At a glance
- The two directives are in principle cumulative: the PED covers the pressure hazard, ATEX the ignition hazard. Where the risk analysis shows both exist, both sets of rules apply alongside each other.
- One hard exception: equipment that is no higher than category I and also falls under 2014/34/EU is excluded from the PED (Article 1(2)(f)(vi)). Only ATEX is then left.
- A passive pressure vessel without its own potential source of ignition does not fall under ATEX — not even inside a hazardous zone. It is not “equipment” within the meaning of Article 2(1).
- Where both apply there is one CE marking and one EU declaration of conformity for all applicable legislation. What may double is the identification number following the marking.
What you will find on this page
- Cumulative or exclusive — and the one exception that turns it around
- Does my pressure equipment fall under ATEX? — the gateway, with a decision tree
- Zones against categories — two systems with nothing to do with each other
- What ATEX requires that the PED does not — five requirements from Annex II
- CE, declaration and bodies — how many of each
- The Netherlands — and why “no ATEX” does not mean “no obligation”
- Where it goes wrong — seven statements and what the text really says
Cumulative, with one exception
The two directives address different hazards and therefore apply alongside each other in principle. The PED says so in recital 8 and more clearly still in Annex I, preliminary observations 3: the manufacturer analyses the hazards and risks applicable to his equipment owing to pressure. Other risks may fall under other directives. The Blue Guide 2022 puts it in general terms: a product may only be made available where it complies with all applicable Union harmonisation legislation, and it names pressure equipment as an example of complementary requirements.
ATEX has a priority rule pointing the other way, but with a narrow reach: Annex II, 1.2.7 lets ATEX give way to other Union legislation, but only for the other hazards named there — contact, surface temperatures, non-electrical hazards, overloading. For the explosion hazard itself ATEX does not give way.
| Your situation | What applies |
|---|---|
| Category I under the PED and ATEX applies | ATEX only. The PED is excluded (Article 1(2)(f)(vi)) |
| Category II or above and ATEX applies | Both, alongside each other. Two assessments, one marking, one declaration |
| Under Article 4(3) (SEP) and ATEX applies | No CE under the PED, but ATEX may require a CE marking and an assessment in its own right |
| Pressure equipment without its own source of ignition | The PED only. ATEX does not apply, not even inside a hazardous zone |
Does my pressure equipment fall under ATEX?
The gateway into ATEX is narrower than almost everyone assumes, and it sits in the definition. Article 2(1) of 2014/34/EU calls “equipment”: machines, apparatus, fixed or mobile devices, control components and instrumentation thereof and detection or prevention systems which, separately or jointly, are intended for the generation, transfer, storage, measurement, control and conversion of energy and/or the processing of material, and which are capable of causing an explosion through their own potential sources of ignition. The list is closed.
That last clause is the whole test. A bare steel pressure vessel with no electrical equipment, no moving parts and no heat source of its own has no potential source of ignition of its own. So it is not equipment within the meaning of Article 2(1), it is not a protective system within the meaning of Article 2(2), and it is not on the exclusion list of Article 1(2) — it simply falls outside Article 1(1).
The ATEX Guidelines say so in three places. Paragraph 41 states that a defining element of equipment is that it has a potential source of ignition of its own, and adds that an item whose electrostatic charge comes solely from the process does not qualify as such — and that it should therefore not be given an Ex or CE marking under this directive. Paragraph 236 deals with the overlap directly and states that PED equipment is assumed to have no ignition source of its own. And the borderline list accompanying the Guidelines names “tank” expressly as outside the scope, for that very reason: no ignition source of its own.
When it does tip over
- An agitator, a pump or another moving part goes on or into the vessel.
- There is electrical equipment on it: a sensor, a heating element, a level switch.
- The item is a protective system within the meaning of Article 2(2) — a bursting disc or flame arrester with an independent explosion-limiting function. That falls under the directive whether or not it has an ignition source of its own, and is therefore marked (Guidelines § 45).
- Pressure compensation occurs that can produce a shock wave or compression; Annex II, 1.3.5, is aimed at precisely that.
Zones against categories: two systems, no conversion
Two things from two different directives get mixed up here, and it pays to set them straight once.
Categories: a property of the equipment
Group I (mining, M1 and M2) and group II (categories 1, 2 and 3) are in Article 2(6) to (8) and are worked out in Annex I of 2014/34/EU. Annex I describes them in terms of how often and how long an explosive atmosphere may be present and what level of protection answers that. The manufacturer chooses group and category; that is his “intended use” (Article 2(9)).
Zones: a property of the place
Zones 0, 1 and 2 for gas and 20, 21 and 22 for dust are not in the product directive but in Annex I of Directive 1999/92/EC, the employer directive. The employer classifies the zones, on the basis of his own assessment. The ATEX Guidelines say it in a footnote in so many words: it is not the manufacturer's responsibility to classify zones.
The link between the two is in Annex II, part B, of 1999/92/EC, and it is not a strict equivalence: in zone 0 or 20 category 1, in zone 1 or 21 category 1 or 2, in zone 2 or 22 category 1, 2 or 3. So a higher category is always allowed, and the explosion protection document may require something else on the basis of the risk assessment. In the Netherlands that link has been transposed into Article 3.5e(e) of the Working Conditions Decree.
What ATEX requires that the PED does not
The PED assessment does not cover the explosion hazard. That is not an interpretation: Annex I, preliminary observations 3, limits the mandatory analysis to hazards owing to pressure, and PED guideline I-24 states expressly that the PED does not consider the prevention of and protection against explosions not caused by pressure. Five requirements from Annex II of ATEX that a pressure equipment manufacturer normally does not do:
| Requirement | Reference | What it means in practice |
|---|---|---|
| Ignition hazard assessment | Annex II, 1.0.1 and 1.3.1; § 142 of the Guidelines | Point 1.3.1 requires that sparks, flames, arcs, hot surfaces, acoustic energy, optical radiation and electromagnetic waves do not occur; that takes an ignition hazard assessment of its own, alongside and separate from your pressure risk analysis. The ATEX Guidelines state in § 142 that such an assessment is needed and is focussed on the ignition hazard |
| Surface temperature | Annex II, 1.2.4, 2.1.2.3 and 2.2.1.2 | The stated surface temperatures must not be exceeded, even where risks arise from abnormal situations anticipated by the manufacturer, and must stay well below the glow temperature of the deposit dust. The PED has no temperature class. Mind the language versions: the Dutch text of 2.2.1.2 speaks of situations the manufacturer did not anticipate, where the English, German and French texts name the ones he did |
| Material choice for explosion safety | Annex II, 1.1.1 to 1.1.3 | A different criterion from the material requirements of PED Annex I, point 4: here it is about reactions with the surroundings, electrical conductivity, abrasion resistance, ageing and the effect of temperature variations — point 1.1.3 names mechanical strength as well, but to a different end than the ductility and toughness requirements of PED Annex I, point 4 |
| Electrostatic charge and stray currents | Annex II, 1.3.2 and 1.3.3 | Charges capable of causing dangerous discharges must be prevented; so must stray and leakage currents in conductive parts |
| Pressure compensation as an ignition source | Annex II, 1.3.5 | Pressure compensation must run in such a way that no shock wave or compression arises that can cause ignition. This is the requirement that shows most sharply that ATEX asks something different of a pressure vessel than the PED |
On top of that comes the marking. Annex II, 1.0.5, requires on every item the specific marking of explosion protection, followed by the symbol of the equipment group and the category, and for group II the letter G for gas or D for dust. Point 1.0.6 requires in the instructions among other things the maximum surface temperatures and the particulars enabling the user to establish whether the equipment can be used without danger in the intended place. Annex I, 3.3, of the PED contains none of those requirements.
CE marking, declaration and notified bodies
One declaration
Both directives contain the same provision, and it is unambiguous. ATEX Article 14(3) and PED Article 17(3): where the product is subject to more than one Union act requiring an EU declaration of conformity, a single declaration shall be drawn up in respect of all such acts, stating the publication references. PED recital 35 adds that this single declaration may take the form of a dossier of individual declarations (ATEX says the same in recital 24) — but one whole it remains.
One CE marking
Here too there is nothing for you to choose. Both directives define the CE marking as the marking by which the manufacturer indicates that the product is in conformity with the applicable requirements set out in Union harmonisation legislation providing for its affixing. On the example of a fork lift truck the ATEX Guidelines state that more than one CE marking or declaration obscures who is responsible, and is not acceptable. One nuance from the Blue Guide belongs here: where you incorporate a product that already carried a CE marking, the finished product can in fact bear two markings — that of the incorporated product and your own.
One or two numbers after the marking
The identification number of a notified body follows the CE marking only where that body is involved in the production control phase — PED Article 19(4) and ATEX Article 16(3) say so in identical words. In practice that gives this picture:
| Overlap | Numbers following the CE marking |
|---|---|
| PED category II + ATEX category 2, neither electrical nor an internal combustion engine | One number: that of the PED body. Article 13(1)(b) puts internal combustion engines and electrical equipment of category 2 on the route involving a body (point (i)), and the other equipment of that category on internal production control with communication of the documentation to a body (point (ii), Annex VIII); that body acknowledges receipt and keeps the file, and so performs no production control. Its number does not belong there |
| PED category II + ATEX category 2, electrical or an internal combustion engine | Two numbers, unless one legal entity is notified under both directives: it has only one number too |
| ATEX category 3 | No number, except on the unit verification route of Annex IX, where a body is involved. The ATEX Guidelines warn expressly against a body number where the directive provides for none |
And one practical point that saves a lot of searching: a legal entity has one identification number in the Commission database, whatever the number of directives it is notified under. So do not go looking for two numbers belonging to the same body. How to check that is on finding a notified body.
The Netherlands: two decrees and one document
For product requirements ATEX has been transposed into the Dutch Decree on equipment for use in potentially explosive atmospheres 2016 (BWBR0037644). It works just like the pressure equipment decree: Article 1 refers the concepts back to the directive, Article 2 prohibits the placing on the market and the use of products that do not meet the requirements, and Article 3(1) makes a listed series of directive articles plus Annex II directly binding.
The language requirements run parallel to those of the pressure equipment decree, which saves work where both apply: instructions and safety information in Dutch (Article 3(2)), the EU declaration of conformity in Dutch or English (Article 3(3)). So one Dutch-language set of instructions and one declaration suffice for both directives.
“No ATEX” does not mean “no obligation”
This is the point where the responsibility shifts rather than disappears. Where your passive pressure vessel falls outside ATEX, it still ends up in the employer's explosion protection document. The Working Conditions Decree requires that document before work begins and on every significant change (Article 3.5c(1)), containing among other things the likelihood that sources of ignition — including electrostatic discharges — are present, become active and actually ignite (paragraph 2(b)), and the zone classification (paragraph 4(c) read with Article 3.5d(5)).
And then the provision that is about your vessel exactly: Article 3.5e(d) declares the admission test of subparagraph (c) to apply by analogy to work equipment and connecting devices which are not equipment or protective systems within the meaning of the ATEX decree, where their incorporation into the installation may give rise to an ignition hazard. Outside ATEX, inside the explosion protection document. Article 3.5e(i) further requires the explosion safety of the installation as a whole to be verified by a competent person before it is first used.
Where it goes wrong
| What gets said | What the text says |
|---|---|
| “My vessel stands in zone 1, so it must be ATEX certified” | A zone is a property of the place, not of the vessel. Without a potential source of ignition of its own it is not equipment within the meaning of Article 2(1) and falls outside Article 1(1). |
| “We will put an Ex marking on it to be safe” | Do not. ATEX Guidelines § 41: such items should not be given an Ex or CE marking under this directive, and § 145 warns against misleading information on equipment. The prohibition itself is in Article 30(2) of Regulation (EC) No 765/2008: the CE marking may be affixed only where Union legislation provides for it. |
| “The PED assessment covers the explosion hazard too” | No. Annex I, preliminary observations 3, limits the analysis to the pressure hazard; guideline I-24 states expressly that the PED does not consider explosions not caused by pressure. |
| “Two directives, so two CE markings and two declarations” | One marking and one declaration (ATEX Article 14(3), PED Article 17(3)). Only the identification number may double. |
| “PED category II is ATEX category 2” | Two separate systems with no conversion rule: the PED category expresses pressure risk, the ATEX category a level of protection against ignition. |
| “Category I plus ATEX means both apply” | Precisely not. The PED then drops out (Article 1(2)(f)(vi)) and only ATEX is left. |
| “The manufacturer determines the zone” | The employer classifies zones, in the explosion protection document (Working Conditions Decree Article 3.5d(5)). The manufacturer chooses group and category as intended use (ATEX Article 2(9)). |
Frequently asked questions
Does a steel pressure vessel in a hazardous zone fall under ATEX?
Not where it has no potential source of ignition of its own. Article 2(1) of Directive 2014/34/EU requires precisely that: equipment capable of causing an explosion through its own potential sources of ignition. A bare steel vessel with no electrical equipment and no moving parts does not have them, is therefore not equipment within the meaning of the directive and falls outside Article 1(1). The ATEX Guidelines name a tank in the borderline list expressly as outside the scope. Add an agitator or a sensor and it tips over.
May I affix an Ex marking to be on the safe side?
No. The ATEX Guidelines state in paragraph 41 that items without an ignition source of their own should not be given an Ex or CE marking under this directive, and paragraph 145 warns against misleading information on equipment, such as the number of a notified body where the directive provides for none. A marking that does not belong there is an incorrect statement about your product.
My equipment is category I and falls under ATEX. Does the PED still apply?
No. Article 1(2)(f)(vi) of Directive 2014/68/EU excludes equipment classified no higher than category I which is also covered by Directive 2014/34/EU. Recital 9 gives the reason: that other directive is deemed to provide adequate protection as long as the pressure risk stays small. Where you come out in category II or above, the PED does apply, alongside ATEX. PED guideline A-39 confirms that the exclusion covers assemblies as well.
How many CE markings and declarations belong to equipment covered by both?
One of each. ATEX Article 14(3) and PED Article 17(3) both prescribe that a single EU declaration of conformity be drawn up in respect of all applicable Union acts, stating the publication references. In both directives the CE marking indicates that the product meets all applicable requirements. What may double is the identification number following the marking, and only where two different bodies are involved in the production control phase.
What do I have to give my customer if my vessel falls outside ATEX?
The particulars he needs for his explosion protection document and that the PED does not ask of you: the earthing provision, the conductivity of any coating or lining, and the surface temperature the contents can produce. Article 3.5e(d) of the Dutch Working Conditions Decree declares the admission test to apply by analogy to work equipment that is not ATEX equipment but may give rise to an ignition hazard once incorporated into the installation. Your vessel falls squarely under that.
Unsure whether ATEX applies to your equipment?
The question can be settled with an ignition hazard assessment and a look at your category. I work through your case and put the outcome on paper with the provisions next to it: that is the classification appraisal.
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