Repairs and modifications

The commissionís Working Group "Pressure", came up with the following guideline (Guideline 1/3)

Question: Are replacements, repairs or modifications of pressure equipment in use covered by the directive ?

1) Entire change: the complete replacement of an item of pressure equipment by a new one is covered by the PED.
 2) Repairs are not covered by the PED but are covered by national regulations (if any).
3) Pressure equipment which has been subject to important modifications that change its original characteristics, purpose and/or type after it has been put into service has to be considered as a new product covered by the directive. This has to be assessed on a case by case basis.

Reason: The directive applies only to the first placing on the market and putting into service.
   See "Blue Guide" chapter 2.1

Read the third answer carefully, its not only modifications that require appraisal under the PED but also a change in the vessels/equipmentís purpose.  Therefore if the contents changed from group 2 to group 1, PED rules would have to be followed, but only in respect of the change.  Such changes in use donít necessarily require the structure of the vessel to be revalidated, providing sufficient evidence exists to prove that itís original construction was sound and that it is fit for its new purpose.  However, further assessment/NDT may be required if the soundness of the vessel canít be guaranteed.  Increases in design conditions such as pressure and temperature, or a reduction in temperature below 0°C, may also require PED appraisal.

If the outer pressure retaining chamber of a vessel is replaced or modified in size, then PED rules should apply as this will most likely constitute a new item, as defined in answer one above.

Modifications, such as the fitting of additional nozzles, are more difficult to access.  If the modification significantly changes the risk associated with the item, PED rules should be applied.  For example, fitting a small nozzle is not likely to change the soundness of the vessel, but a large one could seriously affect the vesselís structural stability and significantly increase its risk of failure, in this case PED rules should be applied.

Heat exchanger replacement tube bundles may require appraisal under the PED if the tubes are different in size, material or design. 

Pipework is the most difficult item to assess. A change in diameter, schedule, material, or even routing may require appraisal under the PED.  Adding small openings that impose no significant loading on the pipework, such as drains, could be exempt from the PED regulations.

  • If in doubt apply PED rules
  • If the risk associated with pressure is changed significantly PED rules apply
  • If the end user takes full responsibility for design and co-ordination of the modification, PED rules do not have to be applied.
Each member state has its own regulations covering in-service operation and inspection of pressure equipment, which must be consulted if PED rules are not applied.

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Page last updated 16 July 2002