Designation: E2778 − 14Standard Specification forCustom Tiled/Mortared Masonry Heaters (Stoves)1This standard is issued under the fixed designation E2778; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification contains specifications for the dimen-sioning of custom tiled/mortared masonry heaters (stoves). Thecustom tiled/mortared masonry heaters (stoves) are individu-ally technically calculated and constructed. This informationcan be used for log (cordwood) wood-fired masonry heatersthat burn one fuel load per storage period with a maximum loadbetween 10 and 40 kg and a storage period (nominal heatingtime) between 8 and 24 h per EN 15544.1.2 This specification is valid for masonry heaters equippedwith fireclay as interior material with an apparent densitybetween 1750 and 2200 kg/m³, a degree of porosity 18 up to33 % by volume, and a heat conductivity from 0.65 up to0.90 W ⁄mK (temperature range 20 to 400°C) per EN 15544.1.3 This specification is valid for masonry heaters withsidewise combustion air supply of the combustion chamber.1.4 This specification is not valid for masonry heaterscombined with water heat exchangers for central heating orother heat-absorbing elements such as glass plates greater than1⁄6 of the combustion chamber surface, open water tanks, andso forth. It is also not valid for masonry heaters combined withheating/fireplace elements in accordance with EN 13229.Furthermore, this specification is not valid for mass-producedprefabricated or partly prefabricated slow heat release appli-ances according to EN 15250.1.5 The calculation method of this specification is used toestablish emissions and energy efficiency when burning logwood or wood briquettes according to the manufacturer’s orbuilder’s manual.1.6 Clearance to Combustibles—When a masonry heater isconstructed according to this specification, the clearance tocombustibles shall be in accordance with TRVB 105 or otherappropriate standards.1.7 Units—The values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E631 Terminology of Building ConstructionsE1602 Guide for Construction of Solid Fuel Burning Ma-sonry Heaters2.2 EN Standards:3EN 13229 Inset appliances including open fires fired by solidfuels—Requirements and test methodsEN 13384–1 Chimneys—Thermal and fluid dynamic calcu-lation methods—Part 1: Chimneys serving one applianceEN 15250 Slow heat release appliances fired by solid fuel—Requirements and test methodsEN 15544 One off Kachelgrundöfen/Putzgrundöfen [tiled/mortared (sic) stoves]: Calculation methods2.3 Austrian National Fire Service Association Standard:4TRVB 105 Fireplaces for Solid Fuels3. Terminology3.1 Definitions: Terms used in this specification are definedin Terminology E631.3.2 Masonry heaters are also known by the following wordsand terms and are further explained in Guide E1602;Kachelofen, Kakelugn, grundofen, Kachelgrundöfen,Putzgrundöfen, and slow heat release appliance.4. Classification4.1 Nominal Heat Output—The nominal heat output shall bespecified.4.2 Load of Fuel:1This specification is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.54on Solid Fuel Burning Appliances.Current edition approved Oct. 1, 2014. Published October 2014. DOI: 10.1520/E2778–14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at

[email protected] For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.3Available from Deutsches Institut fur Normung e.V.(DIN), Burggrafenstrasse 6,10787, Berlin, Germany, http://www.din.de.4Available from Österreichischer Bundes Feuerwehr Verband (ÖBFV), Voit-gasse 4, 1220 Wien, Austria, http://www.bundesfeuerwehrverband.at/shop/contact.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2.1 Maximum Load—The maximum load of fuel is calcu-lated per EN 15544.4.2.2 Minimum Load—The minimum load is fixed at 50 %of the maximum load per EN 15544.mBmin5 ~0.5!~mB! (1)where:mB= maximum load (kg), andmBmin= minimum load (kg).4.3 Design of the Essential Dimensions:4.3.1 Combustion Chamber Dimensions—The design of thedimensions of the combustion chamber is necessary because,on one hand, enough room to place the fuel in it is needed and,on the other hand, the requirements for a clean combustionhave to be fulfilled.4.3.1.1 Combustion Chamber Surface:(1) The dimension of the combustion chamber surface hasto be calculated per EN 15544.(2) For the calculation of the combustion chamber surfaceall its walls, the ceiling, and the base, including the area of thecombustion chamber opening and the combustion chamber exitfor the flue gas, have to be regarded equally.4.3.1.2 Combustion Chamber Base:(1) The combustion chamber base can be varied between aminimum and a maximum value.(2) The minimum value results from the requirement that,at maximum load, a height of the fuel of 33 cm shall not beexceeded. Therefore, a base of 100 cm2per kg fuel is neededper EN 15544.(3) The maximum area of the base of the combustionchamber is defined per EN 15544.(4) When the base is rectangular, the proportion of lengthto width can be varied from 1 to 2, but a minimum width of 23cm is required per EN 15544.4.3.1.3 Combustion Chamber Height:(1) The minimum combustion chamber height is definedper EN 15544.(2) On the basis of the specifications of the combustionchamber base and the combustion chamber surface, the com-bustion chamber height shall be calculated per EN 15544.4.3.2 Minimum Flue Pipe Length:4.3.2.1 Construction without Air Gap—The minimum fluepipe length shall be calculated per EN 15544.4.3.2.2 Construction with Air Gap—The minimum flue pipelength shall be calculated per EN 15544.4.3.3 Gas Groove Profile—The gas groove profile shall becalculated per EN 15544.4.4 Calculation of the Burning Rate—The burn rate shall becalculated per EN 15544.4.5 Fixing of the Air Ratio—Combustion in a masonryheater is a process, which is variable, it is not steady state. Themean air ratio is fixed per EN 15544.4.6 Combustion Air, Flue Gas:4.6.1 Combustion Air Flow Rate—The mean combustion airflow rate shall be calculated per EN 15544.4.6.1.1 Temperature Correction—The temperature correc-tion factor shall be calculated per EN 15544.4.6.1.2 Altitude Correction—The altitude correction factorshall be calculated per EN 15544.4.6.2 Flue Gas Flow Rate:4.6.2.1 The knowledge of the flue gas flow rate is importantfor the calculation of the flue pipe diameter. It is calculated perEN 15544.4.6.2.2 The value, ft, shall be calculated using the flue gastemperature of the flue pipe section. This means that along theflue pipe the decreasing temperature leads to a lower flue gasflow rate.4.6.3 Flue Gas Mass Flow Rate—The flue gas mass flowrate shall be calculated per EN 15544.4.7 Calculations of the Density:4.7.1 Combustion Air Density—The density of the combus-tion air at standard conditions shall be per EN 15544.4.7.2 Flue Gas Density—The density of the flue gas atstandard conditions is 1.282 kg/m3. It shall be calculated perEN 15544.4.8 Calculation of the Flue Gas Temperature:4.8.1 Mean Combustion Chamber Temperature—The com-bustion chamber temperature is necessary to calculate thestanding pressure in the combustion chamber. Because of thecalculation of the combustion chamber surface, the calculationtemperature of all combustion chambers is similar. The tem-perature shall be fixed per EN 15544.4.8.2 Flue Gas Temperature in the Flue Pipe:4.8.2.1 The decrease of the temperature along the flue pipeshall be calculated per EN 15544.4.8.2.2 This development of the temperature is valid fromthe combustion chamber exit to the connecting pipe.4.8.3 Flue Gas Temperature in the Connecting Pipe—Theflue gas temperature in the connecting pipe shall be calculatedbased on EN 13384-1.4.8.4 Flue Gas Temperature at Chimney Entrance, MeanFlue Gas Temperature of the Chimney, and Temperature of theChimney Wall at the Top of the Chimney—The flue gastemperature at chimney entrance, the mean flue gas tempera-ture of the chimney, and the temperature of the chimney wallat the top of the chimney are calculated based on EN 13384-1.The outside temperature for the calculation shall be fixed with0°C.4.9 Calculation of Flow Mechanics:4.9.1 Calculation of the Standing Pressure:4.9.1.1 The standing pressure results in the difference be-tween the densities of the flue gas and the air.4.9.1.2 The standing pressure shall be calculated per EN15544.4.9.1.3 The effective height is the vertical difference be-tween the flue gas exit and the flue gas entrance of a flue pipesection, the connecting pipe, or the chimney. For thecombustion, the combustion chamber height, HBR, shall beused. The air density shall be calculated per EN 15544, and theflue gas density shall be calculated per EN 15544. For thecombustion chamber, the combustion chamber temperature,tBR, shall be used.4.9.2 Calculation of the Flow Velocity:E2778 − 1424.9.2.1 The velocity shall be calculated by dividing the airor flue gas flow rates by the profile per EN 15544.4.9.2.2 The flow velocity in the flue pipe, the connectingpipe, and the chimney shall be between 1.2 and 6 m/s per EN15544.4.9.3 Calculation of the Static Friction—The static frictionin the flue pipe, the connecting pipe, and the chimney shall becalculated with EN 13384–1 as follows:pR5 ~λf!~pd!~L!⁄~Dh! (2)where:pR= static friction (Pa);pd= dynamic pressure (Pa);λf= friction coefficient;L = length of flue pipe section, connecting pipe, or chimney(m); andDh= hydraulic diameter (m).4.9.3.1 Dynamic Pressure—The dynamic pressure shall becalculated per EN 15544.4.9.3.2 Friction Coeffıcient:(1) The friction coefficient shall be calculated according toan approximation per EN 15544.4.9.3.3 Hydraulic Diameter—The hydraulic diameter shallbe calculated per EN 15544.4.9.4 Calculation of the Resistance as a Result of DirectionChange:4.9.4.1 The resistance as a result of direction change shallbe calculated by multiplication of the dynamic pressure withthe resistance coefficient per EN 15544.4.9.4.2 Interim values shall be interpolated linearly.4.9.4.3 If a flue pipe section is shorter than its hydraulicdiameter (short flue pipe section: LDh), the resistances of thedirection changes before and after the section are not fullyeffective. Therefore, the calculation of the resistance coefficientshall be done per EN 15544.4.10 Operation Control:4.10.1 Pressure Condition:4.10.1.1 At nominal heat output, the sum of all buoyancies(ph) shall be compared with the sum of all resistances (pr, pu)per EN 15544.4.10.1.2 The calculation shall be done section by sectionstarting with the air inlet and ending with the exit of thechimney. For the calculation, the conditions (temperature,velocity) in the middle of each section shall be taken per EN15544.4.10.1.3 The following term shall be fulfilled per EN 15544:~Σ pr1 Σ pu! # Σph# ~1.05!~Σ pr1 Σ pu! (3)where:Σpr= sum of all static frictions (Pa),Σpu= sum of all resistances as a result of direction change(Pa), andΣph= sum of all buoyancies (Pa).4.10.2 Dew Point Condition:4.10.2.1 At the lowest load, the temperature of the chimneywall at its top is compared with the dew point temperature ofthe flue gas.4.10.2.2 The following term shall be fulfilled per EN 15544:ti,2$45 (4)where:ti,2= chimney wall temperature at its top (°C).4.10.2.3 For this calculation, a dew point temperature of45°C is used. The chimney wall temperature at its top shall becalculated based on EN 13384-1.4.10.3 Effıciency of the Combustion, η—The efficiency ofthe combustion, η, shall be calculated per EN 15544.4.10.4 Flue Gas Triple of Variates—The flue gas tempera-ture is the outlet temperature of the flue pipe calculatedaccording to 4.8.2 with the total flue pipe length. The flue gasmass flow rate shall be calculated according to 4.6.3. Therequired delivery pressure shall be calculated per EN 15544.5. Calculations5.1 If the calculations of this specification are observed, theminimum energy efficiency of 78 % (fuel low-heat value) andthe emission values of carbon monoxide 1500 mg/mn3(1000mg/MJ), nitrogen dioxide 225 mg/mn3(150 mg/MJ), organi-cally bound carbon 120 mg/mn3(80 mg/MJ), and dust 90mg/mn3(60 mg/MJ) will be observed too.5.2 This calculation method for the dimensioning of tiled/mortared stoves shall be based on appropriate literature as wellas EN 13384-1, in which, besides physical and chemicalformulas, empirically determined correlations are also used.NOTE 1—In case of a calculation method for different interior materialsthan fireclay, the proof of the compliance of the emission values has to bedelivered separately. Furthermore, the empiric data of the combustionchamber dimensions, the minimum flue pipe length, the burning rate, aswell as the combustion chamber temperature and the decrease of thetemperature along the flue pipe have to be determined.6. Keywords6.1 dimensioning; emissions; masonry heater; tiled/mortared stoveE2778 − 143ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. 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