The patented fire extinguishing system comprises of factory-assembled 1.5-mm galvanised sheet metal fire extinguishing baffle plates.
There is a copper or stainless-steel terminal grounding system that accompanies the 5-mm thick galvanised frame.
Galvanised grating covers the baffle plates to allow for maintenance of the whole structure and to allow staff to move around.
Traditional yard stone bed laid on a grating
This solution has been used throughout Australia for decades. There are many transformers which are still protected by this method however, this solution is generally not used in renovation or new construction projects.
A typical installation is illustrated which shows yard stone being placed on top of a pit. A grating is installed below to allow for water (and any oil) to drain through to the sump.
The bund is over designed to accommodate the stone and the actual retention volume of the bund is defined as what is available under the grating. The consequence is that a larger footprint is required when constructing a new bund and in the case of renovation or upgrades, the available oil volume is often too small to consider upgrade to a larger transformer.