Containment is one of those subjects where most sites have done something, fewer have done the right thing, and almost nobody has checked the arithmetic. Here are the four questions an inspector will actually ask.
1. Is the volume right?
The common rule is that containment must hold the larger of the biggest single container or a percentage of total stored volume — frequently ten per cent, and higher in some jurisdictions and for some cargo. Which rule applies to you depends on your state, your cargo and whether you fall under SPCC.
The arithmetic people get wrong is displacement. A containment pallet holding two totes has to hold 275 gallons plus the volume that the remaining tote's footprint occupies inside the sump. A nominal 66-gallon sump under two totes is not containment for a 275 gallon spill, no matter how it is marketed.
Outdoors you also have to account for rainfall. An open berm is a rain collector, and the freeboard you need in April is not the freeboard you need in August.
2. Is the material compatible?
Containment made of the wrong material is theatre. A polyethylene spill pallet is excellent for acids, caustics, brines and most aqueous chemistry, and poor for aggressive solvents. A coated steel berm is the reverse.
The relevant test is not what the containment holds day to day — it is what it has to hold for the duration of a worst-case release, which could be hours or days before anybody notices. That is a different and harsher requirement.
Check the cargo against the containment material the same way you would check it against the tote. Our compatibility chapter covers the HDPE side; your containment supplier should be able to cover theirs.
3. Can it actually drain, and is the drain controlled?
Outdoor containment fills with rain. If it has no drain, it overflows and the containment volume is fictional at the moment you need it. If it has an uncontrolled drain, it is not containment at all.
The correct arrangement is a manually operated, normally closed valve, with a documented procedure for inspecting accumulated water before releasing it. That procedure is the thing inspectors ask to see, far more often than they measure the sump.
4. Can you get to the tote, and can a forklift?
Containment that makes the valve unreachable gets removed by the operator within a week. Containment that a forklift cannot place a tote into gets used for something else. Practicality is a compliance issue, because unusable controls do not get used.
The specific detail worth checking: can you see the outlet valve and the ground beneath it during a normal walk-round? Most releases are slow weeps rather than catastrophic failures, and the whole point of a daily visual is catching them early.
Options, in rough order of cost
- Single-tote spill pallet. Cheapest, simple, and frequently undersized for the regulation that applies.
- Two-tote containment pallet. The common workhorse. Check displaced volume carefully.
- Flexible berm. Good for temporary and jobsite use, poor against punctures from pallet feet without a mat.
- Hard berm or kerbed bay. Permanent, high volume, and the only sensible option above a handful of totes.
- Cage-frame berm. Built from stripped tote cages and a liner — cheap, robust, and one of the patterns from our fabrication bay.
The spill kit nobody checks
Have one, size it to the largest container, keep it adjacent to the storage rather than in a locked store on the other side of the site, and check it on the same schedule as the containment. Absorbent that has been sitting in a damp cupboard since 2019 is not spill response equipment.
What we can and cannot help with
We stock spill containment pallets and berms, and we fabricate cage-frame containment to size. What we will not do is tell you which regulation applies to your site — that is a determination for your environmental coordinator or consultant, and anybody selling you containment who is also willing to tell you it makes you compliant is selling you two things and only one of them is real.
The displacement arithmetic, worked
This is the calculation most sites get wrong, so here it is explicitly.
A two-tote containment pallet needs to hold the contents of the largest container — 275 gallons — while the other tote is still standing in the sump. That second tote occupies volume inside the containment that is therefore unavailable.
A 48 by 40 inch footprint is about 13.3 square feet. If the sump is six inches deep, the standing tote displaces roughly 6.6 cubic feet, or about 50 gallons, of your containment volume. So a nominal 66 gallon sump under two totes gives you about 16 gallons of usable containment against a 275 gallon release.
That is not a rounding error. It is the difference between containment and decoration.
Rain, which is the outdoor version of the same problem
An open berm is a rain collector. A 48 by 80 inch two-tote berm is about 26 square feet; an inch of rain puts roughly 16 gallons into it. A wet spring week can consume your entire freeboard.
Two fixes, and you need one of them: a roof or cover, or a managed drain with a normally-closed valve and a written procedure for inspecting accumulated water before release. The second is more common and it is the procedure inspectors ask to see, far more often than they measure the sump.
What a good inspection routine looks like
Daily or shift-based, and genuinely quick:
- Look under the outlet valve. Most releases are slow weeps, and this is where they show.
- Check the sump is empty, or that accumulated water is water.
- Confirm the drain valve is closed.
- Confirm the spill kit is present and intact.
- Look at the pallet feet and the liner for punctures.
Thirty seconds, somebody's name against it, and a record. The record is the part that turns a control into evidence.
Punctures, and the mat that prevents them
Flexible berms fail by puncture far more often than by overflow, and the thing that punctures them is almost always the pallet feet of the tote set down inside them.
A sheet of plywood or a purpose-made ground mat under each tote turns a single-season berm into a multi-season one. It is the cheapest improvement available and it is skipped constantly.
Compatibility over duration, not over a shift
The test for containment material is not what it tolerates during normal handling. It is what it tolerates holding a full release for however long it takes somebody to notice — which on a weekend could be days.
A polyethylene berm that resists a splash of solvent for ten minutes may not resist 275 gallons of it for sixty hours. If your cargo is aggressive, specify containment for the worst case rather than the normal case, and check the supplier's figures for immersion rather than splash.
The cage-frame option
One of our standard fabrications, and genuinely the best value in hard containment: stripped tote cages bolted into a rectangular frame and lined. Made entirely from steel that was headed for the mill.
It handles forklift traffic in a way flexible berms do not, it does not puncture, and it sizes to one, two or four tote footprints. For any site that will run more than a season it is usually cheaper over its life than replacing berms. Details on the upcycled builds page.
What we will not tell you
Which regulation applies to your site. SPCC applicability, state thresholds, local fire code and your own permit conditions interact in ways that need somebody who has read your permit.
We sell containment and we fabricate it. Anybody selling you containment who also tells you it makes you compliant is selling two things and only one of them is real.
