《BS-EN-13648-3-2002.pdf》由会员分享，可在线阅读，更多相关《BS-EN-13648-3-2002.pdf（14页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS EN 13648-3:2002 Cryogenic vessels Safety devices for protection against excessive pressure Part 3: Determination of required discharge Capacity and sizing The European Standard EN 13648-3:2002 has the status of a British Standard ICS 23.020.40 ? Licensed Copy: sheffieldun sheffie
2、ldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 13648-3:2002 This British Standard, having been prepared under the direction of the Engineering Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 6 D
3、ecember 2002 BSI 6 December 2002 ISBN 0 580 40934 1 National foreword This British Standard is the official English language version of EN 13648-3:2002. The UK participation in its preparation was entrusted to Technical Committee PVE/18, Cryogenic vessels, which has the responsibility to: A list of
4、organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Co
5、rrespondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does n
6、ot of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developm
7、ents and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 11 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd
8、. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13648-3 October 2002 ICS 23.020.40 English version Cryogenic vessels - Safety devices for protection against excessive pr
9、essure - Part 3: Determination of required discharge - Capacity and sizing Rcipients cryogniques - Dispositifs de protection contre les surpressions - Partie 3: Dtermination du dbit vacuer - Capacit et dimensionnement Kryo-Behlter - Sicherheitseinrichtungen gegen Druckberschreitung - Teil 3: Ermittl
10、ung des erforderlichen Ausflusses - Ausflussmassenstrom und Auslegung This European Standard was approved by CEN on 19 August 2002. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national stan
11、dard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other lan
12、guage made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, I
13、celand, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2002 CENAll rights of e
14、xploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13648-3:2002 E Licensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13648-3:2002 (E) 2 Contents Page Foreword3 1Scope.5 2Normative references 5 3
15、Calculation of the total quantity of heat transferred per unit time from the hot wall (outer jacket) to the cold wall (inner vessel)5 3.1General.5 3.2For conditions other than fire .6 3.3Under fire conditions 7 4Calculation of the mass flow Qm (kg h-1) to be relieved by the safety devices 8 5Rule fo
16、r the safety devices installation .9 6Sizing of safety devices.9 6.1Safety valves9 6.2Bursting disc.9 6.3Sizing of safety valves and bursting discs .9 Annex ZA (informative) Clauses of this European Standard addressing essential requirements or other provisions of EU Directives.10 Bibliography11 Lic
17、ensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13648-3:2002 (E) 3 Foreword This document (EN 13648-3:2002) has been prepared by Technical Committee CEN/TC 268 “Cryogenic vessels“, the secretariat of which is held by AFNOR. This European Sta
18、ndard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2003, and conflicting national standards shall be withdrawn at the latest by April 2003. This document has been prepared under a mandate given to CEN by the Eu
19、ropean Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document. EN 13648 consists of the following parts: EN 13648-1, Cryogenic vessels - Sa
20、fety devices for protection against excessive pressure - Part 1: Safety valves for cryogenic service. EN 13648-2, Cryogenic vessels - Safety devices for protection against excessive pressure - Part 2: Bursting discs safety devices for cryogenic service. EN 13648-3, Cryogenic vessels - Safety devices
21、 for protection against excessive pressure - Part 3: Determination of required discharge - Capacity and sizing. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Re
22、public, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13648-3:2002
23、(E) 4 Introduction The capacity of each of the pressure relief devices is established by considering all of the probable conditions contributing to internal excess pressure. The applicable conditions are specified in the product standard of each type of cryogenic vessel. This European Standard provi
24、des a separate calculation method for determining the contributing mass flow to be relieved for each of the specified conditions. Conformity of the pressure protection system with the requirement for each condition is assumed if the applicable method of this standard is adopted. This European Standa
25、rd is based on CGA pamphlet, S-1.2 and S-1.3 and standards prepared by CEN/TC 69. Licensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13648-3:2002 (E) 5 1 Scope This standard provides a separate calculation method for determining the contribu
26、ting mass flow to be relieved resulting from each of the following specified conditions: ? vacuum insulated vessels with insulation system (outer jacket + insulating material) intact under normal vacuum. Outer jacket at ambient temperature. Inner vessel at temperature of the contents at the relievin
27、g pressure; ? vacuum insulated vessels with insulation system remaining in place but with loss of vacuum, or non vacuum insulated vessels with insulation system intact. Outer jacket at ambient temperature. Inner vessel at temperature of the contents at the relieving pressure; ? vacuum or non vacuum
28、insulated vessels with insulation system remaining fully or partially in place, but with loss of vacuum in the case of vacuum insulated vessels, and fire engulfment. Inner vessel at temperature of the contents at the relieving pressure; ? vessels with insulation system totally lost and fire engulfme
29、nt. Good engineering practice based on well established theoretical physical science shall be adopted to determine the contributing mass flow where an appropriate calculation method is not provided for an applicable condition. 2 Normative references This European Standard incorporates by dated or un
30、dated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only wh
31、en incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). prEN ISO 4126-1, Safety devices for protection against excessive pressure - Part 1: Safety valves (identical to ISO 4126-1). prEN ISO 4126-6:2000,
32、Safety devices for protection against excessive pressure - Part 6: Application, selection and installation of bursting disc safety devices (ISO/DIS 4126-6:2000). 3 Calculation of the total quantity of heat transferred per unit time from the hot wall (outer jacket) to the cold wall (inner vessel) 3.1
33、 General p (bar abs) is the actual relieving pressure which is used for the sizing of a safety valve. This shall not be greater than 1,1 PS, where PS is the maximum allowable pressure for which the vessel is designed. Ta (K) is the maximum ambient temperature for conditions other than fire (as speci
34、fied e.g.by regulation/standard) T f (K) is the external environment temperature under fire conditions (in any case Tf = 922 K, i.e. 649C or 1200 F) Licensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13648-3:2002 (E) 6 T (K) is the relieving
35、 temperature to be taken into account: 1) for subcritical fluids, T is the saturation temperature of the liquid at pressure p; 2) for critical or supercritical fluids, T is calculated from 4.3. 3.2 For conditions other than fire 3.2.1Vacuum insulated vessels under normal vacuum : quantity of heat tr
36、ansferred per unit time (Watt) by heat leak through the insulation system: ? 11 UTTW a? ? where U1 is the overall heat transfer coefficient of the insulating material under normal vacuum, in Wm-2K-1 1 1 e U ? ? ? 1 ? is the thermal conductivity coefficient of the insulating material under normal vac
37、uum, between T and Ta, in W.m-1K-1 ; e1 is the nominal insulating material thickness, in m; ?is the arithmetic mean of the inner and outer surface areas of the vessel insulating material, in m. 3.2.2Vacuum insulated vessels in case of loss of vacuum or non vacuum insulated vessels; quantity of heat
38、transferred per unit time (Watt) by heat leak through the insulating material: ? 22 UTTW a? ? where 2 Uis the overall heat transfer coefficient of the insulating material at atmospheric pressure, in Wm-2K-1 2 2 2 e U ? ? 2 ? is the thermal conductivity coefficient of the insulating material saturate
39、d with gaseous lading or air at atmospheric pressure, whichever provides the greater coefficient, between T and Ta, in Wm-1K-1. e2is the minimum insulating material thickness taking into account the manufacturing tolerancies or effects of sudden loss of vacuum, in m. NOTEThis formula cannot apply to
40、 application at very low temperatures with small thickness of insulating material, as the maximum heat transfer coefficient would be given by air condensation. This phenomena has been studied for helium in W. Lehmann, Sicherheitstechnische Aspekte bei Auslegung and Betrieb von Lhe-badgekhlten-SL-Bad
41、kyokasten.“ 3.2.3Quantity of heat transferred per unit time (Watt) by supports and piping located in the interspace ?.? n213 wwwTTW a where n w is the heat leak per degree K contributed by one of the supports or the pipes, in WK-1 Licensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+0
42、0:00 2006, Uncontrolled Copy, (c) BSI EN 13648-3:2002 (E) 7 n n nn l S w? n ?is the thermal conductivity coefficient of the support or pipe material between T and Ta, in Wm-1K-1; n S is the support or pipe section area, in m; n lis the support or pipe length in the vacuum interspace, in m. 3.2.4Quan
43、tity of heat transferred per unit time (Watt) by the pressure built up device circuit with the regulator fully open : W4determined from the type (ambient air, water or steam, electrical ) and the design of the pressure built up device circuit. For example, in the case of ambient air vaporiser: ?TTAU
44、W a? ? 44 where U4is the overall convective heat transfer coefficient of the ambient air vaporiser, in Wm-2K-1; Ais the external heat transfer surface area of the vaporiser, in m. 3.3 Under fire conditions 3.3.1Quantity of heat transferred per unit time (Watt) by heat leak through the vessel walls 3
45、.3.1.1Insulation system remains fully or partially in place during fire conditions ? 820 55 92262 , ,?UTW? where e U 5 5 ? ?, in Wm-2 K-1; 5 ?is the thermal conductivity coefficient of the insulating material saturated with gaseous lading or air at atmosphere pressure whichever provides the greater
46、coefficient between T and 922 K, in Wm-1K-1; eis the thickness of the insulating material remaining in place during fire conditions, in m; ?is the mean surface area of the insulating material remaining in place during fire conditions, in m. If outer jacket remains in place during fire conditions, bu
47、t if insulating material is entirely destroyed, U5 is equal to the overall heat transfer coefficient with gaseous lading or air at atmospheric pressure in the space between outer jacket and inner vessel, whichever provides the greater coefficient between T and 922 K. ? is equal to the mean surface a
48、rea of the interspace. 3.3.1.2Insulation system does not remain in place during fire conditions 82, 04 6 101 , 7?W where ?is the total outside surface area of the inner vessel, in m. 3.3.2Quantity of heat transferred by supports and piping located in the interspace: can be neglected in this case Lic
49、ensed Copy: sheffieldun sheffieldun, na, Sun Oct 29 09:50:18 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 13648-3:2002 (E) 8 3.3.3Total quantity W (Watt) of heat transferred per unit time from the hot wall to the cold wall Total W is obtained by summing the relevant Ws in accordance with requirements of the relevant cryogenic vessel standards. 4 Calculation of the mass flow Qm (kg h-1) to be relieved by the safety devices 4.1The relieving pressure p is less than