TANK STORAGE (15-24-170 et seq.)

Municipal Code of Chicago tit. 15, ch. 15-24, art. II

in effect

Municipal Code of Chicago § 15-24-170 Aboveground tanks.

15-24-170 Aboveground tanks. Aboveground tanks for flammable liquids shall be constructed throughout of open hearth steel or of wrought iron of a thickness in accordance with the following requirements: Less than 1,100 gallons capacity Capacity (gallons) | Minimum Thickness of Material (U.S. standard gauge) 1 to 60, inclusive | 18 61 to 350, inclusive | 16 351 to 560, inclusive | 14 561 to 1,100, inclusive | 12 Any tank built in accordance with the Underwriters' Laboratories Standard 142 shall be acceptable. No open tank shall be used. Nothing in this chapter shall be construed as prohibiting the use of concrete tanks for the storage of liquids heavier than 35 degrees Baume gauge. All concrete tanks shall be constructed in accordance with the requirements of Chapter 14B-19. Horizontal Tanks Containing Over 1,100 Gallons. Tanks having a diameter of six feet or less shall be made of not less than three-sixteenths inch steel. Tanks having a diameter of more than six feet and not exceeding 11 feet, six inches shall be made of not less than one-fourth inch steel. Vertical Tanks Containing Over 1,100 Gallons. Vertical tanks having more than 1,100 gallons capacity shall be so constructed of such material and so arranged as to have a factor of safety of not less than two and five-tenths. The minimum thickness of the shell or bottom shall be not less than three-sixteenths inch. The minimum thickness of roofs shall be not less than one-eighth inch. The tensile strength of the steel plate and the shearing strength of rivets and bolts shall be in accordance with the requirements of Chapter 14B-22. Tanks shall be riveted, welded or brazed and shall be caulked and made tight in a workmanlike manner. The top of tanks shall be securely fastened to top ring with joints having the same tightness as the joints between the rings. All iron or steel tanks shall be thoroughly coated on the outside with a heavy protective paint. Roofs or tops of tanks shall have no unprotected openings and shall be firmly and permanently joined to the tank, and all joints shall be riveted and caulked, brazed or welded. Pressure Tanks. Pressure tanks shall be riveted, welded or brazed and shall be fastened, caulked or otherwise made tight so as to sustain safely a hydrostatic test at a pressure not less than double the pressure at which the tank is to be used. The top of the tank shall be securely fastened to the top ring with joints of equal tightness to the bottom rings. Tanks shall be covered with heavy protective paint. All pipe connections shall be made through flanges or metal reinforcement securely riveted, welded or bolted to the tank and made thoroughly tight. Pressure tanks, including top, sides and bottom, shall be constructed entirely of metal. All openings in such tanks shall be gas-tight except the breather vent. Emergency vents shall be actuated on pressure tanks before the pressure exceeds 1.25 times the working pressure. The size of these vents shall be the same size as the relief valve. Foundations and Grounding. All tanks shall be electrically grounded by resting directly upon moist earth or shall be electrically grounded to permanent moisture. No insulated connections shall be permitted. All steel work for reinforced concrete tanks shall be interconnected and grounded as herein provided for tanks. Tanks more than one foot above the ground shall have foundations and supports of noncombustible material. No combustible material shall be permitted under or within ten feet of any aboveground storage tank; provided, however, that nothing in this chapter shall be construed as prohibiting wooden cushions under tanks. Unprotected steel is prohibited as a means of supporting tanks when such tanks are located 50 feet or less from loading or unloading points, buildings or storage of combustible substances or materials. Over 50 feet, unprotected steel saddles are allowed if less than 12 inches high at the lowest point. Dikes. Every aboveground storage tank containing flammable liquids shall be diked. Every group of tanks containing flammable liquids of Classes II and III may have a total capacity of, but shall not exceed 60,000 barrels within a single dike, and a barrel shall mean a volume of 42 U.S. gallons. Every tank containing flammable liquids of Class I shall be individually diked. Each dike shall have a capacity of not less than one and one-fourth times the combined capacity of the tank or tanks it surrounds. Earth dikes shall be firmly and compactly built of good earth or clay, from which stones, vegetable matter or other foreign material have been removed, and shall have a flat section at top not less than three feet wide and a slope at one to one (45 degrees) on both sides. Earth dikes shall be not less than four feet high on the inside and in no case higher than one-fourth the height of the tank when said tanks exceed 16 feet. Embankments or dikes shall be continuous with no openings for pipe or roadway. Underground piping shall be laid well below the foundation of embankments. The provision of this section shall not apply to fuel oil tanks installed in connection with heating equipment where the aggregate capacity of the tanks does not exceed 550 gallons. Electrical equipment within diked areas shall be of explosion-proof types. Provided, however, that diking of tanks within the area of Lake Calumet, bounded on the north by Slip No. 2, on the east by Stony Island Avenue, extended on the south by the Entrance Basin, and on the west by the Anchorage Basin of Lake Calumet, which area shall be authorized only as a planned development in accordance with the provisions of the Chicago Zoning Ordinance, may comply either with the foregoing provisions of this paragraph or with N.F.P.A. Flammable and Combustible Liquids Code 30 (1993), when such diked area is protected by an approved fire protection system. Capacity Limits. The capacity of any aboveground tank containing flammable liquids of Class I shall not exceed 15,000 gallons. The total capacity of tanks in any storage yard for the storage of Classes I and II flammable liquids shall not exceed 750,000 gallons, and the total capacity of tanks in any storage yard used exclusively for the storage of Class III flammable liquids shall not exceed 1,500,000 gallons; except that 1) in the area of Lake Calumet, bounded on the North by Slip No. 2, on the east by Stony Island Avenue, extended on the south by the Entrance Basin, and on the west by the Anchorage Basin of Lake Calumet, which area shall be authorized only as a planned development in accordance with the provisions of the Chicago Zoning Ordinance, tanks of 2,300,000 gallons or less capacity, containing flammable liquids of Classes I and II or tanks of 4,200,000 gallons or less capacity containing flammable liquids of Class III with no limitations on storage yard capacity, shall be permitted; 2) at Chicago O'Hare International Airport tanks of 3,000,000 gallons or less capacity, containing flammable liquids of Class II with no limitations on storage yard capacity, shall be permitted (crude oil or any other flammable liquids subject to boilover characteristics, and refining of any flammable liquid are prohibited in this area); and 3) at Chicago Midway Airport, aboveground storage tanks containing a total storage capacity of not greater than 2,000,000 gallons of Class II flammable liquids per storage yard shall be permitted (crude oil or any other flammable liquids subject to boilover characteristics, and refining of any flammable liquid, are prohibited in this area). (Prior code § 129.1-14; Amend Coun. J. 7-13-94, p. 53151; 2-7-96, p. 15463; Amend Coun. J. 6-27-01, p. 62535, § 1; Amend Coun. J. 10-7-20, p. 21791, Art. VI, § 26)

Municipal Code of Chicago § 15-24-180 Vents.

15-24-180 Vents. Vents for Underground Flammable Liquid Storage Tanks. (a) Every underground storage tank containing flammable liquids at atmospheric pressure and having a capacity of more than 100 gallons, shall have a galvanized vent opening so located that the discharge point is outside of any building higher than the fill pipe. Vent pipes from tanks storing Class I, II flammable liquids, and for Class III flammable liquids in tanks containing heaters or hot wells shall be so located that the discharge point is outside of the building, higher than the fill pipe opening, and not less than 12 feet above the adjacent ground level. Vent pipes shall terminate in a weatherproof hood. Vent pipes two inches or less in nominal inside diameter shall not be obstructed by devices that will cause a back pressure exceeding working pressure of the tank, and outlets shall be three feet measured horizontally or vertically from any window or door opening or any other building opening and shall not be trapped under eaves or other obstructions. If the vent pipe is less than ten feet in length or greater than two inches in nominal inside diameter, the outlet shall be provided with an Underwriters' Laboratories, Inc. listed vacuum and pressure-relief device, or there shall be an approved flame arrester located in the vent line at the outlet. In no case shall the flame arrester be located more than 15 feet from the outlet end of the vent line, except any underground gasoline tank installed after the passage of this ordinance shall be piped and equipped for vapor recovery. The vent terminal shall be a minimum of 12 feet or higher above the adjacent ground level and in no case less than three feet higher than the transport truck or tank that will supply such tank. The size of the vent shall be in accordance with paragraph (d) of this section. The outlet shall be provided with an Underwriters' Laboratories, Inc. listed vacuum and pressure-relief device. In no case shall the static head, including the relief device pressure-imposed on the tank, be greater than the working pressure of the tank. The fill pipe shall be of the tight seal type and piped below the suction pipe or pump inlet. No manifolding of vents, syphons, equalizers or other connection to any other tank shall be permitted. Overflow protection shall be provided by piping an extension into the tank to enable the contents of the delivery hose and the vapor recovery hose to flow right back into the storage tank. A dry break adapter and lock-type cap shall be provided with every tank and the recovery hose shall be full sized to the tank truck. No gauging opening shall be permitted, and the fill pipe may be utilized as a gauging opening and shall be kept locked when said tank is not being filled or gauged. (b) When wire screen is used as a flame arrester, it shall be of noncorrosive wire screen not less than 30 mesh per inch. The screens on such openings shall be at the outer end of vent pipe and so arranged that it can be removed for cleaning purposes. (c) Where a pump is used with a tight seal fill, the vent shall not terminate on or above any roof. (d) Vent openings and vent pipes for underground Class I, II and III flammable liquid tanks shall be of ample size to prevent pressure in the tank during filling but not smaller than the pipe size as specified below: Capacity of Tank U.S.Gallons | Diameter of Vent, Iron Pipe Size (inches) 500 or less | 1-1/4 501 to 3,000 | 1-1/2 3,001 to 10,000 | 2 10,001 to 20,000 | 2-1/2 20,001 to 35,000 | 3 35,001 to 50,000 | 4 Tanks over 50,000 gallons shall have, in addition to the four-inch vent required for the first 50,000 gallons, an additional vent or vents installed as required by the capacity in the above table. (Prior code § 129.1-15)

Municipal Code of Chicago § 15-24-190 Enclosed tank vents.

15-24-190 Enclosed tank vents. (a) Vent pipes for enclosed storage tanks for fuel oil in connection with oil-burning equipment, and diesel oil in connection with emergency diesel-driven equipment shall be located so that the discharge point is outside of the building, and terminate in a weatherproof hood higher than the fill pipe opening. When such tanks contain heaters or hot wells, the opening of the vent pipe shall not be less than 12 feet above the adjacent ground level. Flame arresters shall be required for two and one-half inch and three inch vent pipes. Where a pump is used with a tight seal fill, the vent shall not terminate on or above any roof. (b) Vent openings and vent pipes shall be of ample size to prevent pressure in the tank during filling but not smaller than the pipe size as specified below: Capacity of Tank U.S.Gallons | Diameter of Vent, Iron Pipe Size (inches) 500 or less | 1-1/4 501 to 3,000 | 1-1/2 3,001 to 10,000 | 2 10,001 to 20,000 | 2-1/2 20,001 to 25,000 | 3 Vents for Aboveground Flammable Liquid Tanks. Every aboveground flammable liquid tank shall have a vent opening for emergency and normal venting capacity not less than specified in Table 15-24-190(b). A. Normal venting capacity requirements shall be obtained without exceeding the operating pressure or vacuum which may be applied regularly to a tank without causing physical damage or permanent deformation to the tank. Inbreathing (vacuum relief) venting capacity requirement for maximum movement out of a tank shall be equivalent to 560 cubic feet of free air per hour for each 4,200 gallons per hour of maximum emptying rate, including gravity flow rate to other tanks, for flammable liquids of any flashpoint. Venting capacity requirement for thermal inbreathing for a given tank capacity for flammable liquids of any flashpoint shall be as shown in Column 2 of Table 15-24-190(a) of this section. Outbreathing (pressure relief) venting capacity requirement for maximum flammable liquids movement into a tank and resulting evaporation: (a) Class II and III flammable liquids shall be equivalent to 600 cubic feet of free air per hour for each 4,200 gallons per hour of maximum filling rate. (b) Class I flammable liquids shall be equivalent to 1,200 cubic feet of free air per hour for each 4,200 gallons per hour of maximum filling rate. Venting capacity requirement for thermal outbreathing, including thermal evaporation, for a given tank capacity: (a) Class II and III flammable liquids shall be as shown in Column 3 of Table 15-24-190(a) and in no case shall be less than one and one-fourth inch nominal inside diameter. (b) Class I flammable liquids shall be as shown in Column 4 of Table 15-24-190(a) and in no case shall be less than one and one-half inch nominal inside diameter. (See Table 15-24-190(a).) B. Emergency Venting Capacity Requirements. Every aboveground storage tank shall have some form of construction or device that will relieve excessive internal pressure caused by exposure fires, as follows: In a vertical tank the construction referred to above may take the form of a floating raft, lifter roof, or a weak roof-to-shell seam. The weak roof-to-shell seam (maximum three-sixteenths-inch single fillet weld) shall be constructed to fail preferential to any other seam. Where entire dependence for emergency relief is placed upon pressure-relieving devices, the total venting capacity of both normal and emergency vents shall not be enough to prevent rupture of the shell or bottom of the tank if vertical, or of the shell or heads if horizontal. The total capacity of both normal and emergency venting devices shall not be less than that derived from Table 15-24-190(b). Such device may be a self-closing manhole cover, or one using long bolts that may permit the cover to lift under internal pressure, or a self-closing gauge hatch, or an additional or large relief valve or pressure vacuum valve or valves, or an open vent. The wetted area of the tank shall be calculated on the basis of 55 percent of the total exposed area of a sphere or spheroid, 75 percent of the total exposed area of a horizontal tank and the first 30 feet above grade of the exposed shell area of a vertical tank. Table 15-24-190(a) THERMAL VENTING CAPACITY REQUIREMENTS (Expressed in Cubic Feet of Free Air Per Hour – 14.7 Pounds Per Square Inch Absolute at 60° F) Tank Capacity* | Inbreathing (Vacuum) All Stocks | Outbreathing (Pressure) (Barrels) | | (Gallons) | Flashpoint 100° For Above | Flashpoint Below100°F Tank Capacity* | Inbreathing (Vacuum) All Stocks | Outbreathing (Pressure) (Barrels) | | (Gallons) | Flashpoint 100° For Above | Flashpoint Below100°F | 1 | | 2 | 3 | 4 60 | | 2,500 | 60 | 40 | 60 100 | | 4,200 | 100 | 60 | 100 500 | | 21,000 | 500 | 300 | 500 1,000 | | 42,000 | 1,000 | 600 | 1,000 2,000 | | 84,000 | 2,000 | 1,200 | 2,000 3,000 | | 126,000 | 3,000 | 1,800 | 3,000 4,000 | | 168,000 | 4,000 | 2,400 | 4,000 5,000 | | 210,000 | 5,000 | 3,000 | 5,000 10,000 | | 420,000 | 10,000 | 6,000 | 10,000 15,000 | | 630,000 | 15,000 | 9,000 | 15,000 20,000 | | 840,000 | 20,000 | 12,000 | 20,000 25,000 | | 1,050,000 | 24,000 | 15,000 | 24,000 30,000 | | 28,000 | 17,000 | 28,000 | 35,000 | | 31,000 | 19,000 | 31,000 | 40,000 | | 34,000 | 21,000 | 34,000 | 45,000 | | 37,000 | 23,000 | 37,000 | 50,000 | | 40,000 | 24,000 | 40,000 | 60,000 | | 44,000 | 27,000 | 44,000 | 70,000 | | 48,000 | 29,000 | 48,000 | 80,000 | | 52,000 | 31,000 | 52,000 | 90,000 | | 56,000 | 34,000 | 56,000 | 100,000 | | 60,000 | 36,000 | 60,000 | 120,000 | | 68,000 | 41,000 | 68,000 | 140,000 | | 75,000 | 45,000 | 75,000 | 160,000 | | 82,000 | 50,000 | 82,000 | 180,000 | | 90,000 | 54,000 | 90,000 | * Interpolate for intermediate sizes. Table 15-24-190(b) VENTING CAPACITY Wetted Area Versus Cubic Feet Free Air Per Hour (14.7 psi and 60° F) Wetted Surface, Square Feet (a) | Venting Capacity Cubic Feet Per Hour | Minimum Opening, Iron Pipe Size, Inches (b) Wetted Surface, Square Feet (a) | Venting Capacity Cubic Feet Per Hour | Minimum Opening, Iron Pipe Size, Inches (b) 20 | 21,000 | 2 30 | 31,600 | 2 40 | 42,100 | 3 50 | 52,700 | 3 60 | 63,200 | 3 70 | 73,700 | 4 80 | 84,200 | 4 90 | 94,800 | 4 100 | 105,000 | 4 120 | 126,000 | 6 140 | 147,000 | 6 160 | 168,000 | 6 180 | 190,000 | 6 200 | 211,000 | 6 250 | 239,000 | 6 300 | 265,000 | 6 350 | 288,000 | 8 400 | 312,000 | 8 500 | 354,000 | 8 600 | 392,000 | 8 700 | 428,000 | 8 800 | 462,000 | 8 900 | 493,000 | 8 1,000 | 524,000 | 10 1,200 | 557,000 | 10 1,400 | 587,000 | 10 1,600 | 614,000 | 10 1,800 | 639,000 | 10 2,000 | 662,000 | 10 2,400 | 704,000 | 10 2,800 and over | 742,000 | 10 (a) Interpolate for intermediate values. (b) These pipe sizes apply only to open vent pipes of the indicated diameter not more than 12 inches long and a pressure in tank of not more than 2.5 pounds per square inch. If tank is to be equipped with venting device or flame arrester, the vent opening must accommodate the venting device or flame arrester sized in accordance with Column 2 of Table 15-24-190(b). (Prior code § 129.1-16)

Municipal Code of Chicago § 15-24-200 Gravity feed.

15-24-200 Gravity feed. Gravity Feed Prohibited. No tanks, drums or other containers holding flammable liquids within a building or discharging within a building, shall be provided with any faucet or other bottom-drawing device. Pipes shall not terminate at any point lower than the level of the source of supply. Nothing in this chapter shall be construed as prohibiting the storage or gravity flow or both storage and gravity flow of flammable liquids when such liquids are used in connection with oil-burning equipment installed in accordance with Title 14M, or in refineries, or in manufacturing and jobbing plants and in stores, plants, and establishments; provided, however, that tanks holding Class I flammable liquids shall be in a room constructed and arranged as provided by Section 15-24-410 for a special room for flammable liquids. Fuel oil gravity feed tanks shall not exceed 550 gallons capacity. No gravity supply to a fuel oil-burning appliance shall exceed three psi. Any oil-fired appliance manufactured with a self-contained supply tank shall not be piped to any other source of supply. (Prior code § 129.1-17; Amend Coun. J. 10-7-20, p. 21791, Art. VI, § 27)

Municipal Code of Chicago § 15-24-210 Gauging and vending devices.

15-24-210 Gauging and vending devices. All flammable liquids, except motor fuels, shall be dispensed through gauging or vending devices which shall be of substantial construction and firmly secured to concrete or masonry foundations, which shall be so located and designed as to prevent motor vehicles damaging such systems, except as permitted under Section 15-24-360. Systems wherein continuous pressure is maintained on the flammable liquid storage tank in connection with gauging or vending devices shall not be permitted unless the hazard of the material is such that no other method of dispensing through gauging or vending devices is possible. The use of aboveground flammable liquid storage tanks, or tank cars or tank trucks, in connection with flammable liquid vending or gauging devices, shall not be permitted except as provided in Section 15-24-221. Tank trucks or tank cars shall not be used to store flammable liquids while the liquid is being used. (Prior code § 129.1-18; Amend Coun. J. 2-16-89, p. 24942; 5-2-95, p. 73)

Municipal Code of Chicago § 15-24-220 Motor fuel dispensing.

15-24-220 Motor fuel dispensing. All flammable liquid gauging, vending and dispensing devices used for motor vehicle fuel shall be of substantial construction, and firmly secured to a concrete foundation, which shall be so located and designed as to prevent motor vehicles from damaging such devices. Systems wherein continuous pressure is maintained, or water is used to displace liquid from storage tanks, shall not be permitted. The use of aboveground storage tanks, tank cars, tank trucks or portable tanks in connection with gauging, vending and dispensing devices, shall not be permitted except for such equipment installed on tank vehicles complying with Section 15-24-1080 and tanks complying with Section 15-24-221 of this Code. Every remote fuel system shall be equipped with a fuel leak detector valve or device located as close as possible to or within the pumping unit. An impact valve shall be provided at the base of each dispenser. Such devices and valves shall be listed by a testing laboratory which has as its primary purpose the testing and evaluation of equipment and materials to meet appropriate standards. Automatic hose nozzle valves with latch-open devices shall not be permitted unless equipped with an automatic shut-off device to stop the flow of liquid when the valve is released from a fill opening or upon impact with pavement. All dispensing devices shall be located so that all parts of the vehicles being served will be on private property. In no case shall the dispensing hose be longer than 16 feet for filling stations and private locations. Where dispensing equipment is used exclusively for trucks or other large vehicles, automatic hose retrievers may be used, and shall not exceed 40 feet of hose. Dispensing devices for motor vehicle fuel, except devices used exclusively for dispensing Class II or Class III flammable liquids within occupancy Group S-2 parking garages, shall not be permitted in buildings hereafter erected, altered or converted. The dispensing of motor fuels which are Class I flammable liquids directly from tank vehicles shall be permitted only from tank vehicles complying with Section 15-24-1080 and tanks complying with Section 15-24-221 of this Code. Retail sales of motor fuel to motor vehicles from tank vehicles shall not be permitted. The filling of fuel tanks from tank vehicles shall not be permitted within buildings. (Prior code § 129.1-18.1; Amend Coun. J. 2-16-89, p. 24942; Amend Coun. J. 10-31-90, p. 22573; Amend Coun. J. 5-2-95, p. 73; Amend Coun. J. 3-19-97, p. 41391; Amend Coun. J. 10-7-20, p. 21791, Art. VI, § 28)

Municipal Code of Chicago § 15-24-221 Aboveground tanks.

15-24-221 Aboveground tanks. The use of aboveground storage tanks, tank cars, tank trucks, or portable tanks in connection with vending, gauging, or dispensing of flammable liquids, other than for equipment installed on tank vehicles complying with Section 15-24-1080, shall be permitted only under the following limited circumstances: (A) The construction and installation of the tanks must satisfy each of the following conditions and restrictions: (1) Tanks shall be enclosed within a two- hour fire-rated assembly. (2) The tank assembly shall provide 100 percent secondary containment of the flammable liquid. Dikes as required in Section 15-24-170 need not be provided. (3) Tanks shall be limited to a capacity of 1,000 gallons. (4) No more than two such aboveground tanks shall be installed or located at any one site. (5) The tank shall be completely surrounded by a protective guardrail which is located a minimum of two feet away from the tank. (6) Dispensing of the flammable liquid shall be by means of a pump which is permanently attached to the top of the enclosing assembly described in subsection (A)(1) above and which is equipped with an anti-syphon valve. (7) Such tanks shall be located a minimum of ten feet away from any building or property line, except that tanks containing Class II or Class III liquids, as defined in Section 15-24-020, may be located within three feet of a fire-resistive wall without openings. (8) Each tank shall bear the words, "Flammable – Keep Fire Away", conspicuously on each side of the tank. The coloring of the letters shall be a color which contrasts with the color of the tank and the letters each must be a minimum of four inches high. (9) A lockable fill cap shall be provided. (10) Tanks shall be electrically grounded. (11) Emergency vents conforming with Section 15-24-190 B shall be provided for both the primary tank and the secondary containment space. (B) Aboveground tanks used pursuant to this section shall not be used for any retail sales. (Added Coun. J. 5-2-95, p. 73)

Municipal Code of Chicago § 15-24-230 Gasoline pumping prohibited.

15-24-230 Gasoline pumping prohibited. Pumping of gasoline from a tank truck into an underground tank shall be prohibited. (Prior code § 129.1-18.2; Amend Coun. J. 2-16-89, p. 24942)

Municipal Code of Chicago § 15-24-240 Warning signs.

15-24-240 Warning signs. Warning signs prohibiting smoking and instructing customers to turn off ignition systems during filling operations shall be posted in a conspicuous location at each island. Such signs shall be metal or other material designed to withstand weather. Such signs shall have a white background with the words "No Smoking" and "Turn Off Engine" in red letters, a minimum of four inches high with a minimum of a one-half-inch stroke. Signs with directions for operation of the dispensing devices shall also be provided. (Prior code § 129.1-18.3; Added Coun. J. 2-16-89, p. 24942)

Municipal Code of Chicago § 15-24-250 Definition of safety clearance.

15-24-250 Definition of safety clearance. Whenever in the following sections the words "safety clearance" are used, said words shall be construed to require a space open its entire area to the sky, and which shall be continuous on all sides of the building or structure; between such building and any other building, or property dividing lot line, or the lot line adjoining or adjacent to a public park, or any main line of street, electric, elevated railway or any other railway right-of-way. (Prior code § 129.1-19)

Municipal Code of Chicago § 15-24-260 Safety clearances.

15-24-260 Safety clearances. 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).) (d) Reference Table 15-24-260(A) for Tables 15-24-260(a), 15-24-260(b) and 15-24-260(c). Table 15-24-260(A) 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) Table 15-24-260(b) 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. Table 15-24-260(c) 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)

Municipal Code of Chicago § 15-24-270 Tanks in buildings.

15-24-270 Tanks in buildings. Tanks for flammable liquids inside of buildings, other than structures used exclusively for the purposes of Group H occupancies for the handling and storage of flammable liquids, shall be constructed as follows: 120 Gallons or Less. Tanks for Class II and III liquids having a capacity of 120 gallons or less shall be of steel or tin plate, soldered and tight. Material shall be of not less than No. 20 U.S. standard gauge; provided, however, that where tanks contain more than six gallons of liquid used in connection with and in the same room with oil-burning equipment, the provisions of the third paragraph shall apply. Nothing in the building provisions of this Code shall be construed as prohibiting the use of original barrels or drums as a source of supply, if such barrels or drums are substantially placed to prevent tipping or rolling. Pumps shall be inserted through a close-fitting connection in the side of the head of the container. These tanks shall be located in rooms constructed in accordance with Section 15-24-410 of this Code. Over 120 Gallons. Tanks for Class II and III liquids having a capacity of more than 120 gallons shall be of the thickness required by Section 15-24-280 or shall be constructed of concrete. These tanks shall be located in rooms constructed in accordance with Section 15-24-410 of this Code. Location and Foundation. Tanks shall be located below the level of any piping to which they are connected, or else shall be equipped with standard antisiphoning devices, and shall be set on a substantial foundation. Tanks exceeding 2,500 gallons capacity shall be supported independently of the floor construction. Storage Tanks for Fuel Oil in Connection with Oil-burning Equipment and Diesel Oil in Connection with Emergency Diesel-driven Equipment. Steel tanks containing more than 285 gallons and installed in connection with oil-burning equipment and diesel oil shall be constructed in accordance with the first paragraph of Section 15-24-280. Fuel oil tanks located inside of buildings shall be located in the basement or lowest story thereof and shall not exceed 550 gallons individual or aggregate capacity if unenclosed. Fuel oil storage tanks having an aggregate capacity of more than 550 gallons shall be enclosed within walls of not less than four-hour fire-resistive construction extending at least one foot above the highest level of the tanks. The ceiling or enclosure above such tanks shall be of not less than four-hour fire-resistive construction, unless such tanks are surrounded with sand or earth within the enclosure and up to not less than one foot above the highest level of the tanks. In lieu of such enclosure, the tanks may be imbedded solidly in reinforced concrete not less than six inches thick at any point. Concrete fuel oil tanks shall have an enclosure as required by this paragraph for steel tanks. Walls of concrete tanks shall be constructed independently of and not in contact with the building walls or enclosing walls. In buildings of Type III or IV construction the gross capacity of fuel oil and diesel oil storage tanks shall not exceed 5,000 gallons. In buildings of Type IB, IIA or IIB construction, the gross capacity of fuel oil and diesel oil storage tanks shall not exceed 10,000 gallons. In any room of a building of Type IA construction the gross capacity of fuel oil and diesel oil may have a capacity of 50,000 gallons, with an individual tank capacity not exceeding 25,000 gallons, provided tank or tanks shall have a separation of four-hour fire-resistive construction from any part of the building. The walls may be extended to and bonded to the underside of the construction above in lieu of a separate top. 15 inches clearance shall be left around the tank for the purpose of inspection. Such tank enclosure shall be capable of withstanding the hydrostatic pressure of the contents of the tank or tanks and shall be provided with a liquid-tight noncombustible sill raised not less than six inches above the floor. An opening which is closed by a self-closing 3-hour-rated fire door shall be provided above the liquid level. Provision shall be made for adequate ventilation of such enclosures prior to entering for inspection. Not more than one integral tank shall be installed on each piece of diesel-driven equipment. It shall be securely mounted on the engine assembly, protected against vibration, physical damage, engine heat and the heat of exhaust piping. A return line shall be provided to return surplus oil from the engine tank to supply tank. A day tank shall not exceed 550 gallons capacity and shall be at a lower level than the engine tank. Doorways of rooms containing tanks, either installed as an integral part of the engine assembly, or day tanks, shall have a noncombustible liquid-tight sill raised not less than six inches above the floor. (Prior code § 129.1-21; Amend Coun. J. 6-28-00, p. 36679, § 8; Amend Coun. J. 11-8-12, p. 38872, § 235; Amend Coun. J. 10-7-20, p. 21791, Art. VI, § 29)

Municipal Code of Chicago § 15-24-280 Underground and enclosed tanks.

15-24-280 Underground and enclosed tanks. Construction Materials. Underground and enclosed tanks for flammable liquids shall be constructed of galvanized steel, or open hearth steel, or of wrought iron of thickness and weight not less than provided in the following table: Capacity (Gallons) | Minimum Thickness of Materials U.S. Standard Gauge | Pounds Per Sq.Ft. Capacity (Gallons) | Minimum Thickness of Materials U.S. Standard Gauge | Pounds Per Sq.Ft. 1 to 285 | 16 | 2.5 286 to 560 | 14 | 3.125 561 to 1,100 | 12 | 4.375 1,101 to 4,000 | 7 | 7.5 4,001 to 12,000 | 1/4 in. | 10 12,001 to 20,000 | 5/16 in. | 12.5 Any tank built in accordance with Underwriters' Laboratories Standard 172 shall be acceptable. All material used in underground and enclosed storage tanks, for which material is lighter than No. 7 U. S. Standard gauge shall be galvanized. If internal bracing is provided, tanks for the storing of Class III liquids, having a capacity of from 12,001 to 30,000 gallons, shall be built of steel plate not less than one-fourth-inch thick. All joints of tanks shall be riveted and caulked, brazed or welded. Underwriters' Laboratories, Inc. labeled or any other nationally recognized testing laboratories approved glass-fiber reinforced plastic tanks may be used for underground storage of flammable liquids. Tanks shall be tight and sufficiently strong to bear without injury the most severe strains to which tanks are subjected. Shells of tanks shall be properly reinforced where connections are made. All connections shall be made through the top of the tank above the liquid level. Tanks and systems under pressure shall be designed for four times the maximum working pressure. All iron or steel tanks shall be coated on the outside with tar or asphaltum or heavy protective paint. All concrete tanks shall be constructed in accordance with the provisions of Chapter 14B-19. Compartmented tanks shall not be permitted. Inlet openings for flammable liquid tanks inside buildings shall be piped down to four inches from the bottom of the tank unless they are equipped with a trap. Gauging openings inside of buildings shall not be permitted. All enclosed and underground tanks when installed shall be tested to a pressure equal to the static head of the height of the vent, but not smaller than five psi. Such test shall be held for not less than 30 minutes without loss of air of more than ten percent air pressure drop. When it is necessary to test such tank to a pressure of more than five psi, the test shall be of hydrostatic nature utilizing water. Pressure tanks shall be tested to one and one-half times their working pressure. Covering for Metal Tanks. All flammable liquid tanks buried underground shall have the top of the tank not less than two feet below the surface of the ground except in lieu of such covering, tanks may be buried under not less than 12 inches of earth, with a cover of reinforced concrete not less than six inches in thickness provided over such tanks, which shall extend not less than one foot horizontally beyond projected limits of the tanks in all directions. All concrete work shall be in accordance with Chapter 14B-19. Where tanks are liable to be displaced because of moisture in the ground, all tanks shall be securely anchored or weighted. Where tanks are located under driveways, such tanks shall not be less than three feet below the top surface of the driveway; provided, however, that if such driveways are paved with concrete not less than six inches in thickness, the total coverage above the top of the tank shall be not less than two feet. Covering for Underwriters' Laboratories, Inc. Labeled Glass-fiber Reinforced Plastic Tanks. Depth and Cover. Glass-fiber reinforced plastic tanks shall be set upon firm earth which has not been previously disturbed and may be set on a minimum of six inches of number 4 run gravel or sand. Glass-fiber reinforced plastic tanks shall be buried with two and one-half feet of compacted well graded granular soil, number 4 run gravel or sand, with a cover of reinforced concrete not less than six inches in thickness provided over such tanks, which shall extend not less than one foot horizontally beyond the projected limits of the tank in all directions, a minimum clearance of eighteen inches between tanks. When anchoring is required, hold down straps shall be installed. A minimum clearance of two inches between bottom end of pipe and tank bottom shall be maintained. Dipstick shall be made of wood without sharp tips. Means shall be provided not to allow dipstick to reach bottom of tank. Capacity. The individual capacity of underground tanks is limited in respect to the lowest floor, basement or lot line as given in the following table: | Class I | Class II and III Gallons | Class I | Class II and III Gallons If top of tank is above the lowest floor, basement or part of any building with a clearance of 10 feet or less | 550 | 50,000 More than 10 feet | 551 to 2,000 | 50,001 to 75,000 More than 20 feet | 2,001 to 5,000 | 75,001 to 100,000 More than 25 feet | 5,001 to 15,000 | 100,001 to 150,000 More than 30 feet | 15,001 to 20,000 | 150,001 to 200,000 More than 40 feet | 20,001 to 50,000 | 200,001 to 500,000 More than 50 feet | Unlimited | Unlimited Clearances on the side adjacent to a public street or alley may be waived. The capacity of any tank containing flammable liquid of Class I shall not exceed 15,000 gallons in any filling station. Distance from sewers, conduits and vaults shall be the same as outlined in the above table. When said sewer, conduits, or vault are below the top of the tank, the term "sewer" includes a line out of the said site; provided, however, these clearances shall not be required from a sewer line out of said site if such sewer is constructed of cast iron with hot poured lead joints. Abandonment or Removal of Underground Tanks. Underground tanks taken out of service shall be disposed of by any one of the three following means: (a) Being placed in "temporarily out of service" condition; provided, however, that no temporarily out of service tank shall be built upon; (b) Abandoned in place; or (c) Removed. Tanks Rendered "Temporarily Out of Service". "Tanks rendered ‘Temporarily Out of Service"' means flammable liquid storage tanks which are temporarily not being used for a period of time less than six months. (a) Remove all flammable liquid that can be pumped out with the service pump; (b) The fill line, gauge hatch and pump suction shall be capped and secured against tampering; (c) The vent line shall be left open. Abandoning Underground Tanks in Place. (a) Remove all flammable liquid from tank and from all connecting lines; (b) The suction, inlet, gauge and vent lines shall be disconnected; (c) The tank shall be flooded with water, pumped out and then filled with an inert solid material; (d) Remove all connecting lines below ground level, and cap or plug all tank openings below ground level. Removal of Underground Tanks. (a) Remove all flammable liquid from tank and connecting lines; (b) Disconnect the suction, inlet, gauge and vent lines; (c) The tank shall be flushed with water and cleaned until rendered gas-free as indicated by combustible gas indicator; (d) If a tank is to be disposed of as junk, it shall be retested for explosive vapors, and rendered gas- free. Before releasing to a junk dealer, a sufficient number of holes or openings shall be made at the bottom of the tank. The net cross-sectional area for such holes shall not be less than 78 square inches per tank; (e) The tank shall be removed immediately from said site. Prohibition of Abandonment of Aboveground Flammable Liquid Tanks. (a) Abandoned aboveground flammable liquid tanks shall be removed. The tank shall be flushed with water and cleaned until rendered gas-free as indicated by a combustible gas indicator. (b) The tank shall be dismantled and junked. If in one piece before releasing to a junk dealer, a sufficient number of holes or openings shall be made in the tank. The net cross-sectional area for such holes shall not be less than 78 square inches per tank. (Prior code § 129.1-22; Amend Coun. J. 10-7-20, p. 21791, Art. VI, § 30)

Municipal Code of Chicago § 15-24-290 Tank testings.

15-24-290 Tank testings. All flammable liquid tanks in use may be tested in accordance with Section 15-24-280 whenever the fire commissioner deems necessary. (Prior code § 129.1-22.1; Amend Coun. J. 5-18-16, p. 24131, § 144)

Municipal Code of Chicago § 15-24-300 Railroad tank car storage prohibited.

15-24-300 Railroad tank car storage prohibited. Railroad tank cars shall not be used for aboveground storage tanks. (Prior code § 129.1-22.2)

Source: City of Chicago, Municipal Code of Chicago (American Legal Publishing, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/chicago/latest/chicago_il/0-0-0-2678265Fetched: 10/24/2026