Underfloor Heating – the Tubing / Pipework
The core of any UFH system is the tubing / pipework. UFH pipes are generally multi-layer / skin, usually made up of five layers, the inner and outer layers being PE-RT (a form of polyethylene) sandwiching a layer of aluminium, which is a total barrier to the passage of oxygen and light. The other two layers are generally bonding layers between the inner aluminium and the inner and outer polyethylene layers. Pipes are generally rated to 10 bar pressure and 95 degrees Celsius as regards temperature.
These need to be made of quality material to ensure a life that have the necessary tensile strength, are long lasting, have endurance etc characteristics. The tests on this page reveal the quality of the piping in question. The pipework is exposed to thermal and mechanical stress over long periods and at different temperatures and internal pressures.
Performance tests include:
Burst test : In burst testing, pipes are subjected to increasing pressure in a test frame until the pipe bursts. The bursting pressure should about at least seven times the maximum operating pressure.
Notch test : The impact resistance of pipes is tested in an impact-test device. A hammer-like pendulum strikes the pipe to be tested. In general, pipes show a very high resistance against this sort of massive mechanical impact.
Tensile-strength test : In a tensile-strength testing machine, pipes are stretched length-ways until they break. The length of the stretched pipe can be many times the original pipe length. The compression sleeve connection should be safe against being pulled apart under operational conditions, and by implication, the pipe should not be pulled out of the connection.
Endurance test : Pipes in domestic installations require a lifespan of a minimum of 50 years. In order to be able to examine long-term effects due to temperature fluctuations, pressure and mechanical stresses, pipes are exposed in long-term tests to high temperature and pressure conditions and periodically tested, using photo-optic techniques.
Other tests may need to be undertaken, including cross linking, shrinkage testing, temperature-change tests, etc.
Pipe / Tubing layout:
See sample layout – this is typical for a residential situation and indeed other types of buildings – but likely even more complicated.
