Spill Control | NFPA Guidelines | Three Types of Spill Control

The NFPA gives three guidelines for protecting against breaches or tank failures which result in environmental damage.

The three methods of Spill Control are:

  • Impounding
  • Diking
  • Secondary Containment

The Four Requirements for Impounding
(1) Drain spilled material to a remote area using a slope of 1% for 50 feet.
(2) The impounding area must have a capacity equal to or greater than the largest tank.
(3) Spill fire cannot impact tanks/property.
(4) Liquid level must be 50 feet from property line.

The Three Requirements for Diking:
(1) Drain spilled material to remote area.
(2) The size or capacity of the diked area must be greater than the volume of the largest tank.
(3) If the diked area will involve more than one tank, the dike should be large enough to contain all volumes of the tanks.

The Eight Requirements for Secondary Containment Tanks:
(1) The capacity of the above ground tank shall not exceed 12,000 gallons.
(2) All piping connections to the tank shall be made above the normal level of liquids.
(3) The liquids must not be allowed to spill by means of a siphon flow.
(4) The tanks must have a method to determine how much liquid is contained within the tank.
(5) Alarms must be installed to alert facility or delivery operators.
(6) Tank spacing must be greater than 3 feet apart.
(7) Tanks shall be impact resistant.
(8) Secondary containment tanks must be vented.

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