Do Double Wall Tanks Need Secondary Containment

The outer tank provides the secondary containment to the primary inner tank.

Do double wall tanks need secondary containment.

Double wall plastic storage tanks have their own secondary containment. Owners and operators must inspect the inner wall and interstitial spaces of a shop built double wall ast using industry standards such as the sp001 00 standard for inspection of in service shop fabricated aboveground tanks for storage of combustible and flammable liquids. An owner or operator of a facility can self certify and their spcc plan if they qualify as a tier i or tier ii facility. These secondary systems must have sufficient volume to hold all of the primary tank s liquid capacity plus a hefty extra percentage to ensure proper containment.

And capacity for secondary containment you need only to address the typical failure mode and the most likely quantity of oil that would be discharged. The epa stipulates that certain requirements must be met for the second wall to be considered a secondary container. This guidance also clarifies when shop built double walled asts satisfy the applicable secondary containment requirements in the spill prevention control and countermeasure spcc rule found at 40 cfr part 112. Such as a tank or pipe will not escape the containment.

The epa refers to the need for containment and secondary containment in two different areas. It is a good idea to ask the manufacturer whether your tank fulfills this requirement. A copy is attached for your reference. Double wall storage tanks and secondary containment systems provide protection against hazardous chemical spills double wall tanks imt provide the best protection against hazardous chemical spills into the environment.

This is in response to your letter of december 28 1992 in which you requested from the occupational safety and health administration osha an interpretation on whether the use of double wall above ground tanks is acceptable for secondary containment of flammable and combustible liquids in place of diking to meet the requirements of 29 cfr 1910 106 b 2 vii. Part of using a double wall fuel tank is making sure it is up to industry standards. Inner tank dome overlaps outer tank sidewall to prevent rainwater snow and debris from entering into the containment basin. Secondary containment may be either active.

Subpart i use and management of containers 40 cfr 264 175 which covers portable storage containers such as 55 gallon drums for hazardous waste and the second in subpart j tank systems 40 cfr 264 193 which covers large stationary containers. Typically secondary storage will be a dike system concrete vault or double wall steel storage tank. Having double walled tanks or other devices that could prevent a release such as man made berms dikes and barriers does not exempt a facility from needing an spcc plan 40 cfr 112 1 d 1 i. Chapter 4 secondary containment and impracticability.

Use of certain double wall aboveground storage tanks asts for secondary containment purposes. When using double walled asts as secondary containment certain inspection requirements apply.