Pressure Equipment

Flow chart pertaining to the Pressure Equipment Directive (PED)

Article 1			p > 0.5 bar Paragraph 3.1 - 3.2.1
Article 9			Group 1 or Group 2
Article 3			Engineering practice Article 3, paragraph 3
Article 9			Diagrams, Annex II
Article 10 Annex II			Depending on categorie

How is pressure equipment classified under the Pressure Equipment Directive ?

Pressure equipment is assigned to categories (I-IV) according to its risk potential as illustrated in the diagrams contained in Annex II. The risk potential is defined by:

 
• the medium's state of aggregation (gaseous, liquid) and its steam pressure
 
• the medium's type and nature of the risk (e.g. toxic, flammable, explosive)
 
• the stored energy (PS x V; PS x DN)

Example: A pressure vessel containing 100 l of a harmless medium is to be classified for a pressure of PS = 12 bar. The vessel must thus be suitable for media group 2. The medium's state of aggregation is gaseous. The product of pressure and content PS x V is 1200. According to the Pressure Equipment Directive, diagram 2 of Annex II applies.

PS = 12 bar, V = 100 liters, PS x V = 1200

The diagram shows that the vessel must be assigned to category III.

For further assistance re category determination in line with the Pressure Equipment Directive; see:

 
• Classification of "vessels" as per Pressure Equipment Directive
 
• Classification of "pipings" as per Pressure Equipment Directive
 
• Classification of hot-water / steam generators as per Pressure Equipment Directive
 
• Classification of safety and pressure accessories as per Pressure Equipment Directive

 
• CD ROM pertaining to Pressure Equipment Directive 97/23/EC

The modules can be described as self-contained test packages addressing the development and production phases of pressure equipment with the goal of furnishing evidence that the basic requirements of the directive have been satisfied. Since not every module covers the development and production phases, module combinations can also be used.

More information is contained in the next step.

Which test module should I use ? 

There are test modules or test-module combinations for every category. Manufacturers can choose freely from among these modules, e.g. depending on their QA systems.

The modules can be described as self-contained test packages addressing the development and production phases of pressure equipment with the goal of furnishing evidence that the basic requirements of the directive have been satisfied. Since not every module covers the development and production phases, module combinations can also be used.

• Description of the procedure by which the manufacturer ensures and declares that the respective pressure equipment conforms with the requirements of the directive
• Definition of the tests and surveillance measures to be carried out by a notified body
• Definition of the documents and documentation to be prepared

The modular approach of the Pressure Equipment Directive means the higher the risk potential of pressure equipment, i.e. the higher the category to which it is assigned, the greater the involvement of the notified body specified in the corresponding test module. The notified body is involved in all modules except for module A, "Internal Production Control", which is applied to category I pressure equipment. Test modules assigned to a higher category can be applied to pressure equipment of a lower category (downward compatibility), but not vice versa.

What personnel and operational requirements must be fulfilled ?

				Application of EN 729 et seq. to ensure expert workmanship of welding processes, more... Welding coordinators EN 719
				Welding on pressure equipment of categories II to IV may only be carried out by persons qualified to perform the task and possessing valid certificates, more...
				Non-destructive tests conducted on permanent joints of pressure equipment may only be carried out by skilled and adequately qualified personnel. Personnel conducting non-destructive tests on pressure equipment of categories III and IV, must be certified by a recognized and independent test body, ...before long more...

More information you can find in our Virtual Exhibition in the categories Welding technology and Testing / inspection.

Operational requirements

In addition to the above prerequisites, the manufacturing company itself must also satisfy certain requirements.

The manufacturer must ensure expert workmanship with respect to welding. This can be effected on the basis of EN 729-1, EN 729-2, EN 729-3 or the AD 2000 codes of practice.

More details about operational requirements... ...further information you can also find under Tools / Welding...

What materials can I be used ? 

According to the present regulations, the use of materials in steam-boiler, pressure-vessel and pipeline manufacturing was governed by the relevant Technical Rules such as TRD, AD codes of practice, TRR. The approved qualities and their scopes of application are described in these documents.

According to the Pressure Equipment Directive, only materials

• conforming to a harmonized standard
• for which a European material approval is available, and
• which have been individually inspected

may be used in future.

Currently, some harmonized standards are available. Since there are no EN product numbers pertaining to the PED so far, other standards, e.g. AD-2000, that satisfy the directive's basic safety-related requirements may be used. With respect to materials use, AD-2000 contains similar regulations to those of previous AD codes of practice of the W (materials) series. The materials listed there are regarded as individually inspected.

An official individual inspection as per Pressure Equipment Directive must be carried out within the scope of document review. In the modules covering the QA system, the materials used by the manufacturer must be subjected to individual inspection and a certificate of such inspection issued by the notified body in addition to its evaluation of the QA system.

Visit also our Virtual Exhibition in the range of Manufacturing / distribution of materials and semi-finished products

More information you get under Aids/Tools/Material.

What Technical Rules do I have to apply ?

In line with Article 5 of the Pressure Equipment Directive (PED), conformity is assumed when harmonized standards are used, i.e. the requirements outlined in Annex I of the Pressure Equipment Directive are regarded as satisfied.

Since the application of harmonized standards is not mandatory, manufacturers may also opt for other solutions to satisfy the requirements of Annex I of the Pressure Equipment Directive.

For this reason, internationally recognized codes of practice such as the AD codes of practice, BS 5500, CODAP were revised with respect to their application within the scope of the Pressure Equipment Directive.

        You can also inform directly in thePressure Equipment Directive and other regulations.