Secondary containment systems for bulk chemical stores
How to use secondary containment systems such as bunds to contain leaks and spills, and prevent pollution incidents.
Store all chemicals in an area where you can contain spills. This should be within a secondary containment system (SCS) such as:
- an impermeable bunded area
- on a bunded pallet or spill pallet
- in a sump pallet
- a bunded storage unit
- a bunded drum store
- a storage cabinet with an integral sump
Use a bunded trolley or mobile sump pallet for moving drums and intermediate bulk containers (IBC) around your site. Before you move drums or IBCs, ensure that they are properly secured on the trolley or pallet and will not fall off.
Your bund and any bunded pallets should be able to contain at least 110 per cent of the volume of the largest tank or 25 per cent of the total volume you are likely to store, whichever is greater.
Ensure that your pallets and bunds are made of a suitable material for the chemical you are storing. For example, you should not use a polyethylene bund to store corrosive chemicals.
Dispose of water from bunds correctly
If rainwater collects in a bund, it will reduce its holding capacity. Put a roof over the bunded area to prevent this if possible.
You must comply with your duty of care when you dispose of water that collects in bunds - see duty of care for business waste.
You must check if you need a discharge consent or groundwater authorisation to allow rainwater from bunds to enter surface waters or groundwater.
You must not discharge rainwater that collects in bunds to drains that discharge to surface waters or groundwater, unless you have permission from the Northern Ireland Environment Agency.
You must not discharge rainwater that collects in bunds to drains that discharge to foul sewer, unless you have permission from NI Water. It is against the law to discharge anything into the sewer that could harm sewers or interfere with the treatment or disposal of sewer contents - see preventing water pollution and discharging trade effluent.
Water that collects in the bund may be contaminated. You must dispose of contaminated water as hazardous waste, unless you have and comply with a discharge consent or groundwater authorisation for a discharge - see dealing with hazardous waste.
Secondary containment for small chemical stores
You may want to use different measures for small chemical stores, such as a drip tray or bunded cabinet - see small-scale chemical storage - cabinets, shelves and vehicles.
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