scope:

NEN-EN-ISO 28765 establishes the requirements for the design and use of vitreous-enamelcoated bolted cylindrical steel tanks for the storage or treatment of water or municipal or industrial effluents and sludges. It applies to the design of the tank and any associated roof and gives guidance on the requirements for the design of the foundation. It applies where a) the tank is cylindrical and is mounted on a load-bearing base substantially at or above ground level; b) the product of the tank diameter in metres and the wall height in metres lies within the range 5 to 500; c) the tank diameter does not exceed 100 m and the total wall height does not exceed 50 m; d) the stored material has the characteristics of a liquid, exerting a negligible frictional force on the tank wall; the stored material may be undergoing treatment as part of a municipal or industrial effluent treatment process; e) the internal pressure in the headspace above the liquid does not exceed 50 kPa and the internal partial vacuum above the liquid does not exceed 10 kPa; f) the walls of the tank are vertical; g) the floor of the tank is substantially flat at its intersection with the wall; the floor of the tank may have a rise or fall built in to allow complete emptying of the tank contents, the slope of which does not exceed 1:100; h) there is negligible inertial and impact load due to tank filling; i) the minimum thickness of the tank shell is 1,5 mm; j) the material used for the manufacture of the steel sheets is carbon steel (tanks constructed of sheets made from aluminium or stainless steel are outside the scope of this International Standard); k) the temperature of the tank wall during operation is within the range -50 °C to +100 °C under all operating conditions. This International Standard also gives details of procedures to be followed during installation on site and for inspection and maintenance of the installed tank. It does not apply to chemical-reaction vessels. It does not cover resistance to fire.