Frequently Asked Questions

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Q. What is the construction of a floor panel?
A. There are various basic floor panel constructions that are outlined below along with various attributes of each type.

• Steel encased chipboard core. This panel construction comprises of a high strength chipboard core that is encased by galvanised steel laminated to the chipboard by a structural polyurethane or epoxy resin adhesive. This construction type is capable of providing high strength and good fire and acoustic performance. By varying the thickness of the steel sheet and the strength of the chipboard core a wide range of structural performance is available.
• Steel laminated chipboard core. Here the chipboard core is not fully encased in galvanised steel. The panel edges are normally finished with an ABS or similar plastic edge trim. This panel construction is normally for use with a factory bonded surface covering which requires edge protection i.e. vinyl or high pressure laminate. By varying the chipboard and steel thickness a range of structural performance is available.
• Bare chipboard panels. Here high strength flooring grade chipboard is machined to the required panel size i.e. 600mm square and supported on pedestals to provide light and medium duty raised access floors.
• Steel/cementitious panels. Here a structural steel shell comprising of a flat steel top and a profiled steel base are welded together to form a hollow shell. This shell is then filled with a foamed cement based core to give a panel that gives good structural performance in conjunction with excellent fire performance. In certain cases the hollow unfilled steel shell will provide a floor panel that gives suitable
structural performance although its acoustic performance is limited.
• Anhydrite based panels. These are constructed from materials such as calcium silicate to give a panel that gives very good acoustic, fire and thermal insulation performance in conjunction with a good structural performance.

Q. What is the construction of a pedestal?
A. Pedestals are a all metal construction comprising of the following components:

• Base plate manufactured from pressed steel at a minimum size of 100mm x 100mm. Normally at least 4 holes are include in the base plate to allow for mechanical fixings. Larger size base plates may be used at higher floor heights.
• Pedestal tube generally manufactured from a minimum of 22mm threaded bar to 25mm diameter tube and 32mm diameter tube for higher floor heights. The tubes are manufactured in a wide range of lengths to cater for the range of variations in project requirements. The pedestal tubes incorporate a locking device to ensure that the pedestals remain locked at their correct height. The pedestal tubes are welded to the pedestal base plates. The use of zinc coated materials gives good protection against corrosion.
• Pedestal heads are produced from zinc plated pressed steel or high pressure die cast aluminium. They have a threaded portion to engage onto the pedestal tube. The design of the pedestals allows for a total of 40mm of adjustment to cater for sub floor variations. Once adjusted at the correct height the locking device prevents any change in adjustment due to vibration. Pedestals for use at low heights may give less than 40mm of adjustment.
• The pedestal heads are designed to readily accept both snap on and bolt on stringers. Snap on stringers are normally used at floor heights above 600mm and bolt on stringers are used to increase the structural performance of a raised floor system.
• The pedestal heads are fitted on site with a snap on plastic cap that provides location for the floor panels. These plastic caps are fitted with copper strips to provide electrical continuity between the floor panel and pedestal. An electrician on a suitable grid basis connects these pedestals to the building’s earth system on completion of the floor installation.
• The pedestals are attached to the sub floor by the use of an epoxy resin based adhesive. This adhesive proves adequate in many cases but if required additional security is achieved through the use of mechanical fixings. The use of mechanical fixings is determined by the finished floor height and/or the results of on site testing that determines the integrity of the pedestal fixing to a specific sub floor.

Q. What are stringers and why use them?
A. Stringers are introduced for various reasons each with their own specific design.

• Snap on stringers. These snap onto the pedestal head and are used to provide additional lateral support to the raised floor. They are normally introduced at floor heights of 600mm and above or for use with floor panels complete with factory bonded finishes. Snap on stringers are normally designed to increase the structural performance of the raised floor.
• Bolt on stringers. These are screwed into the pedestal head and are designed as structural components and as such increase the structural performance of the raised floor system. They will also provide increased lateral stability.
• Air plenum stringers. These stringers are designed only as a means of providing an air seal to the panel joints through the use of a gasket strip. They do not provide any increase to the lateral stability or structural performance of the floor.
• Perimeter stringers. These provide additional support to cut panels around the perimeters if required by the project specification. It must be noted that the use of snap on or bolt on stringers will reduce the floor void depth available for service runs by about 30mm.

Q. What are bridging beams and why use them?
A. Bridging beams are used to bridge across services or obstacles in the floor void in situations when a pedestal cannot be sited in its required location. The bridging beam is supported at either end by a pedestal to which it must be firmly fixed. Whenever possible standard bridging should be used although if required bridging can be designed to overcome special circumstances.

The actual section used varies with the span between the support pedestals, the grade of floor in which it is to be installed and the project specification