Ice and snow melting

How to heat outdoor surfaces?

Electric heating of external surfaces is realized by installing heating cables, heating tracks or heating networks in or under the final layer of traffic or passable surface. The final layers are usually concrete, asphalt and pavers (concrete “cubes”, pavers), and can also be stone or ceramic tiles.

1. Unit heating powers (W/m²) for outdoor traffic areas primarily depend on: climate zone, installation location and specific purpose of the heating itself, and additionally on wind speed, rainfall, altitude, etc .. Taking all this into account, in areas with the Central European continental climate, it is recommended not to heat outdoor surfaces with a unit power of less than 250 W/m².

For certain types of traffic and passable surfaces and heating constructions, the recommendations would be the following:

• surfaces without thermal insulation under the heater

• surfaces with thermal insulation under the heater

Thermal insulation (usually high-density polystyrene) installed under the heater reduces the useless heat dissipation downwards, but complicates and increases the cost of the complete design of the heated object. On detached buildings, such as: stairs, terraces, balconies, bridges, overpasses and garage ramps, it can still pay off, because it reduces both the engaged power and electricity required for thawing. The reduction of heat losses primarily depends on the thickness of the thermal insulation and ranges from 15 W/m² (for insulation thickness of 20 mm) to 30 W/m² (for insulation thickness of 100 mm).

Display of the time required for the start of melting, on different versions of traffic surfaces, with an air temperature of -3 °C and a unit heating power of 250 W/m²:

Regardless of the chosen method of realization of electric heated external surfaces, the general principles that should be adhered to apply:

• install heating equipment only according to pre-made plans only install on flat and clean surfaces
• pass through expansion joints only with inactive parts of the heater (so-called “cold ends”) and protect them with pipes
• place boxes and tubes at the positions of the measuring sensors that will enable their subsequent assembly
• after installing the heaters, and before making the final layer of the outer traffic surface, prohibit and prevent unnecessary trampling and any transport over them
• immediately after installing the heaters, as well as after making the final layer, carry out measurements of working and insulation resistance and enter the results in the record of measurements
• all participants in the construction of outdoor traffic heating, and especially construction workers, that the end result mostly depends on the timely (as soon as possible) and correct (without damaging the heating cables) installation of the final layer

Depending on the final surface, purpose and wishes of the customer, there are several ways to install heating cables in the structure of the outer surface:

1. Installation of heating cables by tying with PVC ties to the upper reinforcing mesh when concreting external traffic surfaces in one layer (eg when making entrances to underground garages …)

2. Installation of heating cables by tying PVC ties to the mounting strip. The mounting strip is previously fastened with impact dowels to the basic reinforced concrete slab (terraces, bridges and overpasses …)

3. Installation of heating tracks in the second – the final layer of concrete. The heating cables are inserted in profiled plastic foil and secured with reinforced aluminum adhesive tape. The foil is placed before the final layer of concrete is made (eg when making parking lots and garage entrances). Heating tracks on the foil can also be placed in the sand when laying pavers (concrete “cubes”, pavers).

4. Installation of thin heating nets (power 250-300 W/m²) in flexible construction adhesive under ceramic tiles or stone (eg when making terraces, balconies and stairs).

5. Installation of heaters in the sand under the pavement (concrete “cubes”, pavers) heating cables are pre-connected with spacers (eg when making access to garages, pedestrian paths, parking lots …). It is also possible to place heating tracks on the foil in the sand.

SMALLER OUTDOOR SURFACES

When heating smaller outdoor surfaces (paths, stairs, landings, balconies, smaller terraces, garages to the garage) on private buildings will satisfy the manual control of heating with thermostatic limitation of operation. Experience shows that manual control is possible where the motive of the user is responsible and rational use of el. energy, and therefore money, to melt snow and ice on passable and busy surfaces.

The best time to turn on the heating is just before it starts to snow or icy rain. This usually happens when the outside temperature is around 0 °C so relatively little energy is needed to prevent snow deposition or ice formation. When it already snows or ice forms and the outside temperature drops, much more energy is needed to melt them (longer heating operation time – higher costs).

With manual control of outdoor surface heating, the thermostats only serve to switch off the heating if the outside temperature rises and the snow and ice melt without heating or no longer exist at all, and the user has forgotten to switch off the heating. Of course, if the outside temperature drops again, below the one set on the thermostat, the heating will turn on even though there is no snow or ice at all !!!

Which thermostat to use in such heating control depends on the power and location of the heating installation, as well as on the location and possibilities of installing the thermostat. The recommendation for the thermostat that is installed in the flush-mounted Φ 60 x 40mm box is RTC70 / MT26, and for the thermostat that is installed on the DIN 35 rail is DT235.

LARGE OUTDOOR AREAS

When heating large outdoor surfaces (garage and access ramps, large stairs and landings, parking lots, overpasses, bridges…) on private, and especially on public buildings, it is necessary to install some of the automated work monitoring systems. Although none of these systems is infallible and needs periodic monitoring, experience shows that it gives good results in facilities where users avoid worrying about the operation of heating.

Regulators of the ETR2-1550 and ETO2-4550 type are used for the realization of such automated heating systems for large outdoor surfaces. They base their work on data obtained from the ETOG-55 and STT-2 humidity and temperature sensors.

How to solve the heating of the outdoor surface?

In over 25 years of work on outdoor heating, we have developed a range of products that successfully melt snow and ice. The choice of the appropriate product depends on several factors, such as: the current state of the surface to be heated, the predicted final layer of the heated surface, the complexity of the shape of the heated surface, the cross-sectional height for installing the heating equipment, the degree of complexity, available installation time and available power electricity. Namely, you should always keep in mind that the minimum required power is 250 W/m² and it often determines how much surface will actually be heated!

The most common way of heating outdoor surfaces is the installation of heating cables by tying PVC ties to the reinforcing mesh or mounting tape. A slightly rarer way is to “touch” and install heating cables using plastic clamps. The good side of such installation methods is the robustness and durability of the heating cables, as well as the complete adaptation to the shapes of the heated surface. The disadvantage of such installation methods is the need for timely planning (before concreting or making a cement screed), higher available height for installation, greater effort and longer time required for installation.

The most common way of heating outdoor surfaces is the installation of heating cables by tying PVC ties to the reinforcing mesh or mounting tape. A slightly rarer way of installation of heating cables is using plastic clamps. The good side of such installation methods is the robustness and durability of the heating cables, as well as the complete adaptation to the shapes of the heated surface. The disadvantage of such installation methods is the need for timely planning (before concreting or making a cement screed), higher available height for installation, greater effort and longer time required for installation.

The installation of prefabricated heating tracks on foil, type GTF, significantly simplifies and speeds up the installation and is especially suitable for heating tracks or footpaths.

When the construction works have already advanced and only the gluing of ceramic tiles or stones remains, the only way to realize the heating of the outer surface is to install thin heating mats in a flexible construction adhesive.

We leave the installation of heaters, heating tracks and heating mats to local installers to whom we submit installation plans and thus reduce the costs of investors to the lowest possible amount.

What products do we offer?

• classic resistive wire heating cables type SSAP or SSAPP
  • for installation in concrete or sand under pavers
• self-regulating heating cables type SM2
  • for installation in concrete or sand under pavers
• classic resistive wire heating cables type SPCA or SSAPP
  • for installation in asphalt
• thin heating mats type TGMt 
  • 250 W / m² for installation under tiles or stone
• heating traces on foil type GTF
  •  power 250 W/m² for installation in concrete
  •  power 300 W/m² for installation under pavers
• heating traces on a metal carrier type GTA
  • power 250 W/m² and 300 W / m² for installation in asphalt
• thermostats and regulators
  • RTC70 / MT26 and DT235 for smaller and simpler heating
  • ETR2-1550 and ETO2-4550 for larger and more complex heating
• measuring senses
  • humidity and temperature sensor ETOG-55
  • temperature sensor STT-2
• complete electrical control boxes for outdoor heating
• mounting material
  • mounting strips with a perforated “lugs” pitch of 10 and 20 mm
  • polyethylene clamps, dowels and nails

Other information related to the topic of outdoor heating can be found in the following documents: 

• Vanjsko grijanje – principi
• Vanjsko grijanje – ugradnja
• Vanjsko grijanje – ugradnja u asfalt
• FORMULAR ZA UPIT s primjerom za uzimanje mjera – vanjska grijanja

If you have questions related to electric outdoor heating, feel free to contact us. Our professional team of certified engineers and thirty years of experience in the implementation of heating systems is at your service.