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SPCC Plan –v– FDEP 62-761
In Florida, How Much Secondary Containment is Needed?
(Unpleasant food for thought)

In the state of Florida, most, if not all operators of hydrocarbon storage tanks know that there are various environmental regulations that must be complied with. These regulations define many aspects of facility design operation, maintenance and documentation. And, as with most governmental regulations, the successful rules from one state can, and often do, spread to other states.

In Florida, there are currently two different environmental requirements that define the necessary secondary containment capacity for storage facilities. The United States Environmental Protection Agency’s (EPA) Title 40 Code of Federal Regulation Part 112 defines the requirements of a Spill Prevention, Control and Countermeasure Plan (40CFR112 - SPCC). The Florida Department of Environmental Protection (FDEP) Chapter 62-761 defines requirements for ASTs and USTs in Florida.

At first glance, there does not appear to be a conflict with these two requirements.  Additionally, most, if not all operators in the state of Florida have upgraded their facilities to comply with the FDEP requirements. Those that have not yet completed their upgrades will be completing them soon.

The wording in the EPA’s regulation, 40CFR112.7(e)(2)(ii), states: “All bulk storage tank installations should be constructed so that a secondary means of containment is provided for the entire contents of the largest single tank plus sufficient freeboard to allow for precipitation.” In other words, this means 100% plus freeboard for rain. The question then becomes, “How much rain can I expect?” Researching the issue with EPA, they recommend using the National Oceanic and Atmospheric Administration’s (NOAA) National Climate Data, which can be found at http://www.ncdc.noaa.gov/ol/climate. EPA recommends using the 24-hour, 100-year rainfall event as the most appropriate number.  The current NOAA data can also be found in Technical Paper 40 (1961) “Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and Return Periods from 1 to 100 Years”.  The bad news is this amount ranges from 10” in the center of Florida, to as much as 14” in the south east corner of the state.  In fact, most of the southeast United States range from 7” to 15”.

The EPA’s secondary containment capacity calculations are reinforced by the National Fire Protection Association’s NFPA 30, ”Flammable and Combustible Liquids Code” 2.3.2.3.2(b) which states, “The volumetric capacity of the diked area shall not be less than the greatest amount of liquid that can be released from the largest tank within the diked area, assuming a full tank.”  This is interpreted as 100% of the largest tank capacity. NFPA makes no provisions for rainfall amounts. However, it must me remembered that NFPA’s main focus is on fire protection and fire fighting, not environmental protection.

The Florida DEP’s regulation 62-761.500(3)(c)3.b states, “Dike field areas with secondary containment shall …. contain a minimum of 110% of the maximum capacity of the tank or of the largest single walled tank within the dike field area.” In other words: “110%”.

A simple calculation will show that these are not always the same dimensions. An operator can have a dike area designed and installed to comply with the FDEP requirements, without supplying an additional 10” to 14” of freeboard. In fact, many facilities within Florida were specifically designed to strictly comply with the 110% FDEP requirements.

As a general rule, the environmental inspector that will come to a Florida facility will usually be an FDEP inspector, or possibly a local environmental inspector, there to review the facilities compliance with Florida environmental rules. They know that the requirements in Florida are 110% and that is the capacity that they are looking for.

Unfortunately, in the event that a federal EPA inspector shows up to audit a Florida facility, they could be specifically looking for the 100% plus free board for rain fall.  Why might a federal EPA inspector come to audit your facility? Possibly the result of a major environmental accident. Possibly the result of a routine audit of other EPA regulated operations. Either way, the facility owner/operator could be sited.

There have been moves in recent years to update the EPA’s SPCC regulation to reflect the 110% capacity of secondary containment, however, as of this writing, this change has not taken place.  The current rule states 100% plus rain. Additionally, FDEP is currently in the process of revising 62-761. They acknowledge that there is an inconsistency between FDEP and EPA. They will look at clearing up this inconsistency, but today the rule is still 110% in Florida.

 The current recommended conclusion is to design the containment to comply with the most stringent requirement. If your current containment does not meet one, or both, of these regulations, make immediate plans to upgrade. This may mean significant capital upgrades for many in Florida.

 
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Last modified: June 19, 2007