23 July 1997
Late in 1996 there was an incident in a laboratory in the Pharmacology Department which witnesses described as "... a loud noise, a flash of light and a "mini volcano" which erupted from a brass plate in the floor". There was a blue flame that burned for several seconds and the room quickly filled with smoke. The occupants of the laboratory evacuated to safety and the fire brigade was called.
Investigators attribute the cause of the fire to a malfunction in a 3-phase electrical power supply conduit located in the concrete floor. The brass plate from which the "mini volcano" erupted was the cover of an electrical power junction box. At first it was thought the problem was due to water affecting the continuos wiring in the conduit but Monash maintenance electricians discovered that the malfunction was the result of water making contact with the electrical terminations in the junction box.
This is a cause for considerable concern, as the brass cover plates are not usually earthed and in the case of a flood or other electrical problem a cover could become "live". Anyone standing on a live cover could potentially provide a path to earth and be electrocuted. Such events could happen without apparent cause as the electricians warn that water may sit in conduits or boxes for a long time (perhaps for months) before conductivity increases sufficiently to cause a short and the type of incident that occurred in Pharmacology.
The following recommendations are intended to prevent such events.
If a flood occurs in your building, contact Works and Services staff at your campus and arrange for the appropriate trades staff to inspect the flooded and adjacent areas. The aim being to establish whether electrical services have been affected and to initiate immediate corrective action to rectify any damage or deficiencies.
When planning new buildings or major renovations in existing buildings, make every effort to avoid laying power cables with terminations in in-floor service ducts in areas which may be subject to flooding, fluid spillages or hosing for cleaning, eg. laboratories, kitchens, toilets, animal houses, etc.
In existing buildings with cabling and junctions in in-floor service ducts, investigate the possibility of re-routing the cables and services to overhead. If this is not practicable, provide earth leakage protection, (30mA general) at the local supply switchboard, or earth the conduits and cover plates at the junction boxes.
Please contact OH&S on: