ASTM E2778-14(2021)

Standard Specification for Custom Tiled/Mortared Masonry Heaters (Stoves)

ABSTRACT
This specification establishes requirements for the dimensioning of custom tiled/mortared masonry heaters (stoves) that are individually technically calculated and constructed. It is valid for masonry heaters with sidewise combustion air supply of the combustion chamber, but not for masonry heaters combined with water heat exchangers for central heating or other heat-absorbing elements such as glass plates greater than 1/6 of the combustion chamber surface, open water tanks, and so forth. This specification includes the calculation method for the dimensioning of tiled/mortared stoves.
SCOPE
1.1 This specification contains specifications for the dimensioning of custom tiled/mortared masonry heaters (stoves). The custom tiled/mortared masonry heaters (stoves) are individually technically calculated and constructed. This information can be used for log (cordwood) wood-fired masonry heaters that burn one fuel load per storage period with a maximum load between 10 kg and 40 kg and a storage period (nominal heating time) between 8 h and 24 h in accordance with EN 15544.  
1.2 This specification is valid for masonry heaters equipped with fireclay as interior material with an apparent density between 1750 kg/m3 and 2200 kg/m3, a degree of porosity 18 up to 33 % by volume, and a heat conductivity from 0.65 W/mK up to 0.90 W/mK (temperature range 20 °C to 400 °C) in accordance with EN 15544.  
1.3 This specification is valid for masonry heaters with sidewise combustion air supply of the combustion chamber.  
1.4 This specification is not valid for masonry heaters combined with water heat exchangers for central heating or other heat-absorbing elements such as glass plates greater than 1/6 of the combustion chamber surface, open water tanks, and so forth. It is also not valid for masonry heaters combined with heating/fireplace elements in accordance with EN 13229. Furthermore, this specification is not valid for mass-produced prefabricated or partly prefabricated slow heat release appliances in accordance with EN 15250.  
1.5 The calculation method of this specification is used to establish emissions and energy efficiency when burning log wood or wood briquettes in accordance with the manufacturer’s or builder’s manual.  
1.6 Clearance to Combustibles—When a masonry heater is constructed in accordance with this specification, the clearance to combustibles shall be in accordance with TRVB 105 or other appropriate standards.  
1.7 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jan-2021
• ICS: 97.100.30 - Solid fuel heaters
• Technical Committee: E06 - Performance of Buildings
• Drafting Committee: E06.54 - Solid Fuel Burning Appliances

Relations

• Refers: ASTM E1602-03(2017) - Standard Guide for Construction of Solid Fuel Burning Masonry Heaters
• Effective Date: 01-Sep-2017
• Refers: ASTM E631-15 - Standard Terminology of Building Constructions
• Effective Date: 01-Mar-2015
• Refers: ASTM E631-14 - Standard Terminology of Building Constructions
• Effective Date: 01-Nov-2014
• Refers: ASTM E1602-03(2010)e1 - Standard Guide for Construction of Solid Fuel Burning Masonry Heaters
• Effective Date: 01-Apr-2010
• Refers: ASTM E631-06 - Standard Terminology of Building Constructions
• Effective Date: 01-Jun-2006
• Refers: ASTM E1602-03 - Standard Guide for Construction of Solid Fuel Burning Masonry Heaters
• Effective Date: 01-Oct-2003
• Refers: ASTM E1602-01 - Standard Guide for Construction of Solid Fuel Burning Masonry Heaters
• Effective Date: 10-Jan-2001
• Refers: ASTM E1602-94 - Standard Guide for Construction of Solid Fuel Burning Masonry Heaters
• Effective Date: 10-Jan-2001
• Refers: ASTM E631-93a(1998)e1 - Standard Terminology of Building Constructions
• Effective Date: 28-Jul-2000

Overview

ASTM E2778-14(2021): Standard Specification for Custom Tiled/Mortared Masonry Heaters (Stoves) establishes the requirements for the dimensioning and technical calculations of custom tiled or mortared masonry heaters. This standard applies specifically to masonry heaters (also known as Kachelofen, Kakelugn, or slow heat release appliances) that are individually designed and constructed, with sidewise combustion air supply. The specification does not apply to masonry heaters combined with water heat exchangers, large glass elements, or mass-produced units.

ASTM E2778-14(2021) sets out procedures for calculating critical design parameters, including combustion chamber dimensions, airflow, and emissions, supporting safer and more efficient log or wood-fired masonry heating installations.

Key Topics

• Scope and Applicability

  • Applies to tiled/mortared, custom-designed masonry heaters.
  • Designed for wood-fired masonry heaters burning a single log load (10 kg to 40 kg) over a storage period (8-24 hours).
  • Valid only for heaters using fireclay interiors with specific material properties.

• Exclusions

  • Not applicable to units combined with water heat exchangers, extensive glass elements, open water tanks, or fireplaces as per EN 13229.
  • Excludes partially or fully prefabricated slow heat release appliances (EN 15250).

• Critical Calculations

  • Methods for dimensioning the combustion chamber, base, and height.
  • Calculation of maximum and minimum fuel loads.
  • Requirements for calculation of air flow, flue gas flow, as well as corresponding correction factors.
  • Determination of essential combustion chamber and flue pipe dimensions.
  • Calculations for static friction, flow dynamics, and pressure differentials, ensuring clean combustion and efficient performance.

• Performance and Safety Requirements

  • Establishes a minimum energy efficiency threshold and emission limits for carbon monoxide, organic compounds, and dust.
  • Specifies clearances to combustibles according to national standards such as TRVB 105.

• Units of Measurement

  • All specifications and calculations use SI units as standard.

Applications

• Design and Construction

  • Provides design professionals and builders with a clear, standardized framework for technically calculating and constructing custom masonry heaters.
  • Supports compliance in residential and commercial masonry heater installations, ensuring safety, efficiency, and environmental performance.

• Building Code Compliance

  • Useful for code officials and inspectors verifying that custom tiled or mortared masonry heaters meet international standards.
  • Enables documentation of emissions and energy efficiency during installation approval processes.

• Regulatory and Environmental Planning

  • Supports emissions management and air quality planning by establishing clear methods for emission and energy efficiency calculations for wood-burning devices.

• Manufacturing and Supply

  • Guides manufacturers and suppliers of fireclay and masonry heater components to meet the intricate requirements for material selection and appliance performance.

Related Standards

• ASTM E1602 - Guide for Construction of Solid Fuel Burning Masonry Heaters.
• EN 15544 - Calculation methods for custom masonry heaters; essential reference for many of the calculations in ASTM E2778-14(2021).
• EN 13229 - Requirements and test methods for inset appliances and open fires fired by solid fuel.
• EN 13384-1 - Methods for thermal and fluid dynamic calculations related to chimneys serving a single appliance.
• EN 15250 - Requirements and methods for prefabricated slow heat release appliances.
• TRVB 105 - Clearance to combustibles for solid fuel appliances (Austrian standard).
• ASTM E631 - Building construction terminology reference.

Practical Value

By rigorously defining the dimensioning and calculation methods for custom tiled/mortared masonry heaters, ASTM E2778-14(2021) enhances operational safety, ensures efficient fuel use, and minimizes emissions. Adhering to this standard supports regulatory compliance and helps designers, builders, and regulators ensure that custom masonry heaters deliver reliable, efficient, and environmentally responsible heating performance.

Keywords: custom masonry heaters, tiled stoves, mortared stoves, dimensioning, combustion chamber, wood-fired heater, emissions, energy efficiency, fireclay, building codes, ASTM E2778-14

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2778 −14 (Reapproved 2021)
Standard Specification for
Custom Tiled/Mortared Masonry Heaters (Stoves)
This standard is issued under the fixed designation E2778; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 Units—The values stated in SI units are to be regarded
as standard. No other units of measurement are included in this
1.1 This specification contains specifications for the dimen-
standard.
sioningofcustomtiled/mortaredmasonryheaters(stoves).The
1.8 This standard does not purport to address all of the
custom tiled/mortared masonry heaters (stoves) are individu-
safety concerns, if any, associated with its use. It is the
ally technically calculated and constructed. This information
responsibility of the user of this standard to establish appro-
can be used for log (cordwood) wood-fired masonry heaters
priate safety, health, and environmental practices and deter-
thatburnonefuelloadperstorageperiodwithamaximumload
mine the applicability of regulatory limitations prior to use.
between10 kgand40kgandastorageperiod(nominalheating
1.9 This international standard was developed in accor-
time) between 8 h and 24 h in accordance with EN 15544.
dance with internationally recognized principles on standard-
1.2 This specification is valid for masonry heaters equipped
ization established in the Decision on Principles for the
with fireclay as interior material with an apparent density
Development of International Standards, Guides and Recom-
3 3
between 1750 kg⁄m and 2200 kg/m , a degree of porosity 18
mendations issued by the World Trade Organization Technical
up to 33 % by volume, and a heat conductivity from
Barriers to Trade (TBT) Committee.
0.65 W⁄mK up to 0.90 W⁄mK (temperature range 20 °C to
400 °C) in accordance with EN 15544.
2. Referenced Documents
2.1 ASTM Standards:
1.3 This specification is valid for masonry heaters with
E631 Terminology of Building Constructions
sidewise combustion air supply of the combustion chamber.
E1602 Guide for Construction of Solid Fuel Burning Ma-
1.4 This specification is not valid for masonry heaters
sonry Heaters
combined with water heat exchangers for central heating or
2.2 EN Standards:
other heat-absorbing elements such as glass plates greater than
EN13229 Insetappliancesincludingopenfiresfiredbysolid
⁄6 of the combustion chamber surface, open water tanks, and
fuels—Requirements and test methods
so forth. It is also not valid for masonry heaters combined with
EN 13384–1 Chimneys—Thermal and fluid dynamic calcu-
heating/fireplace elements in accordance with EN 13229.
lation methods—Part 1: Chimneys serving one appliance
Furthermore, this specification is not valid for mass-produced
EN 15250 Slow heat release appliances fired by solid fuel—
prefabricated or partly prefabricated slow heat release appli-
Requirements and test methods
ances in accordance with EN 15250.
EN 15544 One off Kachelgrundöfen/Putzgrundöfen [tiled/
1.5 The calculation method of this specification is used to
mortared (sic) stoves]: Calculation methods
establish emissions and energy efficiency when burning log
2.3 Austrian Federal Fire Brigade Association Standard:
wood or wood briquettes in accordance with the manufactur-
TRVB 105 Fireplaces for Solid Fuels
er’s or builder’s manual.
3. Terminology
1.6 Clearance to Combustibles—When a masonry heater is
constructed in accordance with this specification, the clearance 3.1 Definitions: Terms used in this specification are defined
tocombustiblesshallbeinaccordancewithTRVB105orother in Terminology E631.
appropriate standards.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This specification is under the jurisdiction of ASTM Committee E06 on Standards volume information, refer to the standard’s Document Summary page on
Performance of Buildings and is the direct responsibility of Subcommittee E06.54 the ASTM website.
on Solid Fuel Burning Appliances. Available from Deutsches Institut für Normung e.V. (DIN), Am DIN-Platz,
Current edition approved Feb. 1, 2021. Published February 2021. Originally Burggrafenstrasse 6, 10787 Berlin, Germany, http://www.din.de.
approved in 2014. Last previous edition approved in 2014 as E2778–14. DOI: Available from Österreichischer Bundes Feuerwehr Verband (ÖBFV), Voit-
10.1520/E2778-14R21. gasse 4, 1220 Wien, Austria, http://www.bundesfeuerwehrverband.at.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2778 − 14 (2021)
3.2 Masonry heaters are also known by the following words 4.4 Calculation of the Burning Rate—The burn rate shall be
and terms: Kachelofen, Kakelugn, grundofen, calculated in accordance with EN 15544.
Kachelgrundöfen, Putzgrundöfen, and slow heat release
4.5 Fixing of the Air Ratio—Combustion in a masonry
appliance, and are further explained in Guide E1602.
heater is a process, which is variable, it is not steady state. The
mean air ratio is fixed in accordance with EN 15544.
4. Classification
4.6 Combustion Air, Flue Gas:
4.1 Nominal Heat Output—Thenominalheatoutputshallbe
4.6.1 Combustion Air Flow Rate—The mean combustion air
specified.
flow rate shall be calculated in accordance with EN 15544.
4.2 Load of Fuel: 4.6.1.1 Temperature Correction—The temperature correc-
4.2.1 Maximum Load—The maximum load of fuel is calcu- tion factor shall be calculated in accordance with EN 15544.
lated in accordance with EN 15544. 4.6.1.2 Altitude Correction—The altitude correction factor
shall be calculated in accordance with EN 15544.
4.2.2 Minimum Load—The minimum load is fixed at 50 %
of the maximum load in accordance with EN 15544. 4.6.2 Flue Gas Flow Rate:
4.6.2.1 The knowledge of the flue gas flow rate is important
m 5 0.5 m (1)
~ !~ !
Bmin B
for the calculation of the flue pipe diameter. It is calculated in
where:
accordance with EN 15544.
m = maximum load (kg), and
4.6.2.2 The value, f, shall be calculated using the flue gas
B
t
m = minimum load (kg).
Bmin temperature of the flue pipe section. This means that along the
flue pipe the decreasing temperature leads to a lower flue gas
4.3 Design of the Essential Dimensions:
flow rate.
4.3.1 Combustion Chamber Dimensions—The design of the
4.6.3 Flue Gas Mass Flow Rate—The flue gas mass flow
dimensions of the combustion chamber is necessary because,
rate shall be calculated in accordance with EN 15544.
on one hand, enough room to place the fuel in it is needed and,
on the other hand, the requirements for a clean combustion
4.7 Calculations of the Density:
have to be fulfilled.
4.7.1 Combustion Air Density—The density of the combus-
4.3.1.1 Combustion Chamber Surface:
tion air at standard conditions shall be in accordance with EN
(1) The dimension of the combustion chamber surface has
15544.
to be calculated in accordance with EN 15544.
4.7.2 Flue Gas Density—The density of the flue gas at
(2) For the calculation of the combustion chamber surface
standard conditions is 1.282 kg/m . It shall be calculated in
all its walls, the ceiling, and the base, including the area of the
accordance with EN 15544.
combustionchamberopeningandthecombustionchamberexit
4.8 Calculation of the Flue Gas Temperature:
for the flue gas, have to be regarded equally.
4.8.1 Mean Combustion Chamber Temperature—The com-
4.3.1.2 Combustion Chamber Base:
bustion chamber temperature is necessary to calculate the
(1) The combustion chamber base can be varied between a
standing pressure in the combustion chamber. Because of the
minimum and a maximum value.
calculation of the combustion chamber surface, the calculation
(2) The minimum value results from the requirement that,
temperature of all combustion chambers is similar. The tem-
at maximum load, a height of the fuel of 33 cm shall not be
2 perature shall be fixed in accordance with EN 15544.
exceeded. Therefore, a base of 100 cm per kg fuel is needed
4.8
...