SIST EN 50553:2012
(Main)Railway applications - Requirements for running capability in case of fire on board of rolling stock
Railway applications - Requirements for running capability in case of fire on board of rolling stock
This European Standard defines requirements for running capability under fire conditions which are applicable to passenger carrying railway rolling stock. In particular, technical measures are specified, compliance with which will contribute to conformity with the Directive and the relevant Technical Specifications for Interoperability (TSI). The standard specifies the fire conditions: - for which it is not necessary to define running capability requirements as there is no significant potential for serious injury or threat to life; - for which it is reasonable to expect trains to continue to run in a controlled manner; - for which it is not reasonably practicable to define requirements which give complete assurance of running in a controlled manner, due to the exceptional nature of the fire incident. The TSI SRT defines running capability requirements in respect of fires within technical areas/equipment only. However for general guidance the scope of this standard is extended to include fires from non-technical causes within passenger/staff areas which may impact train system functions adjacent to and/or passing through the affected area. This extension of applicability significantly increases the number of system functions which are potentially at risk and therefore requires that the "reasonably practicable" principles be extended to this new condition. The standard does not consider situations where a primary non-fire incident is likely to immobilise the train by definition; for example major mechanical defect leading to derailment, even when fire then occurs.
Bahnanwendungen - Anforderungen an die Fahrfähigkeit im Brandfall an Bord von Bahnfahrzeugen
Applications ferroviaires - Exigences en matière d’aptitude au roulement en cas d’incendie à bord des véhicules ferroviaires
La présente Norme européenne définit les exigences en matière d’aptitude au roulement en cas d’incendie, applicables aux véhicules ferroviaires. Elle spécifie notamment des mesures techniques, la conformité à celles-ci contribuant à la conformité à la Directive et aux Spécifications techniques d’interopérabilité (STI) concernées. La norme spécifie les conditions d’incendie: – pour lesquelles il n’est pas nécessaire de définir des exigences d’aptitude au roulement car il n’existe aucun potentiel significatif de blessure grave ou de mise en danger de la vie. – pour lesquelles il est raisonnable de s’attendre à ce que les trains continuent à rouler d’une manière contrôlée; – pour lesquelles il n’est pas raisonnablement possible de définir des exigences en raison de la nature exceptionnelle de l’incendie. La STI STF définit les exigences d’aptitude au roulement pour des incendies ayant lieu seulement au sein des zones/équipements techniques. Toutefois, comme ligne directrice générale, le domaine d’application de la présente norme est étendu aux incendies ayant des causes non techniques au sein des compartiments voyageurs/locaux de service pouvant avoir un impact sur les fonctions de système, adjacents à la zone affectée et/ou la traversant. Cette extension d’applicabilité augmente nettement le nombre de fonctions de système présentant un risque potentiel et nécessite donc l’extension des principes « raisonnablement possibles » à cette nouvelle condition. La norme ne traite pas des situations où un incident déclencheur non lié à un incendie va vraisemblablement conduire par définition à une immobilisation du train; par exemple un défaut mécanique majeur conduisant à un déraillement, même en cas d’incendie.
Železniške naprave - Zahteve za sposobnost vožnje tirnih vozil v primeru požara
Ta evropski standard določa zahteve za sposobnost vožnje v primeru požara, ki se uporabljajo za tirna vozila, ki prevažajo potnike. Opredeljeni so zlasti tehnični ukrepi, pri čemer bo skladnost z njimi pomagala zagotoviti skladnost z direktivo in ustreznimi tehničnimi specifikacijami za interoperabilnost (TSI). Standard določa požarne razmere: – za katere ni treba opredeliti zahtev za sposobnost vožnje, saj ne obstaja velika možnost za resne poškodbe ali življenjsko ogroženost; – za katere je razumno pričakovati, da bodo vlaki še naprej nadzorovano obratovali; – za katere ni razumno izvedljivo opredeliti zahteve, ki v celoti zagotavljajo nadzorovano vožnjo, zaradi izjemne narave požara. Tehnične specifikacije za interoperabilnost v zvezi z varnostjo v železniških predorih določajo zahteve za sposobnost vožnje le za požare znotraj tehničnih območij/opreme. Vendar se za splošne napotke področje uporabe tega standarda razširi na požare zaradi netehničnih razlogov v prostorih za potnike/osebje, ki lahko vplivajo na sistemske funkcije vlaka, ki so poleg in/ali potekajo skozi prizadeto območje. Ta razširitev uporabnosti bistveno poveča število sistemskih funkcij, ki so potencialno ogrožene, zato je potrebno, da se »razumno izvedljiva« načela razširijo na ta novi pogoj. Standard ne zajema primerov, v katerih obstaja verjetnost, da bo nesreča, ki ni požar, sama po sebi povzročila zaustavitev vlaka, na primer obsežna mehanska okvara, ki povzroči iztirjenje, celo kadar nato pride do požara.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Železniške naprave - Zahteve za sposobnost vožnje tirnih vozil v primeru požaraBahnanwendungen - Anforderungen an die Fahrfähigkeit im Brandfall an Bord von BahnfahrzeugenApplications ferroviaires - Exigences en matière d’aptitude au roulement en cas d’incendie à bord des véhicules ferroviairesRailway applications - Requirements for running capability in case of fire on board of rolling stock45.060.01Železniška vozila na splošnoRailway rolling stock in general13.220.99Drugi standardi v zvezi z varstvom pred požaromOther standards related to protection against fireICS:Ta slovenski standard je istoveten z:EN 50553:2012SIST EN 50553:2012en01-april-2012SIST EN 50553:2012SLOVENSKI
STANDARD
SIST EN 50553:2012
EUROPEAN STANDARD EN 50553 NORME EUROPÉENNE
EUROPÄISCHE NORM February 2012
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2012 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50553:2012 E
ICS 13.220.50; 45.060.01
English version
Railway applications -
Requirements for running capability in case of fire on board of rolling stock
Applications ferroviaires -
Exigences en matière d’aptitude au roulement en cas d’incendie à bord des véhicules ferroviaires
Bahnanwendungen -
Anforderungen an die Fahrfähigkeit im Brandfall an Bord von Bahnfahrzeugen
This European Standard was approved by CENELEC on 2012-01-23. CENELEC 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 CEN-CENELEC Management Centre or to any CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
SIST EN 50553:2012
EN 50553:2012 - 2 - Contents Foreword . 4Introduction . 51Scope . 72Normative references. 73Terms and definitions. 84Symbols and abbreviated terms . 105Methodology . 115.1Principles . 115.2Fire Classification Scheme . 115.3Application . 126Verification of compliance . 156.1Specific requirements . 156.2Decision Box 1 - Existence of a Type 2 (or Type 3) fire . 156.3Decision Box 2 - Individual system function . 196.4Decision Box 3 - Redundant array system function . 216.5Decision Box 4 - Presence of a fire fighting system . 226.6Decision Box 5 - Degraded mode . 25Annex A (informative)
Existing standards and background . 27Annex B (normative)
Determination of compliance for degraded mode. 29B.1First method . 29B.2Second method . 29Annex C (informative)
Passenger & staff area detection & fire fighting . 31C.1General . 31C.2Demonstration of Fire Detection by Computational Fluid Dynamic (CFD; "Field") Modelling. 31C.3Demonstration of Fire Detection by Test . 31C.4Fire Fighting Assessment . 33Annex D (informative)
Example of an approach to CFD validation . 35Annex E (informative)
Guidance for a system function approach . 36Annex ZZ (informative)
Coverage of Essential Requirements of EC Directives . 37Bibliography . 38Figures Figure 1 Decision box flow chart . 14Figure 2 Decision box 1 flow chart . 17Figure C.1 Plan View : Standard chamber with additional fog generator . 33Figure C.2 Side View : Fog Generator and fire source . 33SIST EN 50553:2012
- 3 - EN 50553:2012 Tables Table B.1 Formulae for calculating the progression of the train . 30Table E.1 Cross-reference: system function and clauses . 36 SIST EN 50553:2012
EN 50553:2012 - 4 - Foreword This document (EN 50553:2012) has been prepared by CLC/TC 9X, "Electrical and electronic applications for railways".
The following dates are fixed: • latest date by which this document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2013-01-23 • latest date by which the national standards conflicting with this document have to be withdrawn (dow) 2015-01-23 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. This document has been prepared under a mandate given to CENELEC by the European Commission and the European Free Trade Association and supports essential requirements of EU Directives 96/48/EC (HSR) and 2001/16/EC (CONRAIL), both recast by 2008/57/EC (RAIL). For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this document. __________ SIST EN 50553:2012
- 5 - EN 50553:2012 Introduction The purpose of this European Standard is to define requirements for running capability under fire conditions which are applicable to railway rolling stock with passengers, so that a train will be able to reach a "safe area" as defined in the Safety in Rail Tunnels TSI (TSI SRT) 1.1.3. Specifically, this standard is intended to clarify and rationalise the requirements for rolling stock running capability in the EN 45545 series (Operation Categories 2, 3 and 4) and in the TSI SRT (Fire Safety Categories A and B). It is also intended to define specific technical measures, compliance with which will allow a ‘Presumption of Conformity’ with the TSI SRT to be made by the Notified Body assessing the Rolling Stock. NOTE 1 In several cases it might appear that requirements are included which are duplicating requirements given in the EN 45545 series and/or which are dealt with in other ways by the EN 45545 series. This is not the intention and is not the case. The EN 45545 series introduces running capability functional requirements but does not generally define how they are to be met nor to what level of performance. Also, a number of requirements which are included in the EN 45545 series, would be relevant to, or suitable for, running capability use but are not identified for this use within the TS. It is therefore necessary to include requirements which are apparently duplicating the EN 45545 series in this standard but which actually do not duplicate the TS when examined in detail. If desired it should be possible, when converting EN 45545 to an EN, to include these requirements during the process which would allow them to be removed from this standard. Reference to Annex A shows that it is necessary for this standard specifically to address 4.2.5.5 of the TSI SRT. This standard considers the requirement to "improve the probability that a passenger train with a fire on board will continue to operate…" in a "reasonably practicable" context. It is understood that "train" includes all vehicles such as locomotives and power cars which are associated with the passenger vehicles. Requirements for running capability cannot be defined without a knowledge of other fire characteristics of the train, specifically its reaction to fire and fire resistance specification. The assumption is made that the fire standard applied is the EN 45545 series or any standard for which technical equivalence can be demonstrated. NOTE 2 In defining conditions to assure running capability it is only the intention to define requirements which allow the train to remain capable of controlled movement. The general safety level of the train when operating under these conditions (for example the level of lighting within the saloon) is not within the scope. Matters such as this are dealt with in other standards (including, but not limited to, the EN 45545 series). The standard defines requirements based on a philosophy which recognises that stopping a train is not itself a life-threatening event. It is therefore not required to have running capability for all fires; only those fires which may cause serious injury and/or develop to threaten life. For example, situations such as the combustion of an individual electrical component inside a technical cabinet meeting criteria for fire resistance in accordance with the EN 45545 series, do not attract running capability requirements under this standard. In a similar manner, if any fire is extinguished with no reignition during the relevant period of the incident, it is deemed that there is no longer a requirement for running capability and the train can be stopped (as if it was a non-safety threatening technical fault). These examples illustrate how the impracticability of addressing all thermal events that could stop a train is circumvented by the philosophy applied. Compliance with the running capability requirements for any relevant system function is derived from one or more of the following: – absence of a relevant fire; – assuring system function under the fire; – assuring system function for a redundant array under the fire; – extinguishing the fire; – assuring sufficient remaining Tractive Effort under the fire. SIST EN 50553:2012
EN 50553:2012 - 6 - NOTE 3 This document does not cover requirements regarding maintenance, cleaning or prevention of arson. Nevertheless these are important considerations in the management of fire safety and must be recognised by those using this standard. They may be covered appropriately by the Maintenance requirements of Technical Specifications for Interoperability and the Safety Management Systems of Railway Undertakings. SIST EN 50553:2012
- 7 - EN 50553:2012 1 Scope This European Standard defines requirements for running capability under fire conditions which are applicable to passenger carrying railway rolling stock. In particular, technical measures are specified, compliance with which will contribute to conformity with the Directive and the relevant Technical Specifications for Interoperability (TSI). The standard specifies the fire conditions: – for which it is not necessary to define running capability requirements as there is no significant potential for serious injury or threat to life; – for which it is reasonable to expect trains to continue to run in a controlled manner; – for which it is not reasonably practicable to define requirements which give complete assurance of running in a controlled manner, due to the exceptional nature of the fire incident. The TSI SRT defines running capability requirements in respect of fires within technical areas/equipment only. However for general guidance the scope of this standard is extended to include fires from non-technical causes within passenger/staff areas which may impact train system functions adjacent to and/or passing through the affected area. This extension of applicability significantly increases the number of system functions which are potentially at risk and therefore requires that the "reasonably practicable" principles be extended to this new condition.
The standard does not consider situations where a primary non-fire incident is likely to immobilise the train by definition; for example major mechanical defect leading to derailment, even when fire then occurs. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 3-7 +A1 2004 2007 Portable fire extinguishers Part 7: Characteristics, performance requirements and test methods EN 54 Series Fire detection and fire alarm systems EN 403 2004 Respiratory protective devices for self-rescue Filtering devices with hood for escape from fire Requirements, testing, marking EN 15663 2009 Railway applications Definition of vehicle reference masses CEN/TS 45545-1 2009 Railway applications Fire protection on railway vehicles Part 1: General CEN/TS 45545-2 2009 Railway applications Fire protection on railway vehicles Part 2: Requirements for fire behaviour of materials and components CEN/TS 45545-3 2009 Railway applications Fire protection on railway vehicles Part 3: Fire resistance requirements for fire barriers CEN/TS 45545-4 2009 Railway applications Fire protection on railway vehicles Part 4: Fire safety requirements for railway rolling stock design CLC/TS 45545-5 2009 Railway applications Fire protection on railway vehicles Part 5: Fire safety requirements for electrical equipment including that of trolley buses, track guided buses and magnetic levitation vehicles SIST EN 50553:2012
EN 50553:2012 - 8 - CEN/TS 45545-6 2009 Railway applications Fire protection on railway vehicles Part 6: Fire control and management systems CEN/TS 45545-7 2009 Railway applications Fire protection on railway vehicles Part 7: Fire safety requirements for flammable liquid and flammable gas installations EN 50155 2001 Railway applications Electronic equipment used on rolling stock EN 50200 2006 Method of test for resistance to fire of unprotected small cables for use in emergency circuits EN 50216-5 + A1 + A2
+ corr Oct. + A3 2002 2002 2005 2006 2006 Power transformer and reactor fittings Part 5; Liquid level, pressure and flow indicators, pressure relief devices and dehydrating breathers EN 50362 2003 Method of test for resistance to fire of larger unprotected power and control cables for use in emergency circuits EN 60310 2004 Railway applications Traction transformers and inductors on board rolling stock (IEC 60310:2004) EN 61034-1 2005 Measurement of smoke density of cables burning under defined conditions Part 1: Test apparatus (IEC 61034-1:2005) EN ISO 15540 2001 Ships and marine technology Fire resistance of hose assemblies Test methods (ISO 15540:1999) IEC 60331-3 2009 Tests for electric cables under fire conditions Circuit integrity Part 3: Test method for fire with shock at a temperature of at least 830 °C for cables of rated voltage up to and including 0,6/1,0 kV tested in a metal enclosure ISO/TR 9705-2 2001 Reaction to fire tests Full scale room tests for surface products Part 2: Technical background and guidance 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 fire scenarios 3.1.1
type 1 fire fire which, due to its size and/or location, presents no significant risk of serious injury or threat to life and for which it is not necessary to define running capability requirements 3.1.2
type 2 fire fire which, due to its size and/or location, presents a risk of serious injury and/or threat to life and for which it is reasonably practicable to define running capability requirements 3.1.3
type 3 fire fire which, due to its size and/or location, presents a risk of serious injury and/or threat to life but for which it is not reasonably practicable to assure running capability SIST EN 50553:2012
- 9 - EN 50553:2012 3.1.4
reference Type 2 fire fire which has the power vs. time profile of Ignition source 5 of CEN/TS 45545-1; 75kW for 2 minutes followed by 150 kW for 8 min 3.2 electrical power supplies 3.2.1
supply line refer to CLC/TS 45545-5 3.2.2
traction circuit refer to CLC/TS 45545-5 3.2.3 auxiliary supplies 3.2.3.1
auxiliary circuit refer to CLC/TS45545-5 3.2.3.2
train power supply refer to CLC/TS45545-5 3.2.3.3
battery supply circuit refer to CLC/TS45545-5 3.3
equipment required for running capability parts of the equipment required to assure the system function required for running capability Note 1 to entry: For example, relevant parts of the brake system, control cables, power input and output cables, electrical/mechanical devices, the cooling circuit, auxiliary devices for feeding the blower motors and the air supply. 3.4
tractive effort (N) sum of all the traction forces between the train and the track 3.5
fire resistance terminology (examples) E15 and/or I15 are durations of Integrity (E) and Insulation (I) respectively Note 1 to entry: Refer to CEN/TS 45545-3:2009, 6.1. 3.6
relevant period of the incident period of the incident up to the time when the train has reached a "safe area" as defined in TSI SRT 1.1.3 3.7
system function (for equipment defined in 3.4) function of a system including all aspects of the command and control arrangements for the system 3.8
technical cabinet refer to CEN/TS 45545-6 3.9
decision box running capability compliancy test in Figure 1. The number of the Decision Box reflects its position in the flow chart cascade process SIST EN 50553:2012
EN 50553:2012 - 10 - 3.10
redundant array arrangement whereby a system function is assured by two or more independent systems and which continues to be fully assured when one of the systems fails 3.11
running capability (in case of a fire on board) ability of a train to reach a "Safe Area" (TSI SRT 4.2.2.6.1) in case of a fire on board 3.12
degraded mode state whereby less than nominally 100% of the system function capability can be achieved 4 Symbols and abbreviated terms For the purposes of this document, the following symbols and abbreviations apply. TSI Technical Specification for Interoperability TSI SRT Safety in Railway Tunnels TSI (see Bibliography) TSI HS RST High Speed Rolling Stock TSI (see Bibliography) CFD Computational Fluid Dynamics ATP Automatic Train Protection m Design mass [kg] under payload according to EN 15663 t Time [s] g The vertical acceleration due to gravity; taken as 9,81 m.s-2. v0 Initial velocity [m.s-1] vlim Speed limit on the line [m.s-1] i Gradient of line [mm per m] ρ Curve radius of the line [m] x Distance from the beginning of the line under consideration to the position of the head of the train [m]; (thus i(x) and ρ(x)) lt Length of line under consideration [m] NOTE The length of the line under consideration is equal to the length of the structure, (for example tunnel or elevated structure), plus the length of the train. R(v) Running resistance as a function of velocity [N] a, b, c Coefficients ("a" [N]; "b" [Ns.m-1]; "c" [Ns2.m-2]) F(v) Tractive effort [N] between the train and the track as a function of velocity
Acceleration [m.s-2] Am The Optical Density as defined in EN 61034-1 SIST EN 50553:2012
- 11 - EN 50553:2012 5 Methodology 5.1 Principles It is not considered necessary to accommodate the spontaneous occurrence of two or more independent fires, therefore a single fire occurrence only shall be considered. The train is assumed to be in its normal operational state at the start of the analysis.
NOTE "Normal operational state" means that the train is assumed to have no defects which affect its running capability at the start of the analysis. In defining requirements for running capability with a fire on board the train, the following must be considered: – It is necessary to recognise that stopping a train is not, in itself, a life-threatening event and hence stopping a train with a fire which is either contained or will be extinguished, is also not life-threatening. Thus it is important only to define requirements for running capability for those fires which have the potential to cause serious injury and/or threaten life. – It is possible to imagine fire incidents of such severity, possibly a severe arson event or fuel related catastrophic equipment failure, that there is no significant probability of the train systems surviving and of the vehicle continuing to function. For such incidents it is not reasonably practicable to define requirements which will assure the running capability of the train. It should however be recognised that requirements defined to mitigate the effects for these incidents on a lesser scale, which will occur during the fire development towards the extreme scale, will have beneficial effects in these extreme cases but that these benefits are not at a defined level. Given these principles it is necessary to define a classification system for fires, as the nature of the fire needs to be known before any judgement in respect of practicability can be made. The various fires which may occur are therefore placed into one of three types as defined in 3.1. At some stage when considering fires and the sources of fire, specific pieces of equipment will be examined. It is necessary to recognise that it is possible for a piece of equipment to be both a source of fire as well as impacted by fire and that a clear distinction should be made between these two situations in the analysis. Annex E shows the clauses relevant to specific system functions. 5.2 Fire Classification Scheme 5.2.1 Type 1 Fires Typical Type 1 fires are Ignition Models 1-4 of CEN/TS 45545-1, Annex A and these ignition models, in the context of trains constructed to EN 45545, present no significant risk because they are not considered to be large enough to pose a risk in themselves and fire will not develop. Thus for Type 1 fires there are no running capability requirements. NOTE An example of a "no requirement" situation would be a fire within a small equipment case containing safety critical signalling equipment. The fire would be represented by CEN/TS 45545-1 Ignition model 4 and whilst the fire within the case would cause the signalling equipment to fail and hence cause the train to stop, the fire hazard will be very small generally either due to the containment afforded by the case or due to the flame retardant nature of the materials within the case. Both of these situations are defined under CEN/TS 45545-2. 5.2.2 Type 2 Fires Type 2 fire events are related, for example, to luggage fires, vandalised seat fires, some diesel fires and also to significant arson events. These fires present a significant risk but are of a scale such that it is reasonably practicable to define requirements for the protection of train system functions so as to assure a defined level of running capability. Thus for Type 2 fires: SIST EN 50553:2012
EN 50553:2012 - 12 - Running capability is defined only in respect of: – initial development phase of diesel (and other combustible fluid) fires. (Fires are assumed to be either exterior or within a separate technical compartment); – significant arson or accidental ignition of brought in material (for example luggage placed/stored in accordance with operational protocols); – ignition of a vandalised seat. Ignition Model 5 of CEN/TS 45545-1 is a Type 2 Fire and is defined as the Reference Type 2 fire profile (see 3.1.4). For verification of compliance by test the fire profile shall be the Reference Type 2 fire; Ignition Model 5 of CEN/TS 45545-1 using the "Alternative Burner" (2.2 in ISO/TR 9705-2:2001). For verification of compliance by modelling, the fire profile shall be either the Reference Type 2 fire; Ignition Model 5 of CEN/TS 45545-1, or the real fire profile (from test). Specifically in the case of seats, the actual fire profile generated by the test on the vandalised seat (CEN/TS 45545-2) may be used. Specifically in the case of diesel fires, an actual diesel fire profile including any initial development phase relevant to the incident under consideration, may be used. NOTE The duration for which running capability is needed, (the "relevant period of the incident"), does not need to match the duration of the Type 2 fire profile or the duration of any standard test used to determine pass/fail criteria. The reference Type 2 profile is the maximum which is required to be considered. 5.2.3 Type 3 Fires Examples of Type 3 fires are the most severe arson attacks or catastrophic fuel related system function failure. These fires present a significant risk but are so large that it is not reasonably practicable to define requirements which would assure running capability due to the scale of the impact on the vehicle.
The possibility of a Type 3 fire does, however, require that provisions be put in place to deal with the Type 2 fire that will exist, however briefly, as the incident progresses to Type 3 fire status. It is reasonable to expect that the measures taken to assure running capability under the Type 2 fire conditions, which shall be applied to these fires, will be of some benefit for these Type 3 fires but the benefit is not at a defined level. Thus for Type 3 fires: There are no running capability requirements; i.e. none additional to those required by the included Type 2 fires as stated above, arising in respect of: – high power electrical faults on circuits which are not locally protected, electrically and by other means, according to EN 45545 – fully developed diesel (and other combustible fluid) fires resulting from failed equipment. 5.3 Application The logical basis for the application of running capability and hence for determining the state of compliancy in respect of Type 2 fires, is achieved by using the Figure 1. The flow chart should be used for each system function under consideration. When all relevant system functions have been considered and have been found to comply on an individual basis, the train is compliant. Users will commence their assessment at "Start" on the flow chart and enter Decision Box 1. If the analysis demonstrates that the system function under consideration is compliant with Decision Box 1; i.e. there is no Type 2 fire possible, the line followed is "No" to the "Compliant" end box. No further analysis needs to be done for that system function in respect of running capability. Decision Box 1 is an "existence test" for a Type 2 fire and guidance as to how to carry out this "existence test" is given in 6.2 and specifically in Figure 2. SIST EN 50553:2012
- 13 - EN 50553:2012 However, should the system function under consideration not be compliant with the analysis of Decision Box 1 it then enters into Decision Box 2. If the system function under consideration is compliant when analysed under Decision Box 2 the line followed is "Yes" down to the "Compliant" end box. No further analysis needs to be done for that system function in respect of running cap
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