3. The secondary containment system “must have sufficient capacity to contain at least 10% of the total volume of the primary containers or 100% of the volume of the largest container, whichever is greater.”
Okay, take a deep breath. This is the big one, the most well-known of the secondary containment regulations, but also the most confusing! This example may help:
You are storing two 55-gallon drums. So you have a total volume of 110 gallons.
10% of the total of all the containers (two 55-gallon drums) is 11 gallons. (10% of 110 gallons)
100% of the largest container stored is 55 gallons.
55 gallons is greater than 11 gallons, so you would need to have secondary containment for 55 gallons.
Got it? Now, remember, these are just the federal containment regulations. States and municipalities have to follow AT LEAST these values, but may be stricter. In fact, a lot of states require 110% containment of the largest container. So, it’s a good idea to check with your state and local municipality on their secondary containment regulations — you need to be compliant with everything!
4. Precipitation (also know as “run-on”) must be prevented from entering the secondary containment system unless the system has sufficient capacity to contain any run-on in addition to the volume capacity requirements.
Yes, you also have to worry about Mother Nature! When your containment unit is outdoors, any rainwater, snowmelt or other liquid that enters the sump of the secondary containment unit will take up capacity in the containment system. In the event of a spill, this could cause overflow. Regulators are really serious about this one. A no-brainer solution is to put your containment system under shelter or a self-contained cover. Of course, with some larger systems, this may be impossible! If that’s your situation, consider the worst storm your area has had in the last 100 years (NOAA has data on this if your memory isn’t quite that good) and calculate that into your capacity requirements.
5. Any waste that has spilled or leaked into the secondary containment area (or any accumulated precipitation like we talked about) must be removed in as timely a manner as is necessary to prevent overflow.
Simply put — check it out and clean it up! Any liquids that shouldn’t be in the sump take up volume capacity. You already know that is a big problem if you have a spill. You’ve spent so much time meticulously calculating your secondary containment volume requirements. The last thing you need is waste or precipitation in the sump, displacing volume and causing your system to overflow if there is a release from the primary container. Pay attention to your calendar. Routinely inspect your sump and your containment system. If you find any precipitation or waste, pump or drain it, filter the liquid, or absorb small spills with sorbent products.
Disasters averted, regulations understood and complied with. Commence feeling proud of yourself!