The floor structure of industrial halls, ice rinks, and sports fields must withstand extremely diverse loads, and this requires extremely resistant thermal insulation.
The thermal insulation of structures in contact with the ground requires great attention in general, since up to 20% of the building’s heat loss can occur through the floor. In such cases, only thermal insulation that has high permanent compressive strength, is resistant to foot traffic, is resistant to moisture, and maintains its thermal insulation properties in the long term can be used. However, due to some special functions, even more care must be taken when designing/executing the floor structure.
The floor slabs of industrial halls / sports fields / arenas for various purposes and the thermal insulation underneath are subjected to continuous, intensive stress:
- usage loads (vehicles, forklift traffic, high shelves, machines, industrial equipment)
- static load (loads transferred from connecting building structures)
- dynamic load (starting, braking, vibration)
- mechanical stresses during construction.
Despite all these effects, the heat transfer coefficient of the floor structures must be below U=0.3 W/m²K, and taking into account the overall energy aspects, it is absolutely necessary to use XPS thermal insulation under the hall floor – in its entire extent. With this solution, we can reduce the risk of frost, and in the case of a temperature-controlled production hall or warehouse, heat loss can be significantly reduced.
In the case of a sports hall, we are talking about a floor structure that has to perform multiple functions with minimal modification, and the built-in thermal insulation must be able to withstand the associated impacts.
Compressive strength/permanent compressive strength
The nominal compressive strength value stated in the technical documentation represents the resistance of the products to short-term loading during laboratory tests.
For thermal insulation plastic foams, this short-term (nominal) compressive strength value is not applicable for structural calculations, but is only used for strength and comparison categorization of individual products. The compressive strength value for permanent load must be used to determine the load-bearing capacity of the floor structure, including the thermal insulation layer, against permanent and live loads.
The permanent compressive strength
The technical documentation of the products also includes the compressive strength value for permanent loading. This is determined according to the EN1606 standard, which specifies a 50-year service life and a maximum compression of 2%. This means that if RAVATHERM XPS boards are permanently loaded with the designed load value, the compression of extruded polystyrene foam boards is expected to not exceed 2% of the thickness after 50 years.
Cold stores
In cold store floor structures, effective thermal insulation is of paramount importance, not only to save energy, but also to ensure the desired internal temperature at all times. Due to the thermal insulation thickness exceeding 200 mm in some cases, the use of high-strength thermal insulation material is particularly justified. The use of high-strength RAVATHERM XPS 500/700 SL panels with high thermal insulation value enables the creation of a cost-effective load-distributing reinforced concrete structure. In cold stores, underfloor heating may be necessary under the thermally insulated floor structure to prevent frost-sensitive soil layers from freezing.
Ice rink
Modern indoor ice rinks are usually equipped with two pipe systems: cooling and heating. The cooling pipes play a role in the formation and maintenance of ice. They also cool the soil layer under the rink, thereby reducing the economy of the building. If the soil does not thaw when the rink is not in use, there is also a risk of permanent freezing of the lower layers of the soil. Where the operating season lasts longer than six months, heating pipes should be placed under the floor structure, thus preventing the formation of permanently frozen soil layers. In such rinks, the installation of RAVATHERM XPS 500 SL ensures a reduction in heat loss and prevents the formation of permanently frozen soil layers. A well-insulated structure can be thawed faster, thus enabling the rink to be used for multiple purposes. The use of RAVATHERM XPS thermal insulation also reduces the need for earthworks, and thanks to its exceptionally high compressive strength, it can withstand dynamic loads caused by ice-smoothing machines and other equipment without deformation.
Sports fields
RAVATHERM XPS thermal insulation can be used for installation under both indoor and outdoor sports fields. The applied compressive strength depends on the type of field and its multipurpose use.
The subgrade of outdoor sports and football pitches is similar to that of lower-level roads. It is recommended to use RAVATHERM XPS 500 SL or RAVATHERM XPS 700 SL in one layer over the entire surface of the pitch, extending 0.5-1 m beyond the edges. The straight-edged boards should be laid with a 5 mm gap, thus allowing for drainage. The subgrade should be made of 250-350 mm of good quality gravel or crushed stone.
The walking surface of the floor structure of an indoor sports field can be designed as a double-padded swing floor with strip parquet, or with a flexible rubber layer cast on a screed base, or perhaps with PVC with a foam underlay, depending on whether a point-flexible or surface-flexible sports floor is required. The general industrial floor layer system can be used under the sports floor.
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