EN 1745 Masonry and Masonry Products - Methods for Determining Thermal Properties

The European standard “ EN 1745 Masonry and masonry products - Methods for determining thermal properties” describes methods for determining the dry and design thermal conductivity and thermal resistance values ​​of masonry products and masonry.

For the purposes of this standard, the following definitions apply in addition to the terms and definitions given in EN ISO 7345:

• Masonry refers to the assembly of masonry units laid in a specific pattern and joined with masonry mortar.
• Masonry product refers to masonry units, masonry mortars, plasters and plastering mortars.
• A solid masonry unit is a masonry unit that does not contain holes other than external recesses such as retaining holes, grooves, etc.
• A masonry unit with created cavities is a masonry unit with an intentionally created cavities system.
• A composite masonry unit is a masonry unit that contains additional material.
• Thermal value is the general term for thermal conductivity or thermal resistance.
• Dry state refers to the state after drying under the conditions specified in the relevant standards.
• The dry thermal value is the value of the thermal properties of a building material or product in the dry state determined in accordance with this standard as the basis for calculating design thermal values. The dry thermal value can be expressed as thermal conductivity or thermal resistance.
• Design thermal value is the value of the thermal property of a building material or product under specified external and internal conditions under which the performance of that material or product can typically be evaluated when incorporated into a building component or building.

This standard covers the following types of masonry units:

• Solid masonry units
• Masonry units with created cavities
• Composite masonry units

This standard describes methods for determining the dry thermal conductivity of solid masonry units and mortar, and for determining the equivalent dry thermal conductivity of masonry units with formed cavities and composite masonry units. Procedures for determining the design thermal properties of masonry units and masonry are also described. The different methods are illustrated in the table titled "Determination of Thermal Properties of Masonry Units and Masonry" provided within the standard.

The dry value is a characteristic of a masonry material, masonry unit, or structure. The determination of thermal values ​​may be based on tabulated data, measurements, calculations, or a combination of these.

Design thermal values ​​may be determined according to the procedures given in this standard, taking into account the intended application, environmental and climatic conditions, and the purpose of this determination. For example,

• Energy consumption
• Design of heating and cooling equipment
• Determination of surface temperature
• Compliance with national building regulations
• Consideration of unstable thermal conditions in buildings

The EN 1745 standard is considered essential because it provides critical guidelines for determining the thermal performance of masonry materials used in building construction. The key reasons for its importance are:

• Provides accurate thermal calculations: This standard specifies methods to calculate or obtain:
  • Declared and design thermal conductivity values
  • Thermal resistance of masonry units, mortars and bonded walls

This enables designers to use consistent and reliable data in thermal modeling and building energy assessments.

• Supports energy efficiency regulations: Modern buildings must comply with energy performance regulations, such as the EU Energy Performance of Buildings Directive (EPBD). This standard helps:
  • Calculating U values ​​of walls (U values ​​are also known as thermal conductivity values ​​and measure how well a building element such as a wall, roof, window or floor conducts heat. The U value is the value obtained by dividing the heat transfer rate in a structure by the temperature difference across the structure).
  • Demonstrate compliance with national and European thermal requirements
• Improves material selection: Manufacturers and designers use the EN 1745 standard for:
  • Comparing the thermal efficiency of different masonry products
  • Choosing the right materials to improve building insulation and reduce energy loss
• Promotes standardisation across Europe: This standard uses a common methodology to:
  • All EU countries and industry stakeholders speak the same technical language
  • This facilitates trade, building certification and cross-border projects
• Include humidity and usage conditions: This standard takes into account moisture content, installation conditions, and aging effects. These factors influence the actual thermal performance of materials under real-world conditions.

In short, the EN 1745 standard is essential because it standardises how to assess the thermal properties of masonry, ensuring energy-efficient building design, regulatory compliance and the effective use of construction materials.

The EN 1745 standard itself does not define test methods in detail, but instead references test methods from other EN and ISO standards. The primary test methods used or referenced within EN 1745 include:

• Thermal conductivity testing: The EN 1745 standard is based on laboratory test methods for thermal conductivity, typically using a guarded hot plate or heat flux meter. For example,
  • EN 12667 Thermal performance of construction materials and products - Determination of thermal resistance by the protected hot plate and heat flow meter methods - Products with high and medium thermal resistance
  • EN 12939 Thermal performance of construction materials and products - Determination of thermal resistance by the protected hot plate and heat flow meter methods - Thick products with high and medium thermal resistance
  • ISO 8302 Thermal insulation - Determination of steady-state thermal resistance and related properties - Shielded hot plate apparatus
  • ISO 8301 Thermal insulation - Determination of steady-state thermal resistance and related properties - Heat flow meter apparatus
• Considering moisture content: Thermal conductivity in EN 1745 is adjusted depending on the moisture content of the wall. While not specifying a specific moisture measurement method, the relevant standards include:
  • ISO 12570 Hygrothermal performance of building materials and products - Determination of moisture content by high-temperature drying
• Density determination: The thermal conductivity of masonry is generally related to the bulk density of the material. EN 1745 standard allows interpolation or classification based on density groups using:
  • EN 772-13 Test methods for masonry units - Part 13: Determination of net and gross dry density of masonry units (excluding natural stone)
• Declared and design values: The EN 1745 standard provides conversion factors and guidance for converting declared values ​​(from laboratory tests or manufacturer data) to design values, taking into account:
  • Humidity conditions (dry, average, saturated)
  • Type of masonry unit (clay, concrete, autoclaved aerated concrete, stone)
  • Mortar type and joint configuration
• Use of tabulated values: EN 1745 also contains tabulated thermal conductivity values ​​for different types of masonry units and mortars, based on historical tests and national surveys. These values ​​can be used when specific test data are not available.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services in accordance with the EN 1745 Masonry and masonry products - Methods for determining thermal properties.