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Bill Gorham, Sales Manager of AmCor (CO), submits a reminder to Contractors installing aboveground storage tanks. In the case of grounding of ConVault ASTs, Bill reminds everyone that last year in the state of Wyoming an owner/operator’s site was not properly prepared and lightning struck the aboveground storage tank. The effect was to instantly vaporize approximately 150 gallons of unleaded gasoline and gel some of the diesel in the adjoining compartment (the unit in question was a dual-compartment ConVault AST). Although we have had only one incident of a lightning strike to a ConVault AST and there was no collateral damage due to the patented design’s performance, we support the recommendation by Mr. Gorham.

As identified in the ConVault owner’s Manual as well as the local electrical code requirements, the following procedure should be followed:

1. Each ConVault AST has at least two grounding lugs located on outlet fittings.

2. A strand of #17 awg copper or #14 awg aluminum conductor cable should be permanently clamped to the ConVault fitting lug and then extended to the grounding rod.

3. The grounding rod should be eight- feet in length and not-less-than 1/2-inch diameter as required locally.

4. The grounding rod should then be driven into the ground with a 10-foot radius to disperse the charge.

As reported in The Aboveground Storage Tank Guide in 1997, the aboveground storage tank industry experiences an average of 66 lightning strikes to fuel storage facilities (mostly the field-erected types) each year.

It is noteworthy to mention that Federal Guidelines require an annual maintenance schedule described in the ConVault Owner’s Manual.