A. All tanks shall be constructed in accordance with the American Petroleum Institute's Standard Nos. 12-A, 12-B, 12-C, 12-D, as amended.
1. The provisions of this Section shall not apply to drums constructed in accordance with the regulations of the Interstate Commerce Commission.
2. The venting provisions shall not apply to any container of 110 gallons capacity or less; providing, however, that whenever it is essential for fire safety, vents shall be maintained on containers which are permanently installed.
3. No unroofed tanks shall be used.
B. Adequate flame arresters or palate-type vacuum and pressure relief valves shall be provided in all vents on tanks containing liquids which will flash at a temperature of 100° F or less
1. The free area of such flame arresters shall in no case be less than the area of the vent to which flame arrester is attached.
2. All such flame arresters or vents shall be maintained as to be readily accessible for inspection.