Centrifuge incident

A recent incident occurred on campus where an older model of bench-top centrifuge (see Figure 1) was discovered to be spinning at a speed that did not correspond to the speed on the dial of the machine.

A recent electrical incident involving this type of floor box (similar to Fig 1) resulted in the lid shearing off an electrical cable and loss of electrical power.

The centrifuge was being used with a new rotor that had a maximum speed of 2000 rpm. The rotor was spun at a higher speed, which resulted in a warping of the rotor (see Figure 2). Luckily no catastrophic failure of the rotor occurred.

It was found that the speed marked as '2000 rpm' on the dial at the front of the centrifuge was actually causing the rotor to spin at 3000 rpm.

An adjustment can be made to some centrifuges, which allows changes to the rotor speed. If an adjustment has been made it is possible that the rotor will spin at a higher or lower speed than that marked on the dial at the front of the centrifuge. This is potentially very dangerous.

Older centrifuges (those not under a service contract) should be tested and if not running correctly should be calibrated so that the rotor speed corresponds to the speed on the dial.

Avoiding heat related illnesses

Heat strain and stress on the body

Some ANU staff may be required to work outdoors during summer, while many ANU staff and students take the opportunity of warm summer weather to compete in lunchtime sport, ride bikes to and from work, jog, play tennis and other forms of outdoor exercise. The hot weather can make it difficult for the human body to maintain a normal core body temperature of 37 degrees Celsius. In temperatures at or above 35 degrees C, maintenance of internal body temperature during exercise becomes increasingly difficult, as the body is unable to lose the excess heat it is creating. While trying to maintain a normal internal temperature the body will use large amounts of water and salts.

ANU staff and students should be on the lookout, in themselves and others, for symptoms of heat related illnesses including:

• reduced sporting performance or weakness
• mood changes, such as irritability, confusion or the inability to think straight
• muscle cramps
• headache
• dizziness and light headedness
• nausea
• vomiting
• pale, clammy skin

If the symptoms are not treated, a life-threatening condition known as heat stroke can develop.

Where temperatures are predicted to be around 32 degrees C or higher it is wise to restrict sporting activities and heavy exercise to early morning and early evening, particularly avoiding the hottest part of the day between about 11am - 3pm. ANU staff and students who exercise at lunchtime could consider exercising indoors (ie sheltered from radiant heat) or moving their exercise to a cooler time of day.

Fluid intake is important - aim to drink about 500ml of cool water before and after exercise, and about 200ml every 20 minutes throughout the exercise. Special sporting drinks may be useful to replace lost electrolytes during extended physical activity.

Take breaks in a cooler area such as the shade, to allow the body to cool.

If someone is showing symptoms of a heat illness or exhaustion, taking steps to cool them down is imperative to ensure they do not develop heat stroke:

• give cool drinks of water or dilute sports drink
• sponge the body with tepid water (not cold) and fan to increase evaporation
• first aid assistance may be sought from ANU local area first aid officers
• seek medical assistance if the person is not recovering or gets worse - ANU medical centre on campus may be contacted, or for emergencies (heat stroke) call an Ambulance.

Accidents or illnesses that occur to ANU staff during lunchtime sporting activities (on or off campus) should be reported to the OHS Unit via the online reporting system.

For further information please email the OHS Unit or OHS Officer