ACTIV floors

ACTIV Slabs are used as the constructive and aesthetic underside of concrete floors in applications in buildings with concrete floor core activation (BKA). With concrete core activation (BKA) floors are thermally activated by circulating cold or warm water through pipes that are laid in the floor components.

ACTIV Slabs feature under-reinforcement into which the pipe network for the BKA is inserted. The upper reinforcement is applied after installing the ACTIV Slabs. Finally, concrete is poured onto the plates up to the desired floor thickness. The result is a solid concrete floor where the load is perfectly distributed, where the thermal inertia activation is used to regulate the climate.

The Kerkstoel ACTIV Slabs are made of reinforced concrete which complies with:

the PTV 202 Probeton BENOR regulations for Belgium,
the KOMO regulations, regulations for the Netherlands
the certificate with product certificate number K2188/95 and the ISO 9001 standards.

How does an ACTIV floor work?

Concrete core activation aims to keep the temperature within a well-insulated building as constant as possible, day in day out, summer and winter. Gas, electricity and oil costs are constantly rising. It is therefore best to design and build new buildings to be as energy-efficient as possible. In that regard, integrated design leads to more rational choices and is therefore catching on more and more. An integrated design process is necessary for concrete core activation as well.

With traditional heating systems like radiators, the heat is emitted by small appliances demanding high temperatures (> 60 °C), thus consuming much energy. With concrete core activation, the whole ceiling and floor surface is involved in the emission. Using the greatest possible surface area makes it possible to heat the rooms with relatively low temperatures (< 35 °C), and to cool them with relatively high temperatures. This can easily decrease energy consumption by 75%.

In a storage heater, bricks are heated, which then slowly release their heat to the room, ensuring a comfortable interior climate in the winter. The operating principle of concrete core activation is comparable, but better: with concrete core acti- vation, the concrete mass present in a building, particularly the floor slabs, is taken to the required temperature in order to heat in the winter and cool in the summer. That is killing two birds with one stone.

Special high-grade tubes are placed in the floor slabs according to a plan and pattern pre-calcu- lated in two dimensions using the finite element method. Water flows through these tubes – hot in the winter (30-35 °C) and cold in the summer (15-18 °C). The water emits its heat or cold to the concrete slabs, which in turn take the air of the rooms to the desired temperature by radiation and convection. With floor heating, heat emission only goes in one direction, upwards. With concrete core activation, the entire floor slab assists, and as a consequence, the ceiling as well.

Heat management

Kerkstoel Activ Floors can emit up to 60 Watt/m2 of heat or cold. According to specialist consulting engineers, that is generally amply sufficient. 2/3 of the heat is emitted upwards and 1/3 downwards. The reverse applies for cooling, i.e. 2/3 down- wards and 1/3 upwards.

In rooms with an even greater capacity demand, such as bathrooms in homes, or conference rooms in office buildings, intelligent adjustment of the water flow and adapted ventilation can meet the demand to the optimum.

The conductivity characteristics of the tube and the rate of flow and temperature of the water are the principal parameters for calculating the ther- mal capacity. The thickness of the floor, the floor finish with or without (insulating) covering floor and the presence or absence of a raised floor deter- mine the architectural and structural criteria.

Concrete core activation is a self-regulating system. The self-regulating capacity – high heat emission on high heat demand, low cold emis- sion on low heat demand or cooling on low heat demand – results from the buffering of thermal energy in the concrete mass. The static character of the system can be overcome by anticipating via intelligent control programmes. In this way, it is still possible to amply satisfy the daily changing needs constantly.

The advantages of ACTIV floors

BROAD RANGE OF APPLICATION

Kerkstoel Activ Floors are used in numerous types of building: office buildings, schools, hospitals, assisted living centres, rest and care homes and prisons, but also homes. The system does not suit rooms with high relatively humidity, such as catering kitchens, swimming pools and laundries.

LOWER CONSTRUCTION COSTS, NO MAINTENANCE

For the system to operate well, no false ceilings may be fitted. Those costs are therefore saved. The absence of false ceilings also means that the total construction height can be smaller. That too is a saving. In office buildings for instance, con- struction costs can fall by € 100/m2. The pipes and cables for ventilation, electricity and data transmis- sion are typically accommodated in a raised floor. Because the number of moving parts is small, the system is low-maintenance, which makes a differ- ence in maintenance costs. Lastly, using Kerkstoel Activ Floors makes it possible to work fast, which represents yet another saving

LESS ENERGY CONSUMPTION

Concrete core activation decreases energy consumption by 75%. That means a saving of ap- proximately € 10/m2 per annum. For the average home, that boils down to € 1,200 per annum, for an office building of 2,000 m2, the gain can be as much as € 20,000 per annum. Year in year out. Kerkstoel Activ Floors are ideally suited for use in combination with alternative energy sources, such as geothermal energy and heat pumps. Using Kerkstoel Activ Floors instead of traditional heating and cooling systems reduces the CO2 emissions of the building in question by as much as 43%. Important with a view to EPB require- ments: Kerkstoel Activ Floors contribute towards achieving very low E levels (< 40) and K values (25 to 30 and lower). It is also possible to attain the passive house standard.

OPTIMUM COMFORT

Buildings with concrete core activation provide incomparable comfort. Kerkstoel Activ Floors ensure an optimum social, living and working climate not just to occupants or users. All parties involved in the construction process, such as architects, engineers and contractors, reap the benefits of Kerkstoel Activ Floors. Thanks to an integrated design process and prefabrication, they are able to work punctually and risk-free, according to the highest standards of quality, environment and safety.

SUPERIOR SYSTEM

Kerkstoel Activ Floors use a multilayer PE-Xc tube. This contains an aluminium core, so that the coefficient of conductivity is significantly higher than that of a full PE-X tube. This all results in an annual saving of 12%. Moreover, the PE-Xc tube has an oxygen diffusion density of more than 99.9% (PE-X: 96%). This causes less iron carbonate to be produced (7 g per 100 m of pipe per annum) and virtually rules out the silting up of pipes and pumps.

LEVEL CEILINGS

Kerkstoel Activ Floors are made on steel formwork tables and are not prestressed. The ceilings are therefore smooth and level. A thin layer of sprayed plaster or paint suffices for the finish. Because the slabs are not prestressed, no negative bowing differences occur between adjacent slabs, an important aesthetic benefit in open- plan offices. Perfect ceilings without visible joins are obtained by, where possible, using room-wide wide-slabs (e.g. hospitals, pris- ons, assisted living centres, rest and care homes and homes).

HIGH-QUALITY FABRICATION, RISK-FREE INSTALLATION

For the most part, Kerkstoel Activ Floors are produced in the factory, so production is not dependent on the weather, which benefits both quality and punctuality of supply.Because the tubes are encapsulated in the concrete, there is no danger of damage by works by others on the construction site (reinforcing and/or concreting teams, HVAC fitters, etc.).

SIMPLE CONNECTIONS

The connections are made by means of Vision couplings, a guaran- teed watertight system. The connections are situated in the casting layer executed on site, in the raised floor or in special coupling boxes. In the latter case, they are always accessible.

FASTER, THUS LESS COSTLY INSTALLATION

Because the tubes are pre-fitted and tested in the factory, the execution period on site is kept to a minimum. This easily saves one day for a platform of 1,000 m2, typically two weeks’ work. This reduces the indirect construction site costs by at least 10%.

FEWER CONNECTION POINTS

Kerkstoel Activ Floors slabs are 2.40 to 3.00 m wide. This reduces the number of couplings by 50 to 60% compared to traditional 1.20 m wide elements. Faster execution is the logical conse- quence.

Specification guidelines

The works include:

the preparation of the embankments
the delivery and installation of
- the supports and any shuttering
- the ACTIV floor elements as described below
- the additional reinforcement
- the pressure layer
the making of the necessary provisions for cut-outs
removal of the temporary accessories
if necessary, the cleaning of the visible sides and the finishing of the edges

Lastenboek Activ vloer (NL)

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