The structure of OTC series cooling tower is designed to withstand wind load of 30 psf. Trapeziodal cooling towers consists of modular bolted subassemblies cross-braced with tension rods.Casing of galvanized steel sheets give full protection against corrosion, corrugated asbestos cement board casing is applied with vertical corrugations is another alternate for trapeziodal cooling towers. Corrugated casing joints are lapped. Heavy gauge galvanized steel sheets are used to fabricate basins. Tower basins are completed with make up water float control valve as well as over flow,drain and Suction fitting. Preservative-treated Russian or Finn timber are used. Design assures permanent fill alignment and configuration. Gravity water distribution system for uniform distribution of hot water over the entire fill area is considered, using flange and collector. Low speed, multi-blade pressed galvanized steel or aluminum induced-draft propeller fans are standard equipment on some OMRAN TAHVIEH cross flow cooling towers. Fans are designed to grantte adequate air flow between suction and discharge ports for the provision of maximum heat transfer and tower performance requirements .