Cal. Code Regs. tit. 8, § 501
(a) Stationary tanks shall be installed aboveground on firm masonry or concrete foundations, or on full length skids providing a bearing area limiting foundation loadings to not more than 2,000 pounds per square foot. Unless supported by continuous skids welded to pads on the tank shell, aboveground horizontal storage tanks shall have no more than 2 points of support longitudinally. Where necessary, tanks shall be securely anchored or weighted to prevent floating.
A tank may be installed on saddles, directly on concrete foundations, or it may be supported by properly designed metallic structural supports. When the tank is installed directly on concrete foundations, a corrosion pad shall be provided at the points of contact with the foundation. These corrosion pads shall be at least 3/16 inch thick, and shall have a width at least equal to the width of the foundation at the point of contact with the tank, but in no case shall they be less than 8 times the shell thickness in width.
When corrosion pads or pad-type steel supports are used, the pad shall have rounded or semielliptically shaped ends, and shall be attached to the shell with a continuous seal weld. Corrosion pads shall be not less than ¼ the circumference of the shell in length.
Unless installed on concrete pads, skid tanks shall be placed on engineered soil or road base topped with well-drained gravel or oiled sand, capable of supporting 2,000 pounds per square foot.
Sufficient space shall be provided between stationary storage tanks to permit access for fire fighting. This space shall not be less than 5 feet for tanks over 1,200-gallon capacity. Tanks exceeding 1,200-gallon capacity shall be so installed that the bottom outside surface of the tank is at least 12 inches above ground level.
(c) Containers shall be located outside of buildings, or in buildings or sections thereof especially equipped for this service. Consideration shall be given to the adverse health effects of ammonia, as well as the adjacent fire hazards, when selecting the location for a storage container.
Storage areas shall be kept free of readily ignitible materials such as waste, weeds, and long dry grass.
Stationary storage tanks shall be located with relation to property lines, residential buildings, highways, etc., in accordance with the following table:
Minimum distance (feet) from tank to
Capacity of tank in U.S. gallons
Line of property adjoining which may be built upon
Highway or main track of railroad
Residential building
1,200 and less
50
25
50
Over 1,200 to and including 30,000
50
50
50
Over 30,000 to and including 70,000
65
50
65
Over 70,000 to and including 500,000
100
50
100
Over 500,000
150
50
150
Minimum distance (feet) from tank to
Capacity of tank in U.S. gallons
Any Building or area used by the public for deliberation, worship, education, entertainment, amusement, or awaiting transportation
Hospital, jail or other similar institutions
Open well, reservoir, or other source of potable water
1,200 and less
250
750
50
Over 1,200 to and including 30,000
400
1,000
100
Over 30,000 to and including 70,000
520
1,300
100
Over 70,000 to and including 500,000
800
2,000
200
Over 500,000
1,000
2,500
200
Electrical equipment and wiring for use in ammonia installations shall be general purpose or weather resistant as appropriate.
Electrical systems shall be installed and maintained in accordance with the Electrical Safety Orders.
(e) All stationary storage tanks exceeding 1,200 gallons capacity shall have the loading and unloading connections secured to a concrete bulkhead or equivalent designed to withstand a horizontal pull of not less than 2,000 pounds in any direction, unless other suitable protection is provided. This bulkhead shall not be located underneath the tank. The loading and unloading connections shall be firmly secured to this bulkhead and the piping between the bulkhead and tank shall be installed in a manner to provide for expansion, contraction, jarring, vibrations, settling, etc. For skid tanks exceeding 1,200 gallons capacity, such loading and unloading connections shall be securely fastened to the skid or to the tank supports.
Note: 2,000 pounds may not be adequate for all sizes of loading and unloading hoses and connections.
(f) Where excess-flow valves [See Section 507 (e)] are used, liquid and vapor lines shall be at least full size from the excess-flow valve in the tank to the point of discharge or an additional excess-flow valve or equivalent shall be located as close to the point of pipe size reduction or other restriction as is practical, unless the excess-flow valve in the tank is designed to operate at the reduced flow condition, in which case the excess-flow valve in the tank may suffice.
Where excess-flow valves are used and 2 or more tanks are installed in battery, with common loading and/or unloading lines, the common liquid and vapor lines shall be fitted with excess-flow valves or equivalent (unless the common line has a cross-sectional area equal to or in excess of the combined areas of the individual tank lines; or unless the excess-flow valves are designed to operate at the reduced flow condition, in which case the excess-flow valve in the tank may suffice). Where additional excess-flow valves are used in common loading and/or unloading lines, the additional excess-flow valve or equivalent shall be located as close to the point of restriction as practical.
Note: A quick-closing manually operated valve may be considered equivalent to an excess-flow valve at the point of pipe size reduction or other restriction providing:
(3) The quick-closing valve is in the pipeline on the tank side of the bulkhead.
(h) The following minimum equipment shall be installed, properly maintained, and readily available for use at all stationary storage tanks in readily accessible locations.
(5) One quick-acting deluge shower and bubble fountain or other method of simultaneously washing both eyes with clean water.
The minimum water supply shall be a 50-gallon container of clean water.
(7) One fire extinguisher conforming to the provisions of California Administrative Code, Title 19, Chapter 1, Subchapter 3, and having a rating of not less 40B-C.
The employer shall have a program of periodic inspection of the above emergency equipment to maintain it in serviceable condition.
1. Amendment filed 12-8-72 as procedural and organizational; effective upon filing (Register 72, No. 50).
2. Amendment of subsections (a), (c), (d), and (h) filed 3-28-75; effective thirtieth day thereafter (Register 75, No. 13).
3. Amendment of subsection (a) filed 8-6-76; effective thirtieth day thereafter (Register 76, No. 32).
4. Amendment of subsection (f) filed 4-1-77; effective thirtieth day thereafter (Register 77, No. 14).