[HISTORY: Adopted by the Council of the City of Mount Vernon 4-19-1976, approved 4-19-1976. Amendments noted where applicable.]
GENERAL REFERENCES
Fire prevention — See Ch. 131.
A. 
All liquefied petroleum gases shall be effectively odorized by an approved agent of such character as to indicate positively by distinct odor the presence of gas down to concentration in air of not over 1/5 the lower limit of flammability. [NOTE: The lower flammable limits of the more commonly used liquefied petroleum gases are: propane, 2.15%; butane, 1.55%. These figures represent volumetric percentages of gas in gas-air mixtures.]
B. 
The odorization requirement of Subsection A shall be considered to be met by the use of 1.0 pounds of ethyl mercaptan, 1.0 pounds of thiophane or 1.4 pounds of amyl mercaptan per 10,000 gallons of liquefied petroleum gas. However, this listing of odorants and quantities shall not exclude the use of other odorants that meet the odorization requirements of Subsection A of this section.
A. 
Each system utilizing Interstate Commerce Commission containers shall have its container valves, connectors, manifold valve assemblies and regulators (bases, hoods or cabinets), if desired, listed by Underwriters' Laboratories, Inc., or listed by a nationally recognized testing laboratory. [NOTE: Regulations of the United States Interstate Commerce Commission outline specifications for transportation of explosives and dangerous articles (Code of Federal Regulations, Title 49, Parts 171 through 190) and are available from the Government Printing Office, Washington, D.C., or from the Association of American Railroads, Bureau of Explosives, 2 Pennsylvania Plaza, Room 2177, 7th Avenue and West 33rd Street, New York, New York, or the American Trucking Association, Inc., 1616 P Street, Washington, D.C. In Canada, the regulations of the Board of Transport Commissioners for Canada apply and are available from BTC, Union Station, Ottawa, Ontario.]
B. 
Each system for domestic or commercial use utilizing containers of 2,000 gallons' or less water capacity, other than those constructed in accordance with Interstate Commerce Commission specifications, shall consist of a container assembly and one or more regulators and may include other parts. The system as a unit or the container assembly as a unit and the regulator or regulators shall be individually listed by Underwriters' Laboratories, Inc., or listed by a nationally recognized testing laboratory. (NOTE: Where necessary to alter or to repair such listed system in the field in order to provide for different operating pressures, change from vapor to liquid withdrawal and the like, such changes may be made by use of component parts which have been individually listed by one of the above for use with liquefied petroleum gas.)
C. 
In systems utilizing containers of over 2,000 gallons' water capacity, each regulator, container, valve, excess flow valve, gauging device and relief valve installed on or at the container shall have its correctness as to design, construction and performance determined by listing by Underwriters' Laboratories, Inc., or listing by a nationally recognized testing laboratory.
A. 
Welding to the shell, head or any part of the container subject to internal pressure shall be done in compliance with the code under which the tank was fabricated. Other welding is permitted only on saddle plates, lugs or brackets attached to the container by the tank manufacturer.
B. 
Where repair or modification involving welding of Interstate Commerce Commission containers is required, the container shall be returned to a qualified manufacturer making containers of the same type, and the repair or modification shall be made in compliance with Interstate Commerce Commission regulations. [NOTE: Regulations of the United States Interstate Commerce Commission outline specifications for transportation of explosives and dangerous articles (Code of Federal Regulations, Title 49, Parts 171 through 190) and are available from the Government Printing Office, Washington, D.C., or from the Association of American Railroads, Bureau of Explosives, 2 Pennsylvania Plaza, Room 2177, 7th Avenue and West 33rd Street, New York, New York, or the American Trucking Association, Inc., 1616 P Street, Washington, D.C. In Canada, the regulations of the Board of Transport Commissioners for Canada apply and are available from BTC, Union Station, Ottawa, Ontario.]
A. 
Each container shall be marked as specified in the following:
(1) 
With a marking identifying compliance with and other markings required by the rules of the code under which the container is constructed or with the stamp and other markings required by the National Board of Boiler and Pressure Vessel Inspectors.
(2) 
With a notation as to whether the container is designed for underground or aboveground installation, or both. If intended for both and different style hoods are provided, the marking shall indicate the proper hood for each type of installation.
(3) 
With the name and address of the supplier of the container or with the trade name of the container.
(4) 
With the water capacity of the container in pounds or gallons, United States standard.
(5) 
With the pressure in pounds per square inch gauge for which the container is designed.
(6) 
With the rare weight in pounds or other identified unit of weight for containers with a water capacity of 300 pounds or less.
(7) 
With marking indicating the maximum level to which the container may be filled with liquid at temperatures between 20° F. and 130° F., except on containers provided with fixed maximum level indicators or which are filled by weighing. Markings shall be in increments of not more than 20° F. This marking may be located on a liquid level gauging device.
(8) 
With the outside surface area in square feet.
B. 
Markings specified shall be on a metal nameplate attached to the container and located in such a manner as to remain visible.
C. 
When liquefied petroleum gas and one or more other gases are stored or used in the same area, the containers shall be in compliance with U.S.A. Standard Z48.1-1954, Method of Marking Portable Compressed Gas Containers to Identify the Material Contained.
A. 
Each individual container shall be located with respect to the nearest building or group of buildings or lot line of adjoining property which may be built upon in accordance with Table 1:
Table 1
Minimum Distances
Water Capacity per Container
(gallons)
Underground Containers
(feet)
Aboveground Containers
(feet)
Between Aboveground Containers
(feet)
Less than 125
10
None
None
125 to 250
10
10
None
251 to 500
10
10
3
501 to 2,000
25
25
3
2,001 to 30,000
50
50
5
30,001 to 70,000
50
75
1/4 of sum of diameters
70,001 to 90,000
50
100
Adjacent containers
If the aggregate water capacity of a multicontainer installation at a consumer site is 501 gallons or greater, the minimum distance shall comply with the appropriate portion of this table, applying the aggregate capacity rather than the capacity per container. If more than one installation is made, each installation shall be separated from another installation by at least 25 feet. Do not apply the minimum distances between aboveground containers to such installations. [NOTE: The above distance requirements may be reduced to not less than 10 feet for a single container of 1,200 gallons' water capacity or less, provided that such a container is at least 25 feet from any other liquefied petroleum gas container of more than 125 gallons' water capacity.]
B. 
Containers installed for use shall not be stacked one above the other.
C. 
In cases of bulk storage in heavily populated or congested areas, the authority having jurisdiction shall determine restrictions of individual tank capacity, total storage and distance to line of adjoining property which may be built upon and other reasonable protective methods. [NOTE: Generally, aggregate storage of 2,000 gallons' water capacity or more is considered bulk storage.]
D. 
In industrial installations involving containers of 180,000 gallons' aggregate water capacity or more, where serious mutual exposures between the container and adjacent properties prevail, the authority having jurisdiction may require fire walls or other means of special protection designed and constructed in accordance with good engineering practices.
E. 
In the case of buildings devoted exclusively to gas manufacturing and distributing operations, the above distances may be reduced, provided that in no case shall containers of a water capacity exceeding 500 gallons be located closer than 10 feet to such gas manufacturing and distributing buildings.
F. 
Readily ignitable material, such as weeds and long dry grass, shall be removed within 10 feet of any container.
G. 
The minimum separation between liquefied petroleum gas containers and flammable liquid tanks shall be 20 feet, and the minimum separation between a container and the center line of the dike shall be 10 feet. The foregoing provision shall not apply when liquefied petroleum gas containers of 125 gallons' or less capacity are installed adjacent to Class III flammable liquid tanks of 275 gallons' or less capacity.
H. 
Suitable means shall be taken to prevent the accumulation of flammable liquids under adjacent liquefied petroleum gas containers, such as by diking, diversion curbs or grading.
I. 
When dikes are used with flammable liquid tanks, no liquefied petroleum gas containers shall be located within the diked area.