EN 824 Thermal Insulation Products for Building Applications - Determination of Squareness

The European standard “EN 824 Thermal insulation products for building applications - Determination of squareness” describes the equipment and procedure for determining the deviation from squareness for length, width or thickness of full-size products. This standard is also applicable to thermal insulation products. The method is normally applicable to products with straight edges. For products with other shapes, e.g. profiled edges, the method can be adapted accordingly.

For the purposes of this standard, deviation from squareness refers to the distance from one end of a perfect square to the edge of the product at a specified distance from the corner.

In principle, a metal square is applied to the product edges and the deviation between one arm of the metal square and the product edge is measured.

These tests use a flat surface and a metal ruler or metal strip. This equipment should be graduated in millimeters and allow readings to 0,5 mm. A metal square is also used in the tests. This equipment is at least 500 mm long and has limbs that deviate from squareness by no more than plus/minus 500 mm when measured 0,1 mm from the corner. 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.

When determining the squareness of the length and width sides , tests should be conducted at 23 degrees plus/minus 5 degrees Celsius. In case of disagreement, tests should be conducted at 23 degrees plus/minus 2 degrees Celsius and 50 percent plus/minus 5 percent relative humidity . The sample is placed on a flat surface and the deviation of the length and width from squareness is measured as follows:

• The metal square is placed along one of the edges of the sample such that the right angle of the square aligns with the adjacent edge as shown in the figure.
• The distance between the edge of the sample and the edge of the metal square is measured from the corner to the nearest 0,5 mm. For samples with a side less than 500 mm, this distance is the maximum width or length of the sample. For samples with a side greater than or equal to 500 mm, it is the length of the inside of the square.
• The process is repeated for all corners of the sample with angles of 90 degrees or less.
• If there is a significant deviation from linearity of the edges in length or width, this should be reported as the maximum deviation from linearity.

When determining the squareness of the thickness edge, the tests shall be carried out at 23 degrees plus/minus 5 degrees. In case of disagreement, it shall be carried out at 23 degrees plus/minus 2 degrees and 50 percent plus/minus 5 percent relative humidity. The test specimen is placed on a flat surface and the deviation from squareness of the thickness is measured as follows:

• The metal square is placed on the flat surface by leaning it against one edge of the test sample as shown in the figure.
• The distance between the edge of the test specimen and the edge of the square is measured to the nearest 0,5 mm at the point of greatest deviation along the edge.
• The test is repeated for all edges.
• The test sample is inverted and the first three steps are repeated.
• The largest figure is reported as the deviation of the thickness edge from squareness.

Squareness is the property of being square. The most accurate way to measure squareness is to compare it to a known square surface, but this must be done with some measuring instrument, not by eye. One of the simplest tools is a surface meter with a dial test indicator.

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 824 Thermal insulation products for building applications - Determination of squareness" standard.