PP-R water pipes and the systems made from them differ from other systems in the method of joining elements. Polypropylene pipe can be fusion welded, meaning it is joined permanently without the use of any additional substances. This connection is characterised by the fact that the entire system becomes a homogeneous body that responds uniformly to temperature changes. The joints are permanent and leak-free, as no adhesive or sealant is used. Plastic pipes are resistant to all chemical contaminants, so they can be used without restriction in closed-loop CH systems and DHW installations, where intervention in the water composition is not possible. Fusion-welded PP pipe is highly flexible, making it easy to bend and install even in locations requiring exceptional care. Fusion-welded plastic water pipes made of polypropylene have a high coefficient of thermal expansion, meaning they deform significantly under the influence of temperature. Therefore, pipes made from solid PP should be used cautiously for hot water installations – attention should be paid to the use of insulation and adequate compensation, particularly on long, straight runs. Installation is very straightforward. A little reading and practice is sufficient to do it yourself. Longer training is required before fusion welding smaller diameter pipes. PP-R 16 mm pipe, if heated for too long, may collapse internally and reduce the bore. To ensure reliable joints, the welding time guidelines discussed in detail in the PRAWTECH Design and Installation Guidelines should be followed. The main advantages of PP-R systems are ease of installation, temperature resistance, complete resistance to chemical agents in water, mechanical durability of pipes and joints, and low cost.