How to choose good polypropylene pipes for hot water

Polypropylene for hot water is one of the best materials, characterized by durability, ease of installation and resistance to corrosion. However, not every product is suitable for hot water supply. When choosing, you need to take into account the composition, structure and type. These indicators are described in detail below.

Which pipes are suitable for hot water

Polypropylene is used for both cold and hot water. Moreover, if in the first case the requirements are minimal, then in the second they are more stringent. The fact is that classic material expands greatly when heated, which can lead to an emergency.

Therefore, not any polypropylene is suitable for hot water, but only those that belong to the following categories:

• copolymer (consists not of 1, but of 2 organic polymers connected to each other into a single whole);
• pipe with aluminum insert;
• pipe with fiberglass insert;

The last 2 types are composite or reinforced. Compared to homogeneous ones consisting of pure polypropylene, they contain up to 30% of a second component, for example, fiberglass. Since the structure of such products is represented by several layers, they are called “sandwich”.

Thanks to the fiberglass or aluminum insert, the degree of expansion is reduced several times. Moreover, its values ​​are close to the indicator characterizing steel and copper pipes. In their case, the coefficient is about 0.012-0.016.As for reinforced polypropylene, the value corresponds to 0.050.

Along with this, the inserts, as well as the base material, provide a number of other advantages;

• resistance to corrosion (much higher than that of metal);
• low density and light weight;
• easy installation;
• soundproofing.

Criterias of choice

It is clear which polypropylene is best suited for hot water. All that remains is to figure out the criteria for choosing pipes. To do this, you need to know the markings - numbers and letters. So, depending on the nominal pressure that the pipes can withstand, they are classified into 3 types:

1. PN10 – can withstand up to 10 atm, but operate only at temperatures up to +45°C. Suitable only for cold water supply, sometimes also used for drainage.
2. PN16 – withstands up to 16 atm., maximum temperature is +60°C. They are also not suitable for hot water supply, but can be used in a heated floor circuit.
3. PN20 and PN25 - withstand 20 and 25 atm, respectively. These are reinforced products with fiberglass inserts. They operate at temperatures up to +95°C, therefore they are optimally suited for hot water supply pipes.

Another important selection criterion is the composition of the material. Based on this indicator, there are 3 types:

1. Homopolymer (designation PP-H) - consists of only one substance, does not withstand temperature well, therefore it is used only in cold water supplies.
2. PP-B – block copolymer: used in cold and hot water supply, universal common type.
3. PP-R – random copolymer: it is resistant to both temperature and pressure. It is used in networks of any type, including hot water supply.

Thus, when choosing polypropylene for hot water, you should be guided by the operating temperature range and maximum load (maximum pressure). It is better to take the pipe “with a reserve” so that, thanks to its strength, even an emergency situation can be prevented.