STRUCTURAL DESIGN
Tanks manufactured by "MOSTOSTALEX" are designed to store potable water. Structural solutions implemented in the tank, designed by our research and design specialists, comply with the requirements of such standards as: Polish standard PN-90/B-03200 Steel Constructions - Static Calculations and Design; German standard DIN-18800 Stahlbauten - Stabilitäsfälle, Schalenbeulen and American standard ANSI/AWWA-D103 Factory-Coated Bolted Steel Tanks For Water Storage. The cylindrical shell of the tank is made of hot-galvanized sheet metal, made of S350 steel and screwed with class 8.8 screws M12. The supporting structure of the roof in the shape of a truncated cone consists of longitudinal channel-section members, gathered in a steel central ring. The longitudinal members are transversally braced to prevent their buckling. The roof plating is made of flat, hot-galvanized sheet metal, screwed to the bottom side of the structure. The roof is designed to be inclined at the angle of 15 deg.
» The tank structure is dimensioned for two calculation scenarios, namely: the tank filled with water and the empty tank under the impact of a wind load.
SEALING
The tank is sealed with water-proof polyurethane putty of Sikafleax type. All screwed connections and steel metal sheet connections of the shell and the roof plating are finished with a bevel made of the sealing mass. The hermetic roof prevents rain water from penetrating the tank inside.
The Sikaflex-type sealing masses are characterized by high resistance to aging and high adhesion to such substrates as steel and epoxy coatings. The masses do not react with water, neither do they have impact on the smell and taste of water.
The Sikaflex sealing mass has been approved by PZH for applications requiring its contact with potable water.
ANTICORROSION MEASURES
All elements of the tank structure are made of hot-galvanized steel.
Steel sheet metal of the walls and roof plating are coated with epoxy paint by the producer and they are PZH-certified for applications requiring contact with potable water. The minimum coating thickness: 160mm.
THERMAL INSULATION
WALL INSULATION. The thermal insulation of tank walls is made of 10cm thick panels of mineral wool. The mineral wool shield is externally protected with coated 0.70mm thick trapezoidal sheet metal of T18 profile.
ROOF INSULATION. The thermal insulation of the roof is designed to be made of 10 cm thick mineral wool, laid between the channel sections of the roof supporting structure. The wool is covered with 12mm thick, water-proof OSB boards of class 3 (according to PN-EN300) and with 0.70mm thick, flat sheet metal.
BASE PLATE
MOSTOSTALEX may prepare a design of the tank foundation, once it obtains the technological assumptions for the structure and the results of geotechnical survey of the area, where the tank is to be located.
It is recommended to design the tank foundation as a flat RC slab. The bottom inclination toward the foundation chamber is formed by covering the RC slab - after tank assembly - with a screed of C16/20 concrete, with the inclination of the order of 1:100 (see chapter "Zbiorniki na materiały płynne" [Tanks for liquid materials] in Kobiak and W. Stachurski's monograph entitled Konstrukcje żelbetowe [RC structures]). Tank anchoring details are presented in the design guidelines.
TANK CAPACITY
The required capacity can be obtained in several tank models. The wide range of dimension types allows one to select the most appropriate tank for the required capacity.
FITTINGS
The technological pipelines, which the tank is designed to be equipped with, are to be made of galvanized steel or, on the client's request, of stainless steel.
The assembly of the tank pipelines is to be realized according to the technological assumptions.
When determining the ordinates of the flanged penetrations through tank walls should avoid colliding with the rows of screws used to connect sheet metal plates of the shell. Please, contact the manufacturer to determine the appropriate height of the pipe axis.
The delivery of the tank and its piping also covers certified cut-off fittings for the drainage downspout.
The tank is equipped with an external steel ladder. A platform with a barrier and a inspection hatchway are mounted on the roof. A lateral inspection hatchway is installed in the tank shell.
A vent is installed in the roof. The vent is designed to compensate for pressure changes inside the tank during its exploitation.
COLOURING SCHEME
The tank surface - i.e. the trapezoidal sheet metal of the walls and the flat sheet metal of the roof - is painted in RAL colour.
The remaining tank elements, such as the ladder with the platform and the technological stub pipes, are left unpainted.
SCOPE OF WORKS
DESIGN. The tank manufacturer shall prepare a working design of the tank before its delivery and the commencement of assembly works. The design is prepared in the locally-spoken language.
DELIVERY. The delivery covers all tank elements and its fittings, including the unloading of the components at the site or in the client's warehouse.
ASSEMBLY. The tank is assembled on the substructure by means of hydraulic servo-motors.
PUTTY HARDENING. The tank assembly is followed by the putty hardening stage. The hardening rate is ~2mm per day.
LEAK-TIGHTNESS TEST. The tank is filled with water until the rated capacity is reached. According to the relevant standard, the leak-tightness test for tanks with unimbibing walls is to last for 24 hours.
INSULATION. Once the leak-tightness test yields a positive result, the tank walls are covered with mineral-wool insulation, shielded with trapezoidal sheet metal.
CERTIFICATION. Immediately after the leak-tightness test and the completion of electrical works, the manufacturer shall prepare the "as-built" documentation with the indispensable certificates and deliver them to the site. The documentation is prepared in the locally-spoken language.
GUARANTEE
The manufacturer grants a 5 years' guarantee for the tank.
