Spill Pallet Sump Capacity: How to Build a Sizing Brief

Build an inventory before using a percentage

List each container capacity, the number of containers sharing containment, the stored liquid and whether the position is sheltered. Keep nominal container capacity separate from the amount normally filled. Ask the responsible site reviewer which value the applicable rule or design basis requires.

Record units explicitly. US gallons and imperial gallons are different units; a specification that says only gallons can create a procurement error. Use litres as a common comparison unit if supplier documents use different conventions, while retaining the original figures for traceability.

Why there is no universal 110% rule

For covered US oil-storage installations, EPA guidance describes containment for the largest single container plus sufficient freeboard for precipitation. Applicability depends on the SPCC rule and the facility. It is not a blanket rule for every chemical or warehouse.

The cited GOV.UK business oil-storage guidance applies to England and Wales and distinguishes container types, including different provisions for drums and IBCs. HSE guidance also discusses containment in its own technical context. Do not take a percentage from one source and treat it as worldwide product certification. Have the site reviewer identify the relevant requirement first.

Reference: US EPA: Secondary containment for each container under SPCC; GOV.UK: Oil storage regulations for businesses (England and Wales); HSE: Secondary containment technical measures

Turn the requirement into a measurable purchase criterion

Illustrative arithmetic only: if a project reviewer specifies 110% of a 200 L container, the resulting minimum is 220 L before any separately required allowances. That calculation does not establish that 110% is the correct rule for the project, or that a particular 220 L catalogue unit is suitable.

Ask whether the stated sump volume is gross moulded volume or usable liquid retention in the supplied configuration. Clarify the effects of supports, grating, fittings, any permitted interconnected modules and the level at which overflow occurs. Require the supplier to identify how its figure was established.

Allow for conditions that reduce available containment

Liquid already in the sump occupies space. Rainwater, wash water or unresolved leakage can therefore invalidate an otherwise adequate specification. The operating plan needs a method for inspection and controlled recovery, not simply a larger nominal number.

Do not assume adjacent pallets form a combined sump. Separate units remain separate unless an engineered connection and its use conditions are documented. Also check that a leak from a valve or dispensing hose would actually enter the containment area rather than land outside its footprint.

Record the decision and request evidence

A useful sizing sheet records container inventory, regulatory or engineering basis, required usable volume, outdoor allowances, model offered, supplier evidence and reviewer approval. Keep the structural load check on the same sheet but as a distinct item.

Zhuji Trading can coordinate model drawings and supplier capacity information for the available spill-pallet directions. The product page contains indicative examples, not a substitute for the approved site calculation. Send your required capacity and its basis with the enquiry so proposed models can be screened consistently.