Why Secondary Containment Inspections Are Non-Negotiable
Secondary containment — bunds, spill pallets, drip trays, and IBC containment units — is your last line of defence against environmental pollution from chemical or oil spills. But containment that is cracked, corroded, overflowing, or otherwise compromised offers no protection whatsoever. Regular, structured inspection of all secondary containment assets is a legal requirement, not an optional housekeeping exercise.
Under the Control of Pollution (Oil Storage) Regulations 2001, Environmental Permitting (England and Wales) Regulations 2016, and the Water Resources Act 1991, site operators have a statutory duty of care to prevent pollution of controlled waters. The Environment Agency expects to see evidence of regular inspection and maintenance during site visits — and inadequate containment is one of the most commonly cited enforcement triggers.
What to Inspect and How Often
| Asset Type | Inspection Frequency | Key Checks |
|---|---|---|
| Spill pallets (plastic) | Monthly + after each spill | Cracks, UV degradation, grating condition, capacity free |
| Concrete bunds | Monthly visual + annual professional survey | Cracks, rendering integrity, sump pump function, drain valve closed |
| IBC bunds | Monthly | Structural integrity, UV weathering, drain plug present and sealed |
| Drip trays | Weekly or after each use | Accumulated liquid (pump or drain regularly), lid/cover present |
| Drum storage bunds | Monthly | Capacity calculation still valid, no crack ingress, drainage valve status |
Step-by-Step Bund Inspection Procedure
A robust bund inspection should follow a consistent procedure to ensure nothing is missed. Begin with a visual check of all internal and external walls for cracks, gaps at joints, and signs of seepage or staining that indicate previous leakage. Check the rendering or coating — concrete bunds must be rendered with a chemical-resistant coating (typically epoxy) that remains intact and bonded to the substrate. Any flaking, bubbling or delamination requires immediate repair.
Next, verify that all drainage valves or sump pumps are in the closed or off position. Open drain valves are one of the most common and serious failures found during Environment Agency inspections — they render the bund entirely useless. Check valve handles are locked closed and that the lock is functional. If your bund uses a sump pump rather than a drain valve, test the pump operation and confirm the discharge is directed to an appropriate collection point rather than to drain.
Assess the available freeboard — the unused capacity within the bund. Secondary containment must hold 110% of the largest vessel, and this capacity must actually be available at all times. If accumulated rainwater, spilled product, or equipment stored within the bund has reduced available capacity below the required level, take corrective action immediately. Portable bund pumps can assist with rainwater removal from outdoor containment areas.
Spill Pallet Inspection Checklist
For plastic spill pallets, inspect the main body for cracking at corners and stress points — particularly in cold environments where plastic becomes brittle. Check the grating is in place and undamaged (missing grating sections allow drums to contact the base and potentially mask a crack). Verify the bund capacity by measuring any accumulated liquid and comparing against the stated containment volume. Replace pallets showing structural deterioration immediately.
Documentation: Your Legal Paper Trail
Every inspection must be documented. Records should include the date and time of inspection, the name of the inspector, a description of each asset inspected, any defects found, corrective actions taken, and sign-off that the asset is fit for purpose or taken out of service. These records must be retained for a minimum of five years and made available to the Environment Agency or HSE on request. A simple paper log kept adjacent to each containment asset is the minimum standard; a digital asset management system is recommended for multi-site operations.
For replacement spill pallets, IBC bunds, and drip trays to replace failed containment assets, visit Spill Control Products.
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