Pipes that are manufactured for communication lines are made of heat-conducting materials: steel, fiberglass, polymers. Due to this, they freeze through rather quickly and require mandatory insulation. Due to the insulation for pipes made of expanded polyethylene (PPE, polyethylene foam), engineering networks will not be exposed to cold weather. The use of insulation on heating mains will prevent large heat losses.
Types and sizes
The heat insulator is created by foaming a synthetic ethylene polymer, which is synthesized from petroleum products. The result is an elastic polyethylene material with a porous structure.
Thermal insulation material is made of two types:
- Unstitched. A polymer with molecules that do not have additional bonds in space, which is why the material is less elastic, strong and dense.
- Stitched. The material is made by chemical or radiation methods, due to which linear and cross-sectional molecular bonds are created. The insulator is dense, durable and elastic, after squeezing it quickly restores its original shape.
As a rule, the length of pipe sections is equal to two meters, the thickness and diameter are different. The thickness indicator is 6, 9, 13, 20 or 32 mm, the internal section is from 6 to 200 mm.
For thermal insulation of communication lines that are directly exposed to ultraviolet radiation, PPE with a colored surface is used, which reliably protects the heat-insulating material. There is also a foil-coated polyethylene that protects pipes from low and high temperatures. Another type is a roll-type heat insulator with special tape. The material is used to insulate communication networks in places with difficult access.
The most famous PPE manufacturers are Energoflex, Termoflex and Termocom. The first organization produces heat insulators, which include waterproofing materials. The other two are more concerned with keeping the pipes intact.
Specifications
Polyethylene foam is classified as foam. The main technical characteristics of the heat insulator include:
- heat conductivity - from 0.034 to 0.04 W / mK;
- density - 25-200 kg / m³;
- susceptibility to moisture - 0.9–1.1 percent;
- vapor permeability value - 1.8 mg / m * h * Pa;
- flammability group - G1 – G4;
- the degree of dimensional stability is high;
- noise absorption - 16 dB;
- application at temperatures - from -80 to +95 degrees.
A sewn insulation for pipes made of expanded polyethylene with the shape memory effect of insulated structures has greater strength, elasticity, and density. For this reason, in order for the pipe heat-insulating coating to be of high quality and effective, it should be preferred.
For the insulation coating of communication systems, foamed polyethylene in the form of split tubes is most often used, which have a technical slot along the entire length and can be easily put on already installed engineering systems. It turns out a kind of fur coat for heating pipes or water supply. To install such an insulator, there is no need to disassemble the trunk sections.The halves are joined end-to-end with edges and glued with metallized tape.
Areas of use
The material is used to provide a reliable heat-insulating coating of engineering communications. Cases made of polyethylene foam are suitable for insulating pipelines:
- heating;
- hot and cold water supply;
- sewerage;
- air conditioning systems;
- ventilation ducts;
- cooling units.
Sheet insulator based on polyethylene foam is used to insulate the walls of buildings from the outside and from the inside, basements, foundations, attics. It is used for thermal protection of baths and saunas. Bundles made of this material are used to seal interpanel seams, cracks in window and door openings.
Advantages and disadvantages of PPE insulation
The structure of the material is similar to foam rubber and is not resistant to mechanical stress, which is why it cannot be used as a heater for walls and floors. Due to the closed fine-cellular porous structure, polyethylene foam does not absorb moisture and does not allow water vapor to pass through, it is resistant to rust. Condensation does not appear on surfaces covered with foamed polyethylene; when insulating pipes, there is no need for an additional waterproofing layer.
The advantages of the material include:
- Significant thermal insulation qualities. Its use reduces heat loss by up to 75 percent and provides fluids at the same temperature during transport.
- Resistance to temperature jumps in the range from -80 to +95 ºС. Due to this indicator, the insulating material is allowed to be used in harsh climatic conditions.
- Soundproofing properties. Foamed polyethylene does not transmit sounds from the liquid that circulates in communication systems, partly drowns out the level of structure-borne noise.
- Low weight. Thermal insulation with light polyethylene foam pipes does not create additional stress on utility lines.
- Ease of installation - no special equipment required.
- Rapid restoration of the original shape after squeezing.
- Resistance to biological effects. Foamed polyethylene does not form fungal deposits and mold.
- Immunity to chemical elements. The quality indicators of the material do not change upon contact with a variety of mortars, alkaline and acidic media. Thanks to this, it can be used as a heater for pipes that pass through concrete structures or buried in the ground.
- Environmental friendliness. Foamed polyethylene does not emit harmful substances. Such a heat insulator is allowed for insulating pipes in educational institutions, medical centers, as well as technological pipelines in food production.
A distinctive feature of the insulator is its low cost and durability - the operating period can reach 50 years.
With all its advantages, polyethylene foam quickly melts when exposed to open fire. The flame from it can spread to nearby objects. Another imperfection is its high susceptibility to the influence of ultraviolet radiation. Foamed polyethylene becomes brittle, colored and cracked when exposed to direct sunlight. To prevent the negative effects of UV rays, the outside of the material is covered with foil.
The insulator is easily damaged with a sharp object, the resulting rupture can spread along the entire length of the shell. To avoid damage, it is necessary to immediately glue the gap with reinforcing tape.
Installation nuances
Polyethylene foam insulation can be easily installed on a pipeline of any complexity. This does not require special tools.To make installation even easier, cuts are provided on the insulation pipes. However, there are also monolithic insulators that can be easily cut to length using an ordinary office knife with a replaceable blade. A self-cut cylinder, put on a pipe, will have to be fixed in one place, fastened with duct tape on top.
Insulating shell installation:
- Before installing the heat insulator, the pipe surface of the pipe is cleaned from mortars and dirt for a tight fit. If the engineering network is made of metal, anti-corrosion cleaning is carried out.
- The incision is glued with a special adhesive ("Contact Acrol", "KVIK-BOND", "Neoprene 2136", "88-NP"). Also, with the help of glue, the beginning and end of the case are attached to the pipe section.
- After joining the edges, the joint is seized with staples in a step of approximately 20 cm. After the adhesive has dried, the staples are removed, the seam is glued with reinforced tape.
It is necessary to glue the cut along the entire length if the outdoor pipeline is insulated. For engineering structures indoors, you can only fix the edges and close the seam with tape. It is important that the inner cross-section of the case is exactly the same as the size of the pipeline. If the end edge is self-adhesive, installation is even easier. You just need to remove the protective film and fix the cut.
Low price in combination with low heat loss and long service life make foamed polyethylene attractive for use as a heat insulator. Ease of installation allows you to carry out the work yourself, without the involvement of specialists.
