1、BRITISH STANDARD BS 6144:1990 Specification for Expansion vessels using an internal diaphragm, for unvented hot water supply systemsBS6144:1990 This British Standard, having been prepared under the directionof the Refrigeration, Heating and Air Conditioning Standards Policy Committee, waspublished u
2、nder the authorityof the Board of BSIandcomes into effect on 31May1990 BSI 11-1999 First published December 1981 Second edition May 1990 The following BSI references relate to the work on this standard: Committee reference RHE/7 Draft for comment 87/77155 DC ISBN 0 580 17887 0 Committees responsible
3、 for this British Standard The preparation of this British Standard was entrusted by the Refrigeration, Heating and Air Conditioning Standards Policy Committee (RHE/-) to Technical Committee RHE/7, upon which the following bodies were represented: Associated Offices Technical Committee Association o
4、f Consulting Engineers Association of Manufacturers of Domestic Unvented Supply Systems Equipment (MODUSSE) British Marine Equipment Council Building Services Research and Information Association Chartered Institution of Building Services Engineers Heating and Ventilating Contractors Association Hev
5、ac Association Institute of Domestic Heating and Environmental Engineers Sealed System Equipment Association Waterheater Manufacturers Association Amendments issued since publication Amd. No. Date CommentsBS6144:1990 BSI 11-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1
6、 Scope 1 2 Definitions 1 3 Design and construction 1 4 Workmanship 5 5 Testing of vessels and diaphragms 5 6 Performance 5 7 Marking 6 Appendix A Test procedures 7 Figure 1 Types of dished ends 3 Figure 2 A method of clench ring design 4 Figure 3 Sizing of weld fillet for typical water connection bo
7、sses 5 Table 1 Values of joint factor 3 Publications referred to Inside back coverBS6144:1990 ii BSI 11-1999 Foreword This revision of BS6144, which has been prepared under the direction of the Refrigeration, Heating and Air Conditioning Standards Policy Committee, supersedes BS6144:1981, which is w
8、ithdrawn. In this revision, maximum working pressure grades have been discontinued and provision for clench ring design and construction has been introduced. In an unvented hot water supply system, allowance has to be made to accommodate the increased volume of contained water resulting from an incr
9、ease of temperature. Change in volume is directly related to change in temperature and can be calculated for given conditions. Since gases are compressible, it is possible to use a vessel filled with air/gas, connected to the system, to accommodate the water volume increase by compressing the air/ga
10、s. The system pressure thus increases as the gas is compressed. To prevent mixing, a flexible diaphragm is fitted in the expansion vessel to act as a permanent barrier between the gas and the system water. It is common practice, initially, to pressurize the air/gas side of the expansion vessel with
11、air or nitrogen. NOTEAn unvented hot water supply system is a system that does not have an open vent connection to a storage vessel. In this context the terms unvented and sealed are synonymous, but the latter is used more for heating systems. BS 4814 is a companion standard for expansion vessels fo
12、r water heating systems. Product certification. Users of this British Standard are advised to consider the desirability of third party certification of product conformity with this British Standard based on testing and continuing surveillance, which may be coupled with assessment of a suppliers qual
13、ity systems against the appropriate Part of BS5750. Enquiries as to the availability of third party certification schemes will be forwarded by BSI to the Association of Certification Bodies. If a third party certification scheme does not already exist, users should consider approaching an appropriat
14、e body from the list of Association members. 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 itself confer immunity from legal obligatio
15、ns. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, an inside back cover and a back 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 insid
16、e front cover.BS6144:1990 BSI 11-1999 1 1 Scope This British Standard specifies the manufacture and testing of steel expansion vessels, having an internal diaphragm and which are intended for use in systems where the heated fluid is potable water. This British Standard specifies expansion vessels su
17、itable for any maximum working pressure of up to10bar. 1) NOTE 1In this standard, all pressures are gauge pressures unless otherwise stated. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard,
18、 the following definitions apply. 2.1 diaphragm (or membrane) the flexible means by which the chamber of an expansion vessel is partitioned to maintain separation between the expanding hot water and the gas or air which in consequence becomes compressed 2.2 maximum vessel temperature the maximum tem
19、perature at which the vessel may be allowed to operate continuously 2.3 maximum vessel working pressure the maximum pressure that the vessel may be allowed to contain in operation 2.4 charging pressure the initial pressure to which the gas side of the vessel is charged 2.5 total vessel volume the vo
20、lume occupied by gas when the vessel is empty of water 3 Design and construction 3.1 General Expansion vessel manufacturers shall clearly state upon the vessel any limitations in the maximum working pressure. 3.2 Effect of materials on water quality When used under the conditions for which they are
21、designed, all materials in contact with or likely to come into contact with potable water, including any linings that may be necessary to protect the vessel against corrosion shall: a) not constitute a toxic hazard; b) not support microbial growth; c) not give rise to unpleasant taste or odour, clou
22、diness or discoloration of the water. Concentrations of substances, chemicals and biological agents leached from materials in contact with potable water, and measurements of the relevant organoleptic/physical parameters shall not exceed the maximum values recommended by the World Health Organization
23、 in its publication “Guidelines for drinking water quality” Volume1 “Recommendations” or as required by the EEC Council Directive of15July1980 relating to the quality of water intended for human consumption, whichever in each case is the more stringent. NOTE 1Requirements for the testing of non-meta
24、llic materials in these respects are set out in the UK Water Fittings Byelaws Scheme Information and Guidance Note No.5-01-02. NOTE 2Pending the determination of suitable means of characterizing the toxicity of leachates from materials in contact with potable water, listed materials and chemicals ap
25、proved by the Department of the Environment Committee on Chemicals and Materials of Construction for use in Public Water Supply and Swimming Pools are considered free from toxic hazard for the purposes of compliance with this subclause. NOTE 3Products manufactured for installation and use in the Uni
26、ted Kingdom which are verified and listed under the UK Water Fittings Byelaws Scheme, administered by the Water Research Centre, are deemed to satisfy the requirements detailed in this subclause. 3.3 Vessel The vessel shall be constructed of steel plate, sheet or strip suitable for the process of ma
27、nufacture, which has a minimum tensile strength of275N/mm 2 , and which complies with BS1501-1. Deep-drawn vessels shall be constructed from material complying with BS1449-1 or BS1449-2. NOTEAll materials should be capable of verification to the steel makers test certificates. The internal surface o
28、f the vessel shall be smooth and clean, and all internal edges shall be rounded off. The external surface of a carbon steel vessel shall be stove enamelled. Openings in the vessel in excess of51mm diameter shall be compensated in accordance with clause33 of BS5169:1975. Vessels having welded seams s
29、hall be made in accordance with BS5135. 1) 1 bar = 10 5 N/m 2= 10 5 Pa.BS6144:1990 2 BSI 11-1999 The vessel, including diaphragm, shall be capable of continual operation at a normal system temperature up to 65 C but shall also be capable of operating at 100 C for up to1h under fault conditions. 3.4
30、Wall thickness of spherical and cylindrical type vessels 3.4.1 Minimum thickness The minimum thickness of steel sheet for construction of vessels having a maximum stored volume of500L and a maximum vessel working pressure of 6bar shall be as follows: a) 1.00mm for vessel diameters up to and includin
31、g400mm; b) 1.75mm for vessel diameters over400mm and up to and including700mm. The minimum wall thickness t (in mm) of all finished vessels shall be calculated as follows: cylindrical shells spherical shells where NOTEFor carbon steels the design stress (in N/mm 2 ) is For stainless steels the desig
32、n stress (in N/mm 2 ) is the lower of: a) b) 3.4.2 Vessel ends thickness The following equations and values shall be used for design and calculation of the minimum thickness t (in mm) of material for hemispherical, semi-ellipsoidal, torispherical ends for use with cylindrical shells. Each, except th
33、e hemispherical end, shall incorporate a skirt 2) . a) Hemispherical ends. SeeFigure 1(a). b) Semi-ellipsoidal ends. An end of semi-ellipsoidal form, in which half the minor axis (inside depth of end minus the skirt length) equals one-quarter of the inside diameter of the skirt. SeeFigure 1(b). c) T
34、orispherical ends. An end in which the inside crown radius R is not greater than the outside diameter of the skirt and the inside knuckle (or corner) radius r is not less than6% of the inside crown radius. SeeFigure 1(c). where NOTEFor carbon steels the design stress (in N/mm 2 ) is For stainless st
35、eels the design stress (in N/mm 2 ) is the lower of: a) b) p is the maximum vessel working pressure (inbar); D is the inside diameter (in mm); f is the design stress (in N/mm 2 ). J is the joint factor (see Table 1); c is the corrosion allowance (in mm); c = 0 for vessels internally coated with rust
36、 inhibitor or made of stainless steel; c = 0.5 for all other conditions. tensile strength 3 - tensile strength 4.5 - 0.2 % proof stress 1.75 - 2) In the pressure vessel industry, a skirt is also known coloquially as a straight flange. p is the maximum vessel working pressure (inbar); R is the inside
37、 radius (spherical or crown) (inmm); f is the design stress (in N/mm 2 ); J is the joint factor as shown inTable 1 for any joint in the end, and the end-to-shell joint for hemispherical ends; c is the corrosion allowance (in mm); c = 0 for ends internally coated or made of stainless steel; D 1 is th
38、e inside diameter of end skirt (in mm); M is the shape factor tensile strength 3 - tensile strength 4.5 - 0.2 % proof stress 1.75 -BS6144:1990 BSI 11-1999 3 Table 1 Values of joint factor 3.5 Approval testing of welding procedures: welder and operator approval Approval testing of welding procedures
39、shall be conducted, recorded and reported in accordance with BS4870-1. Approval testing of welders and operators shall be conducted, recorded and reported in accordance with BS4871-1. 3.6 Vessels with clench ring construction The wall thickness of the two halves of the vessel at the clench ring junc
40、tion shall be constructed in accordance with3.4.1. The dimensions of the clench ring to enable the expansion vessel to sustain a maximum working pressure shall be obtained using the following formula in relation toFigure 2. where 3.7 Alternative methods of construction Vessels to designs which are n
41、ot readily calculable to the formulae in3.4 and3.6 shall be subjected to a proof hydraulic test in accordance with5.8.6 of BS5500:1988 or ASME Boiler and Pressure Vessel Code, Section VIII, Division 1UG-101, in the presence of an inspector of an independent inspection authority. 3.8 Vessel mounting
42、Where the vessel mountings are attached to the vessel, the method of attachment shall not involve full penetration of the vessel shell. The manufacturers instructions for mounting and positioning shall be specific and clearly stated, and shall be such that no distortion of the vessel occurs. These i
43、nstructions shall be included with each vessel. For vessels mounted directly on to a wall, a marking-out template shall be provided in order to reduce the possibility of causing distortion to the vessel. Type of seam and condition for welding Joint factor, J No welded seam (i.e. mechanical joints) 1
44、.0 Machine welded seam with removable backing material or joggled joint, procedure approved, operator approved, a test coupon for each 300m of welded seam 0.8 Machine welded seam with no backing material, procedure approved, operator approved 0.6 Manually welded seam, procedure approved, welder appr
45、oved 0.5 R is the ; t r is the thickness of clench ring; t v is the thickness of rim of vessel; is the angle of the rim in respect to vertical; L is the length of rim; p is the maximum vessel working pressure. radius of clench ringradius of shell + 2 - Figure 1 Types of dished endsBS6144:1990 4 BSI
46、11-1999 Manufacturers shall prescribe a means for mounting and positioning the expansion vessel that allows access to the water connection and the gas filling valve. 3.9 Water connection Threaded water connections (male or female), shall comply with BS21 and shall be designation R3/4 for vessels up
47、to and including 300L total vessel volume, and a minimum of designation R 1 for vessels exceeding300L and up to1000L total vessel volume. The thread shall be fitted with a cap or plug for protection during storage and handling. The construction of the vessel and water connection shall be such that i
48、t is possible to make a watertight joint without distortion of the vessel. The method of connection to the system shall be via a mechanical joint. The water connection shall be welded in accordance with BS5135. The sizing of weld fillets shall be as given inFigure 3. The material used for connection bosses shall comply with BS1387. The material used for connections for vessels manufactured from stainless steel shall have a composition compatible with BS1449-2. 3.10 Air/gas filling valve Th
