Potable water storage tanks

Potable water tanks are used as sources of water supply in installations and water networks. These tanks are designed for storing water in hygienic conditions. To maintain sterile conditions inside a tank, we use approved for contact with liquids and food products materials.

We are able to provide steel ground potable water storage tanks with a wide range of dimensions and capacity. You can easily match the appropriate tank to the specificity of the installation place, design requirements, operating conditions or its assignment.

It is possible to design and manufacture tanks with non-standard dimensions and capacities.

The structure of potable water storage tanks is made of hot-dip galvanized steel panels with dimensions of 2500 x 12500 mm. The minimum thickness of the panels is 2,5 mm. The panels are bolted with a single or double vertical row of 8,8 class bolts. Thanks to the PVC membrane vulcanized during assembly on the construction site, a tank remains completely tight. PVC membrane is 1,5 mm thick and is approved for contact with drinking water. Another advantage of using it is elimination the contact of water with steel walls of a tank.

The roof of an aboveground steel potable water tank is made as a self-supporting structure on steel "Z" beams with a slope to the outside. The roof structure ensures efficient and effective removal of snow and rainwater outside a tank.

The roof of a tank can be equipped with an insulated or non-insulated roof covering. The insulated cover is made of T35 trapezoidal sheet metal or sandwich insulated panels with a mineral wool core, PIR foam or polystyrene. The covering width of the roof panels is 1150 mm, which ensure quick, simple and convenient installation to the roof structure using pass-through fasteners. The tongue-and-groove locks make the roof structure tightly connected to the structure of the steel ground potable water storage tank. If necessary (according to the statistical and strength calculations results) we additionally use peripheral system clamps, the so-called "wind reinforcements". Providing easy access to the tank roof, we install a steel ladder with platforms on the structure. The roof of a tank is topped with a manhole, which enables the inspection of the inside of the steel potable water storage tank.

As part of the waterproofing protection, we use a prefabricated EPDM membrane or a PVC film welded at the construction site. Each of these solutions eliminate the risk of contact of the stored water with a thermal insulation or steel walls of a tank, thus preventing corrosion centres.

EPDM membrane

  • thickness: 0,75mm -1,00 mm, 
  • guaranteed service life of min. 30 years, 
  • very good properties in terms of expansion and contraction in the range of up to 300% elongation, 
  • delivered to the construction site in the form of a ready-to-install bag, adapted to the dimensions of the tank, assembled on site, 
  • 14 days for replacement in case of 

PVC film

  • thickness: min. 1,5 mm, 
  • guaranteed service life of min. 35 years, 
  • high resistance to mechanical damage, 
  • vulcanized on construction site,
  • 24 hours for replacement in case of leakage.

The membrane is protected against puncture by a geotextile with a minimum density of 150 g / m2, laid directly on the tank basis

The insulation of potable water storage tanks is made of an external 100 mm thick mineral wool. The wool is covered with a trapezoidal facade sheet, painted with any color from the RAL palette. The steel pipes placed inside a tank for storing drinking water are made of AISI 304 steel. All elements of a tank that come into direct contact with drinking water are provided with the PZH hygiene certificate.

Aboveground steel fire tanks are equipped with automation and control systems. One of them is a system that monitors 4 water levels. This system consists of internal conductance probes suspended at appropriate levels of the tank. The signals generated by the probes are led to the relay implemented in the switch cabinet.

On the roof of the tank, there is a Pt100 sensor suspended 1 m from the roof level, which continuously measures temperature. The sensor transmits an analog signal about temperature inside the tank to the controller implemented in the switch box.

Water level monitoring system monitors water level in a tank in 4 preconfigured modes:

  • Minimum level - level of the minimum tank filling, which signals starting of emptying a tank to the lower dead zone. The probe informing about this mode is placed 50 mm above the edge of the suction pipe anti-vortex plate. An alarm triggered by a probe indicating the minimum level, prevents the pumps from dry running (running without water).
  • Intermediate level - level of half (50%) filling of the tank. It is useful to be signaled during service and repair works on the tank. The intermediate level may indicate a different water level.
  • Maximum level - the level of the maximum permissible filling of a potable water storage protection tank. Lowering the maximum level is a signal that the water system is out of order. If the water level drops below the maximum level, the automation system will turn off the heaters.
  • Overflow level - the level of the highest, alarm filling of a tank. If a potable water storage tank reaches such a level of the water surface, it means that the float valve fails. If the overflow level is reached, the water from the tank may overflow.

All levels of water level monitoring system are signaled with red lamps in the tank operation controller located in the switch box.

The water tank controller is usually installed on the wall, outside of the tank. It enables constant monitoring of the tank's efficiency. If any irregularities are detected, an alarm is triggered to inform about the occurrence of faults or failures. The device complies with the IP 65 standard.

The heating system turns on automatically when the water temperature in the tank drops below 5oC and turned off when it reaches the temperature of 6oC. If water in the tank reaches temperature of 3oC, the heating control system will signal the failure with a red "low temperature" indicator. The heaters turn off automatically when the water level in a tank drops below the maximum level. This is to protect the internal insulation layer of a tank.

Steel aboveground potable water storage tanks are equipped with the necessary design equipment. The equipment is properly installed according to the standards requirements.
The standard equipment of ground potable water storage tanks consists of: 

  • supply pipeline terminated with the so-called free outlet, 1-2 automatic float valves responsible for automatic filling of the tank (not required by law), 
  • suction pipeline with double anti-vortex plate,
  • overflow pipe, 
  • drainage pipeline with a manual shut-off damper. 

Each pipeline may be led through the foundation or tank wall, according to the requirements. 
Potable water storage tanks are additionally equipped with: 

  • electrical switchboard, water level probes and heaters, 
  • bottom service hatches (if required),
  • in accordance with the current health and safety regulations, steel cage ladders leading to the roof, platforms with protective barriers, service hatches on the roof.

Designing

Before delivering the fire tank to the site and its installation, we make a detailed design of both the tank and the foundation slab. Along with the detailed design, we provide the necessary documentation, which includes, among others a design of a tank construction.

Delivery

After designing a fire protection tank we deliver it with the necessary equipment and unload the tank at the construction site or in the customer's warehouse. Usually, the day of delivery is a day of assembly start-up.

Assembly

Our team of 3-4 people assemble the tank by means of external hydraulic pistons. The steel structure with internal insulation, membrane and equipment is sequentially installed. The tank is fixed to the foundation plate with anchors. The foundation plate is also the bottom of the fire tank.

Leak test

After the assembly is completed a tightness test is performed. It consists of filling the tank with water to a height of approx. 1.5 m. At this stage the tightness of the pipelines flanged connections are checked. In the second tightness test, a tank is filled in to its nominal capacity. The second leak test lasts 24 hours and allows us to verify the tightness of a tank accurately.

Electrical devices commissioning

When a tank is already finished an electrical devices are stared-up. Our experts verify the correct operation of electrical devices and installations along with the automation systems necessary for the correct operation of a fire tank.

Warranty

The whole works are completed with the delivery of as-built documentation with the materials approvals and a warranty card.

Thanks to the developed tank assembly system, we are able to significantly reduce the need for heavy equipment and we can install the tank in the shortest possible time.

1. Step - site preparation

In the first step, we prepare the area for pouring a concrete foundation slab on which the tank will be installed. During this stage of works, we pour the slab and deliver all the necessary building and construction materials to the construction site to erect the tank.

2. Step - tank assembly

In the next step of works, qualified employees of SD Tank Sp. z o.o. start assembling the tank on a dry and ready-to-install foundation plate. Our tanks are installed using external hydraulic pistons. The steel structure of a tank is assembled in stages along with the simultaneous installation of the internal insulation, membrane and the tank equipment.

3. Step - finishing works

In the third step of a fire tank assembly, an external piping of a tank with its optional additional equipment is installed. After this assembly step, we proceed to leak tests, start-up of electrical devices and issue as-built documentation.

We provide a 5-year warranty for a tank construction and a 24-month warranty for mechanical and electrical devices. In order to maintain a warranty, it is necessary to perform at least one technical inspection with cleaning the membranes in the third year of operation of a tank from the date of its first filling with water.

You can extend the standard warranty period up to 15 years on the basis of a Full Service Contract.