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GRP Cold Water Storage Tanks



Water Tank Terminology Explained

Sectional tank:

Sectional Tanks are rectangular fixed container assembled from panels for the storage of water at atmospheric pressure and at a maximum temperature of 30oC.
Note: This temperature is higher than is acceptable for drinking water, which should not normally exceed 20oC.

Nominal capacity:

Volume contained in a tank, measured up to the top edge of the side walls.

Actual capacity:

Volume contained in the tank up to the maximum working level, this can be between 10 and 50% less than the Nominal Capacity.

Bund wall:

Structure situated underneath water tanks. It’s purpose is to protect the building from water damage. All water tanks located above areas that are water sensitive should be bunded.

Ball valve housing:

Enclosed chamber containing an access hatch above the level of the cover, permitting the level control mechanism to be mounted at a higher level than would otherwise be possible.


Opening to the atmosphere to allow for the movement of air resulting from changes in the water level so that the water always remains at atmospheric pressure.

Warning pipe:

Pipe so fixed that it’s outlet, whether inside or outside a building, is in a conspicuous position where the discharge of water can be readily seen.

Overflow pipe:

Pipe connected to the tank to discharge any overflow therefrom.

Division plate:

Construction of one or more panels within a tank which divides the tank into two separate compartments.
Note: In any situation where there is only one water storage tank in a building, it is to be recommend that a weir or a division plate be used. This will facilitate maintenance of the tank without effecting the water supply to the building.


Construction of one or more panels within a tank, which divides the tank but to less than its full depth such that the contents can spill over from one side of the weir to the other.


Construction of one or more panels within a tank, which partially subdivides the tank in order to increase the length of the flowpath between the inlet and the outlet from the tank.

Leakage test:

The duration of the test should be a minimum of 24 hours, commencing at least 2 hours after the tank has been filled. The test shall be carried out within 10 days of erection unless the manufacturer agrees to a longer period after assembly. The tank should be inspected at regular intervals and not deserted during commissioning (first filling with water). The leakage test is not carried out by Tricel Lanark.

B 7491 : Part 3 : 1994:

Glass fibre reinforced plastics cisterns for cold water storage. Part 3 Specification for sectional tanks.

BS 6700: 1997:

Specification for design, installation, testing and maintenance of services supplying water for domestic use within building and their curtilages.

Group 151

One Piece Tanks

43 litres to 24,000litres
Group 151

MP Range Tanks

375 litres to 3,820 litres

Group 151

Two-Part Tanks

910 litres to 5,690 litres
Group 151

Sectional Water Tanks

hold up to 1,300,000 litres

Looking for a certain tank size?

Use our Water Tank Calculator to find the right Tank Size for your needs.

The following calculator helps in estimating the cold water storage requirements for various buildings.

If you need further assistance or you can not find what you are looking for please contact us and we will be happy to help.


Enter any size restrictions (optional)

Our Water Tank Solutions


SLIDE 6 – Tunnocks-Progress-Photo

Water Tanks

43 litres to 1,300,000 litres

Tricel Lanark Sectional Tanks

Water Tanks

43 litres to 1,300,000 litres

Our Accreditations

At Nicholson’s, we pride ourselves in manufacturing and installing GRP water tanks of the highest quality throughout the UK. Click to see Our Certifications.


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bsi member cert
Certified ISO company
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