EN 679 Determination of Compressive Strength of Autoclaved Aerated Concrete

The European standard “EN 679 Determination of compressive strength of autoclaved aerated concrete” describes a procedure for determining the compressive strength of autoclaved aerated concrete.

In principle, compressive strength is determined as the ratio between the fracture load under axial compression in test specimens and the cross-sectional area of ​​the test specimen perpendicular to the loading direction.

The EN 679 standard includes a method for determining the heat transmittance (U-value) of insulated glass units. This method is widely used in the construction and glazing industries to evaluate how well double or triple glazing prevents heat transfer.

The EN 679 standard focuses on the following:

• Measurement of thermal conductivity and heat transfer through insulated glass.
• Determination of the U-value under controlled laboratory conditions.
• Applicability to double and triple glazing units.
• Consideration of gas-filled voids (e.g., argon, krypton)

The U-value (heat conductivity) is a measure of how easily heat passes through a material or structure (e.g., wall, roof, window, or door). This value indicates how much heat is lost (or gained) through 1 m² of material when the temperature difference between the interior and exterior is 1 degree (or 1 K). A lower U-value indicates better insulation. It is critical for improving energy efficiency in buildings.

The EN 679 standard typically uses a shielded hot plate or heat flow meter method. Here,

• The glass sample is placed between two environments with different temperatures.
• Heat flow through the glass is measured.
• The U-value is calculated based on steady-state heat transfer.

This testing method provides the following:

• Stable temperature conditions
• Accurate measurement of thermal resistance.

The EN 679 standard takes the following into account (these are the factors that affect the results):

• Thickness of glass panels
• Type of gas in a vacuum (air, argon, krypton)
• Intermediate material and edge effects
• Coatings such as low-emission layers

The EN 679 standard is part of the framework supporting compliance with the EN 1279 standard, which is required for CE marking of insulating glass.

EN 679 and related standards are as follows:

• EN 673 Glass used in buildings - Determination of thermal transmittance (U-value) - Calculation method
• EN 674 Glass used in buildings - Determination of thermal transmittance (U-value) - Protected heating plate method

Practical applications of the EN 679 standard are as follows:

• Residential and commercial windows
• Curtain wall systems
• Roof windows and facades
• Energy performance certification of buildings.

In short, the EN 679 standard focuses on precise laboratory determination under defined conditions. Standards for determining U-values ​​are not merely technical formalities; they solve real problems in construction, manufacturing, and energy management. The main reasons why this standard is considered important are as follows:

• It provides reliable and comparable results: Without a standard method, different laboratories or manufacturers may measure thermal performance in different ways, leading to inconsistent results. This standard ensures:
  • Everyone uses the same test conditions.
  • The results are accurate and comparable.
• It supports energy efficiency regulations: Modern buildings must meet stringent energy requirements. These and similar standards provide verified data needed to comply with regulations such as the energy performance directive for buildings. Without standardized U-values,
  • Energy calculations are unreliable.
  • Compliance checks become impossible.
• It improves product quality and innovation: Manufacturers rely on standardized testing for the following purposes:
  • Evaluating and improving glass performance
  • Developing better products (e.g., low-emission glass, gas-filled units)
  • Making comparisons with competitors

This standard creates a level playing field for innovation.

• It provides certification and CE marking: These and similar standards for thermally insulated glass units are part of the broader EN 1279 standard framework. This is required for:
  • CE marking in Europe
  • Legal market access
  • Product labeling and declarations
• It reduces energy consumption and environmental impact: Accurate U-values ​​help designers choose better materials, which leads to:
  • Lower heating and cooling demand.
  • Reduced carbon emissions
  • More sustainable buildings
• It protects consumers and designers: Architects, engineers, and buyers need reliable data. This standard ensures the following:
  • Absence of misleading performance claims
  • Better decision-making
  • Predictable building performance
  • In Conclusion

EN 679 and similar standards are necessary because they translate thermal performance into a measurable, reliable, and legally usable value. This is crucial for energy efficiency, product quality, and fair competition.

In conclusion, the EN 679 standard is a critical thermal performance test standard for insulating glass. By providing a consistent and accurate method for measuring U-values, it plays a central role in energy-efficient building design, product quality assurance, and regulatory compliance across Europe.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services in accordance with the EN 679 standard.