Secondary Containment Tanks

Secondary containment exists to catch a spill or leak before it reaches the ground, stormwater, or waterways, and is a standard requirement for sites storing bulk chemicals, fuels, and other regulated liquids in Australia. A welded plastic bund or containment tank sits beneath or around a primary storage tank, sized to capture the full contents of the largest tank in the bunded area plus an allowance for rainfall where the bund is outdoors.

Custom fabrication allows a bund to be shaped to fit around existing tanks, pumps, and pipework on site, rather than requiring a full re-layout of an existing chemical or fuel storage area.

HDPE sheet is the most common material for secondary containment structures, chosen for broad chemical resistance and ease of welding into large, low, rectangular bund shapes. Polypropylene is specified where the stored chemical falls outside HDPE's resistance range or where the bund will see elevated temperatures. Rigid PVC sheet is used for smaller ancillary bunds or drip trays rather than large primary containment structures.

Wall height and floor thickness are calculated based on required containment volume and any expected foot or vehicle traffic across the bund floor.