Floor Distribution Systems

Building technology and architecture has changed vastly that has resulted in the increased use of glass facades in buildings. This change, in combination with the open plan office concept has resulted in the application of floor distribution systems to ensure access of power and telecom services to ‘islands’.

Floor Distribution Systems or FDS as they are called, are probably the most abused systems in any given setting. As these are laid out on the floor, the trunkings and boxes come in direct contact with heavy static and dynamic loads that could render significant stress on the systems.It is therefore important to ensure that the FDS is properly designed to take the right loads, for the right application.Various parameters define the selection and application of floor distribution systems. These are as follows :-

Screed Depth and Methodology of Implementation A lesser screed depth could dictate the usage of shallow boxes and ductings/trunkings. Most systems are adapted to be fixed within 80mm screeds. However, pre-cast concrete slabs will result in the usage of poke-through systems, unless provisions are made for fixing floor ducts/trunkings within the slab, at the time of pre-cast manufacture.

Budget provisions for floor systems

If an inscreed duct sytem is used, the costs of the FDS could be lowered. Further cost savings may be achieved by using
uPVC conduits to feed the boxes within screeds. As flushfloor trunkings utilize a lot of steel, the costs could be high for
the same layout. When cavity floor or false floor systems are used, the costs of the Raised Floor Trunking System fall
between that of the screeded and the flushfloor system. The costs of the raised flooring could offset the potential
savings achieved while installing a raised floor trunking system. However, the potential benefit of the raised floor trunking system should not be ignored, as there is tremendous flexibility that can be achieved in a raised flooring, which cannot be duplicated in other systems.


The three systems are applied in three different circumstances. An inscreed system is applied in projects
where the final position of different service points is known in advance. This implies that the project design must be detailed to such an extent that the end user / occupant is fully aware of the usage and implementation of the points that have been designed. If this is not taken into consideration,the inscreed system could end up being under utilized, resulting in ugly extension connectors stretching across floors.

A Flushfloor trunking system is used in projects where the final positions of the floor box are approximately known,
with a level of flexibility being offered to the end user for repositioning the floor outlet. The reorganization is limited to Customercentric® 5 a few meters, with the option to move the boxes along the run of the trunking. As long as trunkings are fixed, the boxes can be relocated. Lateral movement is however, not feasible in a flushfloor trunking system.

Additionally the flexibility of the raised floor trunking system is through 360 degrees on the raised floor plane. The boxes are independent of the trunking, and can be repositioned on any point within the raised flooring, as long as it is serviced and connected to the trunking through flexible conduits.

Impinged Loads

A flushfloor trunking system has a lesser loading capability than an inscreed system, as the entire trunking is fixed flush with the finished floor. As loads constantly impinge on the floor trunking, the load bearing capability of the system is reduced. In a raised floor trunking system the boxes are the only load carrying components within the floor system. The boxes are suspended within the raised flooring, and are capable of carrying dynamic loads normally seen within floor spaces.
The average design loads on floor distribution system are as shown below. As the traffic increases, the load expected to impinge on the floor boxes could increase, and increase the stress on the floor boxes.

The system chosen should be capable of taking the following loads per square meter.
Commercial office                  – 3kN
Shopping mall                        – 6kN
Exhibition Halls                     – 6kN
Conference rooms / Hotels – 3kN
Corridors                                 – 5kN


The following standards are applicable for the floor distribution systems, including the ducts, and the service/junction boxes where


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FLUR PLAN Inscreed Duct Systems

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Flur Plan Flushfloor Trunking Systems

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