1、BRITISH STANDARD BS 470:1984 Specification for Inspection, access and entry openings for pressure vessels UDC 621.772.4774:621.183.4BS470:1984 This British Standard, having been prepared under the directionof the Pressure Vessel Standards Committee, was published under the authority of the Board of
2、BSI and comes intoeffect on 31 January 1984 BSI 03-1999 First published October 1932 First revision September 1957 Second revision February 1976 Third revision January 1984 The following BSI references relate to the work on this standard Committee reference PVE/11 Draft for comment 82/77675 DC ISBN
3、0 580 13452 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Pressure Vessel Standards Committee (PVE/-) to Technical Committee PVE/11 upon which the following bodies were represented: Associated Offices Technical Committee Association
4、of Consulting Engineers British Chemical Engineering Contractors Association British Gas Corporation Chemical Industries Association Electricity Supply Industry in England and Wales Engineering Equipment and Materials Users Association Health and Safety Executive Institution of Gas Engineers Institu
5、tion of Mechanical Engineers Process Plant Association Amendments issued since publication Amd. No. Date of issue CommentsBS470:1984 BSI 03-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 General 1 4 Sizes 1 5 Minimum number of openings and thei
6、r positions 2 Figure 1 Length of hole 2 Figure 2 Viewing for sightholes, handholes and headholes 3 Table 1 Maximum lengths of manholes 2 Table 2 Minimum number of openings 3BS470:1984 ii BSI 03-1999 Foreword This revision of this British Standard has been prepared under the direction of the Pressure
7、 Vessel Standards Committee. It supersedes BS470:1976, which is withdrawn. This standard has been revised in order to clarify the size and length requirements of access and inspection openings. Opportunity has also been taken to clarify the text in general. The BSI committee responsible for this sta
8、ndard is firmly of the view that, for adequate safety, the openings in vessels should be either sufficiently large for rescue operations or too small for entry. Considerations which support the committee view are as follows: a) a user, having specified a manhole on the basis that rescue from a vesse
9、l is not foreseeable, may find that due to some unforeseen change in the vessel usage it becomes necessary to provide a large opening for rescue; b) experimental work has indicated that460mm diameter is a reasonable minimum for rescue by persons wearing air-line breathing apparatus but it is not lar
10、ge enough for persons entering with self-contained breathing apparatus; c) section30of the Factories Act1961requires an opening of18in (now interpreted as460mm) as a minimum wherever a person is liable to be overcome in a vessel. Access to a vessel by any opening other than that specifically provide
11、d for the purpose is deprecated; responsibility for such entry rests with the user. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itse
12、lf confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendmen
13、t table on theinside front cover.BS470:1984 BSI 03-1999 1 1 Scope This British Standard specifies requirements for the provision and dimensions of sighthole, handhole, headhole and manhole openings into static and mobile pressure vessels requiring inspection facilities. It does not include openings
14、for steam raising plant because of the different problems associated with these vessels, which may require separate consideration. 2 Definitions For the purposes of this standard the following definitions apply. 2.1 access insertion into a vessel of no more than a persons head and arm 2.2 entry inse
15、rtion into a vessel of more than a persons head and arm 2.3 sightholes holes that are intended for viewing only 2.4 handholes holes that are intended for insertion of one hand gripping a lamp during viewing 2.5 headholes holes that are intended for insertion of the head and one arm 2.6 manholes hole
16、s that permit a person entry and exit 2.7 length of hole the perpendicular distance from the face of the flange to the inside of the opening including lining or any projection of the branch within the vessel. Inthe case of a hole in a cylindrical shell the length is measured as the shortest distance
17、 at the intersection, accepting that the length of the hole increases to a maximum at a plane at 90 to this to an extent dependent on the diameter of the vessel (see Figure 1) 2.8 purchaser the organization or individual who buys the finished pressure vessel for its own use or as an agent for the ow
18、ner 2.9 manufacturer the organization that designs and fabricates the pressure vessel in accordance with the purchasers specification. The design and fabrication may be carried out by separate organizations 2.10 inspecting authority the body or association that checks that the design, materials and
19、construction comply with the purchasers specification 3 General 3.1 Holes shall be either large enough to permit entry and the rescue of persons, or so small that persons cannot enter. NOTEIt is for this reason that the headhole sizes given in this standard are maximum values. 3.2 Detachable ends, o
20、r covers, or branches and fittings that are easily removed shall be used as access openings, if their dimensions are at least equal to the minimum dimensions required by this standard, and permit a general view of the interior at least equal to that obtained by the examination holes that would other
21、wise be required. 3.3 The dimensions of openings in lined vessels shall be maintained after the lining is applied. NOTEIt is recommended that in large vessels, consideration be given to the provision of footholds and/or hand-holds on the vessel surfaces. 4 Sizes 4.1 General. The sizes of inspection,
22、 access and entry openings shall be as specified in 4.2 to4.5. Diameters and axis dimensions refer to actual internal measurements. Where lengths of sightholes and handholes exceed the stated limits, the size shall be modified to give an equivalent inspection facility, either by increasing the size
23、of the hole or by providing a conical hole. In the case of vessels having non-interconnecting pressure compartments, the requirements of this standard shall apply to each compartment as if it were a separate vessel. 4.2 Sightholes. The minimum diameter shall be30mm for vessels up to300mm diameter wh
24、en the length does not exceed30mm; the minimum diameter shall be50mm for vessels above300mm diameter when the length does not exceed50mm. For greater lengths see 4.1.BS470:1984 2 BSI 03-1999 4.3 Handholes. Where one hole only is provided, the minimum size shall be180mm diameter or180mm 120mm oval; w
25、here more than one hole is provided, the minimum size shall be130mm diameter or 130 mm 110mm oval. The above sizes are related to a length of hole not greater than65mm. For greater lengths see 4.1. 4.4 Headholes. The maximum size shall be320mm diameter or 320mm 200mm oval. The maximum length of hole
26、 shall be 100mm. NOTEThe minimum size should not be substantially less than320mm diameter or 320mm 200mm oval. 4.5 Manholes. The minimum size shall be460 mm diameter or460mm 410mm oval. The minimum size to afford full rescue facilities with self-contained breathing apparatus shall be575mm diameter o
27、r minor axis. The maximum length of a manhole is dependent on the diameter, or, if oval, the major axis, and shall be in the relationship given in Table 1. Table 1 Maximum lengths of manholes Maximum lengths shall be interpolated linearly for hole diameters between460mm and 575mm. NOTE 1Minimum manh
28、ole sizes of18 in diameter or18 in 16 in oval in line with current practice will be acceptable pending re-tooling by manufacturers. NOTE 2Lengths should be kept to a practical minimum. NOTE 3Where design considerations make it impossible to satisfy the maximum length requirement, the design of the m
29、anhole should be the subject of special consideration and agreement among manufacturer, purchaser and inspecting authority. 5 Minimum number of openings and their positions 5.1 In pressure vessels, the minimum number and type of openings provided shall be in accordance with Table 2 and5.2, except wh
30、ere suitable optical devices (e.g. fibre optic probes) are to be used. Spherical vessels shall be treated as vessels with zero length of cylindrical section. NOTE 1This standard does not specify requirements for the minimum number, size and type of openings for optical devices and these should be ag
31、reed by the purchaser, manufacturer and inspecting authority. NOTE 2For optic probe inspection openings, reference may be made to the Liquefied Petroleum Gas Industry Technical Association (UK), Code of practice No. 1, Part 2, “Inspection and Testing of Bulk Liquefied Petroleum Gas Storage at Consum
32、ers Premises”. 5.2 All parts subject to inspection by means of sightholes, handholes or headholes shall be within a distance of 1 200mm of sightholes and handholes, and 1 700mm of headholes. NOTEThis facility may be achieved by any combination of the three types of holes, provided that the requireme
33、nts of Table 1 are satisfied. The distance should be measured along a straight line from the area to be inspected to the centre of the opening at the external face of the flange, taking into account that the path of viewing need not be in a straight line, e.g. when optical devices are used (see Figu
34、re 2). Figure 1 Length of hole Diameter or major axis Maximum length mm mm over 460 575 575 250 500 not restrictedBS470:1984 BSI 03-1999 3 Table 2 Minimum number of openings 5.3 Where there are openings provided for entry into internal compartments of a vessel, the openings shall be not less than th
35、e size of the external manhole. NOTE 1In view of the difficulties associated with rescue through side entry manholes, their position should be sited with regard to platform access. Manholes should be provided at the location on the vessel which provides easy entry, especially for rescue. NOTE 2The n
36、umber and siting of holes should take into account the shape and the internal structure of the vessel, e.g.agitators, baffles, etc. and the need for adequate illumination to be provided. When cleaning out of a vessel prior to inspection is required, the opening(s) provided should be of adequate size
37、, and positioned for cleaning to be carried out. Vessel inside diameter Length of cylindrical section Minimum number and type of openings Sight Hand Head Manholes mm Up to 450 mm Unlimited 2 or 1 or 1 0 Over 450 up to 800 Up to 1500 Over 1500 Up to 2000 Over 2000 2 0 0 or 1 2 3 or or or 1 1 1 or or
38、or 1 1 1 Over 800 up to 1500 Up to 2000 Over 2 000 0 0 2 3 or or 1 1 or or 1 1 Over 1500 Unlimited 0 0 0 1 NOTEThis is a typical example illustrating the effective viewing range provided by sightholes, handholes and headholes (see 5.2). Hatching indicates the range of viewing for each hole. All dime
39、nsions are in millimetres. Figure 2 Viewing for sightholes, handholes and headholesBSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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