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The minimum required safety clearance for aboveground flammable liquid storage tanks in reference to any building or lot line shall be regulated as follows:
Wherever unstable liquid is used in this section it shall mean a liquid which in pure state or as commercially produced or transported will vigorously polymerize, decompose, condense or will become self- reactive under conditions of shock, pressure or temperature.
(a) Every aboveground tank for the storage of flammable or combustible liquids, except unstable liquids, operating at pressures not in excess of 2.5 p.s.i.g. shall be located in accordance with Table 15-24-260(a).(See Table 15-24-260(a).)
(b) Every aboveground tank for the storage of flammable liquids, except unstable flammable liquids, operating at pressures exceeding 2.5 p.s.i.g. shall be located in accordance with Table 15-24-260(b). (See Table 15-24-260(b).)
(c) Every aboveground tank for the storage of unstable liquids shall be located in accordance with Table 15-24-260(c). (See Table 15-24-260(c).)
Capacity Tank Gallons | Minimum Distance in Feet From Lot Line |
Capacity Tank Gallons | Minimum Distance in Feet From Lot Line |
275 or less | 5 |
276 to 750 | 10 |
751 to 12,000 | 15 |
12,001 to 30,000 | 20 |
30,001 to 50,000 | 30 |
50,001 to 60,000 | 50 |
Over 60,000 gallons | – |
The minimum distance for safety clearance shall be increased one foot for each additional 3,000 gallons increase in the capacity of tanks; provided, however, that the safety clearance need not exceed 250 feet. The aforesaid maximum safety clearance of 250 feet may be reduced to 175 feet where every tank is equipped with an approved floating raft or an approved permanently attached extinguishing system. No underground tank or dike shall be located nearer than 50 feet to the river, lake or other waterway. Truck loading docks and platforms shall be located not less than 25 feet from the storage tanks, plant buildings and property lines.
The safety clearance between tanks shall be regulated according to capacity as follows:
Capacity of the Larger of the Two Tanks (Gallons) | Minimum Clearance Between Tanks (Feet) |
Capacity of the Larger of the Two Tanks (Gallons) | Minimum Clearance Between Tanks (Feet) |
300 or less | 3 |
500 | 3 |
1,000 | 3 |
8,000 | 3 |
12,000 | 3 |
18,000 | 3 |
24,000 | 3 |
30,000 | 3 |
48,000 | 10 |
75,000 | 10 |
100,000 | 13 |
150,000 | 15 |
200,000 | 15 |
Over 200,000 | Distance equal to the diameter or the greatest horizontal dimension of the larger tank. |
A tolerance of ten percent in capacity shall be allowed in all tanks. The minimum required safety clearance for flammable liquid storage tanks aboveground, required by this section may be reduced to the minimum safety clearance between tanks, as provided above, whenever such tank is individually diked and protected by fire walls of four-hour fire-resistive construction, extending not less than three feet above and beyond each tank, and provided with a fender or return wall for each such fire wall of the same height and thickness at each end and extending not less than three feet on each side of such fire wall.
Nothing in this section shall be interpreted or construed to apply to any group of oil storage tanks, every part of which group has an open space of not less than 1,000 feet, continuous on all sides of the group of tanks or between such group of tanks and any building or property dividing line, or the opposite side of each adjoining and adjacent public way or public park or any main line of a steam, electric, elevated railway or any other railway right-of-way; provided, that the provisions of this paragraph shall apply only to oil storage tanks storing liquids above the ground, and which liquids have a flashpoint above 150 degrees Fahrenheit. This paragraph shall not apply to any liquids stored under the ground.
Table 15-24-260(a)
Type of Tank | Protection | Minimum Distance in Feet from Lot Line |
Floating Roof | None | Diameter of tank but need not exceed 175 ft. |
Vertical with weak roof to shell seam. | Approved foam or inerting system on the tank. | 1/2 times diameter of tank and shall not be less than 5 ft. |
None | 2 times diameter of tank but need not exceed 350 feet. | |
Horizontal and vertical, with emergency relief venting to limit pressures to 2.5 p.s.i.g. | Approved inerting system on the tank or approved system on vertical tanks. | 1/2 times Table 15-24-260(A) but shall not be less than 5 ft. |
None | 2 times Table 15-24-260(A) |
Type of Tank | Minimum Distance in Feet from Lot Line |
Any type | 3 times Table 15-24-260(A) but shall not be less than 50 ft. |
Type of Tank | Protection | Minimum Distance in Feet from Lot Line |
Horizontal and vertical tanks with emergency relief venting to permit pressure not in excess of 2.5 p.s.i.g. | Tank protected with any one of the following: Approved water spray, approved inerting, approved insulation and refrigeration, approved barricade. | See Table 15-24-260(A), but the distance may not be less than 25 ft. |
None | 5 times Table 15-24-260(A), but not less than 100 ft. |
(Prior code § 129.1-20)