SIST EN 12952-15:2004
(Main)Water-tube boilers and auxiliary installations - Part 15: Acceptance tests
Water-tube boilers and auxiliary installations - Part 15: Acceptance tests
This European Standard covers direct-fired steam and hot water generators, including the auxiliaries. For the purposes of this standard, steam and hot water generators are vessels and pipework systems in which:
3 steam at a pressure higher than atmospheric pressure is generated for use external to the system;
3 water is heated to a temperature higher than the saturation temperature at atmospheric pressure for use external to the system.
A steam generator normally consists of the flue gas-heated evaporator, the superheater, the reheater, the feedwater heater, the air heater, the fuel heater, if any, and the fuel burning equipment.
The term 'direct-fired' relates to equipment by means of which the chemical heat in the fuel of known composition is converted to sensible heat. Such equipment can involve stoker firing, fluidized-bed combustion or burner systems.
The auxiliaries include the fuel feeders, the pulverizer, the FD (forced draught) fan, the ID (induced draught) fan, the facilities for removal of the refuse (combustion residues), the steam air heater, the main air heater, the fuel heater, if any, and the dust collector.
Wasserrohrkessel und Anlagenkomponenten - Teil 15: Abnahmeversuche
Diese Europäische Norm behandelt Dampfkessel und Heißwassererzeuger mit eigener Feuerung einschließlich der zugehörigen Hilfseinrichtungen. Im Sinne dieser Norm sind Dampfkessel und Heißwassererzeuger Behälter und Rohrleitungen, in denen:
3 Wasserdampf von höherem als atmosphärischem Druck zur Verwendung außerhalb der Anlage erzeugt wird,
3 Wasser auf eine höhere Temperatur als die Siedetemperatur bei atmosphärischem Druck erhitzt wird, zur Verwendung außerhalb der Anlage.
Ein Dampferzeuger besteht üblicherweise aus dem rauchgasbeheizten Verdampfer, dem Überhitzer, dem Zwischenüberhitzer, dem Speisewasser-, dem Luft- und gegebenenfalls dem Brennstoffvorwärmer und der Feuerungseinrichtung.
Unter dem Begriff ?eigene Feuerung" wird eine Einrichtung verstanden, mit deren Hilfe die chemisch gebundene Wärme eines Brennstoffes bekannter Beschaffenheit in fühlbare Wärme umgesetzt wird. Es kann sich dabei um eine Rostfeuerung, eine Wirbelschichtfeuerung oder eine Brennerfeuerung handeln.
Zu den Hilfseinrichtungen gehören die Brennstoffzuteiler, die Mahlanlage, das Frischluftgebläse, das Rauchgasgebläse, die Einrichtungen für die Abfuhr der Verbrennungsrückstände, der Dampf-, der Luft- sowie gegebenenfalls der Brennstoffvorwärmer und der Entstauber.
Diese Norm gilt nicht für:
3 Anlagen für Sonderbrennstoffe (z. B. Müll);
3 druckbeaufschlagte Dampferzeuger (z. B. druckbeaufschlagte Wirbelschichtfeuerungskessel);
3 Dampferzeuger in Kombianlagen.
Sinngemäß kann diese Norm auch angewendet werden für die Abnahmeversuche bei:
3 Anlagen ohne eigene Feuerung (z. B. Abhitzekessel);
3 Anlagen mit anderen Wärmeträgern (z. B. Gase, Thermoöle, Natrium).
Wenn diese Norm als Grundlage für die Abnahmeversuche an Wärmeübertragungssystemen dienen soll, sollten bereits bei Vertragsabschluss Vereinbarungen getroffen werden im Hinblick auf die Besonderheiten, die die Messungen und die Auswertung der Versuchsergebnisse beeinflussen können.
1.2 Zweck
Diese Norm bil
Chaudieres a tubes d'eau et installations auxiliaires - Partie 15: Essais de réception
La présente Norme Européenne couvre les générateurs de vapeur et d'eau surchauffée a chauffe directe, y compris les accessoires. Pour les besoins de la présente norme, les générateurs de vapeur et d'eau surchauffée sont des récipients et des circuits dans lesquels :
de la vapeur est générée a une pression supérieure a la pression atmosphérique pour des besoins extérieurs au circuit ;
de l'eau est chauffée a une température supérieure a la température de saturation a la pression atmosphérique pour des besoins extérieurs au circuit.
Un générateur de vapeur est normalement constitué de l'évaporateur chauffé au gaz de combustion, du surchauffeur, du resurchauffeur, du réchauffeur d'eau d'alimentation, du réchauffeur d'air, le cas échéant du réchauffeur de combustible et de l'équipement de chauffe.
Le terme "a chauffe directe" fait référence a un équipement au moyen duquel l'énergie chimique d'un combustible de composition connue est convertie en chaleur sensible. De tels équipements peuvent comprendre la chauffe a alimentation automatique, des systemes de combustion ou de chauffe a lit fluidisé.
Les accessoires comprennent les alimenteurs doseurs de combustible, les installations de pulvérisation, le ventilateur FD (tirage forcé), le ventilateur ID (tirage induit), les installations d'évacuation des résidus (résidus de combustion), le réchauffeur d'air a vapeur, le réchauffeur d'air principal, le cas échéant le réchauffeur de combustible et le dépoussiéreur.
La présente norme ne couvre pas :
3 les unités chauffées avec des combustibles spéciaux (par exemple des déchets) ;
3 les générateurs de vapeur sous pression (par exemple des chaudieres a combustion a lit fluidisé (PFBC)) ;
3 les générateurs de vapeur dans des systemes a cycle combiné.
Par analogie, la présente norme peut etre appliquée aux essais de réception :
3 d'unités a chauffe indirecte (par exemple des chaudieres de récupération) ;
3 des unités fonctionnant avec d'autres vecteurs thermiques
Vodocevni kotli in pomožne napeljave - 15. del: Prevzemni preskusi
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Vodocevni kotli in pomožne napeljave – 15. del: Prevzemni preskusiWasserrohrkessel und Anlagenkomponenten - Teil 15: AbnahmeversucheChaudieres a tubes d'eau et installations auxiliaires - Partie 15: Essais de réceptionWater-tube boilers and auxiliary installations - Part 15: Acceptance tests27.060.30Grelniki vode in prenosniki toploteBoilers and heat exchangersICS:Ta slovenski standard je istoveten z:EN 12952-15:2003SIST EN 12952-15:2004en01-junij-2004SIST EN 12952-15:2004SLOVENSKI
STANDARD
SIST EN 12952-15:2004
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12952-15September 2003ICS 27.040English versionWater-tube boilers and auxiliary installations - Part 15:Acceptance testsChaudières à tubes d'eau et à tubes de fumée - Partie 15:Essais de réceptionWasserrohrkessel und Anlagenkomponenten - Teil 15:AbnahmeversucheThis European Standard was approved by CEN on 12 June 2003.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions 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 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and UnitedKingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2003 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12952-15:2003 ESIST EN 12952-15:2004
EN 12952-15:2003 (E)2ContentsPageForeword.31Scope and field of application.41.1Field of application.41.2Scope.41.3General information.52Normative references.53Terms and definitions.64Symbols and abbreviations and coefficients.64.1Symbols and abbreviations.64.2Coefficients.105Guaranteed parameters.115.1Basis for determining guaranteed parameters.115.2Parameters subject to guarantee.125.3Additional measurements.125.4Supply of steam generator components by several manufacturers.126Basic test conditions.136.1Methods of determining efficiency.136.2General conditions.136.3Preliminary test runs.136.4Condition of steam generator.136.5Steady-state conditions.136.6Performance of test.146.7Other information.177Instrumentation and methods of measurement.177.1General.177.2Pressure measurements.187.3Temperature measurements.187.4Mass and mass flow.187.5Calorific values.197.6Chemical composition.207.7Electric power.218Heat balance and thermal efficiency.218.1Heat balance and envelope boundary.218.2Reference temperature.278.3Heat input, heat output and losses.278.4Thermal efficiency.539Corrections to guarantee conditions.599.1General.599.2Correction for deviations of water/steam side inlet parameters.619.3Correction of efficiency by input-output method to guarantee conditions.619.4Correction of efficiency by heat loss method to guarantee conditions via heat balance.629.5Correction of efficiency by heat loss method to guarantee conditions with change in flue
gastemperature.659.6Efficiency under guarantee conditions.6910Averaging and uncertainty of measurement.7010.1General.7010.2Averaging and corrections.7010.3Fundamentals of calculating uncertainty.7110.4Guide values for measurement uncertainties.7310.5Calculation of uncertainty.82Annex A (normative)
Statistical Combustion Calculation.85Bibliography.87SIST EN 12952-15:2004
EN 12952-15:2003 (E)3ForewordThis document EN 12952-15:2003 has been prepared by Technical Committee CEN/TC 269 “Shell and water-tubeboilers”, 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 orby endorsement, at the latest by March 2004, and conflicting national standards shall be withdrawn at the latest byMarch 2004.This document has been prepared under a mandate given to CEN by the European Commission and the EuropeanFree Trade Association. This European Standard is considered as a supporting standard to other application andproduct standards which in themselves support an essential safety requirement of a New Approach Directive andshould appear as a normative reference in them.The European Standard series EN 12952 concerning water-tube boilers and auxiliary installations consists of thefollowing parts:¾ Part 1:General.¾ Part 2:Materials for pressure parts of boilers and accessories.¾ Part 3:Design and calculation for pressure parts.¾ Part 4:In-service boiler life expectancy calculations.¾ Part 5:Workmanship and construction of pressure parts of the boiler.¾ Part 6:Inspection during construction, documentation and marking of pressure parts of the boiler.¾ Part 7:Requirements for equipment for the boiler.¾ Part 8:Requirements for firing systems for liquid and gaseous fuels for the boiler.¾ Part 9:Requirements for firing systems for pulverized solid fuels for the boiler.¾ Part 10:Requirements for safeguards against excessive pressure.¾ Part 11:Requirements for limiting devices of the boiler and accessories.¾ Part 12:Requirements for boiler feedwater and boiler water quality.¾ Part 13:Requirements for flue gas cleaning systems.¾ Part 14:Requirements for flue gas DENOX-systems.¾ Part 15:Acceptance tests.¾ 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 of the manufacturer.Although these Parts may be obtained separately, it should be recognized that the Parts are interdependent. As such,the design and manufacture of water-tube boilers requires the application of more than one Part in order for therequirements of the Standard to be satisfactorily fulfilled.NOTEPart 4 and 15 are not applicable during the design, construction and installation stages.Annex A is normative.This document includes a Bibliography.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following coun-tries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Slovakia, Spain, Sweden, Switzerland and the United Kingdom.SIST EN 12952-15:2004
EN 12952-15:2003 (E)41 Scope and field of application1.1 Field of applicationThis European Standard covers direct-fired steam boilers and hot water generators, including the auxiliaries. For thepurposes of this standard, steam boilers and hot water generators are vessels and pipework systems in which:¾ steam at a pressure higher than atmospheric pressure is generated for use external to the system;¾ water is heated to a temperature higher than the saturation temperature at atmospheric pressure for use ex-ternal to the system.A steam generator normally consists of the flue gas-heated evaporator, the superheater, the reheater, the feedwaterheater, the air heater, the fuel heater, if any, and the fuel burning equipment.The term 'direct-fired' relates to equipment by means of which the chemical heat in the fuel of known composition isconverted to sensible heat. Such equipment can involve stoker firing, fluidized-bed combustion or burner systems.The auxiliaries include the fuel feeders, the pulverizer, the FD (forced draught) fan, the ID (induced draught) fan, thefacilities for removal of the refuse (combustion residues), the steam air heater, the main air heater, the fuel heater, ifany, and the dust collector.This standard does not cover:¾ units fired with special fuels (e.g. refuse);¾ pressurized steam generators (e.g. pressurized fluidized-bed combustion (PFBC) boilers);¾ steam generators in combined cycle systems.This standard can be applied by analogy to the acceptance testing of:¾ indirect-fired units (e.g. waste heat boilers);¾ units operated using other heat carriers (e.g. gases, thermal oils, sodium).Where this standard is to serve as the basis for the acceptance testing of heat-transfer systems, an agreement shouldhave been reached by the time the contract has been concluded with regard to any special features which may havean effect on the measurements and interpretation of test results.1.2 ScopeThis standard is intended as the basis for the thermal performance (acceptance) testing of direct-fired steam boilersand hot water generators. Such tests are designed to demonstrate that the guarantees with respect to efficiency andoutput or other parameters have been met.This standard includes (among other things):¾ recommendations for the performance of acceptance tests (see clause 6);¾ a definition of the envelope boundary of the steam generating unit and of the efficiency (see clause 8);¾ details on the uncertainty of measurement (see clause 10).SIST EN 12952-15:2004
EN 12952-15:2003 (E)51.3 General informationThe standard provides information on agreements relating to the type and scope of acceptance tests. Such agree-ments should be made prior to testing or at the time when the steam or hot water generator is ordered.The agreements can refer to the following:¾ scope of supply, envelope boundary, reference temperature;¾ method of determining thermal efficiency, direct (input-output) method or indirect (heat loss) method;¾ additional measurements;¾ test conditions, such as degree of cleanliness, time to reach steady-state condition and test duration;¾ any deviating test conditions;¾ blowdown and sootblowing;¾ functional use of instrumentation other than specified in clause 6;¾ steam table and tables for other thermodynamic properties to be used;¾ any special correction methods;¾ location and position of measuring points.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 837-1, Pressure gauges — Part 1: Bourdon tube pressure gauges — Dimensions, metrology, requirements andtesting.EN 12952-1:2001, Water-tube boilers and auxiliary installations — Part 1: General.EN 26801, Rubber or plastics hoses — Determination of volumetric expansion (ISO 6801:1983).EN 60584-1, Thermocouples — Part 1: Reference tables (IEC 60584-1:1995).EN 60584-2, Thermocouples — Part 2: Tolerances (IEC 60584-2:1982 + A1:1989).EN 60751, Industrial platinum resistance thermometer sensors (IEC 60751:1983 + A1:1986).EN ISO 3170, Petroleum liquids — Manual sampling (ISO 3170:1988, including Amendment 1:1998).EN ISO 3993, Liquefied petroleum gas and light hydrocarbons — Determination of density or relative density —Pressure hydrometer method (ISO 3993:1984).EN ISO 5167-1, Measurement of fluid flow by means of pressure differential devices — Part 1: Orifice plates,nozzles and Venturi tubes inserted in circular cross-section conduits running full (ISO 5167-1:1991).ISO 157, Coal — Determination of forms of sulfur.ISO 334, Solid mineral fuels — Determination of total sulfur — Eschka method.SIST EN 12952-15:2004
EN 12952-15:2003 (E)6ISO 589, Hard coal — Determination of total moisture.ISO 609, Solid mineral fuels — Determination of carbon and hydrogen — High temperature combustion method.ISO 625, Solid mineral fuels — Determination of carbon and hydrogen — Liebig method.ISO 1217, Displacement compressors — Acceptance tests.ISO 1928, Solid mineral fuels — Determination of gross calorific value by the bomb calorimetric method, and calcula-tion of net calorific value.ISO 1988, Hard coal — Sampling.ISO 5389, Turbocompressors — Performance test code.3 Terms and definitionsFor the purposes of this European Standard, the terms and definitions given in EN 12952-1 and the following apply.3.1direct methodinput-output methodefficiency is determined as the ratio of heat absorbed by the working fluids (water and steam) to the heat input(chemical heat plus heat credits added to the steam generator)3.2indirect methodheat loss methoddetermination of all accountable heat losses, heat credits and the heat in the fuel. The efficiency is then equal to100 minus the ratio of the sum of all heat losses to the sum of heat in the fuel plus heat credits3.3standard conditionembraces the condition at pn = 1,01325 bar and tn = 0 °C3.4refusecombustion residues that are obtained in the form of flue dust or in the molten and/or agglomerated solid state(slag), including the fuel contained in them4 Symbols and abbreviations and coefficients4.1 Symbols and abbreviationsFor the purpose of this part, the symbols given in EN 12952-1:2001, Table 4-1 and those given in Table 4.1-1 andTable 4-1-2 shall apply.SIST EN 12952-15:2004
EN 12952-15:2003 (E)7Table 4.1-1 — Latin LettersSymbolDescriptionUnitAAsh content of fuel related to daf-based fuel—AUInfluence factor—cSpecific heat capacityakJ/(kgK)cIntegral specific heat capacityakJ/(kgK)ffactor (transient fraction of heat output)—fLimit of (permissible) error—HCalorific value (CV)kJ/kghSpecific enthalpykJ/kgiNumber of samples—JEnthalpy of flue gas or combustion air related to fuel mass flowkJ/kgLLatent heat (heat of vaporization)kJ/kglSingle loss—lInflow lengthmluRatio of unburned combustibles to supplied fuel mass flow—MMolar mass—mMass flow (rate)kg/snAir factor at boiler outlet—nLime ratio—PPowerkWpPressureN/mm2QHeat flowkWTThermodynamic temperatureKtTemperature Celsius°CuUnburned combustibles content (by mass)kg/kguMUncertainty of measurement—VCombustion air and flue gas volume (per unit mass of fuel)m3/kgVVolume flow (rate)m3/hvSpecific volumem3/kgwVelocitym/sWMoisture content of fuel related to dry, ash free based fuel—xFlue gas/combustion air components content by masskg/kgxAdCombustion air content by masskg/kgyContent by volumem3/m3yAdCombustion air content by volumem3/m3NOTE 11 N/mm2 = 1 MN/m2 = 1 MPaNOTE 2The units shown are those normally used. Conversion can be necessary for use in the dimensionless equations.a"specific heat", for short.SIST EN 12952-15:2004
EN 12952-15:2003 (E)8Table 4.1-2 — Greek lettersSymbolQuantityUnitaHeat transfer coefficientW/(m2/K)¶Partial differential—DDifference—eRelative uncertainty of measurement—eEmissivity—hThermal efficiency—hS'LAsh collection efficiency—hSDesulfurization efficiency—gFuel content (by mass)kg/kguVolatile matter content of ashkg/kgrDensitykg/m3sStandard deviation—mCombustion air/flue gas mass to fuel mass ratiokg/kgttest durationh or sSIST EN 12952-15:2004
EN 12952-15:2003 (E)9Table 4.1-3 — SubscriptsSymbolDescriptionAAirAshAshASAtomizing steam or airBBoilerBDBlowdown waterccorrectedCnConvectionCCarbonCaCalcium (lime)COCarbon monoxideCO2Carbon dioxidedDry (basis)dafDry, ash-freeDCDust collectoreFinal valueECExternal coolingFAFlue dust (fly ash)FFuel, burned fuelFoFuel suppliedFWFeedwaterGFlue gas (combustion gas)(G)Gross valuegGuaranteedHHydrogenH2OWaterKLime (when used as additive)LLossLALeakage (infiltrated) air / tramp airMPulverizermAveragemeasMeasuredminMinimumNUseful, effectiveNNitrogen(N)Net valuenStandard conditionoStoichiometricO; O2OxygenpConstant pressureSIST EN 12952-15:2004
EN 12952-15:2003 (E)10Table 4.1-3 (continued)SymbolDescriptionrReferenceRRadiationRCRadiation and convectionRHReheat steamSSulfurSSSpray waterSASteam air heaterSLSlagSamSamplingSenSensorSTLive steamtotTotaltrTrue (value)uUnburned matterUCirculating pump or recirculating fanVMVolatile matterWWallZHeat input0At 0 °C1Upstream, inlet2Downstream, outletI, IIReheater stages^Maximum4.2 CoefficientsFor the purpose of this part, the coefficients given in Table 4.2-1 shall apply.SIST EN 12952-15:2004
EN 12952-15:2003 (E)11Table 4.2-1 — CoefficientsDesignationSymbolValueUnitSpecific latent heat at 25 °CLr2442,5kJ/kgSpecific heat of steam between 25 °C and 150 °CpStc1,884kJ/(kg K)Specific heat of water between 25 °C and 150 °CpWc4,21kJ/(kg K)Specific heat of air between 25 °C and 150 °CpAc1,011kJ/(kg K)Specific heat of ash and flue dust between 25 °C and 200 °CFAAshcc,0,84kJ/(kg K)Specific heat of slagDry-bottom furnaceSLc1,0kJ/(kg K)Slag-tap furnaceSLc1,26kJ/(kg K)Specific heat of additives between 25 °C and 200 °CCacCaCO30,97kJ/(kg K)Ca(HO)21,32kJ/(kg K)CaO0,84kJ/(kg K)Specific heat of dry and ash-free coal between 25 °C and 150 °CFdafc1,03(1 + gVm)kJ/(kg K)CV of carbon monoxideHCOn12,633MJ/m3CV of unburned matter:Hard coalHuu33,0MJ/kgBrown coalHuu27,2MJ/kgCV of total organic carbon (10 °C)Huu33,0MJ/kg5 Guaranteed parameters5.1 Basis for determining guaranteed parametersThe following factors shall be considered when establishing the guaranteed parameters:¾ fuel properties (composition, net calorific value (NCV), grindability, ash fusibility) and fuel group, if relevant;¾ feedwater and spray water characteristics (pressure, temperature);¾ cold reheat steam pressure, temperature and mass flow;¾ air temperature, relative humidity, air pressure, negative-pressure condition at boiler outlet.Parameters and thermodynamic properties relate to the envelope boundary (see 8.1) only.SIST EN 12952-15:2004
EN 12952-15:2003 (E)125.2 Parameters subject to guaranteeAn acceptance test of a steam generator shall be carried out to verify compliance with the guarantees.The main parameters that shall be guaranteed are:¾ the maximum continuous rating (MCR);¾ the pressure and temperature of the generated live and reheat steam;¾ the efficiency or losses, or the flue gas temperature.The following parameters may also be subject to guarantee:¾ the efficiency or losses for given fuels and/or partial loads;¾ the steam condition for given fuels and at partial loads;¾ the pressure drop across boiler high pressure (HP) system and reheater;¾ the pressure loss in the combustion air and flue gas flows at agreed points;¾ the air factor (ratio of actual to stoichiometric combustion air masses) at agreed points;¾ the maximum throughput of reheater spray water;¾ the unburned combustibles content of flue dust;¾ the emission of flue gas.Unless otherwise agreed, guarantees shall relate to steady-state conditions.5.3 Additional measurementsThe following parameters may also be taken into consideration when evaluating the steam generating unit:¾ pressure and temperature of water and steam at different points;¾ combustion air pressure, temperature and velocity (flow rate) at different points along the ducting system;¾ flue gas composition, pressure, temperature and velocity (flow rate) at different points along the ducting sys-tem.5.4 Supply of steam generator components by several manufacturersIf steam generator components are supplied by several manufacturers, additional measurements may be neces-sary in order to provide proof of conformance to the guarantees.SIST EN 12952-15:2004
EN 12952-15:2003 (E)136 Basic test conditions6.1 Methods of determining efficiencyThe thermal efficiency of steam generators shall be determined using the direct or indirect method (see clause 3).It is recommended that the major heat losses also should be determined when using the direct method.Which method is to be given preference depends on the technical resources. Where solid fuels are used, for ex-ample, it is not possible or extremely difficult to accurately measure large mass flows. Here, the only viable choiceis the indirect method, which should also be adopted when the fuel properties are subject to large fluctuations. If itis possible to take accurate measurements of fuel flow, the direct method may be the better choice, especially forsmall steam generators, owing to the uncertainty involved in the measurement of radiation and convection losses.The two methods have different levels of uncertainty. The method with the highest accuracy should always be em-ployed.The method shall be agreed with the purchaser, and stated in the contract.6.2 General conditionsThe parameters listed in 5.1 shall be determined before carrying out acceptance tests. If the operating conditionsdo not allow this, the tests may, subject to prior agreement, be performed under different conditions. However, de-viations shall be kept to a minimum. It shall then be necessary to correct the efficiency to the guaranteed condi-tions. See clause 9 for details.6.3 Preliminary test runsPrior to the regular acceptance test, the supplier shall be given the opportunity to conduct preliminary test runswhich serve to check the accuracy of test equipment and methods and to train test personnel.If a preliminary test yields satisfactory results, it may be declared an acceptance test, subject to agreement of allparties involved.6.4 Condition of steam generatorIt shall be assumed that a steam generator is so designed that the guaranteed values can be attained with normalfouling. The supplier shall be given the opportunity to inspect the heating surface prior to the acceptance test. Thetime of the acceptance test shall be agreed between the operator and supplier. However the test should be carriedout after optimization and the test run being carried out.Where the steam generator has been supplied with cleaning equipment (e.g. sootblowers or a shot cleaning plant),such equipment shall be employed for cleaning before the acceptance test.6.5 Steady-state conditions6.5.1 Attaining steady-state conditionsAs the guaranteed values refer to steady-state conditions only, it shall be ensured that the steam generator hasreached equilibrium.The time required to attain equilibrium shall vary widely with the boiler design. Normally, the steam generator shallhave been in continuous operation for several days prior to the test.Equilibrium shall have been reached before the test starts, which shall be established by all parties to the test.For certain firing systems (e.g. slag-tap furnaces, fluidized-bed combustion systems) it may take an extremely longtime to reach steady-state conditions.SIST EN 12952-15:2004
EN 12952-15:2003 (E)146.5.2 Monitoring the steady-state conditionDuring the test, particular characteristic and significant measured values shall be continually monitored to verifythat steady-state conditions have been maintained. Interim evaluation of results shall be recommended when de-termining efficiency by the direct method.6.5.3 Adjustment of firing systemThe test fuel shall be made available well in advance so that the supplier has sufficient time to adjust the fuel-burning equipment and to ensure that steady-state conditions with respect to the fuel are reached.6.6 Performance of test6.6.1 Test durationFor the direct method, the duration of testing depends on the type of boiler and firing system as well as on the levelof measurement accuracy desired.For the indirect method, the duration of testing is usually governed by the extent of traverse measurements ('trav-erses', for short) of flue gas losses or, in the case of fluidized-bed combustion systems, the time it takes to deter-mine losses due to enthalpy and unburned combustibles.The recommended duration of the test shall be in accordance with Table 6.6-1.Table 6.6.1 — Recommended duration of testsDirect testsDurationSolid fuel equipment giving steady burning rates4 hSolid fuel equipment giving possible cyclic variation
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