5003.2.4 Installation of tanks

When there is a possibility of water intruding into the space between the primary tank and secondary containment by precipitation, infiltration, or other means, the facility shall be designed and constructed with the capability to monitor and remove such water intrusion. Secondary containment systems shall have a nationally recognized testing laboratory listing or a Los Angeles Fire Department Equipment Approval.

All underground piping in connection with underground tanks shall comply with the following:

1. Piping shall lead out of the top.
2. Piping shall be covered with at least 1 foot (305 mm) of earth or 4 inches (100 mm) of earth and 4 inches (100 mm) of concrete except for necessary riser pipes.
3. Piping shall be equipped with means for disconnection.
4. At any point of change from the vertical to the horizontal or from the horizontal to the vertical, there shall be installed an approved flex connector assembly.

Fill pipes of underground tanks shall not exceed 8 inches (203 mm) inside diameter and shall be kept closed with a tight-fitting cap. Every fill opening shall be located in a fill box outside of buildings except openings for underground waste oil tanks used in connection with public garages or auto fueling stations inside buildings. Fill openings inside buildings shall be equipped in a manner to prevent escape of vapors to the inside of the buildings.

Atmospheric tanks containing hazardous materials may be insulated by the application of insulating material approved by the Chief. Insulating materials shall be fire resistant and shall not decompose rapidly if exposed to fire.

Tanks, pressure vessels, vaporizers and associated equipment used in conjunction with liquid or gaseous hazardous materials at ambient temperatures and pressures in excess of 0.5 psig shall be in accordance with Sections 5003.2.4.3.1 through 5003.2.4.3.6.

Above-ground tanks and pressure vessels used to store liquid or gaseous hazardous materials at ambient temperatures and pressures in excess of 0.5 psig shall be in accordance with the following:

1. Tanks and pressure vessels installed aboveground shall be provided with substantial masonry or noncombustible structural supports so installed as to prevent accidental movement.
2. Horizontal, above-ground tanks and pressure vessels shall be mounted on saddles in such a manner as to permit expansion and contraction, not only of the container but also of the connected piping. Only two such saddles shall be used and every container shall be supported to prevent the concentration of excessive loads on the supporting portion of the shell.

Underground tanks and pressure vessels used to store liquid or gaseous hazardous materials at ambient temperatures and pressures in excess of 0.5 psig shall be in accordance with Sections 5003.2.4.3.2.1 through 5003.2.4.3.2.8.

Storage containers or regulating equipment shall not be buried below ground unless written approval is first obtained from the Chief.

Every storage container installed underground shall be buried not less than 6 inches (150 mm) below the surface of the natural grade level except where the container might be subject to abrasive action or physical damage due to vehicular traffic or other causes in which case it shall be:

    Installed not less than 2 feet (610 mm) below the surface of the natural grade level; or otherwise protected against physical damage.

The exterior surfaces of every such container shall be covered with an approved corrosion-resistant coating material applied in an approved manner.

Every such vessel shall be set on a 6-inch (150 mm) thick bedding of water-washed sand (beach sand shall not be used) free from soil, rock, or gravel. Before any back filling is done, the position of the vessel and the sand bedding shall be approved by the Chief. After such approval, the excavation shall be back filled with the same quality water-washed sand in such a manner that the sand back fill on the sides, ends, and the top of such vessel shall be at least 6 inches (150 mm) thick.

Every opening for the attachment of piping and appurtenant equipment shall be in the top of such vessel. No pipe or equipment connection to any such vessel shall be buried underground, but shall be above ground, connected to a dome or manway which is an integral part of the vessel, or shall be in a valve pit constructed as provided in Section 5003.2.4.3.2.6.

No pit shall be used or maintained in connection with any underground vessel which is greater than 2 feet (610 mm) in depth or contains in excess of 18 cubic feet (0.51 m³) of space.

A collision barrier and a security fence, constructed as provided in Section 312, shall be installed and maintained to provide a minimum clearance of 5 feet (1525 mm) from the outer portion of every pit, vaporizer, pump, valve, or pipe riser.

All buried containers shall be completely uncovered for an inspection of all external surfaces at least once every 3 years. The intervals may be changed at the discretion of the Chief if a test plate is buried adjacent to the container and shows no appreciable corrosion on inspection by the Department after 3 years of service; provided, however, that every container shall be uncovered at least every 15 years. The test plates shall be of the same material as the shell of the tank and shall be at least one-fourth of the container diameter in length and 6 inches (150 mm) wide, and shall be buried in the water-washed sand at least as deep as the lowest surface of the container and shall not be coated. Test plates shall be provided in accordance with the following:

1. Containers 10 feet (3050 mm) or less in length—one test plate.
2. Containers more than 10 feet (3050 mm) but less than 20 feet (9096 mm) in length—two test plates, one on each side near opposite ends.
3. Containers 20 feet (9096 mm) or more in length—one test plate for each 10 feet (3050 mm) of length, placed on alternate sides at 10-foot (3050 mm) intervals.

The filling pipe inlet connections for tanks filled on consumer's premises shall not be located less than 15 feet (4572 mm) from any opening into or under a building where such opening is below the level of the filling connections; and in no case shall the filling pipe inlet connection be located less than 10 feet (3050 mm) from any building, street, or alley.

Indirect fired vaporizers shall be equipped with the following safeguards:

1. The device that supplies the necessary heat for producing steam, hot water, or other heating medium shall be separated from all rooms containing vaporizers, pumps, and central gas mixing devices by a vapor-tight 1-hour fire-resistive separation.
2. Gas-fired heating systems supplying heat exclusively for vaporization purposes shall be equipped with automatic safety devices to shut off the flow of gas to main burners, if the pilot light should fail.
3. A shut-off valve shall be installed on the liquid line to the vaporizer unit outside of any vaporizer room or building.

Direct-fired vaporizers shall be equipped with the following safeguards:

1. Every direct-fired vaporizer shall be marked with the name of the manufacturer, the rated BTU input to the burners, the area of the heat exchange surface of the vaporizer in square feet, the outside surface area in square feet, and the maximum vaporizing capacity in gallons per hour.
2. Direct-fired vaporizers shall be separated from storage vessels, buildings, streets, and adjacent property lines that may be built upon in accordance with Table 5003.2.4.3.5.
3. Every direct-fired vaporizer shall be located not less than 50 feet (15 240 mm) from filling connections.
4. Direct fired vaporizers shall be provided with a means for shutting off the fuel to the main burner and pilot from outside the vaporizer housing.

TABLE 5003.2.4.3.5
REQUIRED SEPARATIONS FOR VAPORIZERS

VAPORIZING CAPACITY IN GALLONS PER HOUR	BUILDINGS, STREETS, & ADJACENT PROPERTY LINES THAT MAY BE BUILT UPON (feet)	STORAGE VESSELS (feet)
Less Than 25	25	5
25 — 100	40	5
More Than 100	50	5

Where the relief of excess pressure from process vessels might result in undue hazard to persons or property through excessive release of flammable or toxic materials, the Chief may require the operating pressure of process vessels to be a suitable margin below the design pressure. In determining the required margin, due consideration shall be given to the operating characteristics of the processes and of the facilities for relieving excess pressure. As an alternative thereto, the Chief may permit a system for safe disposal of materials vented from the facilities for relieving excess pressure.