Anti-icing roofs - types of
systems In addition to the damaging effect of ice on the truss system, the icicles that are formed represent a direct threat to people and cars on the street. It is much easier to prevent the icing of the roof, rather than sweat the ice with crowbars, at the risk of damaging the roof. And the only effective step in this direction is the artificial heating of the roof.
The roof anti-icing system is an extremely simple engineering solution. It is based on heating electrical cables laid in the places of the most probable icing from around the projections of the structures, along the roof edges, in the valleys and along the drainage system.
There are two types of heating cables: resistive and self-regulating. The first consist of a metal wire, insulation with a copper sheath and a shell. Cables can be single- and double-core, the latter being more convenient to install and reliable in operation, although they are somewhat more expensive.
Having the same resistance along the entire length, they also radiate evenly along the entire length and heat when electric current passes through them. In the event of a dense layer of fallen leaves, dirt or other length of cable falling on the cable, a normal heat dissipation is disrupted in this section, the wire overheats and there is a danger of its burning out.
For this reason, the resistive cable is most often used with the use of a complex of automation, which turns off the system in case of overheating. Structurally, the cable is made in the form of sections of a certain length, which creates inconvenience in the design and installation of roofs of non-standard configuration. The life of a resistive cable is 5 years.
Self-regulating roof anti-icing system
In the case of a self-regulating cable, heat is emitted by a polymer semiconductor matrix located between the two conductor cores. The basis of the action of the cable is the property of the matrix to increase its resistance as the temperature increases.
That is, when the matrix is heated to a certain value, its resistance also increases, the current strength decreases accordingly, which leads to a decrease in the temperature of the matrix. And this, in turn, reduces the resistance. The strength of the current starts to rise again, and the temperature rises again. The process is self-regulating, which gave the name to the cable.
Self-regulating cable is a continuous strip, which is easily cut into lengths of the required length. The flat section of the cable ensures a tight contact with the roof surface, which contributes to a more rational use of heat. The life of the self-regulating cable is 20 years.
Nuances of installing the
The roofing can be adjusted manually or automatically. Naturally, the automation is more comfortable and ensures the inclusion of the system without the intervention of the owners, which is very convenient in a country house or at night. Heating cables are located not only on the roof, but also on the main gutters. In case they go directly to the storm sewer, the cable is laid along the drain to the level of freezing of the soil.
The installation of the heating cable depends largely on the roofing. So, natural ceramic tiles do not require an anti-icing system, since almost nothing on the surface of the glaze. If the roof is metal, then before laying the cable it is desirable to cover it with a special rubberized cloth.