Environmental guidance for your business in Northern Ireland & Scotland

Secondary containment systems for chemicals

Secondary containment systems for chemicals

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 IBCs 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.

Duty of care: your waste responsibilities

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 or Scottish Environment Protection Agency. You may be able to discharge uncontaminated rainwater but you should contact your environmental regulator if you are unsure about what you can discharge.

Contact your environmental regulator

You must not discharge rainwater that collects in bunds to drains that discharge to foul sewer, unless you have permission from your water and sewerage company. 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.

Trade effluent: managing liquid wastes

Preventing water pollution

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.

Hazardous/special 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 the page in this guideline on small-scale chemical storage - cabinets, shelves and vehicles.

Further information

GPP 2 Above ground oil storage tanks (Adobe PDF - 276KB)

PPG 26 Drums and intermediate bulk containers (IBC) (Adobe PDF - 351KB)

CIRIA 736 - Containment systems for the prevention of pollution. Secondary, tertiary and other measures for industrial and commercial premises.

In this Guideline

REACH and storing chemicals

Storage, handling and delivery of chemicals

Bulk chemical storage - tanks and drums

Secondary containment systems for chemicals

Small-scale chemical storage - Cabinets, shelves and vehicles

Chemical labelling and information

Avoiding and dealing with chemical spills

Temperature controlled chemical storage

Waste chemicals and chemical containers

Chemical storage environmental legislation

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