EN 14707 Thermal Insulation Products for Building Equipment and Industrial Plants - Determination of Maximum Service Temperature for Preformed Pipe Insulation

The European standard “EN 14707 Thermal insulation products for building equipment and industrial plants - Determination of maximum service temperature for preformed pipe insulation” defines the equipment and procedures for determining the maximum service temperature for preformed pipe insulation. This standard is also applicable to thermal insulation products.

For the purposes of this standard, the maximum service temperature refers to the highest temperature at which the insulation product, when installed at the recommended thickness for a particular application, will continue to perform within the specified performance limits. The required performance may be in the areas of dimensional stability, thermal and mechanical properties, and resistance to the creation of hazards such as changes in appearance and internal self-heating. In the present test procedure used as a reference, the test specimen is exposed to a temperature difference ranging from ambient temperature to the maximum service temperature. This may not reflect actual application conditions when products are exposed to different temperatures on two main surfaces, for example in multilayer systems or in products with surfaces where the surface may limit the maximum service temperature.

In principle, the thickness and length are measured after single-sided heat treatment for a specified period of time at the maximum service temperature achieved using a specified rate of temperature increase. The thickness of the test specimen is measured during heat treatment and its length only after cooling to ambient temperature. The procedure may be an iterative process. Additional requirements for assessing the maximum service temperature of specific materials are described in the normative annexes of this standard or the relevant product standard or any other technical specification.

A general arrangement of the device is shown in the figure given in the standard and consists essentially of:

• Hot pipe: A pipe having a uniform temperature distribution in the hot surface measuring zone and a heat flux perpendicular to the surface of the pipe within the measuring zone (two pipes with diameters meeting the requirements of this standard are required). The hot pipe shall be linear in the measuring zone to plus/minus 1 mm at ambient temperature. The hot pipe shall be controllable to within plus/minus 60 percent of a predetermined temperature of plus/minus 2 degrees, whichever is less, along the central 10 percent of the total pipe length. The hot pipe shall be capable of being heated at 50 degrees/hour or 300 degrees/hour.
• Tip insulation: A gap between the tip insulation and the protection part of the test specimen should be as small as possible (e.g. no more than 3 mm), allowing the test specimen to move freely during testing.
• Temperature sensors (e.g., thermocouples): Temperature sensors placed in grooves on the hot pipe that can record the hot surface temperature of the test pipe in centigrade to the nearest plus/minus 1 percent but not less than plus/minus 1 degree.
• Flexible metal foil: 3 pieces, (e.g. brass), 500 mm plus/minus 5 mm test length of test specimen and two end protectors can exert a uniform pressure of 250 Pa on the upper surface of a 5 mm plus/minus 500 mm length. The pressure shall be calculated using, for example, the product of the 500 mm test length and the diameter of the hot pipe.
• Electromechanical device: A device for measuring the thickness of a test specimen, for example during testing, to the nearest 0,1 mm. When determining the thickness of the test specimen, the thermal movement of the device (e.g. quartz rod) up to its maximum service temperature must be taken into account.

The dimensions of the test samples should be:

• The test specimen, 1000 mm plus/minus 10 mm in length, is cut at right angles to its length to give two end protectors, each 250 mm plus/minus 5 mm in length, and a test length of 500 mm plus/minus 5 mm.
• The thickness should be 100 mm or the largest available thickness under 100 mm.
• Inner diameter: Two sizes are tested, ranging from 22 mm to 220 mm.

The dimensions shall be as specified in the relevant product standard or in an annex to this standard. In the absence of a product standard or other technical specification, the dimensions may be freely agreed between the parties. Testing may be carried out on multilayer systems to simulate the conditions existing in practice. If the pipe insulation is cut from a homogeneous, isotropic flat product, the maximum service temperature may be obtained from tests on flat product with similar properties in accordance with EN 14706.

The number of test samples shall be as specified in the relevant product standard. If the number is not specified, at least one test sample shall be used for each dimension. In the absence of a product standard or other technical specification, the number of test samples may be freely agreed upon between the parties.

Test samples must be conditioned 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 or for at least 24 hours.

The initial temperature of the test sample and the hot pipe should be 23 degrees plus/minus 5 degrees.

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 standard “EN 14707 Thermal insulation products for building equipment and industrial facilities - Determination of maximum service temperature for pre-formed pipe insulation”.