1、The mechanical integrity of plant containing hazardous substancesA guide to periodic examination and testingEEMUA Publication 231 - Ed 1SAFed Publication IMG 1The mechanical integrity of plant containing hazardous substancesA guide to periodic examination and testingEdition 1 - September 2012Forewor
2、dThis document has been developed and written by the Safety Assessment Federation (SAFed)and the Engineering Equipment competent person means a competent individual person (other than an employee) or acompetent body of persons corporate or unincoporate; and accordingly any reference in theseRegulati
3、ons to a competent person performing a function includes a reference to his performing it through his employees;The Approved Code of Practice (ACoP) to the regulations gives comment on the role as follows;The term competent person is used in connection with two distinct functions:a) drawing up or ce
4、rtifying schemes of examination (regulation 8); andb) carrying out examinations under the scheme (regulation 9).And;In general terms, the competent person should have:a) staff with practical and theoretical knowledge and actual experience of the relevant systems;b) access to specialist services;c) e
5、ffective support and professional expertise within their organisation; and d) proper standards of professional probity.However, the term competent person, has also been used in other publications in acontext much wider than PSSR.1.2.2 Inspection/ExaminationWithin this guidance these are considered i
6、nterchangeable terms to describe variousactivities aimed at assessing the integrity of plant and equipment.Inspection and examination are considered as focussed activities that lead to a report onthe condition of a piece of equipment and its suitability, or not, for further service. Theymay consist
7、of a single part of an activity, e.g. a visual examination, or be the sum ofseveral parts, e.g. a visual examination and a range of non destructive examinationtechniques (ultrasonic thickness measurements, crack detection etc).The reader should be aware that other documents may use these terms in ot
8、hercontexts, or as interchangeable terms.1.2.3 TestA component of an examination and a discrete activity aimed at providing information foran examination report. However, in itself it would not usually provide information into allaspects of the current condition or assessment of ongoing equipment in
9、tegrity. Examplesinclude a hydraulic test, a holiday test (standard practice for checking discontinuities) or athickness test. 1.2.4 IndependenceIndependence is the management structure that ensures that the individuals and teamsmaking key decisions relating to integrity management are isolated from
10、 other factors thatmight result in a conflict of interest (e.g. a desire to maximise production may createpressure to operate equipment beyond the time for which its integrity may be assured).8 of 55The mechanical integrity of plant containing hazardous substancesA guide to periodic examination and
11、testingEdition 1 - September 20121.2.5 Integrity assessorThe integrity assessor is the person, team or corporate body, who (like the competentperson) takes responsibility for all elements of an examination (including those carried outby another person or body), the interpretation and the formulation
12、 of the conclusions ofthe examination.This term has been introduced to cater for those who do not wish to use the termcompetent person in situations where PSSR does not apply. Equally it can apply wherethe site operator does not wish the PSSR competent person to carry out the extra worknecessary to
13、meet the requirements of other regulations such as COMAH or PUWER.9 of 55The mechanical integrity of plant containing hazardous substancesA guide to periodic examination and testingEdition 1 - September 20122.0 OVERVIEW OF INTEGRITYMANAGEMENT THROUGHOUT THE PLANT LIFECYCLESuccessful management of pl
14、ant integrity requires a clear strategy; not just for periodicexamination, but for the whole plant lifecycle. This is especially important on sitesstoring and processing hazardous substances, where the consequences of integrity failurecan be major.Whilst this guidance is focussed towards examination
15、, it is very useful to put this intocontext, as this is only one element of an integrity management strategy. If the plant wasnot specified, designed or constructed correctly, ongoing integrity management mayrequire a unique approach and be problematic. Also key to maintaining integrity is theassess
16、ment of the results of examinations, especially where the report states that theequipment has defects.Diagram 1 on page 10 shows a Overview of integrity management throughout the plantlifecycle. This flowchart provides an overview of the different elements of the strategy, and how they link together
17、 and inform one another. All elements of the flowchart arediscussed briefly in this chapter, but some are beyond the main scope of this guidance document.2.1 SPECIFICATIONGetting the original plant specification correct is key, so that plant is designed to besuitable for the intended duty. Some of t
18、he issues that need to be addressed include:How big does the vessel / storage tank need to be?What will it contain in normal use?What will it contain during other operating circumstances, such as during start-up,shut-down and cleaning?What are the hazards of this substance?How might the contents aff
19、ect the vessel / tank / pipe-work?What temperature a high hazard situation will require a morerigorous examination regime than a low hazard one.The following examples illustrate this point:What is considered to be a reasonably practicable examination regime for a simple airreceiver in a remote part
20、of a site would be much less than that expected for a reactorvessel, containing hazardous substances, sited in a populated area and which is subjectto complex process conditions, giving rise to multiple degradation mechanisms.Where the likelihood of a degradation mechanism affecting a vessel is very
21、 remote,but the consequences of a release from that vessel are high, it may still be consideredreasonably practicable for the examination regime to take it into account and employinspection techniques to detect it, should it occur.This guidance is aimed at equipment providing the primary containment
22、 boundary forhazardous substances, where consequences of release are likely to be significant, and it isconsidered reasonably practicable to go beyond the requirements of a PSSR examinationregime. The focus of this document is where hazards are high, and the examination has tobe sufficiently robust
23、to manage the risk of loss of containment.17 of 55The mechanical integrity of plant containing hazardous substancesA guide to periodic examination and testingEdition 1 - September 20123.3 OTHER ACTIVITIES AND REGULATIONSThe Lifting Operations and Lifting Equipment Regulations 1998 (LOLER), includere
24、quirements for thorough examination by a competent person. While thoroughexamination of lifting equipment is not covered in this guidance, it is worth noting thatsome principles contained here may be applicable to such a regime. For example, wherefailure of lifting equipment could lead to a major ac
25、cident on a COMAH site, perhapsbecause lifting operations take place close to equipment containing a hazardous substance,then it is reasonable to expect that the examination regime will be to a higher standardthan that for equipment used in less hazardous circumstances (for example there may bean in
26、creased frequency of examination, or greater safety margins).While maintenance and examination schedules to ensure the operability of mechanicalitems (such as pumps, agitators, valves etc) may be a requirement of PUWER or PSSR, itis not the focus of this guidance. However, many of the principles con
27、tained here may berelevant to these schedules. For example competent personnel are still required, as is astructured process for defining the work scope or any subsequent repair, and onlyauthorised postponements should be allowed.It is also important to consider that where the failure of a machine c
28、ould affect theintegrity of the primary containment boundary (e.g. agitator failure), then this should beconsidered in the integrity management regime.18 of 55The mechanical integrity of plant containing hazardous substancesA guide to periodic examination and testingEdition 1 - September 20124.0 EXA
29、MINATION POLICYAn examination regime is something which would be expected to cover the life of theplant or equipment, and be made up of several examinations / tests of the asset.Therefore careful thought and planning is required, particularly where the consequencesof release are significant.The main
30、 tool used in planning and specifying examination / testing requirements is theWSE, which is covered in more detail in Chapter 6. However, there are several basicissues that need to be considered in order to identify the approach to planning andimplementing an examination regime and any testing tech
31、niques to be used.4.1 OBJECTIVES OF EXAMINATIONThe ultimate aim of an examination regime is to ensure that the plant is safe. However,the specific objectives of any examination or test may vary, therefore it is important to beclear about what an examination regime is intended to achieve.It may be ex
32、pected to monitor damage from known degradation mechanisms or it may berequired to guard against or identify an unexpected degradation mechanism. A combinationof both may be the aim. Alternatively, a one off examination may be required to provideinformation for a fitness for service assessment or to
33、 allow specification of a repair.Whatever the objective, clear identification will help in determining the best approachto take.4.2 TYPES OF EXAMINATIONThere is a range of examination options available. Usually the more onerous offer greaterbenefit in terms of scope and detailed information gained.
34、However the simplest ofchecks can still provide benefit, and gain value from the ease and frequency with whichthey can be performed.Selection of the most appropriate, and effective, approach is likely to differ betweenequipment types and service duties. Therefore, there is no one size fits all answe
35、r to theproblem. The solution will be a combination of methods.To illustrate this point commonly used options are described below:a) Thorough internal examination: A detailed examination from both the interiorand exterior of the equipment. It is usually considered onerous because of the need totake
36、the equipment out of service, clean and make safe and therefore the frequency ofinspection can be an issue. Most commonly used on vessels, and may not be an optionfor smaller equipment such as pipework.b) Intermediate external examination: A detailed examination but undertaken fromthe exterior only
37、and therefore can sometimes be carried out when the equipment isstill in service, or at least with out the requirements for internal cleaning and confinedspace entry. It is usually accepted that this provides less information than an internalexamination, but it is considered less onerous and for tha
38、t reason it can be carried outat greater frequency. It is often used to supplement the less frequent thorough internalType A for an inspection body providing third party services,Type B for an inspection body providing services to its parent organisation (i.e. an in-house arrangement), orType C for
39、an in-house inspection body that also provides services to external parties.Whatever arrangements are in place for actually carrying out the inspection, it is likelythat a team will be required to implement an effective integrity management regime. Thisis because a range of different disciplines and
40、 competencies will be required to bring inthe required information and control the whole process from planning and executionthrough to decision making and review. More information is given below.Note: It is the readers responsibility to check for the latest edition of all Standardsreferenced.5.1 COM
41、PETENCEThose responsible for managing and undertaking maintenance, testing and inspectionshould be competent for this. Someone with an appropriate engineering qualification andrelevant experience would be expected to manage the maintenance, inspection andtesting systems and arrangements.Inspection b
42、odies should be able to demonstrate competence. One way to achieve this isthrough UKAS accreditation to BS EN ISO/IEC 17020.NDE personnel should be able to demonstrate training and competence. Principles ofqualification and certification of NDE personnel are given in BS EN ISO 9712. Suchcertificatio
43、n can be achieved under either a central certification scheme (e.g. PCN) or anemployer based scheme (e.g. ASNT). There should also be a means of validating any NDEtechniques proposed, to ensure that they are fit for the intended purpose and conditionsto be encountered.In addition to the formal arran
44、gements for qualification and accreditation described above,it should be remembered that an effective integrity management regime will requireconsideration of all aspects of the potential degradation, inspection and assessment of theequipment involved. Therefore the team involved will require compet
45、ency to provideinput in the following areas;22 of 55The mechanical integrity of plant containing hazardous substancesA guide to periodic examination and testingEdition 1 - September 2012Design of the equipmentProcess conditions and potential consequences of a loss of containmentOperating conditionsM
46、aintenanceMaterials technology (including, where relevant, corrosion or metallurgy expertise)Inspection techniquesAchievement of this will almost certainly require input from organisations or departmentsoutside the inspection body. That is, at the very least, input of process specific knowledgefrom
47、the site operational team.A site operator using third parties in asset integrity management should have checks inplace to confirm the competency of those parties involved. These should includecompetence checks as part of the selection and monitoring processes for contractors.This is likely to be ach
48、ieved by a range of means including review of previous experience,provision of references, demonstration of technical competence and externalaccreditation or membership of trade associations.Where a site operator uses in house resource, it is equally important that there aremeans to ensure the compe
49、tence of those involved.The Approved Code of Practice to PSSR9 sets out the attributes required for acompetent person against three different categories of equipment increasing in size andcomplexity. However, it should be noted that in some cases (e.g. a major hazard site) thehigh consequence of equipment failure may warrant higher levels of expertise for thoseinvolved in integrity assessment. See also EEMUA Publication 193 for recomendations onthe competence assurance of in-service inspection personnel10.5.2 ROLES AND RESPONSIBILITIESCareful clarification of ro
