Hot press steel sectional tanks

Tank construction

Balmoral steel sectional tank illustration


  1. Screened air vent
  2. Pitched weatherproof cover
  3. Rafter
  4. Internal bracing
  5. Balmoral FireFlowTM vortex inhibitor (Fire tanks only)
  6. Hot press steel sectional tank panel
  7. Low level access manway
  8. Aluminium or galvanised steel gated ladder
  9. 600mm manhole access
  10. Gable end fillers

Note: This is not a typical tank design. Panels and components are shown for illustration purposes only

General construction

Balmoral pressed steel tanks are bolted mild steel sectional water storage containers. Plates are hot-pressed in our factory in the UK to BS1564:1975 Type 1.

The panels are manufactured in 1.22m2 (4ft2) sizes with thicknesses ranging from 4-6mm depending on tank depth and use. Half plates are available. Steel used in plates, stays, cleats, etc, conforms to BSEN10025:1993 S275JR (43A equivalent).

Tank plates are bolted together using an approved sealant. For ease of access to bolts, tanks are supplied with external flanges unless customers specify otherwise.

To support pressures exerted by the tank’s contents, the sides of all tanks at the junction of four plates are supported by rolled steel angle stays attached to cleats of equal strength bolted to tank plates. The pattern of internal stays depends on tank size and varies between horizontal, vertical and diagonal.


Storage of liquids

The bolted construction of the tanks allows storage of water up to 90ºC. Temperatures in excess of this would require the tank to be fully seam welded. For clarification of storing other liquids please consult our engineering department.

To maintain water quality, tanks should be periodically drained, cleaned and disinfected. To ensure continued water supply during cleaning, divided tanks can be supplied where one compartment is used while the other is cleaned. See BS6700:1997 for additional advice.


Surface coatings and finishes

A wide range of coatings can be applied to the inside and outside of the tanks which include hot dip galvanising (BSEN ISO 1461:1999) and WRAS approved systems. Balmoral Tanks also offers a DWI (Drinking Water Inspectorate) approved coating which meets the requirements of Regulations 31-33 (Reg 25 in Scotland) of the Water Supply (Water Quality) regulations.


Cover and roofs

The roof construction of all steel sectional tanks is designed to support the weight of maintenance personnel and their equipment. Design superimposed load is 0.75kN per m2.

Flat covers can be provided for use inside buildings. Pitched roofs are recommended for outdoor use to allow rainwater to run off. All roofs are fitted with a lockable 600mm2 hinged and sealed manhole. Screened (0.65mm mesh) cowl ventilators are provided as standard.

The ends of pitched roofs are closed with stiffened gable fillers which are bolted to the roof and wall plates.

All joints incorporate jointing strip to make them weather and vermin proof.

Pressed steel tanks are not designated as pressure vessels, but in special circumstances the roof can be constructed from standard plates to allow a slight internal pressure.


Laser cutting

Balmoral Tanks uses the latest laser cutting technology to bring high levels of accuracy to its panels. The cutters use a 3D capability providing precise, repeatable, burr-free profiles and are BSEN ISO 9001 certified.



When a constant pressure head of water is required for supply purposes, tanks can be mounted on a steel tower at a suitable height. Towers must be designed with suitable seismic and wind loads to accredited standards.

Balmoral Tanks provides a full design and supply service for towers, to BS5950. When specifying tower requirements it may be advisable to anticipate future increases in tank capacity. Customers are advised to consider foundation requirements and to let Balmoral know what additional loadings on towers may be required in the future.

On request Balmoral can supply loading and uplift details enabling contractors to design suitable foundations.

Case studies

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