Uninterruptible Power Supply (UPS) failure

Fire risk from failure of UPS

A recent smouldering event started because of an electrical fault within an uninterruptable power supply (UPS) unit that was brought into the University. The unit was not connected to the mains power nor was it supplying power at the time of the incident. A number of staff were placed in a potentially hazardous situation and thousands of dollars of equipment and research were also at risk.

An UPS is an electrical appliance that provides emergency power to equipment when the normal power supply fails. The near instantaneous protection from power interruptions is generally provided by energy stored in batteries. A UPS typically protects telecommunication, computer network and vital equipment for a period long enough to save important data or to transition to an alternate supply.

To ensure the safety of UPS equipment, please ensure that appropriately qualified staff:

• always follow the manufacturer's instructions and warnings
• if recommended by the manufacturer, disconnect UPS battery packs when in storage
• monitor the UPS's parameters and act upon any abnormalities or alerts
• replace battery packs according to the manufacturer's directions
• aquiring second hand UPSs is discouraged but if this is done, they should be thoroughly inspected and tested before being put into service
• enure that, where applicable, UPSs are tested, inspected and tagged as required by the ANU Electrical Safety Procedure.

The University has many UPS devices, the majority expertly controlled and maintained by Networks and Communications, Division of Information. However, there are many UPSs supporting research and other building infrastructure whose control and maintenance must be reviewed and may require improvement to achieve best practice

For further information, please see:

• AS 62040.1.1-2003 Uninterruptible power systems (UPS) -ÂÂ General and safety requirements for UPS used in operator access areas.
• AS 62040.1.2-2003 Uninterruptible power systems (UPS) - General and safety requirements for UPS used in restricted access locations.

Heat gun failure

Potential fire risk from electrical failure of a heat gun

A recent chemistry laboratory fire was found to have started as a result of electrical failure within a heat gun. Use of the appliance had caused twisting of the internal active and neutral wires within the flex. This could not have been observed without stripping back the flex. The consequence of twisting the internal wiring was localised heating, which led to an electrical short circuit that in this case progressed to the fire.The laboratory was fire damaged and surrounding rooms affected by smoke.

Most heat guns have a very large heating capacity (2 kW) potentially reaching temperatures up to 700 degrees Celsius. This far exceeds the temperature requirements of a laboratory worker.

All users of heat guns should:

• consider using alternate means of heating samples.  For example a hot plate on a low setting can be used to dry TLC plates
• use only equipment suitable for the task
• always use a heat gun on the minimum setting necessary to do the job
• use equipment only when and in areas that it is safe to do so
• do not use a heat gun near flammable materials and solvents or chemically contaminated atmosphere
• never touch the hot metal nozzle with clothing or skin
• consider mounting the heat gun in a fixed and permanent position.  Use a ring clamp or loop holder where possible
• turn heat guns (and hot plates etc) off when not in use.  Switch the equipment off at the wall socket and remove the plug from the power point when it’s not required for long periods
• ensure the heat gun air intakes and exhaust are clear of surfaces and other materials.  Never lay a heat gun on its side, whether it is in use or not.  Most air intakes are located in the sides of the motor housing and reducing the airflow over the heating elements will dramatically increase the temperature
• regularly inspect, test, and tag electrical equipment within the laboratory environment.  See the University’s Electrical Safety Procedure
• do not use damaged or faulty equipment. Tag it, take it out of service and report it.  Repairs must be undertaken by competent persons.