Glassfibre Reinforced Concrete (GRC) – a cementious material that forms a complete bond with concrete sub and other floors.
As a proven and acceptable material for civil engineering applications, GRC is the ideal material from which to manufacture filter floor panels. For example, it can easily be worked on-site using standard construction tooling and tests, carried out by the British Cement Association, indicate a dramatic reduction in corrosion rates when GRC is used in conjunction with reinforcing steels.
Apart from being totally acceptable for use with potable water and tertiary treatment, the GRC filter floors are both easy and trouble free to install.
Weighing only 30Kg per square metre, the filter panels can easily be positioned manually. In addition, the size of each panel and the density of its nozzles can be produced to suit individual installations. The position of each nozzle head is accurately determined during the panel manufacturing process by casting inserts into each panel, simplifying filter nozzle installation.
Once installed – on either dwarf walls or plastic piers – and levelled using either mechanical or laser techniques, the GRC floor panel joints are again, easily sealed with mastic or grout.
Choice of Panel Design
As an alternative to the conventional corrugated filter floor panel which is installed on specially constructed dwarf walls, BCM have developed a GRC flat panel that rests on 150mm diameter plastic piers. The installation procedure illustrated in this literature is identical for both types of panel. However, when using plastic piers, the starter bars are positioned inside the plastic tubes which are leveled to plus or minus 3mm using stainless steel shims. Having positioned the flat panels onto the plastic piers, the plastic tubes are then filled with concrete at the same time the floor is cast, forming a complete structure. Special edge and corner panels are available if required. The standard nozzle density for the flat panel design is 45 per square metre, but much higher densities can be achieved if necessary.
Precision Moulded Filter Nozzles
Filter nozzles both retain and prevent the ingress of the media into the under drain system and, at the same time, they help to accurately gauge and distribute the air scour
Consisting of a nozzle head and a tailpipe, the filter nozzles are easily installed. the nozzle stem is screwed into the pre positioned bush in the GRC floor panel and a disposable sealing cap is fitted to prevent the ingress of concrete while the floor slab is being cast. Once the floor slab has been cast, the disposable cap is removed and the filter nozzle head screwed into position.
The nozzle head incorporates 0.2mm slots – ideal for most potable water applications because they allow direct contact with the media – but larger slots can be incorporated for other applications, flow rates, or media’s.
The variable length nozzle tailpipe includes an accurately positioned slot in its base.The primary function of this slot is to meter and distribute air during the air scour. Its positioning is controlled by the level of the floor surface. The use of monolithic floor panels simplifies this requirement.