1、BRITISH STANDARD BS EN12952-11:2007Water-tube boilersand auxiliaryinstallations Part 11: Requirements for limitingdevices of the boiler and accessoriesICS 27.040; 27.060.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51
2、g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Incorporating corrigendum January 2010National forewordThis British Standard is the UK implementation of EN 12952-11:2007. Together with BS EN 12952-1:2001, BS EN 12952-2:2001, BS EN 12952-3:2001, BS EN 12952-5:2001, BS EN 12952
3、-6:2002, BS EN 12952-7:2002 and BS EN 12952-10:2002, it supersedes BS 1113:1999 which remains current and obsolescent. The obsolescent status means that the standard will no longer be updated. This status is given to BS 1113:1999 on the basis that there are numerous boilers throughout the world with
4、 long expectations of life that will require use of this standard for service and repair, enabling justification of contin-ued service of the boilers. The UK participation in its preparation was entrusted to Technical Committee PVE/2, Water-tube and shell boilers.A list of organizations represented
5、on this committee can be obtained on request to its secretary.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 cannot confer immunity from legal obligations.BS EN 12952-11:20
6、07This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 August 2007 BSI 2010Amendments/corrigenda issued since publicationDate Comments 31 January 2010 National foreword supersession details updatedISBN 978 0 580 69570 4EUROPEAN STANDARDNORME EU
7、ROPENNEEUROPISCHE NORMEN 12952-11July 2007ICS 27.040English VersionWater-tube boilers and auxiliary installations - Part 11:Requirements for limiting devices of the boiler and accessoriesChaudires tubes deau et installations auxiliaires - Partie11: Exigences pour les dispositifs de limitation de lac
8、haudire et de ses accessoiresWasserrohrkessel und Anlagekomponenten - Teil 11:Anforderungen an Begrenzungseinrichtungen an Kesselund ZubehrThis European Standard was approved by CEN on 26 May 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the condition
9、s for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three offic
10、ial versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Be
11、lgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR
12、STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12952-11:2007: EEN 12952-11:2007 (E) 2 Contents Pa
13、ge Foreword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .6 4 Requirements for limiters .8 4.1 General8 4.2 Materials and design .8 4.3 Electrical equipment9 4.4 Fault assessment.9 4.5 Marking .11 5 Special requirements for water level limiters .13 5.1 Components.13 5.
14、2 Design .13 5.3 Floating devices.14 5.4 Level electrode devices 14 5.5 Examination of functional capability .15 5.6 Fault detection .18 6 Special requirements for pressure limiters 18 6.1 Components.18 6.2 Additional fault assessment requirements .18 6.3 Design .18 6.4 Electrical equipment19 6.5 Ex
15、amination of functional capability .19 6.6 Fault detection .21 7 Special requirements for temperature limiters.21 7.1 Components.21 7.2 Design .21 7.3 Electrical equipment23 7.4 Examination of functional capability .23 8 Special requirements for flow limiters.24 8.1 Components.24 8.2 Design .24 8.3
16、Electrical equipment24 8.4 Examination of functional capability .24 Annex A (informative) Limiting device25 Annex B (informative) Example of an examination plan .26 Annex C (informative) Marking of limiters 28 Annex D (normative) Immunity against electrical and electromagnetic influences Requirement
17、s and testing.31 Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC 35 Bibliography 36 BS EN 12952-11:2007EN 12952-11:2007 (E) 3 Foreword This document (EN 12952-11:2007) has been prepared by Technical Committee CEN/TC 269 “Shel
18、l and water-tube boilers”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2008, and conflicting national standards shall be withdrawn at the lates
19、t by January 2008. 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). For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of th
20、is document. The European Standard EN 12952 concerning water-tube boilers and auxiliary installations consists of the following Parts: Part 1: General. Part 2: Materials for pressure parts of boilers and accessories. Part 3: Design and calculation for pressure parts. Part 4: In-service boiler life e
21、xpectancy calculations. Part 5: Workmanship and construction of pressure parts of the boiler. Part 6: Inspection during construction, documentation and marking of pressure parts of the boiler. Part 7: Requirements for equipment for the boiler. Part 8: Requirements for firing systems for liquid and g
22、aseous fuels for the boiler. Part 9: Requirements for firing systems for pulverized solid fuels for the boiler. Part 10: Requirements for safeguards against excessive pressure. Part 11: Requirements for limiting devices of the boiler and accessories. Part 12: Requirements for boiler feedwater and bo
23、iler water quality. Part 13: Requirements for flue gas cleaning systems. Part 14: Requirements for flue gas DENOX-systems using liquefied pressurized ammonia and ammonia water solution. Part 15: Acceptance tests. Part 16: Requirements for grate and fluidized bed firing systems for solid fuels for th
24、e boiler. CR 12952 Part 17: Guideline for the involvement of an inspection body independent of the manufacturer. Although these Parts can be obtained separately, it should be recognised that the Parts are inter-dependent. As such, the design and manufacture of water-tube boilers requires the applica
25、tion of more than one Part in order for the requirements of the standard to be satisfactorily fulfilled. NOTE Parts 4 and 15 are not applicable during the design, construction and installation stages. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the foll
26、owing countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Repub-lic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sl
27、ovenia, Spain, Sweden, Switzerland and United Kingdom. BS EN 12952-11:2007EN 12952-11:2007 (E) 4 Introduction The types of limiters which shall be fitted to boilers are specified in EN 12952-7 and the design of the safety systems are specified in EN 50156-1. A limiter (or limiting device) is one ele
28、ment of a water-tube boiler safety system. It comprises a sensor and monitoring elements to achieve the desired level of reliability. In order to provide the necessary safety function, for example, to cut off the heat supply to the boiler in the event of a low water fault, the limiter is connected t
29、o other elements in the safety system such as actuators and safety logic circuits. BS EN 12952-11:2007EN 12952-11:2007 (E) 5 1 Scope This European Standard specifies requirements for limiters (or limiting devices) which are incorporated into safety systems for water-tube boilers as defined in EN 129
30、52-1. A limiter (or limiting device) can be either: a safety accessory as defined in the Pressure Equipment Directive, Article 1, clause 2.1.3, and needs to include the safety logic and final actuator, or one element of a safety system, for example, a self-monitoring water level sensor used as part
31、of a safety accessory as defined in the Pressure Equipment Directive, Article 1, clause 2.1.3. The overall boiler pro-tection function shall be provided in association with additional safety logic (where appropriate) and a final actuator. The design requirements and examination of functional capabil
32、ity for the limiters are covered in this European Standard. For an explanation of the extent of the limiter (or limiting device) see Figure A.1. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition ci
33、ted applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 298:2003, Automatic gas burner control systems for gas burners and gas burning appliances with or with-out fans EN 50156-1:2004, Electrical equipment for furnaces and ancillary e
34、quipment Part 1: Requirements for ap-plication design and installation EN 60529:1991, Degrees of protection provided by enclosures (IP code) (IEC 60529:1989) EN 60730-1:2000, Automatic electrical controls for household and similar use Part 1: General requirements (IEC 60730-1:1999, modified) EN 6100
35、0-4-2:1995, Electromagnetic compatibility (EMC) Part 4: Testing and measurement techniques Section 2: Electrostatic discharge immunity test Basic EMC publication (IEC 61000-4-2:1995) EN 61000-4-3:2006, Electromagnetic compatibility (EMC) Part 4-3: Testing and measurement techniques Radiated, radio-f
36、requency, electromagnetic field immunity test (IEC 61000-4-3:2006) EN 61000-4-4:2004, Electromagnetic compatibility (EMC) Part 4-4: Testing and measurement techniques Electrical fast transient/burst immunity test (IEC 61000-4-4:2004) EN 61000-4-5:2006, Electromagnetic compatibility (EMC) Part 4-5: T
37、esting and measurement techniques Surge immunity test (IEC 61000-4-5:2005) EN 61000-4-6:1996, Electromagnetic compatibility (EMC) Part 4: Testing and measurement techniques Section 6: Immunity to conducted disturbances, induced by radio-frequency fields (IEC 61000-4-6:1996) EN 61000-4-8:1993, Electr
38、omagnetic compatibility (EMC) Part 4: Testing and measurement techniques Section 8: Power frequency magnetic field immunity test; basic EMC publication (IEC 61000-4-8:1993) BS EN 12952-11:2007EN 12952-11:2007 (E) 6 EN 61000-4-11:2004, Electromagnetic compatibility (EMC) Part 4-11: Testing and measur
39、ement techniques Voltage dips, short interruptions and voltage variations immunity tests (IEC 61000-4-11:2004) EN 61000-6-2:2005, Electromagnetic compatibility (EMC) Part 6-2: Generic standards Immunity for in-dustrial environments (IEC 61000-6-2:2005) EN 61508-3:2001, Functional safety of electrica
40、l/electronic/programmable electronic safety-related systems Part 3: Software requirements (IEC 61508-3:1998 + Corrigendum 1999) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 limiter limiting device that, on reaching a fixed value (e.g. pres
41、sure, temperature, flow, water level) is used to inter-rupt and lock-out the energy supply NOTE Limiting device comprises: a measuring or detection function and an activation function for correction, or shutdown, or shutdown and lockout, and which is used to carry out safety related functions as def
42、ined in the PED, as on its own or as part of safety (protective) system (e.g. sensors, limiters) (see also Figure 3.1). If this is achieved by multi channel systems, then all items or limit-ers for safety purposes are included within the safety (protective) system. Figure 1 Protective devices and sa
43、fety accessories according to Directive 97/23/EC (PED) 3.2 actuating element component which produces changes in other electrical circuits or volume flows (e.g. fuel, air) as a result of the effect of changes in signal NOTE For example, a gas shut off valve is not an actuating element. 3.3 fail-safe
44、 limiter is fail-safe if it possesses the capability of remaining in a safe condition or transferring immediately to another safe condition in the event of certain faults occurring 3.4 self-monitoring regular and automatic determination that all chosen components of a safety system are capable of fu
45、nctioning as required BS EN 12952-11:2007EN 12952-11:2007 (E) 7 3.5 redundancy provision of more than one device or system which, in the event of a fault, will still be provided by the necessary facilities 3.6 diversity provision of different means of performing the required function, e.g. other phy
46、sical principles or other ways of solving the same problem 3.7 complex electronics assemblies which use electronic components with more than one functional output 3.8 safety shut-down process which is effected immediately following the detection of a fault within the limiter or caused by exceeding t
47、he threshold of the process value limit resulting in a defined state with deactivated terminals of the safety output(s) 3.9 lock-out safety shut-down condition of the limiter, such that a restart can only be accomplished by a manual reset of the limiter or by a manual reset of the safety logic and b
48、y no other means. This will be achieved by a competent operator taking account of the physical situation 3.10 sensor transducer which, on reaching a defined limit value, outputs a signal and/or cuts out and only reverses the output signal in the event of a specific change in the performance quantity
49、 (e.g. pressure, temperature, flow, level) NOTE Sensors are used for signalling or for triggering control processes. BS EN 12952-11:2007EN 12952-11:2007 (E) 8 4 Requirements for limiters 4.1 General 4.1.1 The requirements set out below shall be followed to ensure uniform assessment of different devices. A limiter shall be such that a single fault in any related part shall not lead to a loss of the safety function. This shall be achieved by fault avoidance techniques such as self-monitoring wit
