The European standard "EN 12088 Thermal insulation products for building applications - Determination of long-term water absorption by diffusion" defines equipment and procedures for determining the long-term water absorption of test samples by diffusion. This standard also applies to thermal insulation products.
This standard is intended to simulate the water absorption of products exposed to high relative humidities of up to nearly 100 percent on both sides and exposed to a water vapor pressure gradient for an extended period of time, such as inverted roof or unprotected floor insulation. This test method is not applicable to all thermal insulation products. The product standard should specify which products, if any, this test applies to.
For unprotected floor insulation, the 50 degree temperature can be replaced by a lower temperature when more data is available.
In principle, long-term water absorption by diffusion is determined by measuring the increase in mass of a test sample exposed to the water vapor pressure difference and temperature gradient over a period of 28 days.
The main equipment used in these tests includes:
The principle of the test device assembly is shown in the figure given in the standard.
The thickness of the test specimens shall be the thickness of the original product. Test specimens shall be squares with square cut edges measuring 500 mm plus/minus 1 mm. If the product is not large enough to allow this test specimen size, the test specimen size shall be reduced accordingly. Test specimens shall contain no joints.
The number of test samples shall be at least two. Test samples shall be cut so that they do not include the edges of the original product. Test samples shall be prepared by methods that do not significantly alter the original structure of the product. Any coating, leather or covering shall be retained. Specific preparation methods, where necessary, are given in the relevant product standard or any other technical specification.
Test samples should be stored at a temperature of 6 degrees plus/minus 23 degrees for at least 5 hours. In case of disagreement, they should be stored at a temperature of 23 degrees plus/minus 2 degrees and a relative humidity of 50 percent plus/minus 5 percent for at least 6 hours for the period specified in the relevant product standard.
The dimensions of the test samples shall be measured in accordance with EN 12085. The initial mass of the test sample shall be weighed to the nearest 0,1 g. The test sample is placed on the frame of the container. If the product is facing one side, the test shall be started with the side facing upwards. The lower edge of the test sample shall be sealed to the container. The width of the seal shall be no more than 10 mm. The insulated cooling plate shall be placed on top of the test sample.
By keeping the water at 50 degrees plus/minus 1 degree and the other side cooling at 1 degree plus/minus 0,5 degree, the test sample is subjected to a temperature and water vapor pressure difference for 28 days. The test sample is turned every 7 days. After 28 days, the test sample is removed and the water on the surface is wiped off. The test sample is weighed again to determine its mass.
The test result shall be the average value of the individual values. For each test sample, the long-term diffusion water absorption is calculated in kilograms per square metre or in percent by volume using the formulas given in the standard.
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 in accordance with the standard “EN 12088 Thermal insulation products for building applications - Determination of long-term water absorption by diffusion” are also provided to businesses.
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