KKL tanks are designed for the storage of liquids with a variety of purposes in industry, agriculture, and wastewater treatment plants. In addition to the storage of liquids, they can be used for storing maize, cement, sawdust, and other materials.
KKL tanks are bolted elevated steel tanks comprising individual standard elements. Initially, we submit a draft design to our customers based on our customer’s specific requirements regarding the storage volume of the tank and the material to be stored, and other required specifications. Tanks are constructed with a final surface protection of shell steel sheet resistant to the material to be stored.
Shell Steel Sheets
Tanks are manufactured from steel sheets of S350GD Z 450 quality in accordance with EN 10326. The individual thickness of sheets and the type of perforation are designed in accordance with the valid standards of EN 1993-4-2, and the regulations and standards of the EC 1990, EC 1991and EC 1993 series.
Surface Protection of Shell Sheets
The surface protection is selected for the material to be stored to guarantee high resistance.
External Reinforcement of Shell
Tank sheets are flanged with an external reinforcement, or shaped segments curved according to the tank diameter at the top and bottom. Based on a statics test, tank sheets are further reinforced with additional reinforcement rings. External elements are constructed from S235 and S355 steel and finished with a surface protection according to the material to be stored.
For connecting of sheets, special bolts of a quality of at least 8.8 and a hot-dip galvanizing surface protection are used. The head of the bolt is located inside the tank and is covered with a layer of plastic. The mechanical properties of the bolt are tested by an accredited testing laboratory. For other parts of the tank, galvanised screw joints of a minimum quality of 8.8 are used.
During the manufacturing of our tanks, all of the joints ensuring the tightness of sheets and the connections of necks and entrances are sealed with a high quality, permanently flexible certified sealant which is produced by DOW MAIZEING and SIKA. The sealant application process is determined by the erection assembly regulations of the tank supplier.
Tanks are anchored to foundation concrete with anchoring angle beams and M16 chemical anchors.
Tanks may also be anchored with a starter ring which is supplied and established by the supplier of the tank before casting the bottom with waterproof concrete to a prepared framework.
KKL tank roofs are usually constructed as self-supporting structures, or as a structure with poles, and have a gradient of at least 2% from the centre of the tank to the edge. The steel load-bearing roof structure is designed with respect to the expected snow load of the location the structure will be installed at, in accordance with the regulations. Roofing material consists of profiled steel sheets shaped to fit the tank. All construction elements of the roof are surface protected by hot-dip galvanising and the roofing material has an Aluzinc coating.
Tanks can be fitted with a self-supporting membrane roof with a gradient towards the tank’s centre, where drainage is fitted to collect rainwater from the roof’s surface. This roof type is made of bolted steel sheets which are sealed in a similar fashion as for the tank shell.
Tanks can be fitted with a conical roof with an 18° gradient. A major section of this roof is self-supporting. It is reinforced with beams around its diameter. The surface of the roof sheets is treated identically as for the shell sheets. The sheets are assembled in the same way as the shell sheets. If required, the roof can be fitted with a railing or a central platform with stairs.
In most cases, the tank bottoms consist of a waterproof concrete foundation. The casting of the tank bottom is not included in the contract with the tank manufacturer.
The bottom may alternatively be fitted with a PVC foil sealed to the bottom row of steel sheets. Foils are selected according to their resistance to the material to be stored. They can be installed on the entire surface of the tank shell. Another alternative for the tank bottom is a steel bottom. Steel bottoms have the same surface protection as the shell, including bolt joints.
The erection of all KKL tanks is carried out in accordance with supplier submitted design documents and erection documents provided to the assembly group responsible for the observance of KKL tank erection technological procedures, instructions in the erection documents, with special attention to the general instructions of occupational health and safety and taking into consideration the local construction requirements provided by the customer.
Inspection and Maintenance
All inspections of tanks are stipulated by relevant customer operational regulations in accordance with general requirements.
Construction of KKL Tank Foundations
The construction of tank foundations is not carried out by Kohimex, spol. s r. o. The tank supplier will provide initial source documents for the preparation of final building documents by a specialised engineer.