EUROPEAN STANDARD EN 13648-3 NORME EUROPEENNE EUROPAISCHE NORM October 2002 ICS 23.020.40 English version Cryogenic vessels - Safety devices for protection against excessive pressure - Part 3: Determination of required discharge Capacity and sizing Récipients cryogeniques - Dispositifs de protection contre Kryo-Behalter - Sicherheitseinrichtungen gegen les surpressions - Partie 3: Determination du debit a Druckuberschreitung - Teil 3: Ermittlung des erforderlichen évacuer - Capacite et dimensionnement 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 standard 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 language 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, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMITE EUROPEEN DE NORMALISATION EUROPAISCHESKOMITEEFURNORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels @ 2002 CEN Ref. No.EN 13648-3:2002 E worldwide for CEN national Members EN 13648-3:2002 (E) Contents Page Foreword .3 1 Scope. 2 Normative references ..... Calculation of the total quantity of heat transferred per unit time from the hot wall (outer jacket) to 3 the cold wall (inner vessel)... 3.1 General.. 3.2 For conditions other than fire 3.3 Under fire conditions ... 4 Calculation of the mass flow Qm (kg h"') to be relieved by the safety devices , ..8 5 Rule for the safety devices installation 6 Sizing of safety devices.... 6.1 Safety valves .. 6.2 Bursting disc. 6.3 Sizing of safety valves and bursting discs ... Annex ZA (informative) Clauses of this European Standard addressing essential requirements or other provisions of EU Directives Bibliography 2 EN 13648-3:2002 (E) 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. 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 European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). EN 13648 consists of the following parts: EN 13648-1, Cryogenic vessels - Safety 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 for protection against excessive pressure - Part 3: Determination of required discharge - Capacity and sizing. France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. 3 EN 13648-3:2002 (E) Introduction The capacity of each of the pressure relief devices is established by considering all of the probable conditions type of cryogenic vessel. each condition is assumed if the applicable method of this standard is adopted. This European Standard is based on CGA pamphlet, S-1.2 and S-1.3 and standards prepared by CEN/TC 69. 4 EN 13648-3:2002 (E) Scope 1 This standard provides a separate calculation method for