Potable water tanks

• Download file with size table
• The diameter of the tanks ranges from 3.1 m to 21.7 m
• Tank height from 2.4 m to 13.2 m
• It is possible to build a tank with a higher height

• PN-EN 1990:2004/AC:2010 „Eurokod. Basics of structural design.”

• PN-EN 1991-1-1:2004/AC:2009 „Eurokod 1. Actions on structures. Part 1-1. General impacts. Volumetric weight, self weight, payload in buildings.”

• PN-EN 1991-1-3:2005/AC:2009  „Eurokod 1. Actions on structures. Part 1-3. General impacts. Snow load.”

• PN-EN 1991-1-4:2005 „Eurokod 1. Impact on structures. Part 1-4: General actions. Wind actions”.

• PN-EN 1993-1-1:2006/AC:2009  „Eurokod 3. Steel structure design. Part 1-1. General rules and rules for buildings.”

• PN-EN 1993-1-3:2008/AC:2009 „Eurokod 3. Steel structure design. Part 1-2: General rules. Supplementary rules for structures made of cold-formed sections and sheets.”

• PN-EN 1993-4-2:2009 „Eurokod 3. Steel structure design. Part 4-2: Tanks.”

• PN-EN 1993-1-6:2009 „Eurokod 3. Steel structure design. Part 1-6: Strength and stability of coating structures.”

• PN-EN 1090-2+A1:2012 „Execution of steel and aluminum structures. Part 2: Technical requirements for steel structures.”

• PN-EN ISO 13788:2013-05 „Thermal and humidity properties of building components and building elements. The internal surface temperature necessary to avoid critical surface humidity and interlayer condensation. Calculation methods.”

• PN-EN 12831:2006 „Heating installations in buildings. Method for calculating the design heat load.”

• PN-EN ISO 12944-2:2018-02 „Paints and varnishes. Corrosion protection of steel structures with protective paint systems. Part 2: Classification of environments.”

• PN-EN ISO 12944-5:2020-03 „Paints and varnishes. Corrosion protection of steel structures with protective paint systems. Part 5: Protective painting systems.”

• PN-EN ISO 14713:2000 „Corrosion protection of steel and cast iron structures. Zinc and aluminum coatings. Guidelines.”

Foundation slab
The MILTOM system tanks intended for storing drinking water are placed on a reinforced concrete foundation slab. Reinforced concrete foundation slab is designed individually for a specific location, based on soil and water conditions received from the Investor. It is made of hydrotechnical concrete min. class B25 (C20 / 25) W8 F100, frostproof and waterproof. Top and bottom reinforcement of the tank bottom plate made of A-IIIN BSt500 steel. Cover of the reinforcement from the bottom and sides 5 cm, from the top 7cm. The bottom slab is made on a B10 concrete foundation with a minimum thickness of 10 cm. The diameter of the foundation slab is made in the form of a circle or polygon with a diameter of about 0.9 m larger than the internal diameter of the tank.

Only the weight of water accumulated in the tank can be taken for calculating the strength of the foundation. The weight of construction and piping is up to 2% (for tanks up to 300 m3) up to 5% of the weight of water. Therefore, it can be omitted by using other safety factors resulting e.g. from the possibility of tank overfilling. The decision on the calculated weight of the tank and the size of the safety factors is up to the designer.

Applied technologies
Our drinking water tanks are made in two technologies. With internal membrane made of EPDM or with sealing of metal sheets for Sabatack 750 or 780 mass.

The tank is sealed with an EPDM membrane

with PZH certificate, it is placed on a properly prepared and maintained foundation slab. The membrane is a polymer geosynthetic barrier, made of vulcanized EPDM. Calendered in two layers, without reinforcement. This gives it unique properties especially when it comes to flexibility and elasticity (300% stretch). The membrane is separated from the tank foundation with a polypropylene geotextile with a grammage of 300g / m2, which protects it from mechanical damage during assembly and operation.

Sealed tank constructions for Sabatack mass

are placed in a previously prepared technological groove 45 mm wide and 50 mm deep located at the height of the perimeter of the tank shell structure. In order to permanently and tightly connect the tank walls with the bottom plate, the tank groove is filled with SABA self-filling mortar. After the resin has hardened, the groove is additionally secured with a permanently elastic Ecoseal Bio HM material, which is approved for contact with drinking water. The bottom of the tank is additionally protected with Aquafin-1K M-PLUS mortar.

Tanks with sealing and protection of all connections of tank shell elements with Sabatack 750, 780 mass are painted from the inside with Faproxyd 620 powder paint in signal blue (RAL5005) from WODROL.

Tank walls
In both technologies, the tank walls are made of galvanized steel grade S350GD + Z275 or acid-resistant AISI 304 (1.4304) or AISI 316L (1.4401) with sheet dimensions of 1.25 mx 2.5 m. The thickness of the jacket depends on the size of the tank and the required standards . Individual sheets are overlapped vertically and horizontally using M12 screws, class 8.8. The tank walls are reinforced horizontally with rings made of sheet metal 2.0 – 4.0 mm thick. The tank is attached to a concrete foundation using galvanized L70x50x5 angle brackets made of S235 steel, brackets and expansion anchors.

Additional options
At the customer’s request, it is possible to powder paint the surface of the sheets or cover the installation jacket with trapezoidal sheet in the selected RAL color from the available “Pruszyński” color palette.

Painting the tank shell or the facade made of trapezoidal sheet is an additional layer of protection against the external environment, significantly extending the correct operation of the tank and its trouble-free operation, as well as provides an additional visual and aesthetic effect.

Tank roof

Depending on the investor’s needs, we cover drinking water tanks with a dome made of polyester-glass composite or a conical roof. All our roofs are self-supporting structures, which causes no contact of water with structural elements, significantly affecting their life expectancy.

The use of roof covering in the form of “KS” dome (self-supporting dome).

This cover consists of spherical elements (i.e. the shell of the element is a fragment of the sphere) with lateral flat flanges lying on the spherical surface of the sphincter, sphincter cover and drip cap (without a gutter) around the entire perimeter of the tank. The spherical elements are joined together with a lap screw connection. Each lap screw connection of the cover elements’ flanges is sealed with two rows of 10×15 [mm] EPDM gaskets. The distance between the axis of the torsion screws and anchors fixing the cover elements to the steel structure of the tank is not greater than 330 [mm]. A drip made of polyester-glass laminate is located between the flange of the extreme element and the steel structure. Between the drip and the wall of the tank and between the drip and the cover elements there are two rows of EPDM gaskets with a cross section of 10×15 [mm]. Spherical elements made of polyester-glass laminate insulated with 60 [mm] thick PU foam – the foam is not placed at screw joints.

Conical tank roof construction (truncated cone)

is articulated on the tank walls. The roof pitch is approximately 15º. Roof bearing beams made of cold-bent galvanized profiles Pruszyński steel sheets 2xC150x48x2.0 made of S350GD steel are arranged radially evenly. Roof support beams fastened in the roof crown with a round duct with a diameter of d = 856 mm and a calculation equivalent I-section Hśr x Bpg x Bpd = 172x344x158 welded from steel plates with a thickness of 8 mm made of S235 steel. Connection of support beams with M12-class 8 screw jumper. 100 mm thick Styrodur-3000CS insulation was laid between the support beams. The roof is covered with flat sheet, 1.0 to 3.0 mm thick. All roof connections in the tank are secured from the inside with Sabatack mass. The shape of the roof structure ensures free drainage of rain and snow from the roof surface to each side of the tank.

Regardless of the shape and type, each roof of the drinking water tank is equipped with:

• Supply ventilation chimneys (air intake) enabling free air flow to the space under the roof covering (protection of the roof covering against negative pressure caused by the variable level of liquid in the tank); a gravitational inflow of air is assumed.
• Pipe connectors permanently laminated into the cover coating to ensure the connection of a ventilation system for collecting contaminated air from the space under the roof. The ventilation designer determines the number, size and location of the connectors. The proposed solutions must be consulted with the roofing manufacturer.
• Manhole dimensions of 800 x 800 [mm] The hatch is equipped with hinges and swing limiters for an opening angle of up to 95 °. The fittings are made of A4 steel. The location of the manhole, sockets and ventilation chimneys is agreed at the stage of detailed arrangements for the technical implementation of the cover.
• A filter protecting the penetration of insects, rodents, birds, dust made of stainless steel mesh with a mesh density of 0.5mm is placed in the ventilation fireplace, which also prevents the entry of atmospheric pollution.
• Each of the tanks is equipped with external thermal insulation made of ProRox SL 960 PL mineral wool, 10 cm thick, additionally protected with T18 x 0.7 “Pruszyński” trapezoidal sheet painted in any color from the RAL color palette. This location of the insulation ensures long-term preservation of thermal properties and no degradation of the material under the influence of moisture.
• The equipment of tanks also includes: supply (pressure) pipeline, suction pipeline, overflow pipeline and drain pipeline, made of acid-resistant steel or polyethylene with a diameter adapted to the requirements of the Employer.
  All the materials we use ensure that the investor is provided with the highest quality product that meets the stringent requirements of the norms and required standards.

The full modularity of the structure allows for quick assembly, as well as the possibility of any modifications to increase the required tank capacity if necessary. Our tanks are equipped with all necessary connections and devices required for efficient cooperation in Water Treatment Stations or plumbing installations. High quality workmanship allows you to get a long-term warranty, ensuring long-term trouble-free use of the tank.