1、 2005 THE ENGINEERING EQUIPMENT however, the guidance given in the technical part of this publication (the case studies in the Appendix) are essentially unaltered from the original internal document. EEMUA encourages comments on this publication from both Members and non-members of the Association.
2、Comments will be considered by the EEMUA Piping Systems Committee (PSC). For further details see Consultation and Feedback, p. iii. 1 INTRODUCTION The European Pressure Equipment Directive 97/23/EC, to give the PED its full title, sets out the requirements for pressure equipment placed on the market
3、 or put into service for the first time. The requirements for modifications and maintenance are not described in detail, and although official guidelines exist, they are general in nature. So, the involved parties (user, manufacturer and notified body) may need further guidance in interpreting the r
4、equirements of the PED applicable to their particular circumstances. In cases where it is concluded that the PED does not apply, consideration should be given to whether relevant national regulations such as the Pressure Systems Safety Regulations in the UK, or their equivalent in the other countrie
5、s of the European Economic Area* do apply. In the UK, particular consideration needs to be given to whether Regulation 13, Modification and Repair, applies. 2 SCOPE This publication gives guidance to the user of piping concerning the application the PED to piping modifications and maintenance. Guida
6、nce is in the form of cases that are typical of the range of piping issues: it is not intended to be a comprehensive list. The examples represent a consensus of EEMUA PSC members based on their understanding of the applicable regulations at the time of publication. It should be noted that despite an
7、y advice given in this document regarding repairs and modifications to pressure equipment, it is the ultimate responsibility of the owner of the equipment to ensure compliance with the applicable regulations. 3 PIPING AS AN ITEM OF PRESSURE EQUIPMENT The definition of piping in Article 1 (2.1.2) of
8、the PED (piping components when connected together for integration into a pressure system) includes: in particular a pipe or system of pipes, tubing, fittings . Article 3 (1) and (1.3) recognise piping as being pressure equipment. The term item our emphasis of pressure equipment first appears in Art
9、icle 15, 2, first indent, with back reference to Article 3 (1); there is no restriction placed on the extent of piping that could constitute an item of pressure equipment. The interpretation is that a system of connected pipes and fittings, such as may be assigned a dedicated line number in a piping
10、 schedule, can be a single item of pressure equipment as can, say, a short flanged spool connecting two items of pressure equipment. The user (either the plant owner/operator or a contractor working on behalf of the owner/operator) should therefore indicate for each job whether the item of pressure
11、equipment for piping is to be the flanged spool or the complete line. This applies whether a *The European Economic Area, in which the PED applies, comprises the European Union, Iceland, Liechtenstein and Norway. Switzerland has also transposed the Directive into law, which becomes fully effective a
12、t the beginning of July 2005. 1completely new line, or a flanged spool for an existing line, is being purchased. In most cases, unless otherwise agreed, the complete line (as given by a specific line number) should be considered as an item of pressure equipment. This also applies when all the piping
13、 (comprising several lines) on a plant is considered an assembly and stamped with a single CE mark. 4 IMPORTANT CHANGES The European Commission Blue Guide*(Chapter 2) uses the term product to describe things complying with various Directives. Products includes equipment and assemblies, the terms use
14、d in the PED. Two other statements are significant: A product, which has been subject the word should be subjected to important changes that aim to modify its original performance, purpose or type after it has been put into service, may be considered as a new product. This has to be assessed on a ca
15、se-by-case basis . Where a rebuilt or modified product is considered as a new product, it must comply with the provisions of the applicable directives . Products which have been repaired (for example following a defect), without changing the original performance, purpose or type, are not to be consi
16、dered as new products according to the New Approach directives. The PED does not, therefore, apply to repairs and maintenance, but it does apply to replacement and important changes. For piping, the distinction between repairs, replacement and modifications is often blurred. The process industry con
17、siders all changes to be potentially significant, from a process safety point of view. Indeed, a fundamental feature of process safety management is management of change, (sometimes referred to as control of modifications), requiring careful assessment and implementation of all modifications. There
18、are two official PED guidelineson this subject: Guideline 1/3 Question: Are replacements, repairs or modifications of pressure equipment in use covered by the directive? Answer: 1) Entire change: the complete replacement of an item of pressure equipment by a new one is covered by the PED. 2) Repairs
19、 are not covered by the PED but are covered by national regulations (if any). 3) Pressure equipment which has been subject should be subjected 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 pro
20、duct covered by the directive. This has to be assessed on a case by case basis. Note 1: Operating instructions in the sense i.e. context of the PED (see guideline 8/3) cover documentation concerning safe operation including maintenance, but not necessarily detailed information concerning repair or m
21、odification of the equipment (e.g. material certificates or qualification of welding procedures). Such information may be provided by a specific contractual agreement between manufacturer and user. Note 2: The directive applies only to the first placing on the market and putting into service. See Bl
22、ue Guide chapter 2.1. *Guide to the Implementation of Directives Based on the New Approach and the Global Approach The full set of guidelines can be viewed and downloaded on http:/. 2Guideline 1/4 Question: When is a modification of a piping system not covered by the PED? Answer: When the content, m
23、ain purpose and safety systems remain essentially the same, it may be regarded as a non-important modification of an existing piping system and is therefore not covered by the PED. Reason: See guideline 1/3. * To assist in this matter, EEMUA PSC suggest that the following examples should each be con
24、sidered an important change: 1 Change resulting in an increase in PED Category (for example due to a change of fluid, pipe size, or pressure). 2 Change to process duty to provide a major new process function minor changes in fluid/composition or flow rate would not normally be regarded as a change i
25、n process duty. 3 Change of (piping) material type (not grade within a type). 4 Changes of pressure and/or temperature resulting in significant changes to loads on equipment and stresses, considerably increasing those in the original design. In summary, all changes need to be controlled by effective
26、 management of change procedures, and conform to the PED and in-service regulations (e.g. Pressure Systems Safety Regulations in the UK) as appropriate. 5 CASE STUDIES To examine the applicability of the PED, the case studies in Tables 1 and 2 of the Appendix have been prepared. The opinion of EEMUA
27、 PSC on PED compliance is given in each case, and will be amended only in the event that information to the contrary is received. Case Nos 1.1, 1.2, 1.5, 1.6, 1.14 and 2.2 are the subject of ongoing discussions with the Health and Safety Executive (HSE) in the UK. 6 UNDER THE RESPONSIBILITY OF THE U
28、SER Regulation 4(2) of the UK Pressure Equipment Regulations*states: For the avoidance of doubt these Regulations do not apply to the assembly of pressure equipment on the site and under the responsibility of the user. (This accords with the last part of Recital 5 of the PED.) A letter from the HSE
29、responding to an enquiry from an EEMUA member company offers the following interpretation: “ under the responsibility of the user includes a case where the user assembles it the pressure equipment himself, or where it was assembled by contractors acting under his control. But it does not extend to a
30、 case where the user places an order for an assembly, specifying what he wishes it to achieve, and the person to whom the order is given designs, fabricates etc. it and hands it over after installing it at the site. That is to say, the user could naturally be described as the customer. “The company
31、mentions that In some cases the contractor must submit deviations from the contract specs etc. to the user companys technical authority for endorsement, implying that that user may be taking responsibility for the assembly. Up to a point he is taking responsibility of something. But that seems to fa
32、ll a long way short of what regulation 4(2) contemplates by assemblyunder the responsibility of the user.” Based on the above, HSE subsequently issued operational circular OC 308/14 (12.9.03) as an interpretative guide for their inspectors. Guidelines 3/1 and 3/2, pertaining respectively to global c
33、onformity assessment and joining operations, also have some bearing on the issue. *The transposition of the PED into UK law. 3APPENDIX: DETAILED CASE STUDIES TABLE 1: CHANGES TO PIPING WHICH IS NOT CE MARKED CaseNo. Case PED Compliance Background1.1 A line contains a number of flanged spools and som
34、e of these require replacement because of corrosion Not required. This is not an entire change of an item of pressure equipment, and none of the important changes listed in Sec 4 above applies.1.2 A line contains some flanged valves and some flanged spools, one of which contains a welded-in valve. A
35、ll the valves have to be replaced because of corrosion. Required for valves. Not required for spools. All valves are purchased under the PED. The PED does not apply to the spool with the valve welded in because none of the important changes listed above applies. 1.3 A line, either welded or containi
36、ng a number of flanged spools, is to be partially re-routed without a change of design pressure, design temperature, material type or process duty. PED compliance is required if the modification is deemed important by the user and piping manufacturer; otherwise, it is not.An important change is one
37、where the stresses in the new layout significantly exceed those in the original layout. 1.4 Two existing lines are to be linked by fitting a new flanged spool between flanges on the lines. Required. A new line is being created with a new process duty. This is an occasion where an individual spool wo
38、uld be CE marked (unless the item is to Sound Engineering Practice (SEP). 1.5 A drain or vent branch is to be added to an existing line by welding on a branch, by welding in a tee section or by fitting a new intermediate flanged spool within the existing line which incorporates a tee. Branch will no
39、rmally terminate with a valve and blind. Required for valves (but likely to be SEP because of size). Not required for the tee or spool. The branch does not provide a major new process function and a new line number is not being created for it.1.6 A branch is welded onto an existing line and fitted w
40、ith a valve which feeds through an impulse line to a dead headed measurement instrument. Alternatively, a thermowell pocket is welded into a line. Required for valves. Not required for either the branch or thermowell pocket. The branch does not provide a major new process function and a new line num
41、ber is not being created for it. Not generally required. The PED does not apply because the process flow is not significantly altered. 1.7 A by-pass pipe is fitted to run around a control valve, filter or heat exchanger. Required if the by-pass affects the safety system. Effect on pressure relief ne
42、eds to be considered. The relief stream may be sized on the basis of a control valve. The by-pass pipe may invalidate this.1.8 An additional lifting lug or pipe support is attached to a pipe by welding. Not required. Not an important change. 4Table 1 (contd): Changes to piping which is not CE marked
43、 CaseNo. Case PED Compliance Background1.9 An existing line in one grade of material (e.g. carbon steel) is to be replaced either partially or totally by another grade of material (e.g. stainless steel). Required. The important change relating to material applies. 1.10 A new section of line, i.e. a
44、spool with no flanges, is welded into a line because the original section was corroded or damaged. Not required. This is a repair and, under Answer 2 of Guideline 1/3, repairs are not covered by the PED.Not required if the re-rating does not exceed the PED category that would have applied to the ori
45、ginal design.*Not an important change.1.11 New flanges are fitted throughout a line because the line is being re-rated and the revised design conditions exceed the original flange rating. Required in the event that the re-rating exceeds the PED category that would have applied to the original design
46、.*If the re-rating results in a higher PED category, the line cannot be used for the re-rated duty without being re-certified and CE marked.Not required if the re-rating does not exceed the PED category that would have applied to the original design.*Not an important change.1.12 A complete line is r
47、e-rated because of a change in design pressure and/or temperature, but no change to the line is required (because the revised design conditions still fall within the original class on the piping specification data sheet). Required in the event that the re-rating exceeds the PED category that would h
48、ave applied to the original design.*If the re-rating results in a higher PED category, the line cannot be used for the re-rated duty without being re-certified and CE marked.*Note that the assigned PED category and re-rating should be applied to the line number on the line list and not to the piping
49、 specification data sheet.1.13 A fully welded line is entirely replaced in the same material, on the same route, with no change to the fluid parameters, but with flanged spools over its length (to avoid issues over hot work at a later date or to allow easier operations or maintenance access). Required. As the whole line is being renewed, under Answer 1 of Guideline 1/3, relating to complete replacement of an item of pressure equipment, the PED applies. 1.14 A
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