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30966 Hemmingen

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Quality protection at sleeve systems

Tests on joint systems are carried out according to EN 489 as soil pressure tests (sand-box-test and water impermeability test). Tests can be done under conditions close to reality for district heating systems, as well as for bends, joints and tee-branches according to given specifications of the supplier with defined parameters and special conditions like for instance traffic loads. Sandboxes of 32 m, displacement equipment up to 500 kN, and vibrators for simulating real traffic loads are available. Following the tests in the sand box the bends, joints and tee-branches will be undergoing a quality- and system check up.

General conditions of a test:

In order to achieve a result wich can be reproduced, the tests are done in a 1:1 scale. The tests are carried out according to the requirements of the EN 489, and a clear statement can be given in relation to the usage in real condition. Some of the requirements for carrying out the test in observation with EN 489 are mentioned below:



  Recording a relative movement between medium pipe and casing pipe at a close to real environmental test in observation with EN 489


  • A sandbox with sufficient room has to be available in order to fulfil the requirements of the EN 489. At the FFI are tests possible up to DN 1000.

  • The sand has to be dry (by air) with a max. of 0,5 % water content at room temperature.

  • Each test specimen must be 3 m long.

Criteria for testing:

The following criteria has to be adhered to according to EN 489:

  • The temperature of the medium pipe of (120±2) °C has to be kept for 24 hours before testing,

  • a vertical earth pressure of 18 kN/m² is realized from a 30 cm sand overlap and a bending resistant plate,

  • displacement of 75 mm,

  • speed in pressure direction of  10 mm/min, 

  • speed in pull direction 50 mm/min,

  • 100 cycles, one cycle is defined as one displacement in pressure and one displacment in pull direction without any interruption.

Water impermeability test with a PE-sealing at a plastic jacket pipe of a dimension from DN 700/900

After the test each pipe connection has to put in a container of (23±2) °C  heated water under a pressure of 30 kPA over a period of 24 hours. 

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