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1、AS 43432005 Australian Standard Pressure equipmentHazard levels AS 43432005 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 10 Oct 2008 This Australian Standard was prepared by Committee ME-001, Pressure Equipment. It was approved on behalf of the Council of Standards Australia on 29 July 2005. This St
2、andard was published on 15 September 2005. The following are represented on Committee ME-001: ACT WorkCover Australasian Institute of Engineer Surveyors Australian Aluminium Council Australian Building Codes Board Australian Chamber of Commerce and Industry Australian Industry Group Australian Insti
3、tute for the Certification of Inspection Personnel Australian Institute of Energy Australian Institute of Petroleum Bureau of Steel Manufacturers of Australia Department for Administrative and Information Services, SA Department of Consumer (b) record in more detail its important requirements and so
4、 supplement Clause 2; (c) discuss its origin, development from AS 3920.1 and its relationship to other Standards; (d) provide a comparison with EU-PED (Ref. 1) to avoid confusion in trade; and (e) advise on the standards use for purposes other than originally intended. WHY WAS THIS STANDARD NEEDED?
5、In 1978, the late Alex Wilson AM, Chief Metallurgist, Electricity Commission of NSW, asked a new Chief Inspector of Boilers to clarify the law that required Government design approval, manufacturing inspection, registration and in-service inspection by government or licensed Inspectors, for a 30 L 1
6、 MPa air receiver, but did not require this for 660 MW, 16 MPa high-temperature steam turbine, which was potentially far more hazardous. The 1962 Boiler and Pressure Vessel Regulations in NSW covered all equipment above or below atmospheric pressure, except vessels forming part of domestic cold wate
7、r supply or those containing liquid below 100C when pressure was due solely to height of liquid. By various exemptions, this was not applied to most small or very low-pressure equipment for practical reasons and because hazards were extremely low. Obviously, a more logical and reasonable basis was n
8、eeded. By 1978, most regulations in Australia were still mainly based on boilers and air receivers associated with mines. Major developments after World War II had greatly increased pressure equipment types and numbers used in industry and by the public, e.g. mains pressure hot water heaters, gas cy
9、linders, automotive LP Gas pressure vessels and many other types of consumer equipment. These serially produced vessels, which are now addressed by AS 29712002, Serially produced pressure vessels, (first issued in 1987), are used by millions in Australia and very few serious accidents have occurred,
10、 those that have occurred being mainly due to misuse or inadequate protection. The existing regulations were similar across Australia but varied in important details and needed to be improved and unified to cover the burgeoning consumer market in pressure equipment. Also in the 1970s, the world reco
11、gnized the value of Quality Assurance (QA) systems to enhance quality management and hence safety. This was introduced into ASME Section VIII in 1973 but was not recognized in Australian pressure equipment regulations or Standards, although in effect was partly used by inspectors. The main problem t
12、hen was how to improve the total system of pressure equipment Standards and achieve the following: (a) Relate hazards (pressure, volume, content fluid type, temperature) to regulatory controls in design verification, fabrication, inspection, and design and equipment registration. In-service inspecti
13、on was not considered at the time. (b) Accommodate the new move by advanced industries to quality assurance. Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 10 Oct 2008 5 AS 43432005 (c) Continue to meet governments desire to ensure that risk levels of occupational (and public) safety and health are lo
14、w. (d) Make the system consistent across Australia. After 1995, these functions were largely deregulated and made self-regulatory by industry itself as part of a major shift of philosophy on the role of government. This aimed to provide more flexibility, reduce cost to industry and the public, and u
15、se legal prosecution to maintain a very low risk record. BACKGROUND TO THE STANDARD General As the pressure (p) and volume (V) of pressure equipment increase, the pressure energy also increases; and as this energy increases, probability and potential consequences of any serious failure also increase
16、. This was clear from the major disasters, that had occurred with pressure equipment since the 1800s. One boiler explosion killed 1800 persons, while in the 1980s about 500 were killed in Mexico City in a gas vessel explosion and nearly 4000 in a toxic gas vessel explosion in Bhopal. These and other
17、 pressure equipment failures also resulted in billion dollar losses around the world. Such accidents were far more complex than anticipated from just pressure and volume considerations; and so this made it difficult to simply quantify hazards and, particularly, to introduce into regulations a radica
18、lly new concept of varying controls according to hazard or risk. However, in 1980, a German engineer advised that German Pressure Equipment Law had just made significant step forward. A copy of the legislation in German legal terminology was made available but was not translated. It contained the te
19、rm with p V and importantly, it also gave clear evidence that a regulatory authority had tackled the problem of hazard quantification. This was a key to resolving Alex Wilsons request and the application of quality assurance (QA). During the early 80s, the above ideas were developed for a solution r
20、elating the level of design verification, fabrication inspection and QA to different hazard levels. This involved: (a) Review of many major failures and their consequences around the world, which showed that contents and the location or exposure of the equipment must be taken into account as well as
21、 pressure and volume. (b) Review of world practices, which showed that ASME had based their exclusions on p and V. (c) Finding more rational lower hazard limits when special regulatory requirements should apply; (d) Use of QA on a trial basis to maintain safety and reduce costs to Government and ind
22、ustry by (i) authorizing fabricators to transfer plate identification marks themselves using QA; and (ii) full QA with intermittent Government audit and inspection for a large fabricator in a remote area where economic inspection was difficult. (e) Preliminary use of the above ideas to improve and u
23、nify requirements in AS 1210, Pressure vessels. ME-001 support The above ideas and work were supported by Committee ME-001 in 1984, provided that QA was not mandatory. Also it was agreed that new work include: Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 10 Oct 2008 AS 43432005 6 (a) A Standard on s
24、mall, low hazard serially produced pressure vessels. This resulted in AS 29711987, probably the first ME-001 true performance standard. This partly involved the control and hazard concept with the introduction of pV criteria. (b) A Standard to cover in-service inspection of pressure equipmenti.e AS
25、3788 1990, which also adopted in part the pV criteria for different types of vessels. (c) Revision of AS 1210, which resulted in the 1989 edition but did not directly cater for QA or pVbecause of the work in progress on AS 3920.1. The first draft of AS 3920.1 in 1987 was aimed specifically at pressu
26、re vessels and was to be added to AS 1210. Its basis at the time, which did not refer to risk, was, briefly as follows: (a) Probability of deaths with all pressure vessels should be at a very low level, e.g. less than one death per year from the 100 000 vessels (e.g. as in Australia, probability of
27、about 10-6 per vessel per annum). (b) Regulatory controls for QA, inspection etc to be increased to reduce probability of failure (PF) when the hazards (or consequence of failure) (CF) increased, in order to achieve a very low probability of fatality or serious consequence with any vessel. (c) AS 12
28、10 technical requirements primarily aimed to achieve a consistent very low probability of failure for all vessels, i.e. like most PE Standards throughout the world. Committee ME-001 accepted the concept and agreed it should also cater for other pressure equipment i.e. boilers and pressure piping. Ga
29、s cylinders were outside the scope of the committee but nevertheless successful gas cylinder practice would be taken into account as a guide. QA was not mandatory. AS 3920.11993 Initial drafts of AS 3920.1, made in 1988 and 1989, were reviewed by ME-001 who formed Sub-Committee ME-001-21. This Commi
30、ttee first met in 1991 to develop AS 3920.1 to provide methods to assure the quality of pressure equipment for different hazard levels. This was submitted for public comment in November 1991. The title of AS 3920.1, issued in 1993, was Assurance of product qualityPart 1: Pressure equipment manufactu
31、re. It was probably the first National Standard in the world to address this particular problem. It provided the flexibility needed by industry by having 12 different control methods that could be used with 5 different hazard levels. EU Development In the latter stage of development of AS 3920.1, ME
32、-001-21 learnt of similar proposals being developed for a European Union-Pressure Equipment Directive for Conformity Assessment requirements, a new term that embraced inspection and QA controls. Later, in 1997, the EU finally adopted their approach with pV and contents into two groups only (not four
33、 as in AS 3920.1, which included lethal and non-harmful contents). They also had not covered location, which ME-001 felt was important and this was subsequently proven by a billion dollar failure in 1998 in USA. There, one vessel ruptured in a large plant and destroyed four more vessels, seriously i
34、njuring about 30 people in the blast and from the contents, and damaging a town nearby. The EU later identified their groups I, II, III, IV as Hazard Categories similar to but not the same as AS 3920.1, Hazard Levels D, C, B, A, respectively. The EU draft was partly used to fine-tune the draft for A
35、S 3920.1 prior to ballot. Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 10 Oct 2008 7 AS 43432005 FUNDAMENTAL BASIS OF AS 3920.1 Hazards Almost all pressure equipment is hazardous, i.e has the potential to harm, or cause injury or illness, or damage to plant, property, the environment and business. C
36、ontrols Failure to control pressure equipment hazards is almost always due to human inadequacy and has resulted globally in many minor to catastrophic incidents. These clearly show the need for suitable controls. These controls primarily aim to mitigate the probability of failure, but sometimes also
37、 to minimize the consequences by various means of emergency response and safeguarding. Concept When issued, AS 3920.1 (the forerunner of AS 4343) embraced the above ideas and the concept that: as the hazard (or consequence of failure) with pressure equipment increases, controls (OHS, regulations, in
38、spection, QA etc) should increase to provide a very low risk. This Standard only applied to new construction. Pressure equipment and risk Standards for pressure equipment such as AS 1210 have technical requirements aimed to give a very low probability of failure (PF) for all classes of vessels; and
39、they are not related to different consequences of failure, except for equipment with lethal contents. Hence risk (R) is controlled to a very low value. This value of R is primarily determined and accepted by society, governments and industry, based on national and global safety performance. Numbers
40、of PE (N) The number of vessels of a given design in service (N) influences the national risk. It has only a slight effect on the factors determining hazard levels; but it was significant in determining the hazard level limits, which influence the conformity assessment controls needed. This recogniz
41、ed that society wants low risk for individual items of pressure equipment, and also for the total numbers particularly those used by the public. Typical world failure rates are 10-5/PE/year for complex industrial pressure equipment. However, with 107 gas cylinders and more smaller equipment, this wo
42、uld mean 100 to 1000 serious failures per year in Australia which is unacceptable. DEVELOPMENT OF AS 4343 Amendment 1 to AS 3920.1 (1995) After 18 months initial use, industry identified that an excessive range of equipment with HL-C would require registration and significant national expense. Thus
43、the upper limit of HL-C was tripled, and HL-B and HL-C for lethal fluids, were increased by multiples of 30 and 10 to make the system consistent. Hazard levels for boilers, previously based on rated MW, used the same p V basis as pressure vessels to avoid anomalies with fired vessels. It includes th
44、e 3 factor for fired equipment to simplify use. Piping hazard levels were adjusted similarly to vessels, and other editorial improvements made. Amendment 2 to AS 3920.1 (1999) This major amendment resulted from changed philosophy of Australian governments to provide flexibility to industry and adopt
45、 a performance-based approach rather than Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 10 Oct 2008 AS 43432005 8 prescriptive details such as technical details and when and how QA etc. should be applied. This generally followed the approach in the National Standard for Plant1994, which adopted the i
46、ncreasingly recognized risk management concept. NOTE: Risk management was also taken up in ME-001 Standards with provisions in AS/NZS 3788 (1996), Pressure equipmentIn service inspection and AS 1210 (1997). Thus the Hazard Levels were transferred to the new AS 4343, and revision of AS 3920.1 was com
47、menced to provide for Conformity Assessment, a new term introduced by ISO/IEC in 1994 and which was being adopted worldwide, for pressure equipment to include design verification, fabrication inspection, quality management (rather than quality assurance), and other checks. AS 4343 AS 4343 was issued
48、 in 1999 and comprised of the Hazard Level section of AS 3920.1 with some improvements, such as the following: (a) Modified hazard levels for vacuum vessels. (b) Addition of an extensive Table 2, based on an earlier document trialled in industry for 2 years, which classified most fluids to simplify
49、the use of the Standard. (c) An equation to facilitate use by computer. (d) General improvements to enable the Standard to be directly referenced by authorities Australia-wide without conflicting with new government philosophy. AS 43432005 This new edition makes further improvements in the light of extensive use. These and their basis are identified in the Standards Preface and this Foreword. SOME GENERAL FEATURES OF THE STANDARD Separate standard Issuing a separate standard on hazard levels facilitates its use for a variety of p