Australian Pressure Equipment Knowledge

GN 012 - Signs or Indications in In-service Inspection of Pressure Equipment

Details

Category: Use & In-Service Inspection

Developed for:  ACA, AICIP, AIES, AINDT, CAAA, Eng Aust, Met Aust, NATA, Stds Aust, WTIA, & PE Industry & Regulators

1   Scope
 .1  This Note gives the basis, procedure and intended use of a voluntary, co-operative system for pressure equipment inspectors and others to input and view freely on AICIP website, cases or examples in colour of various signs (unusual features) observed during in-service inspection of pressure equipment (PE).
 .2  It lists most of the different signs encountered (see Appendix A) and refers to the supporting website for the first 50 cases shown in colour in user-friendly form and with relevant details. Others added to the website will provide an expanding library of PE signs. Each case will be limited to non-confidential, essential technical data.
 .3  The Note also gives guidance in Appendix B on the use of signs in inspection and assessment of PE integrity, risk and remaining life.
 .4  These signs are a major early step in inspection (including examination and testing) in determining integrity of PE.

2   Purpose
This Note is intended to:
 a)  help all interested PE personnel, users, manufacturers, inspectors, and NDT, maintenance, education and training bodies and personnel, as well as trainees to learn from experience and identify and use signs effectively.
 b)  enhance the quality and efficiency of PE inspection and industry performance, safety, economy, and facilitate ready access to information from any part of Australia via the internet.
 c)  supplement AS/NZS 3788 (Ref 1) and AS 3978 (Ref 2) by direct reference. (see “www.aicip.org.au” for examples in colour).
 d)  harness, condense to manageable levels and share the huge experience and knowledge now becoming available e.g. as in excellent AICIP inspectors’ reports for renewal and recertification. [If shared knowledge saves life and plant, it is worthwhile].
 e)  encourage and facilitate further communication, exchange and co-operation within industry and between inspection personnel.
 f)  possibly set an example of a system for condensing, sharing and communicating latest technical knowledge for the benefit of all; and if successful, use for improvement of laws, standards and other knowledge areas.

3   Signs
The signs covered are unusual, abnormal or unexpected appearance, features, indications, imperfections (flaws), defects, damage, condition, deficiencies, or wrong or missing items, nameplates and marks which:
 a)  may indicate acceptable,  doubtful or unsafe or dangerous condition requiring special attention
 b)  are observed mainly on surfaces (external, internal, section, macro or micro) primarily by visual examination (VT)
 c)  may be detected at any stage in the life cycle of the equipment;  
 d)  occur primarily in metals but also in non-metallic materials;  
 e)  occur primarily in welded and non-welded pressure equipment but also in other similar equipment and structures (tanks, bins, silos and pipelines) in virtually in all industries: PE, Power Generation, Alumina, Petrochem, General industry, Pipeline, Water, Building, Mining etc.
 f)  may be single or in combination.

4   Background
 .1  The need for such a note was identified many years ago by industry, inspection authorities, training bodies and others, particularly when self-regulation was being introduced in the Australian PE industry about 1995. It was raised as a possible AICIP project in Sept 2005. Since then, there has been much research and examination to arrive at this Note.
 .2  The real component or part, or a 3 dimensional replica with varying surface signs are the best way to assess signs but are rarely available to most. The next best are colour photographs which are now readily available through the use of digital cameras which can be adjusted with detail to suit the user.
 .3  Reports from AICIP inspectors for renewals or recertification have shown what is capable with over a thousand excellent confidential photographs with valuable data, showing and explaining various signs and future action to ensure safety and performance of PE.
 .4  These reports have identified over 100 different signs, all of which give excellent guidance for the future action needed.
 5.  Computer systems are now readily in use with easy access to websites, compatible with electronic cameras, and able to retrieve data using key words. These can be used to readily and economically record, transmit and access colour photographs of signs and their details from anywhere.
This is the crux of the system used for this note and the cases given.
 .6  Verbal discussions with a number of inspectors and PE industry personnel indicated support for such a system.
 .7  Final proposals were given AICIP agenda item 17 “Project background – PE surface signs – Guidance Note” 30 Nov 2009.

5   Terms, Abbreviations and Units
 .1 General For optimum communication, it is desirable to use clear, universally accepted words and especially key words to facilitate use of the library of cases.
For this note and all cases, keywords should align with:
- standard titles for the type of PEs e.g. as in AS/NZS 3788 etc.
- AS 4942 PE Terms and definitions (Ref 3)
- ISO 14224 Taxonomy for Oil and Gas equipment – types of equipment (Ref 4.
Alternative names (eg. ends and heads, branches and nozzles) are acceptable. Abbreviations should be those commonly used or in Standards.  Units should be metric, and pipe and tube should use DN number.
 .2 Signs - this Note aligns with medical practice with “sign” meaning:
- “outward or objective evidence or indication what the inspector finds as abnormal or unusual when inspected”  [c.f. “Symptoms – subjective evidence the patient reports to the doctor” e.g. reduced PE output or heat exchange or increased cleaning.]
- Terms have been partly aligned with AS  2337 (Ref 5), ISO 10464 (Ref 6), API RP 571 (Ref 7).
 .3 Inspection – “activities such as measuring, examining, testing, gauging, calculating, checking, verifying one or more characteristics of a product design, material, manufacture, product, service, process, plant or reports and determination of their conformity with specific requirements or on the basis of professional judgement with general requirements” – (Ref 8).
 .4 Pressure Equipment – “boilers, pressure vessels and pressure piping” which includes gas cylinders, attachments, valves, instrument, supports, coatings and access facilities. This Note can also apply to similar equipment e.g .pressure machines, tanks, bins, silos and pipelines, and to supports, stacks and ducts.

6   Use of Signs in Inspection
 .1  Signs are extremely valuable in:
 a) in-service inspection and investigation of PE;
 b) diagnosing, with other PE data, what failure modes (or damage mechanisms) are involved;
 c) determining the most probable cause(s) of the sign;
 d) assessing the current and future safety, performance and life of PE;  (e.g. see Case A04);
 e) deciding the actions required to provide optimum outcomes. [Actions may be continue as is, repair,
 replace, re-rate (P, T, throughput), shut-down immediately, safeguard, or disposal].
 .2  For optimum identification of signs, failure mode, causes and necessary action, signs often need to be supplemented with some additional data e.g. Plant, process, PE, component or part, dimensions, manufacture, materials, prior history (age, service, repairs etc), current service conditions (contents, P, T, flow, stress, vibration, internal and external environment), drawings, MDR, test results etc.). See Appendix B.

7   Signs – Types etc
 .1  Types   The main signs encountered during in-service inspection of PE are listed in Appendix A.
 .2  Origin   They may have originated during manufacture, transport or installation, but more likely during operation or maintenance.
 .3  Occurrence   They may be on various pressure parts and also on internal trays, baffles, attachments, supports, coatings (paint etc, refractory, insulation, wear plates, anodes, and any other component which may influence PE integrity and safety e.g. ladders, platforms, stacks and ducts) and may be on various metals and non-metals and various forms (e.g. plate, castings, forgings, extrusions).
 .4  Causes  All signs have a cause and almost always includes inadequate human performance (ignorance, error, omission, sabotage). Various cases to this note give examples.
 .5  Acceptability   They may be DNC, C, acceptable or unacceptable (repairable or not) or doubtful (and requiring more assessment) depending on their severity and effect. See section 17.

8   Description & Features of Signs
The following features should be used where necessary to suitably describe the observed signs and can be invaluable in determining failure mode and cause:
 a) location/position – component, with respect to openings, supports, stress raisers, etc, top/overhead/bottom, inside/outside, internal, in weld, HAZ or parent metal.
 b) direction – circumferential or longitudinal to PE; axial or transverse to weld; aligned etc
 c) dimensions – l, w, h, d - in mm or area in mm2; %; or mass loss, etc.
 d) extent – local, general, scattered, intermittent.
 e) material(s) – type, thickness
 f) see Fig B1 for other basic PE data which may be needed.

9   Detection of Signs
 .1  Here the main method of detecting signs initially is VT during in-service inspection, if necessary using low magnification aids, rules, gauges or boroscopes, etc. Other senses – smell, hearing, touch (or feel -heat), and taste - are sometimes also used. Sometimes a 6th sense is useful – don’t ignore.
 .2  Various NDT and other tests may also assist where appropriate, e.g. MT, PT, ECT, PMI, HT etc.
 .3  Knowing the PE construction, operation, contents, prior history, experience and Ref 1 give a good idea when and where to look for significant signs e.g. welds, joints, change of shape, openings, attachments, cavities or areas subject to flame or change of fluid flow.
 .4  Signs may be detected properly, but not necessarily identified or assessed, by any competent person e.g. AICIP and WTIA Certified Inspectors, AINDT personnel, or equivalent.
 .5  See Ref 2 for VT (e.g. lighting, safe access, cleanness, viewing aids, etc).

10  Identification of Signs
Usually this is straight forward but training, assistance and tests may be needed to properly identify some cracks and corrosion. There are may types of both. Location, material, stresses, temperature, content and other service conditions may need to be known for correct identification. Further guidance is being considered. Ref 1 gives some guidance.

11  Assessment of Signs
This should be done by competent persons in accordance with acceptance criteria listed in:
the appropriate Standards for new or repaired PE, components and material;
the variations provided for in AS/NZS 3788; (appendices N and O); or
the equivalent (i.e. gives comparable outcomes to a) and b) and is safe and acceptable to the PE owner/user.

12  Cases and Content
The first cases or examples, A 01 etc are shown in colour on the dedicated website address www.aicip2.org.au
These show the standardised format to be used for all cases where practicable i.e:
•    Size   max of 1 or 2 A4 pages per case (to facilitate possible reproduction).
•    Layout   as in present cases.
•    Title   minimum, sufficient and including most main key words. Other key words in text should be bold.
•    Case No and Date entered – added by AICIP in sequence using ISO date method. [A=AICIP]
•    1 Photo   1 (or 2) digital photos in realistic colour with a scale, etc to indicate size and, if practical, in position similar to that in service preferably with lighting from above.  Photo on web should be sufficient size for ready identification of the equipment or component, permit expansion for detail and if needed have an arrow or indicator to the sign.
•    2 PE Involved   brief but sufficient details. Add country of occurrence if not Australia (may use two ISO letter method for email country identification).
•    3 to 10   minimum words but sufficient to support each case with significant data e.g. as in Section 5.2 as appropriate
•    11 References   may be added if readily available (also results of vital tests).
•    Contributor   if agreed, the inspectors registered number or equivalent

13  Use of Cases and Data
 .1  The cases are intended to be used to identify signs observed in inspection, and also preferably with credit (quote case no.) and any necessary amendment for inspector’s reports, training notes etc.
 .2  For conditions for the use of the data, see 18 below.  
 .3  See Appendix B for use of signs in inspection and assessment of PE integrity, risk and remaining life.
 .4  The official copy of the note and its cases is that on the AICIP website. (Trainers etc may wish to amend and add personal comments for their students, etc).
 .5  For optimum use, check the website for any revisions or new entries covering the same subject.
 .6  Remember each case may differ even though they look identical. Circumstances may differ.
 .7  If in doubt, contact a colleague, comment on the Case No, or later use the Forum (Section 22).

14  Adding Cases
 .1  Cases from any contributor to be added to the web should be presented in form and layout similar to that in the first cases and as in 9 above.
 .2  To give credibility to knowledge on this subject, each case added to the web must be:
 a) checked by the contributor for permission for AICIP to add to its web.
 b) supplied in compliance with AICIP code of ethics (Ref 8 or equivalent) and this note.
 c) checked  by an inspector’s peer before email submission to AICIP.  
 d) authorised by the contributor for use by AICIP in accordance with this note.
 e) checked by AICIP prior to giving a Case number and date and adding to the AICIP web.
 .3  Checks are to ensure the Code of Ethics is complied with, there are no unacceptable words or comment of bodies or persons, and only factual technical information is presented except if suitably cleared by the contributor or in the public domain e.g. Royal Commission, WorkSafe, or Coroners’ Reports or equivalent.
[Note: To date, AICIP holds samples and data on over 50 PE signs supplied by industry for the benefit of inspectors and industry on the condition they not traceable].

15  Case Confidentiality
 .1  AICIP records will only list the contributor identification and date the case is supplied – all confidential unless cleared by the contributor
 .2  Data on the Web aims at full transparency but recognizes confidentiality is essential for the system to work well i.e. In general, no specific names of people, bodies, equipment, places or times will be listed unless cleared as in section 16 3rd Para.

16  References
[1]   AS/NZS 3788     Pressure equipment – In-service inspection
[2]   AS 3978     Non-destructive testing – Visual inspection of metal products and components
[3]   AS 4942     Pressure equipment – Glossary of terms
[4]   ISO 14224     Petroleum and natural gas industries – Collection and exchange of reliability and maintenance data for equipment
[5]   AS 2337     Gas cylinder test stations - General requirements, inspection and tests
[6]   ISO 10460:2005     Gas cylinders – welded carbon-steel - gas cylinders - Periodic inspection and testing
[7]   API RP 571     Damage Mechanisms affecting fixed equipment in the refining industry
[8]   SAA/NZS MP76:1997     Pressure equipment – Inspection bodies and personnel

Appendix A     Types of Signs
Appendix B1    Use of Signs in PE ISI
Appendix C     Australian Pressure Equipment Knowledge System
Appendix D    List of Cases

Website for cases, and this note GN 03, see “www.aicip.org.au”

[Drafting Note: Not yet installed on Web but available on temporary www.stan.ambrose.id.au/pesigns]

 Appendix D

 List of Cases

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