EN 825 Thermal Insulation Products for Building Applications - Determination of Flatness

The European standard “EN 825 Thermal insulation products for building applications - Determination of flatness” describes the equipment and procedures for determining deviation from flatness for full-size products. This standard is also applicable to thermal insulation products.

For the purposes of this standard, deviation from flatness refers to the maximum distance between the product placed on a flat surface with the convex side uppermost and the flat surface.

In principle, the maximum distance between the product placed on a flat surface and the flat surface is measured.

These tests use a flat surface and a metal ruler or metal strip. This equipment should be graduated in millimeters and should allow readings to 0,5 mm. A rigid frame is also used in the tests. This equipment consists of a 0,5 mm diameter disk fixed to a graduated pin or dial indicator graduated to at least 30 mm. This frame has a movable measuring device that applies a load of at least 2,0 N plus/minus 0,1 N. However, any testing equipment that provides at least the same result with the same accuracy can be used.

Test samples must be full-size products. The number of test samples must be as specified in the relevant product standard. In the absence of a product standard, the number of test samples can be agreed upon between the parties. Test samples must be stored at 6 degrees plus/minus 23 degrees for at least 5 hours. In case of disagreement, they must be stored at 23 degrees plus/minus 2 degrees and 50 percent plus/minus 5 percent relative humidity for the period specified in the relevant product standard.

The tests shall be carried out at 23 degrees plus/minus 5 degrees. In case of disagreement, they shall be carried out at 23 degrees plus/minus 2 degrees and 50 percent plus/minus 5 percent relative humidity. The test specimen shall be placed on a flat surface. If there is a noticeable deviation from flatness along the length only or along the width only, the maximum distance between the lower edge of the specimen and the flat surface shall be measured using a metal tape or ruler, rounded to the nearest 0,5 mm. If there is a deviation from flatness along both the length and width (crooked products), the maximum and minimum distances from the flat surface shall be determined using a measuring device as shown in the figure. The distances at these positions shall be read to the nearest 0,5 mm. If the test specimen is at rest at only three points, there is the possibility of alternative flatness measurements and all of them shall be measured.

For test specimens that deviate from flatness in only one direction, the deviation is reported as the maximum value measured in millimetres. For warped products, the deviation from flatness is calculated in millimetres using the formula given in the standard.

In short, deviation from flatness is the maximum distance between the product placed on a flat surface, convex side up, and the flat surface.

The surface flatness of the thermal insulation material must be produced within the specified thickness tolerances for adequate thermal conductivity. Proper flatness of insulation products is a must for effective thermal insulation to save energy by minimizing the negative effects of heat transfer or heat loss. In this context, the EN 825 standard helps to measure the maximum distance between the product placed on a flat surface with the convex side up and the flat surface.

The standard provides the best industry guidance on the number of samples, dimensions, conditioning and test procedure, as well as the instrument requirements for testing thermal insulation samples. The result is an assessment of whether the products can withstand deformation caused by temperature changes, thus playing a positive role in the operation of the final application.

Our organization, which has been trying to support businesses from every sector with its testing, measurement, analysis and evaluation studies carried out in a wide range for years, has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. In this context, testing services are also provided to businesses in accordance with the "EN 825 Thermal insulation products for building applications - Determination of flatness" standard.