1、BRITISH STANDARD BS 2790:1992 Incorporating Amendment Nos. 1, 2, 3 and 4 Specification for Design and manufacture of shell boilers of welded construction ICS 27.060.30BS2790:1992 This British Standard, having been prepared under the directionof the Pressure Vessel Standards Policy Committee, waspubl
2、ished under the authorityof the Standards Boardand comes into effect on 1January1992 BSI 02-2000 First published December1956 Second edition as BS2790-1 February1969and BS 2790-2 August 1973 Third edition August 1982 Fourth edition May 1986 Fifth edition April 1989 Sixth edition January 1992 The fol
3、lowing BSI references relate to the work on this standard: Committee reference PVE/16 ISBN 0 580 20075 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Pressure Vessel Standards Policy Committee (PVE/-) to Technical Committee PVE/16, up
4、on which the following bodies were represented: Associated Offices Technical Committee Association of Shell Boilermakers British Combustion Equipment Manufacturers Association British Steel Industry Department of Health Department of the Environment (Property Services Agency) Engineers Surveyors Sec
5、tion of the Msf Health and Safety Executive Independent Engineering Insurers Committee Lloyds Register of Shipping Amendments issued since publication Amd. No. Date Comments 7437 October 1992 8435 March 1995 9346 December 1996 9551 July 1997 Indicated by a sideline in the marginBS2790:1992 BSI 02-20
6、00 i Contents Page Committees responsible Inside front cover Foreword vi Section 1. General 1.1 Scope 1 1.2 References 1 1.3 Definitions 1 1.4 Responsibilities 2 1.5 Interpretation 3 1.6 Terminology and symbols 3 1.7 Information and requirements to be agreed and to be documented 3 Section 2. Materia
7、ls 2.1 General 5 2.2 Selection of materials 5 2.3 Material specifications 5 2.4 Forming of plates 6 2.5 Elevated temperature properties 6 Section 3. Design 3.1 Design criteria 9 3.2 Cylindrical shells under internal pressure 11 3.3 Dished and flanged ends 12 3.4 Openings in cylindrical shells 15 3.5
8、 Fillet welds attaching pads and compensating plates to cylindrical shells 16 3.6 Openings and branches 16 3.7 Access and inspection 18 3.8 Stays, stiffeners and supported surfaces 19 3.9 Tubes and tube plates 24 3.10 Furnaces, furnace components, wet back reversal chambers and fireboxes of cylindri
9、cal form subject to external pressure 26 Section 4. Workmanship and construction in fabrication other than welding 4.1 Plate identification 70 4.2 Cold forming of plate 70 4.3 Cutting of forgings 70 4.4 Cylindrical shells 70 4.5 Reinforcing plates 70 4.6 End plates and tube plates 71 4.7 Plain tubes
10、 and stay tubes 71 4.8 Access and inspection openings 71 4.9 Seatings for mountings 72 4.10 Horizontal cylindrical furnaces 72 4.11 Fireboxes and reversal chambers 73 4.12 Cross tubes and stays 74 Section 5. Workmanship and construction in welding 5.1 General 75 5.2 Materials 75 5.3 Design 75BS2790:
11、1992 ii BSI 02-2000 Page 5.4 Fabrication and welding approval 76 5.5 Heat treatment 82 5.6 Non-destructive testing 85 5.7 Acceptance criteria for weld defects revealed by visual examination and non-destructive testing 90 Section 6. Inspection and pressure testing 6.1 Inspectors 97 6.2 Inspection dur
12、ing construction 97 6.3 Pressure tests 97 Section 7. Documentation and marking 7.1 Drawings, documents and data sheets 99 7.2 Certificates 99 7.3 Marking 99 Section 8. Safety valves, fittings and mountings 8.1 Safety valves 100 8.2 Water-level gauges 101 8.3 Water-level alarms 101 8.4 Connecting pip
13、es for water-level fittings 101 8.5 Pressure gauges 101 8.6 Boiler feedwater valves 101 8.7 Boiler blowdown and drain mountings 101 8.8 Boiler main stop valves 102 8.9 Vent pipes 103 Section 9. Automatic controls 9.1 General 104 9.2 Automatic controls for steam boilers 104 9.3 Automatic controls for
14、 hot water boilers 105 Appendix A Information to be supplied by the purchaser to the manufacturer 107 Appendix B Typical examples of acceptable weld details 108 Appendix C Calculation of tube plate temperatures 139 Appendix D Boiler operation 154 Appendix E Recommendations for access and internal in
15、spection 156 Appendix F Example of a calculation, carried out in accordance with Appendix G of BS 5500:1991, to determine the shell stresses for a boiler with leg supports 157 Appendix G Calculation of sustainable pressure for “Walker” type reversed curvature sections of non circular reversal chambe
16、rs 160 Figure 3.1(1) Wet back boiler 30 Figure 3.1(2) Dry back boiler 30 Figure 3.1(3) Semi-wet back boiler 31 Figure 3.1(4) Reverse fired boiler 31 Figure 3.1(5) Vertical boiler 32 Figure 3.1(6) Relationship between furnace diameter and permissible heat input 34 Figure 3.2.5.2 Design of saddle supp
17、orts 35 Figure 3.3(1) Typical dished ends 37BS2790:1992 BSI 02-2000 iii Page Figure 3.3(2) Shape factor 38 Figure 3.3(3) Openings in ends 39 Figure 3.3(4) Limits of reinforcement 39 Figure 3.4.4 Compensation of welded branch up to one-third of the diameter of the boiler shell 40 Figure 3.5 Welding o
18、f manhole frames and compensating plates 41 Figure 3.6.2(1) Welding detail for manhole frame in flat end plate 42 Figure 3.6.2(2) Compensation for elliptical manholes and inspection openings in flat end plates 42 Figure 3.6.2(3) Compensation for branch in flat end plate 43 Figure 3.8.1(1) Typical ar
19、rangement of end plate on a multitubular boiler 44 Figure 3.8.1(2) Typical arrangement of end plate on a Cornish boiler 45 Figure 3.8.1(3) Typical arrangement of end plate on a Lancashire boiler 46 Figure 3.8.2(1) Use of sub-circles (twin furnace) 47 Figure 3.8.2(2) Use of sub-circles (single furnac
20、e) 48 Figure 3.8.2(3) Determination of factor y 49 Figure 3.8.2(4) Example of a gusset stay that impinges on the main circle other than at a tangent 50 Figure 3.8.2(5) Attachment of firebox and reversal chamber stays 51 Figure 3.8.2(6) Attachment of bar stays with washers 52 Figure 3.8.2(7) Access o
21、pening for wet back boilers 54 Figure 3.8.2(8) Typical methods of fitting welded girders to reversal chambers 55 Figure 3.8.3 Flat end plates of a vertical boiler 58 Figure 3.8.5.1 Bar stays for the rear plate of wet back reversal chambers 59 Figure 3.8.8.3(1) Attachment of welded gusset stays 60 Fi
22、gure 3.8.8.3(2) Typical details for welded and pinned gusset stays 61 Figure 3.8.8.4 Typical details for diagonal link stays 61 Figure 3.9.2(1) Typical attachment of stay tubes 62 Figure 3.9.2(2) Typical attachment of plain tubes 63 Figure 3.10.1.2 Second moments of area I and cross-sectional area F
23、 64 Figure 3.10.1.9.2 Furnace stiffeners for plain and corrugated sections 67 Figure 3.10.1.9.3 Bowling hoops 68 Figure 3.10.3 Attachment of fireboxes to shells 69 Figure 5.4.6.1.3 Cutting up of the test plate 94 Figure 5.4.7.4 Transverse bend test specimen 94 Figure 5.4.7.5 Side bend test specimen
24、95 Figure 5.4.7.7 V-notch test piece 95 Figure 5.7.2 Assessment of inclusions 96BS2790:1992 iv BSI 02-2000 Page Figure B(1) Plate preparation for butt-welded longitudinal and circumferential seams 111 Figure B(2) Cross seams in end plates 111 Figure B(3) Attachment of unflanged flat end plates or tu
25、be plates to shell 112 Figure B(4) Attachment of end plates or tube plates to reversal chamber or firebox wrapper plates 113 Figure B(5) Attachment of furnaces to end plates or reversal chamber tubeplates 115 Figure B(6) Attachment of furnaces to flanged end plates 116 Figure B(7) Typical method of
26、attachment of ash drop-out tube 117 Figure B(8) Fusion welds of cross tubes 118 Figure B(9) Foundation ring 118 Figure B(10) Typical method of attachment of firehole opening 119 Figure B(11) Standard weld preparation details 120 Figure B(12) Set-on branches 121 Figure B(13) 122 Figure B(14) 123 Figu
27、re B(15) 124 Figure B(16) 125 Figure B(17) 126 Figure B(18) Weld details for set-in branches 127 Figure B(19) Set-in branches (partial penetration weld) 128 Figure B(20) Set-in branches (full penetration weld) 129 Figure B(21) 130 Figure B(22) Set-in branches (full penetration asymmetrical welds) 13
28、1 Figure B(23) Set-in branches (full penetration welds, welded from one side only) 132 Figure B(24) Forged branch connections 133 Figure B(25) 134 Figure B(26) Set-on branches with added compensation rings 135 Figure B(27) Set-in branches with added compensation rings 136 Figure B(28) Butt-welded st
29、udded connections 137 Figure B(29) Fillet-welded studded connections 138 Figure B(30) Oval manhole frame 138 Figure C(1) Radiation coefficient h Rfor black exchange (F = 1) 144 Figure C(2) Determination of overall exchange factor F 145 Figure C(3) Ratio A R /A Cfor cylindrical chamber, diameterD, le
30、ngth L 146 Figure C(4) Basis convection coefficient 147 h 9 COBS2790:1992 BSI 02-2000 v Page Figure C(5) Determination of correction factor 148 Figure C(6) Determination of correction factor h CE /h CO 148 Figure C(7) Non-dimensional tube area 149 Figure C(8) Non-dimensional plate area 150 Figure C(
31、9) Tube/plate area ratio 151 Figure C(10) Factor 152 Figure C(11) Factor 153 Figure C(12) Factor 154 Figure F(1) Assumed boiler dimensions for example of a calculation of the shell stresses in a boiler with leg supports 159 Table 1.1.1 Limits of application 1 Table 2.5(1) Carbon and carbon manganese
32、 steels with specified minimum elevated temperature properties 6 Table 2.5(2) Carbon and carbon manganese steels without specified elevated temperature properties 7 Table 2.5(3) Values of E tfor materials without specified elevated temperature properties 8 Table 3.8.1.3 Breathing space 19 Table 3.8.
33、2.6 Value of constant j 21 Table 3.8.8.6 Weld attachments 23 Table 3.9.1 Minimum thickness of tubes under external pressure 24 Table 3.9.4.1 Minimum thickness of straight tubes under internal pressure 25 Table 5.4.7(1) Number of test specimens for weld procedure approval and production control tests
34、 79 Table 5.4.7(2) Bend test requirements 79 Table 5.5.1.1(1) Recommended preheating temperatures for thermal-cutting of plates, sections, bars and forgings 83 Table 5.5.1.1(2) Recommended preheating temperatures for welding of plates, sections, bars and forgings 83 Table 5.6.2.2.1 Extent of radiogr
35、aphic or ultrasonic testing for butt welds 86 Table 5.7(1) Visual acceptance levels 91 Table 5.7(2) Radiographic acceptance levels 92 Table 5.7(3) Ultrasonic acceptance levels for welds of thickness 7 mm or greater 93 Table 8.9 Minimum open vent pipe size 103 Publications referred to 174 h CO /h 9 C
36、OBS2790:1992 vi BSI 02-2000 Foreword This British Standard, first published in1956under the title “Cylindrical land steam boilers of welded construction”, superseded by BS2790-1in1969and BS2790-2 in 1973, and subsequently revised in 1982, 1986 and 1989, has been prepared under the direction of the P
37、ressure Vessel Standards Policy Committee. This edition supersedes BS2790:1989which is withdrawn. This1992edition incorporates all technical changes up to and including Amendment No. 3 (31 October 1991) associated with the1989 edition. Changes of significance are to: a) recommend the operation of a
38、quality system to BS 5750; b) the tube plate metal temperature for waste heat boilers; c) safety factors for furnaces in waste heat boilers; d) the accumulator tests for safety valves. This British Standard sets forth engineering requirements deemed necessary for the design and construction of shell
39、 boilers of welded construction. The purpose of this British Standard is unchanged from previous editions. Because of the wide range of shell boilers that may be designed and manufactured in accordance with this British Standard, general guidance has been given on some aspects with specific requirem
40、ents being for agreement between the parties concerned according to the particular design and manufacturing details. The user is cautioned that this British Standard is not a design and manufacturing handbook. It has been assumed, therefore, that the execution of its provisions is entrusted to appro
41、priately qualified and experienced people. Purchasers ordering to this British Standard are recommended to specify in their purchasing contract that the manufacturer operates a quality system in compliance with the appropriate Part of BS5750to assure consistency in quality management. As with previo
42、us editions the loose-leaf format adopted will facilitate amendment and the standard will be kept up to date by the issue from time to time of replacement pages, or additional pages when necessary. Each replacement or added page will carry an issue number (with date) indicating its relationship to t
43、he original issue of this standard, the pages of which are marked “Issue 1”. For example, Issue 1 will indicate an original page or one that has been added to the original standard and has not been amended since insertion; Issue 2 will indicate a first amendment of either an original page or an adde
44、d page; Issue 3 will indicate either an original page amended for the second time since publication or an added page amended for the second time since insertion. Side-lining on replacement pages will indicate that changes of technical or of reference significance have been made at that point. This s
45、tandard may be referred to by the UK Health and Safety Executive (HSE) 1)when giving guidance. 1) Health and Safety Executive, Rose Court, 2 Southwark Bridge, London SE1 9HS.BS2790:1992 BSI 02-2000 vii A British Standard does not purport to include all the necessary provisions of a contract. Users o
46、f British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to viii, pages1 to 174, an inside back cover and a b
47、ack cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.viii blankBS2790:1992 BSI 02-2000 1 Section 1. General 1.1 Scope 1.1.1 This British Standard specifies requirements for the
48、 design and the construction, including materials, workmanship, inspection, testing, documentation and marking, of directly fired and waste heat shell boilers. The boilers dealt with are of cylindrical design, either horizontal or vertical, constructed from carbon or carbon manganese steels by fusio
49、n welding to class I, class II or class III classifications, for which the limits of application are given in Table 1.1.1. They are intended for land use to provide steam or hot water. This standard does not apply to water-tube boilers (see BS 1113) nor to boilers of the locomotive type. Additionally requirements relevant to saf
