This standard outlines the specifications for rectangular pressed mild steel tanks intended for storing liquids up to 100°C, excluding those subjected to earth or external pressures aside from wind. It details tank classifications, materials, dimensions, fabrication, welding, coatings, and testing, serving as a comprehensive guide for manufacturing and installation. The code is indispensable for professionals designing, fabricating, and erecting pressed steel liquid storage tanks.
Overview
This standard outlines the specifications for rectangular pressed mild steel tanks intended for storing liquids up to 100°C, excluding those subjected to earth or external pressures aside from wind. It details tank classifications, materials, dimensions, fabrication, welding, coatings, and testing, serving as a comprehensive guide for manufacturing and installation. The code is indispensable for professionals designing, fabricating, and erecting pressed steel liquid storage tanks.
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Frequently Asked
The standard applies to sectional rectangular tanks constructed from pressed mild steel sheets with a uniform thickness of approximately 3.15 mm. It includes modular tanks that are assembled from standardized pressed panels, primarily intended for water and similar liquid storage. These tanks are designed for ease in assembly, transport, dismantling, and reinstallation.
Steel plates used must comply with IS 226-1962 for mild steel quality, while the pressed sheets should meet IS 1079-1963 grade St 34. Plates are to be uniformly heated and formed either by furnace heating or cold pressing with V-die flanges, ensuring no cracks. Bolt hole spacing must not exceed 80 mm, with bolt diameters typically 12 mm for smaller tanks and 14 mm or greater for larger tanks. Minimum plate thickness varies with liquid type and is generally 6 mm for hot liquids with specific gravity up to 1.0.
Plate thickness requirements depend on the tank's depth and the stored liquid's characteristics. For cold liquids with specific gravity up to 1.0, bottom and side plates range from 3.15 mm (for shallow cubic tanks) to 8 mm (for deeper tanks). For hot liquids with similar specific gravity, all plates must be at least 6 mm thick. When storing liquids with specific gravity greater than 1.0, the thickness is agreed upon between the purchaser and manufacturer to ensure adequate strength.
The prescribed welding process is metal arc welding (SMAW) following IS 816-1956 standards, utilizing electrodes compliant with IS 814-1957. Preparation includes cleaning plates to remove rust and paint, smooth edges, and proper contact of pads before welding. All welds must be performed in the down-hand position, adhering to size specifications from the standard’s figures. Welds should be uniform, free from cracks, blowholes, undercuts, and must be fully fused to parent metal to ensure structural integrity and leak-tightness.
Yes, the tanks are designed to store liquids with temperatures up to 100°C. The jointing materials used must be chemically insoluble in the stored liquid and capable of withstanding its temperature variations. Tanks are not meant to endure earth or external pressures other than wind. Suitable tank types are selected based on installation conditions, with certain types intended for installation on level floors and others for different flange arrangements.
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