of objects, each with its own classification regime.

Equipment type	Operational definition	Annex II
Vessels	Housings designed to contain a fluid under pressure, fixed or mobile	Tables 1 and 2
Piping	Tubular components intended for the transport of fluids under pressure, connected together	Tables 6 to 9
Safety accessories	Devices protecting pressure equipment against exceeding allowable limits (relief valves, bursting discs, safety pressure switches)	Category IV by article 4(1) point d
Pressure accessories	Devices with an operational function whose housing is subject to pressure (valves, regulators, pressure gauges)	Inherit the classification of the main vessel
Fired pressure equipment	Steam generators and superheated water boilers	Tables 3, 4, 5
Assemblies	Combinations of equipment put together by the manufacturer to form an integral, functional whole	Article 4(2), classification of the assembly as a whole

Equipment explicitly in scope

Article 1 and Article 4 list typical objects the directive covers:

hot-water boilers and low-pressure steam generators above the thresholds,
domestic pressure cookers above a defined volume and pressure,
CO2 cylinders and extinguishing cartridges,
industrial gas cylinders and breathing-air cylinders,
industrial hydraulic lines,
portable and fixed fire extinguishers (the pressurised body),
vehicle airbags and seat-belt pretensioners (under a specific carve-out).

Main exclusions

Article 1(2) lists a limitative set of exclusions:

equipment falling under other sector-specific directives (transportable, marine, nuclear safety, aviation),
equipment for the supply, refrigeration or lubrication of aircraft or ships,
specifically military equipment,
radiators and pipes in hot-water heating networks,
vessels for carbonated beverages where PS x V does not exceed certain thresholds,
equipment intended for the functioning of road vehicles (except airbags and pretensioners).

Where equipment falls under Directive 2014/29/EU (SPVD, simple pressure vessels), it falls outside the PED. See the comparison further down.

The four fluid groupings

The fluid contained drives the category. The PED distinguishes four combinations along two axes: group (1 or 2) and physical state (gas or liquid). A further distinction separates stable and unstable fluids.

Combination	Definition	Typical examples
Group 1, gas	Gases, liquefied gases, dissolved gases, vapours and superheated liquids whose vapour pressure exceeds 0.5 bar above atmospheric at the maximum allowable temperature, and which are dangerous under the CLP regulation (flammable, oxidising, toxic, explosive)	Hydrogen, oxygen, chlorine, propane, natural gas, ammonia
Group 1, liquid	Liquids dangerous under CLP whose vapour pressure stays below 0.5 bar at maximum allowable temperature	Flammable solvents at room temperature, concentrated acids when hot
Group 2, gas	All gases and vapours not in group 1	Compressed air, nitrogen, argon, helium, CO2 (non-dangerous under CLP)
Group 2, liquid	All liquids not in group 1	Water, non-flammable hydraulic fluids, non-classified thermal oils

Unstable fluids (substances liable to spontaneous decomposition, runaway polymerisation, etc.) are systematically classified in group 1 gas, regardless of their nominal physical state. The CLP classification is the regulatory reference: a change in CLP classification of a substance can move equipment from one group to the other, which is why a permanent watch on process fluids is needed.

Categories I to IV: the nine tables of Annex II

Annex II contains nine tables, each pairing an equipment type and a fluid group with a (PS, V) or (PS, DN) grid. The category is determined by the position of the equipment's representative point on the relevant table.

Table	Equipment	Fluid
Table 1	Vessels	Group 1, gas
Table 2	Vessels	Group 2, gas
Table 3	Vessels	Group 1, liquid
Table 4	Vessels	Group 2, liquid
Table 5	Fired pressure equipment	All fluids
Table 6	Piping	Group 1, gas
Table 7	Piping	Group 2, gas
Table 8	Piping	Group 1, liquid
Table 9	Piping	Group 2, liquid

Each table splits the (PS, V) or (PS, DN) plane into successive zones. A low zone, below the entry curve, places the equipment under the SEP regime (Sound Engineering Practice). Higher zones, in increasing severity, designate categories I, II, III, IV. The entry curve and transition curves are specified numerically in Annex II; this page does not reproduce those values, which are the regulatory reference and must be read on the official text.

A few structural rules to keep in mind:

for the same product (PS x V or PS x DN), the category is higher in group 1 than in group 2,
for the same product, the category is higher for gases than for liquids,
safety accessories are, by the general rule of Article 4, classified in category IV as soon as they protect a PED equipment, regardless of size,
pressure accessories inherit the category of the main equipment they serve,
for an assembly, the category is set by the most demanding equipment, save for specific provisions.

Practical reading of the tables

The method to use the tables follows a simple sequence:

determine the equipment type (vessel, piping, fired equipment, accessory),
determine the nominal physical state of the fluid at the maximum allowable temperature (gas, vapour, superheated liquid vs liquid),
determine the CLP group of the fluid (group 1 dangerous vs group 2),
select the corresponding table (1 to 9),
compute PS x V (vessels, fired equipment) or PS x DN (piping),
plot the point on the table and read off the category.

A common error is to apply the gas table to a fluid whose vapour pressure stays below 0.5 bar at the maximum allowable temperature (so liquid in the PED sense), which over-classifies the equipment. The reverse error, applying a liquid table to a fluid that goes to vapour under service conditions, under-classifies and creates a recall risk.

Sound Engineering Practice (SEP): below the category I threshold

Equipment located in the low zone of the tables, below the entry curve of category I, falls under Sound Engineering Practice (article 4(3)). The regime is, in summary:

the equipment is designed and manufactured in accordance with the sound engineering practice of a Member State,
it is not CE-marked under the PED,
it does not entail an EU declaration of conformity nor Notified Body intervention,
it remains subject to general product safety obligations and, where applicable, to other applicable directives (EMC, Low Voltage, Machinery).

SEP is neither a favour nor a blank cheque: the manufacturer's internal documentation (sizing calculations, weld qualification, proportionate non-destructive testing) remains demandable under market surveillance. The SEP/category I boundary is also narrow: a small increment in PS, V or DN can move the product into category I and trigger the obligations of EU declaration of conformity and CE marking.

Conformity assessment modules per category

Article 14 and Annex III list the admissible combinations of modules drawn from Decision 768/2008/EC. The logic is progressive: the higher the category, the broader the Notified Body coverage.

Category	Admissible modules	Notified Body
Category I	A (internal production control)	No
Category II	A2, D1, E1	Yes (production surveillance)
Category III	B (EU-type examination, design or type) + D, E or F; B1 (EU design examination) + D or F; H (full quality assurance)	Yes
Category IV	B + D, B + F, G (EU unit verification), H1 (full quality assurance + design examination)	Yes (design AND production)

A few clarifications on the modules most used under the PED:

module B comes in two flavours: EU-type examination (physical sample) and EU design examination (B1, dossier only);
module D is production quality assurance, analogous to ISO 9001 but focused on PED requirements, with periodic NB audit;
module H1 adds, on top of module H, a specific examination of the final design by the NB, and is reserved for category IV equipment;
module G (EU unit verification) is the typical route for unique or very small-series equipment, the NB examining each unit.

On personnel qualification for design, calculation, welding and non-destructive testing, the PED requires qualification of operators and processes. Welders and welding procedures must be qualified against the applicable harmonised standards. NDT inspectors (radiography, ultrasonic, penetrant, etc.) must be qualified to EN ISO 9712. The NB verifies these qualifications under the production modules (D, E, F, H, H1).

See the self-declaration vs Notified Body page for the general module mechanics.

Main harmonised standards under the PED

Presumption of conformity attaches to the application of the harmonised standards published in the Official Journal of the European Union under the PED. The main families are as follows.

Standard	Domain	Coverage
EN 13445	Unfired pressure vessels	Design, manufacture, inspection, welding, materials
EN 13480	Industrial metallic piping	Design, manufacture, inspection, welding
EN 12952	Water-tube boilers	Design, manufacture, auxiliary equipment
EN 12953	Shell boilers	Design, manufacture, auxiliary equipment
EN ISO 4126	Safety devices against overpressure	Relief valves, bursting discs, testing
EN 13458	Static vacuum-insulated cryogenic vessels	Design, manufacture
EN 1252	Materials for cryogenic applications	Specifications, low-temperature testing
EN 12266	Industrial valves	Testing of metallic valves

Presumption of conformity only attaches if the applicable version of the standard is cited on the OJEU list in force. A standard published but not yet cited, or a withdrawn standard, no longer gives presumption. Tracking the OJEU list (published periodically by the Commission) is a permanent burden on the manufacturer.

CE marking and Notified Body number

A PED equipment of category I to IV bears:

the general CE marking, whose dimensional and visual rules are common to all directives (see CE marking dimensions and visual rules),
for categories II, III and IV, the four-digit number of the Notified Body intervening on the production phase, placed next to the CE,
the PED nameplate recalling the manufacturer name, year of manufacture, equipment identification, PS, TS (maximum and minimum allowable temperatures), V or DN, and category where applicable.

CE is not affixed in category I without a Notified Body on production: module A operates without an NB, but CE is affixed by the manufacturer on the basis of its own EU declaration of conformity. For SEP equipment, no CE marking under the PED: any CE mark borne on the product results from other applicable directives (EMC, Machinery).

PED 2014/68/EU vs SPVD 2014/29/EU: key takeaways

The SPVD (Simple Pressure Vessel Directive, 2014/29/EU) covers a narrowly defined subset, mutually exclusive with the PED.

Criterion	PED 2014/68/EU	SPVD 2014/29/EU
Material	Any material (steel, aluminium, cast iron, composite, etc.)	Non-alloy carbon steel or non-alloy aluminium only
Joining process	Any process (welded, brazed, mechanical, monolithic)	Welded only
Fluid	Gases, vapours, liquids, groups 1 and 2	Air or nitrogen only, not intended for the production of steam
PS	Above 0.5 bar	Between 0.5 and 30 bar
PS x V	Above the thresholds of the Annex II tables	Between 50 and 10 000 bar.L
Equipment type	Vessels, piping, accessories, assemblies, fired equipment	Simple vessels only
Categories	I, II, III, IV (Annex II)	Simplified categories driven by PS x V (SPVD Annex II)
Modules	A, A2, B + C2, B + D, B + E, B + F, D1, E1, G, H, H1 (by category)	B + C, B + C1, B + C2 (by SPVD category)

A vessel that falls outside any one of these SPVD criteria (for example a welded stainless-steel vessel, or a vessel for industrial CO2) drops back under the PED. Verifying scope is an indispensable scoping step before freezing the assessment dossier.

The historical motive for keeping a separate SPVD is operational. Compressed-air receivers for workshop networks, instrument-air tanks and similar small commodity items represent a very large unit count across the Union, with a tightly bounded risk profile. The SPVD lets these items follow a simplified, predictable assessment route, while equipment with mixed materials, mixed processes or any non-air or non-nitrogen fluid is funnelled into the more open PED corpus where the Annex II tables capture the actual hazard envelope.

A practical consequence for designers: the choice of fluid on a vessel that would otherwise sit comfortably in SPVD scope (welded carbon steel for air) is load-bearing. Specifying nitrogen-blanketed equipment instead of plain air, or moving from carbon steel to stainless steel for a cleanability requirement, both shift the regulatory regime to the PED and may change the assessment cost and lead time. Such decisions are best taken jointly with the dossier owner before procurement freezes the materials list.

Interaction with other directives

The PED interacts with several new-approach directives. The main intersections:

ATEX 2014/34/EU: a PED equipment installed in an explosive zone (ATEX zones 0, 1, 2 or 20, 21, 22) must also be ATEX-certified for the category required by the zone. The two directives do not replace each other, they stack. See the ATEX / IECEx page.
Machinery Directive 2006/42/EC (then Regulation 2023/1230): pressure equipment integrated into machinery remains subject to the PED for its pressure-bearing components, and to the Machinery Directive for the assembly. The machine manufacturer is not exempt from CE marking under the PED for the relevant components. If a sub-supplier delivers a pressure component without applicable PED CE marking, the machine manufacturer must address the non-conformity before integration.
Gas Appliances Regulation 2016/426/EU: covers combustion appliances using a gaseous fuel. A domestic gas-fired boiler falls under Regulation 2016/426, but its internal pressure-bearing components remain classified under the PED if the thresholds are crossed.
Transportable pressure equipment (TPED 2010/35/EU): gas cylinders, road and rail tankers, and CGEMs fall under the TPED rather than the PED. The split rests on the transportable character and the associated ADR/RID regime.

For imports into the EU, the importer remains responsible for the PED conformity of the product placed on the market. See the authorised representative and importer obligations page.

Inspections, surveillance and qualified personnel

The PED provides for a conformity assessment in several phases that goes beyond documentary examination:

Phase	Object	Typical actors
Design review	Sizing calculations (thickness, stress, fatigue), material selection and compatibility with the fluid	Manufacturer + NB (modules B, B1, H1, G)
Welding procedure qualification	WPS, WPQR to EN ISO 15614 or harmonised equivalents	Manufacturer + NB
Welder qualification	EN ISO 9606 (steel, aluminium, etc.)	Manufacturer + NB
Non-destructive testing (NDT)	Radiography, ultrasonic, penetrant, magnetic-particle; inspectors qualified to EN ISO 9712	Qualified NDT personnel + third party for categories III and IV
Hydrostatic test (or pneumatic)	Pressurisation at 1.43 x PS (hydrostatic) or 1.1 x PS (pneumatic, subject to conditions)	Manufacturer + NB on sample
Final inspection	Documentary review, marking, nameplate, EU declaration of conformity	Manufacturer + NB per module

For categories III and IV, non-destructive testing on permanent joints must be carried out by personnel qualified and approved by a recognised third-party organisation within the meaning of point 3.1.3 of Annex I of the directive. This specific approval is distinct from a plain EN ISO 9712 qualification and is a frequent point of attention.

Manufacturer-side classic pitfalls

Pitfall	Consequence
Reading the wrong Annex II table (gas vs liquid mix-up)	Wrong category, inadequate modules, invalid EU declaration of conformity
Forgetting the Article 4(1) point d rule for safety accessories (always category IV)	Relief valve without CE + NB number, non-compliance of the assembly
Welds not qualified (WPS / WPQR missing or expired)	NB validation refused, production blocked
NDT personnel not approved by a recognised third party in category III or IV	NDT reports inadmissible, EU-type examination blocked
Bought-in components (valves, flanges, fittings) presumed CE-marked when they are SEP or out of PED scope	Inherited non-conformity on the main equipment
PED vs SPVD confusion on a welded stainless-steel vessel	Wrong SPVD module applied, declaration invalid
PED vs TPED confusion on a mobile cylinder	Wrong regulatory frame, marking missing or inadequate
Mid-life fluid change under CLP without reassessment	Equipment moves from group 2 to group 1, category below the required level
Re-using a withdrawn EN 13445 version on the OJEU list	Loss of presumption of conformity, dossier vulnerable in surveillance
Site-assembled assembly with no assembly-level PED evaluation	Components individually compliant but the assembly is not covered