Heat expansion and contraction are a common property of all the materials from which the pipes are made. As the water temperature or the outside temperature rises or falls, the length of the pipe changes accordingly. The longer the duration, the greater and more pronounced the change in length, so the rules of expansion and contraction must be taken into account when implementing extensions of more than 5 meters.
Not accounting for expansion and contraction while designing a plumbing system can create significant stresses on pipes and connections. Over time, this stress may cause the pipe and connections to weaken, resulting in leaks and the need to repair the pipe shortly after its installation.
But the risk of thermal expansion and shrinkage can easily be prevented by using reinforced pipes or loops and expansion adjustments.
PPR is reinforced with the purpose of reducing linear expansion, not to increase wall resistance. Fiberglass reinforced pipes have a coefficient of expansion 3.5 times less than non-reinforced pipes. As for aluminum reinforced tubes, the coefficient of thermal expansion is 0.03 mm / mK, which is 5 times less than non-reinforced tubes, in addition, the aluminum layer is also an oxygen barrier.
Due to the flexibility of polypropylene pipes, they can be bended safely to certain degrees without any damage. Expansion loops and adjustments take advantage of this flexibility and allow pipes to move through the system while reducing stress from expansion.
The pipeline will be subjected to temperature fluctuations, in other words, the pipeline will experience significant differences between cold and heat levels starting from the installation and throughout its life. If the temperature change is more than a degree celsius, then the water piping system must include thermal expansion rings and adjustments, and it is also preferable for the pipes to be reinforced with either fiberglass or aluminum.
It is important to follow best practices when permitting thermal expansion and contraction, which include:
- Installation of expansion rings with straight tubes and 90 degree elbows, which are welded together with solder.
- Avoid restricting the tube's natural movement toward expansion and contraction.
- Always leave adequate space between elbows and clamps.
- Always refer to local laws and the manufacturer's instructions.
In the "Alpha" system of RTP there are PPR pipes of all kinds:
✔PP-R \ AL \ PP-R PN25 - for closed type heating systems (including residential buildings)
✔PP-R \ PP-R GF \ PP-R PN25 - for open heating systems
✔PP-R \ PP-R GF \ PP-R PN20 - for DHW
✔PP-R PN20 - for hot and cold water
✔PP-R PN10 - for cold water