Document Y9pMD04dMY1qDrnZg4XBJmB2N

compartment is recommended, and perma nent high-level markings should be installed Tank construction Tanks should be constructed and installed as recommended by the National Fire Pro tection Association in its latest Flammable ir Combustible Liquids Code, Standard No 30 Vents Storage tanks should be provided with vents of a type and size recommended by the National Fire Protection Association in its Flammable ir Combustible Liquids Code Vent pipes of underground tanks storing Class 1 flammable liquids should terminate outside buildings, higher than the fill pipe opening, and not less than 12 ft above the adjacent ground level They should not be located so that flammable vapors will enter FlC 34-14 --Track designed for transporting safety cans and other flammable liquid containers to points of use in the plant Figures courtesy Western Electric Co FlC 34-13 -- A well designed flammable liquid storage room with both high and low level ventila tion and automatic fire extinguishment Ventila tors are designed for 12 air changes per hour building openings or be trapped under eaves or other obstructions Vent pipes from under ground tanks storing Class II or Class III liquids should terminate outside buildings and higher than the fill pipe opening Vent oudets should be above normal snow level Some authorities have questioned the ef fectiveness of mesh brass or copper screens as flame arresters in vent terminals Un derwriters' Laboratories state (Oil Tank Vents --Hazards of Screens, Card Data M60, Senal No UL-31) that "under some favorable conditions, screens of fine mesh may be effec tive in arresting flame, but their use in general is not dependable Under service conditions, they are subject to clogging and freezing, when attempts are made to clean them there is danger of mechanical injury The displace ment of one or more wires renders the screen useless as a flame arrester " Dependence should be placed on safe lo cation of a vent so that escaping vapors will be properly dispersed and clear of ordinary 1027