Application of PUF pipes in heat supply
First applications of PUF for thermal insulation of pipes
First samples of polyurethane foam were obtained in Germany in the late 1930s using polyol and polyisocyanate. The new substance had excellent thermal and acoustic insulating properties, and was ductile at the same time, making it suitable for use in many industries.
However, only in the middle 1980s polyurethane foam became widely used as thermal insulation for pipes. It was the time when European countries and the USA were challenged by the energy crisis and the need to efficiently use whatever resources were available.
What did they use to insulate heating pipes before?
Before polyurethane foam became widespread in the thermal insulation of pipes, other materials had been used instead with the objective of minimizing heat losses.
Comparison of thermal insulation material characteristics:
|
PUF | Mineral wool | Plastic foam | Foam rubber | Foam Polymer Insulation |
---|---|---|---|---|---|
Thermal conductivity | 0,033 W/(m·К) | 0,04 W/(m·К) | 0,038 W/(m·К) | 0,036 W/(m·К) | 0,047 W/(m·К) |
Density | 80-100 kg/m3 | 55 kg/m3 | 15 kg/m3 | 40-80 kg/m3 | 200-250 kg/m3 |
Service life | > 30 years | > 30 years | > 30 years | 10-20 years | > 30 years |
Strength | 0,3 MPa | 0,1-0,15 MPa | 0,2-0.4 MPa | - | 0,3 MPa |
Material structure | Closed pores | Layered | Honeycomb | Porous | Closed pores |
Heat resistance | Moderately flammable | Practically inflammable | Moderately flammable | Weakly flammable | Strongly flammable |
Water absorption | None | Up to 30% | 1% | 2,4% | 7% |
Adhesion to pipe | At least 0.12 | None | None | None | 0,4 |
Environmental friendliness | High | Medium | Releases toxins when burning | High | High |
RRCS included | Yes | No | No | No | No |
Laying method | Above-ground, underground | Above-ground | Above-ground | Above-ground | Above-ground, underground |
Insulation thickness |
As per GOST DN 273mm – 57 DN 426mm – 58 |
25-220 мм | 20-100 мм | 6-32 мм |
As per Technical Specifications: DN 273mm – 43 DN 426mm – 44 |
Today PUF pipes have become widely acknowledged in heat network installation both for household and industrial use. They are in high demand when obsolete parts of pipelines are refurbished or replaced. Moreover, the use of RRCS allows to monitor the healthiness of the complete heat network system and promptly respond to small failures before a serious accident occurs.