GRP Tank Specification & Size Range

Technical specification 

Manufactured in accordance with BS EN13280 and BS EN13121, the Water Supply (Water Fittings) Regulations 1999 and approved for use with potable water under the WRAS Regulations.

Our products are manufactured under the ISO 9001:2015 Quality Management System, with specific quality control arrangements being based upon BS4549-1 (reinforced plastic mouldings).

The raw materials of the GRP shall conform as appropriate to BS 3532, resin systems and BS EN14020, E glass rovings.

Internal isophthalic gelcoat surface on all tanks which is impervious to water and resistant to bacterial growth.

Our products meet the maximum deformation requirements of 1.5% or 15mm – whichever is the lesser.

The tanks are fitted with a cover, whilst not designed to be airtight, will exclude light and therefore prevent the ingress of particles and insects. All tanks that hold more than 1,000 litres actual capacity have a provision for inspection and cleaning.

Our tanks are suitable for internal or external locations and can be supplied pre-insulated or uninsulated depending upon the application.

The insulation used has an Ozone Depletion Potential of zero and Global Warming Potential of less than five and is HCFC & CFC free encapsulated Insulation with the following thermal conductivity values:

Installation requirements:

Tanks should be sited on a base that complies with BS EN 13280 and therefore conforms to the following requirements:

The area must be 170mm longer and wider than the nominal footprint of the tank.

In the unloaded state, the horizontal plane of the foundation shall not vary more than 2mm in any one metre or a total of 6mm in any six metres measured laterally or diagonally.

Flat screeded concrete foundations shall additionally be free from local irregularities and be capable of supporting the full tank without further deflection. Our tanks have a corrosion free design so once installed there is virtually no requirement to attend to its structure.

We do, however, recommend inspecting the tank annually in accordance with BS EN 806-5:2012.

Connections and Fittings

Dewey Waters supply a variety of fittings including float valves, overflows, warning pipes and threaded flanges.

We can also provide most of our range with a raised float valve housing which will increase the usable volume of water.

Two-Piece Tanks

Our tanks can be manufactured in two parts with a flange running horizontally through the middle to assist with access requirements.

Divisions

Division We can supply most of the range with a division used to give the tank two compartments.

This option allows for one side of the tank to be drained down for maintenance while the other side is still live in accordance with BS EN806 Part 2.

Air Gaps 

Air Gaps Air gaps are a requirement by the water authorities to ensure that there is a clear break between the mains supply and a building or a device to prevent any contaminated water getting back into the mains supply.

We can supply our tanks with the following; AA fluid category 5, AB fluid category 5, AF fluid category 4 and AG fluid category 3.

Stock Tanks

Our range of standard tanks are usually available as a stock item, complete with 25mm insulation and with or without a raised float valve housing.

Stock tanks can be delivered within 2-3 working days. Please note stock tanks are supplied undrilled with recess positions as detailed above. Recess provisions are the areas suitable for drilling and fitting connections