1、September 2007DEUTSCHE NORM English price group 15No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 27.040!$I3U“1381650w
2、ww.din.deDDIN EN 12952-11Water-tube boilers and auxiliary installations Part 11: Requirements for limiting devices of the boiler and accessoriesEnglish version of DIN EN 12952-11:2007-09Wasserrohrkessel und Anlagenkomponenten Teil 11: Anforderungen an Begrenzungseinrichtungen an Kessel und ZubehrEng
3、lische Fassung DIN EN 12952-11:2007-09www.beuth.deDocument comprises 38 pages 11.07DIN EN 12952-11:2007-09 2 National foreword This standard has been prepared by Technical Committee CEN/TC 269 “Shell and water-tube boilers” (Secretariat: DIN, Germany). The responsible German body involved in its pre
4、paration was the Normenausschuss Rohrleitungen und Dampfkesselanlagen (Piping and Boiler Plant Standards Committee), Technical Committee NA 082-00-18 AA Dampfkesselanlagen. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12952-11 July 2007 ICS 27.040 English Version Water-tube boilers and auxil
5、iary installations - Part 11: Requirements for limiting devices of the boiler and accessoriesChaudires tubes deau et installations auxiliaires - Partie 11: Exigences pour les dispositifs de limitation de la chaudire et de ses accessoires Wasserrohrkessel und Anlagenkomponenten - Teil 11: Anforderung
6、en an Begrenzungseinrichtungen an Kessel und Zubehr This 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 conditions for giving this European Standard the status of a national standard without any alte
7、ration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN 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 tra
8、nslation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germa
9、ny, 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 STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG
10、Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12952-11:2007: EEN 12952-11:2007 (E) 2 Contents Page Foreword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms a
11、nd 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 5.2 Design .13 5.3 Floating devices.14 5.4 Level electrode devices 14 5.5 E
12、xamination 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 Examination of functional capability .19 6.6 Fault detection .21 7 Special
13、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 Electrical equipment24 8.4 Examination of functional capability .24 Annex
14、 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 Requirements and testing.31 Annex ZA (informative) Relationship between this Europea
15、n Standard and the Essential Requirements of EU Directive 97/23/EC 35 Bibliography 36 EN 12952-11:2007 (E) 3 Foreword This document (EN 12952-11:2007) has been prepared by Technical Committee CEN/TC 269 “Shell and water-tube boilers”, the secretariat of which is held by DIN. This European Standard s
16、hall 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 latest by January 2008. This document has been prepared under a mandate given to CEN by the Europ
17、ean 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. The European Standard EN 12952 concerning water-tube boilers and auxiliary inst
18、allations 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 expectancy calculations. Part 5: Workmanship and construction of pressure parts of the boiler
19、. 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 gaseous fuels for the boiler. Part 9: Requirements for firing systems for pulverized solid fu
20、els 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 boiler water quality. Part 13: Requirements for flue gas cleaning systems. Part 14: Requiremen
21、ts 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 the boiler. CR 12952 Part 17: Guideline for the involvement of an inspection body independent
22、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 application of more than one Part in order for the requirements of the standard to be satisfactoril
23、y 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 following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, C
24、yprus, Czech Repub-lic, 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. EN 12952-11:2007 (E) 4 Introduction T
25、he 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 element of a water-tube boiler safety system. It comprises a sensor and monitoring elements to achieve the desired
26、 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 to other elements in the safety system such as actuators and safety logic circuits. EN 12952-11:2007 (E) 5 1 Sco
27、pe This European Standard specifies requirements for limiters (or limiting devices) which are incorporated into safety systems for water-tube boilers as defined in EN 12952-1. A limiter (or limiting device) can be either: a safety accessory as defined in the Pressure Equipment Directive, Article 1,
28、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 of a safety accessory as defined in the Pressure Equipment Directive, Article 1, clause 2.1.3. The overall boiler pro-tection func
29、tion shall be provided in association with additional safety logic (where appropriate) and a final actuator. The design requirements and examination of functional capability for the limiters are covered in this European Standard. For an explanation of the extent of the limiter (or limiting device) s
30、ee Figure A.1. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 298:2003
31、, 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 equipment Part 1: Requirements for ap-plication design and installation EN 60529:1991, Degrees of protection provided by enclosures
32、 (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 61000-4-2:1995, Electromagnetic compatibility (EMC) Part 4: Testing and measurement techniques Section 2: Electrostatic discharge immu
33、nity 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-frequency, electromagnetic field immunity test (IEC 61000-4-3:2006) EN 61000-4-4:2004, Electromagnetic compatibility (EMC) Part 4-4
34、: 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: Testing and measurement techniques Surge immunity test (IEC 61000-4-5:2005) EN 61000-4-6:1996, Electromagnetic compatibility (EMC)
35、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, Electromagnetic compatibility (EMC) Part 4: Testing and measurement techniques Section 8: Power frequency magnetic field immunity test;
36、basic EMC publication (IEC 61000-4-8:1993) EN 12952-11:2007 (E) 6 EN 61000-4-11:2004, Electromagnetic compatibility (EMC) Part 4-11: Testing and measurement techniques Voltage dips, short interruptions and voltage variations immunity tests (IEC 61000-4-11:2004) EN 61000-6-2:2005, Electromagnetic com
37、patibility (EMC) Part 6-2: Generic standards Immunity for in-dustrial environments (IEC 61000-6-2:2005) EN 61508-3:2001, Functional safety of electrical/electronic/programmable electronic safety-related systems Part 3: Software requirements (IEC 61508-3:1998 + Corrigendum 1999) 3 Terms and definitio
38、ns 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. pressure, temperature, flow, water level) is used to inter-rupt and lock-out the energy supply NOTE Limiting device comprises: a measuring or detection f
39、unction and an activation function for correction, or shutdown, or shutdown and lockout, and which is used to carry out safety related functions as defined 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
40、channel systems, then all items or limit-ers for safety purposes are included within the safety (protective) system. Figure 1 Protective devices and safety accessories according to Directive 97/23/EC (PED) 3.2 actuating element component which produces changes in other electrical circuits or volume
41、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 limiter is fail-safe if it possesses the capability of remaining in a safe condition or transferring immediately to another safe condition in the ev
42、ent of certain faults occurring 3.4 self-monitoring regular and automatic determination that all chosen components of a safety system are capable of functioning as required EN 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
43、 provided by the necessary facilities 3.6 diversity provision of different means of performing the required function, e.g. other physical 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 s
44、afety shut-down process which is effected immediately following the detection of a fault within the limiter or caused by exceeding the 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 l
45、imiter, 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 by 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
46、, outputs a signal and/or cuts out and only reverses the output signal in the event of a specific change in the performance quantity (e.g. pressure, temperature, flow, level) NOTE Sensors are used for signalling or for triggering control processes. EN 12952-11:2007 (E) 8 4 Requirements for limiters
47、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-mon
48、itoring with redundancy, diversity or a com-bination of these methods. Fault assessment for the electrical components shall be in accordance with 4.4. The fault assessment chart, see Figure 2 shall also be applied for faults in hydraulic, pneumatic and mechanical components. NOTE The various element
49、s of limiters are given in Annex A. An example of an examination plan is given in Annex B. 4.1.2 Limiters shall function independently of each other and of controls unless their safety function cannot be affected by other such functions. Manual resetting can be realised as a part of the limiter or as a part of the safety logic. Instructions shall be delivered together with the limiter including necessary precautions for a safe installation of it. 4.2 Materials and design 4.2.1 The use of ma
