Where a total of 2000 liters or more of petrol and/or diesel is stored the person in charge of the farm must ensure that fuel is stored in a compound (bund). Where the total is below 2000 liters the fuel may alternatively be located so that any spillage will not endanger any building, or flow into any natural water body. Any tanks must be maintained so that valves, hoses and dispensers do not leak.
A compound is a form of secondary containment consisting of a hollow, pit or structure which is capable of containing any fuel spill from the fuel storage. To comply with HSNO regulations it must:
- Be of a size capable of holding 110% of the contents of the largest fuel tank; and be constructed of non-flammable materials (concrete, brick, HDPE, clay, earth or similar); and effectively retain the fuel if there is a spillage.
- In areas with light, free draining soils (e.g. pumice or sandy soils), a compound must be lined with an additional impermeable layer (e.g. concrete, clay or brick) to stop spills entering groundwater.