Frequently asked questions

A very relevant question, since apartments are now commonly sold without internal plumbing. The scope of application for polypropylene pipes and fittings states:

• cold and hot drinking water pipelines in residential and administrative buildings, hospitals, schools, etc., including: building water supply stations; boiler connections; water distribution; water risers; floor distribution (standard, or at each draw-off point with an individual connection);
• connecting pipelines to existing water supply networks made of metal pipes.

In terms of technical specifications: for heating it is better to use reinforced pipe from a proven manufacturer (the market has plenty of low-quality products and counterfeits). Such pipe withstands pressure testing and the pressure and temperature surges that are common in our heating networks. Pressure testing is brief, and the pipe has a considerable safety margin — at least 1.5. AQUA-S reinforced pipe meets oxygen permeability standards.

For hot water, PN20 pipe is used to guarantee safety and welding quality. PN10 can be used, but the savings are so small that labour and rework cost more. PN10 must not be used in buildings above 9 storeys. In buildings above 16 storeys we recommend only PN20–25 for cold and hot water supply.

How a polypropylene pipe behaves when water freezes depends on many factors: short-term or long-term freezing; full or partial filling; whether the system contains metal elements. What can be said for certain is that water must be drained from the system.

Nevertheless, polypropylene pipelines have an “emergency reserve” — they withstand short, irregular freezing and thawing. SP 40-101-96, the main regulatory document on polypropylene, states that this is permissible.

We are used to heating systems made of steel pipes and cast-iron radiators. But iron has drawbacks: it rusts, and flax-sealed joints can start leaking over time. In winter the system is under pressure around the clock, and a burst pipe while the owners are away is a serious risk. Another downside is the complexity and labour of installation.

Other options are metal-plastic, polymer and copper pipes. Each has its pros and cons, and the range is constantly updated, so an experienced plumber can advise more precisely based on what is available in your area.

Polypropylene — the most reliable of the inexpensive options, with good protection against leaks. The main drawback of ordinary polypropylene is its high coefficient of linear expansion: the pipes lengthen when hot water is turned on. So for heating use only reinforced polypropylene (with aluminium or fibreglass) — its expansion is an order of magnitude smaller and practically unnoticeable.

Copper pipes — the most reliable but considerably more expensive option: the business class of heating.

Metal-plastic pipes with collet joints are the least desirable option: the joints must be tightened once a year, otherwise they can start leaking at any moment. If you have such pipes, it is better to replace them with polypropylene.

In short: the budget option is polypropylene pipes (reinforced ones are a must for heating); the premium option is copper.

An electric underfloor heating system consists of the following layers:

1. Floor slab (reinforced concrete or timber)
2. Thermal insulation material
3. Heat-reflecting material
4. Mounting rails
5. Electric heating cables
6. Concrete screed
7. Floor covering
8. Thermostat
9. Temperature sensor

Both electric and water underfloor heating work perfectly with any type of floor covering (linoleum, tiles and so on). The only exception is wooden coverings such as parquet and solid wood: timber does not cope well with constant temperature changes. However, there are ways to combine underfloor heating with wood — including laying a vapour barrier and other measures.

Overall, underfloor heating is an exceptionally good alternative to conventional radiator heating — both in terms of indoor climate and safety for the human body. The same applies to pets, for whom a warm floor is not only harmless but exceptionally comfortable.