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(A) (1) Location of an aboveground tank for storage of flammable liquids with respect to distance from the nearest line of adjoining property which may be built upon, which shall be such that the distance between any part of the tank and the line shall be not less than that set forth in the following table:
Minimum distance of outside aboveground tanks for flammable liquids other than crude petroleum to line of adjoining property which may be built upon.
Capacity of Tank (in gallons) | Class of Flammable Liquid | Minimum Distance (in feet) |
0 to 275
|
III-B
|
0
|
276 to 750
|
III-B
|
5
|
0 to 750
|
I, II and III-A
|
10
|
751 to 12,000
|
III-B
|
10
|
751 to 12,000
|
I, II and III-A
|
15
|
12,001 to 24,000
|
I, II, III-A and III-B
|
15
|
24,001 to 30,000
|
I, II, III-A and III-B
|
20
|
30,001 to 50,000
|
I, II, III-A and III-B
|
25
|
(2) Tanks with capacities in excess of 50,000 gallons and all tanks for the storage of crude petroleum shall be located in accordance with the following provisions (applicable to gas-tight tanks including conservation type tanks constricted in compliance with these or equivalent standards):
Product Stored | Tank Protection | Distance From Line of Adjoining Property Which May Be Built Upon Shall Be Not Less Than |
(1) An approved permanently attached extinguishing system or | Greatest dimension of diameter or height of tank, except that such distance need not exceed 120 feet | |
Refined petroleum products or other flammable liquids not subject to boilover | (2) An approved floating roof not equipped with either of the above | One and one-half times the greatest dimension of diameter or height of tank except that such distance need not exceed 175 feet |
(1) An approved permanently attached extinguishing system or | Two times the greatest dimension of diameter or height of tank except that such distance shall not be less than 20 feet and need not exceed 175 feet | |
Crude petroleum* | (2) An approved floating roof not equipped with either of the above | Three times the greatest dimension of diameter or height of tank except that such distance shall not be less than 20 feet and need not exceed 350 feet |
* Or other non-petroleum product, handled in special process and chemical plants, which have boilover characteristics somewhat like those of crude petroleum. | ||
(B) Location of any aboveground tank for the storage of flammable liquids on the premises of any Division VI, commercial and industrial establishment, or any Division VII, processing plant, with respect to the distance to the nearest building or line of adjoining property which may be built upon, shall be such that the distance between any part of the tank and such building or property line is not less than that set forth in the following table:
Minimum distance between any outside aboveground tank for flammable liquids on the premises of any Division VI or VII occupancy to the nearest building of line of adjoining property which may be built upon.
Diameter of Tank Minimum Distance to
(in feet) Building (in feet)
Under 15 15
15 to 30 tank diameter
30 to 60 30
Over 60 ½ tank diameter
(C) In particular installations these provisions may be altered at the discretion of the Building and Safety Inspector after consideration of the special features such as topographical conditions; nature of occupancy and proximity to buildings on adjoining property and height and character of construction of such buildings; capacity and construction of proposed tanks and character of liquids to be stored; degree of private fire protection to be provided, and facilities of the Fire Department to cope with flammable liquid fires.
(D) Where two tank locations of diverse ownership have a common boundary, the Building and Safety Inspector may, with the written consent of the owners of the two properties substitute the distances provided in § 120.053 for the minimum distances set forth in the tables under this section.
('81 Code, § 5.40.130) Penalty, see Ch. 13
(A) The location of a tank for the storage of any flammable liquid with respect to any such other tank shall be such that the distance between them shall be not less than three feet.
(B) For banks above 50,000 gallons individual capacity storing any flammable liquid, except crude petroleum in producing areas, the distance shall be not less than one-half the diameter of the smaller tank.
(C) In producing areas, for tanks storing crude petroleum and having capacities not exceeding 126,000 gallons (3,000 bbls.), the distance between tanks shall not be less than three feet; in excess of 126,000 gallons (3,000 bbls.), the distance shall be not less than the diameter of the smaller tank.
(D) The minimum separation between an LP gas container and a flammable liquid tank shall be 20 feet. Suitable means shall be taken to prevent the accumulation of flammable liquids under adjacent LP gas containers such as by diking, diversion curbs and grading. When flammable liquid tanks are diked, the LP gas containers shall be outside the diked area and at least 10 feet away from the centerline of the dike. The provisions set forth in this section shall not apply when LP gas containers of 125 gallons or less capacity are installed adjacent to Class III-B flammable liquid tanks of 275 gallons or less capacity.
('81 Code, § 5.40.140) Penalty, see Ch. 13
(A) Tanks shall rest directly on the ground or on foundations or supports of concrete, masonry, piling, or steel.
(B) Exposed piling or steel supports shall be protected by fire-resistive materials to provide a fire resistance rating of not less than two hours.
('81 Code, § 5.40.150) Penalty, see Ch. 13
Stairs, platforms and walkways hereafter installed, elevated more than three feet above the surrounding ground level, shall be of noncombustible construction.
('81 Code, § 5.40.160) Penalty, see Ch. 13
(A) Required. Tanks or groups of tanks shall be protected from the effects of flammable liquid spills originating at or encroaching upon the tank setting.
(B) Methods. Diversion walls or drains safely directing the flow to catchment basins, impounding basins formed by dikes around tanks or groups of tanks, or combinations thereof shall be used.
(C) Capacity. The net capacity of a catchment basin, diked impounding basin, or any combination thereof shall be equal to the capacity of the largest tank, plus six inches of freeboard. In computing the required capacity of a catchment basin, diked impounding basin or combination thereof:
(1) The volume of the largest tank up to the height of the dike shall be considered as part of the available capacity of a diked impounding basin.
(2) No part of the volume of tanks other than the largest tank shall be considered as part of the available capacity.
(3) The capacity of a separate catchment basin may be used to reduce the required capacity of a diked impounding basin provided drainage sufficient to prevent overflow of the dike and effective control of flow are provided.
(4) The capacity of a single separate catchment basin may be applied to reduce the required capacity of each of the diked impounding basins draining to it.
(D) Dike construction, drainage and division. Where dependence is placed in whole or in part on diking for compliance with this subchapter, dikes shall be constructed, drained, and divided as follows:
(1) Construction. Dikes shall be of earth, concrete or solid masonry designed to be liquid-tight to withstand a full hydraulic head, and shall be maintained at full design capacity. Where piping passes through dikes, provision shall be made for movement without damage to the dikes and to minimize leaks under emergency conditions. Earthen dikes shall be built and maintained at a minimum height of two feet. The distance between the inside toe of any dike and the shell of any tank not over 30 feet in diameter shall be not less than five feet, and for tanks over 30 feet in diameter shall be not less than 10 feet.
(2) Spill dikes. Where tanks within a common diked impounding basin may cause mutual exposure from spills, spill dikes shall be provided between tanks of 10,000 barrels or greater individual capacity. Groups of tanks of less than 10,000 barrels individual capacity and not in excess of 15,000 barrels aggregate capacity may be enclosed within a single spill dike. The height of such spill dikes shall not exceed 50% of the height of the main or perimeter dikes.
(3) Drainage. Drainage shall be provided at a consistent slope of not less than one percent away from tanks and fittings toward a sump, drain box or other safe means of disposal located within the diked impounding area and at the greatest possible distance from the shell of the tank. Traps with not less than six inches of liquid seal shall be provided between the sumps, drain boxes or drain openings within the diked area and the sewers or drains intended for disposal of spills. A valve, operable from outside the dike, shall be provided in the dike drain system and shall normally be kept closed.
(4) Disposal. Approved provision shall be made for disposing of water and oil retained by diked impounding basins or catchment basins.
(E) Deviations. In particular installations, deviations from the provisions of this section may be granted by the Building and Safety Inspector, after consideration of special features such as:
(1) Topographical conditions, nature of occupancy and proximity to buildings on the same or adjacent property;
(2) Capacity and construction of proposed tanks and character of liquids to be stored and nature and quantity of private and public fire protection provided.
('81 Code, § 5.40.170) Penalty, see Ch. 13
(A) Materials. Tanks shall be built of steel or concrete unless character of liquid stored requires other materials. Steel commonly known as “mill seconds” shall not be used. Tanks built of materials other than steel shall be designated to specifications embodying safety factors equivalent to those specified in this section for steel tanks. Concrete tanks shall be built in accordance with sound engineering practice. Unlined concrete tanks shall only be used for storage of liquids having a gravity of 40° A.P.I. or heavier. Concrete tanks with special linings may be used for other services provided the design is approved by the Bureau of Fire Prevention. Steel tanks shall be built in accordance with the requirements of divisions (B) through (E) of this section. All shop-built tanks shall be tested at a pressure of not less than five and not more than 10 pounds per square inch (measured at the top of the tank) for a period of at least 10 minutes without leakage or permanent deformation.
(B) Field erected vertical tanks. Vertical tanks erected in the field shall be built in accordance with the following specifications:
(1) A.P.I. Standard No. 12A, September, 1951, Specification for Oil Storage Tanks with Riveted Shells;
(2) A.P.I. Standard No. 12C, September, 1955, Specification for Welded Oil Storage Tanks;
(3) A.P.I. Standard No. 12B, September, 1955, Specification for Bolted Production Tanks;
(4) A.P.I. Standard No. 12D, August, 1955, Specification for Large Welded Production Tanks;
(5) A.P.I. Standard No. 12F, August, 1955, Specification for Small Welded Production Tanks.
(C) Small, shop-built vertical tanks. Vertical tanks not over 1,100 gallons capacity shall meet the following requirements.
Capacity Minimum Thickness of Steel
(in gallons) U.S. Standard
1 to 60 18 gauge
61 to 350 16 gauge
351 to 560 14 gauge
561 to 1,100 12 gauge
(D) Large, shop-built vertical tanks. Vertical tanks over 1,100 gallons capacity shall meet the following requirements:
(1) For tanks up to 25 feet in height the shell shall be not less than three-sixteenths of an inch thick. For tanks from 25 to 30 feet high the bottom ring shall be not less than one-quarter of an inch thick and the remainder of the shell not less than three-sixteenths of an inch thick. For tanks between 30 and 35 feet high, the first two rings shall be not less than one-quarter of an inch thick and the remainder of the shell not less than three-sixteenths of an inch thick. All one-quarter of an inch thick rings shall be not less than five feet wide.
(2) The tops of tanks shall be either dished or cone-shaped and of not less than No. 10 U.S. standard gauge steel.
(3) Tanks shall be welded, or riveted and caulked, or otherwise made tight in a workmanlike manner. The roof of the tank shall be securely fastened to the top ring of the shell with a joint having the same tightness as the joints between rings. The joint between roof and shell shall be weaker than any other joints in the shell of the tank. Joints in the roof shall be welded or riveted or made tight by other process satisfactory to the Chief of the Bureau of Fire Prevention. Roofs of tanks shall have no unprotected openings.
(E) Shop-built horizontal tanks. Horizontal tanks shall be constructed in accordance with accepted engineering practice and shall meet the following minimum requirements: joints shall be riveted and caulked, riveted and welded, or welded. Tanks heads over six feet in diameter shall be dished, stayed, braced, or reinforced.
(1) Small, shop-built horizontal tanks. Horizontal tanks not over 1,100 gallons capacity shall meet the following requirements:
Capacity Minimum Thickness of Steel
(in gallons) U.S. Standard
1 to 60 18 gauge
61 to 275 14 gauge
276 to 550 12 gauge
551 to 1100 10 gauge
(2) Large, shop-built horizontal tanks. Horizontal tanks over 1,100 gallons capacity having a diameter of not over six feet, made of steel, shall be three-sixteenths of an inch or greater nominal thickness. Tanks having a diameter of over six feet and not more than 12 feet, made of steel, shall be one quarter of an inch or greater nominal thickness.
('81 Code, § 5.40.180) Penalty, see Ch. 13
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