Physical Hazards and Safety
Page Contents
Include: Visual Display Units | Filing Cabinets | Manual Handling- Lifting and Carrying | Drying and Sterilising Ovens | Microwaves | Low Temperature Freezers | Dry Ice | Ultraviolet Light | Electrical Faults
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Visual Display Units
Posture
The operator should sit directly in front of the screen and keyboard, and adjust the work to prevent twisting of the body or neck. The back should be kept straight, with the feet flat on the floor (or foot rest), and the thighs supported by the chair and aligned parallel to the floor. The height of the keyboard (or chair) should be adjusted so that the arms are roughly parallel to the thighs. A minimum 10 minutes break to do other activities should be taken every hour.
Eye strain
To avoid glare and reflections, the best position to sit is well away from the windows, with the light coming from above and slightly behind the operator. However, regardless of the location, glare and/or reflections can usually be minimised by adjusting the angle of the VDU screen and/or by using blinds or screens. The VDU screen should be dusted regularly, and the brightness should be set at a moderate level. In some locations, operators may find that reverse contact may be more comfortable for their eyes. See the duty programmer if this is required. Again, it is important for operators to have a 10 minute break to rest their eyes after each 1 hour session.
Filing Cabinets
The weight of paper in a filled filing cabinet drawer is considerable. It is important to correctly adjust both the load and the contents to prevent the cabinet from overbalancing. When filling a cabinet, spread the contents evenly, preferably filling the bottom drawers first. Do not overfill the top drawers, and always have one drawer open at a time. This will also prevent you from banging your head if you have been delving into a low drawer. Never leave drawers open. Close drawers gently, holding the handle to prevent your fingers from being jammed. Boxes, files, etc are not to be stored on top of the office compactus otherwise serious injury may arise when it is opened.
Manual Handling - Lifting and Carrying
Always assess the load, and seek assistance with heavy or awkward loads that are beyond your capabilities. Wherever possible use trolleys to transport loads.
If you are going to lift and carry a heavy or large item:
- Check that there are no obstacles in the route you wish to take, and ensure that the area where you wish to put it down is clear BEFORE YOU PICK IT UP.
- Stand straight on and close to the object with feet spread apart for balance.
- Squat down bending your knees, and, KEEPING YOUR BACK STRAIGHT, grasp the object firmly, breathe in and lift by slowly straightening your legs. Then return your back to vertical.
- Carry the object close to your body and use the reverse procedure when putting it down.
- Avoid twisting movements when lifting.
- REMEMBER: If the item is large, heavy or awkward, ASK for some assistance.
Drying and Sterilising Ovens
Contact with items at the temperatures reached by these ovens (100ºC - 200ºC) can produce burns to the fingers, hands, forearms and upper arms.
When loading or unloading hot ovens, always wear protective heat resistant gloves, preferably elbow length and have gown sleeves rolled down to protect the upper arm in case of accidental contact with the hot door or sides of the oven. Unload the hot objects directly onto an adjacent bench or trolley.
Microwave Ovens
Whilst microwave ovens heat the fluid itself, protective heat resistant gloves should still be worn when hot liquids are removed from the microwave ovens. This precaution will protect the operator from transferred heat and steam.
Additional care must be taken when agar is being melted, since the solution can be superheated and boil over rapidly when the flask is moved.
No closed vessel may be heated in a microwave. Take off caps and lids. Even a loosened lid can result in pressure build-up, and is not permitted. If sterility is required, use an autoclave set to zero minutes instead.
Low Temperature Freezers
Insulated gloves must be worn when accessing and handling material from low temperature freezers (i.e. -70ºC to -80ºC), as direct contact with items, particularly metal objects, can cause frostbite.
Dry Ice
Dry ice (solidified CO2) has a temperature of about -60ºC. Thus, direct contact with dry ice, or objects which have been in contact with it, can produce frostbite to unprotected skin. Protective leather gloves must be worn during all handling procedures.
One kilogram of dry ice evaporates to give 535 litres of CO2 gas. Thus good ventilation is required in areas where dry ice is in use, as an excess of CO2 gas will displace the normal air leading to asphyxiation. As CO2 is heavier than air, pockets of CO2 can collect in enclosed low spaces.
When transporting dry ice, or items stored in dry ice, use a thermally insulated container with a loose-fitting lid. The thicker the insulation, the slower the dry ice will sublimate, ie change from solid to CO2 gas. Do not use a completely airtight container, as the sublimation of dry ice to CO2 gas will cause any airtight container to expand, and possibly rupture or explode.
Provided the dry ice is within a suitable container, transportation in an elevator should not be a problem. In a well-insulated container, dry ice does not change state very rapidly and in the event of a elevator malfunction, CO2 emissions should not reach levels high enough to be hazardous.
NOTE: CO2 is the body's regulator of the breathing function. It is normally present in the air at a concentration of 300 ppm by volume. Appreciable increases above this level will cause acceleration of breathing and heart rate. Concentrations in the order of 10% can cause respiratory paralysis. As the gas is odourless, colourless and tasteless, it cannot be detected by human senses. Therefore, this may happen without warning.
NOTE: Ear protection should be worn during the production of dry ice due to the noise level.
Ultraviolet Light
The wavelengths of ultraviolet light used either for germicidal action (eg. in laminar flow and biohazard units) or visualisation of DNA (eg. transilluminators) are extremely damaging to the eyes, and prolonged exposure can also produce dangerous "sunburning" of the skin.
For this reason biohazard units are fitted with safety interlock switches to ensure that the UV lamp is off when the visible light and fans are on. Biohazard units are also provided with "night covers", which should be fitted to close off the work face opening when the UV lamp is in operation.
The safety glasses supplied by the Department provide full screening of the eyes from UV light, but full UV absorbing face masks and gloves should be worn when you are working at a transilluminator.
Electrical Faults
Repairs or modifications to apparatus or equipment should only be undertaken by a qualified tradesman.
Cracked plugs, frayed leads or faulty insulation should be replaced by a suitably qualified electrical tradesman.
Any faulty equipment should be immediately tagged out using the guidelines in the Departmental
Tag Out (Danger Tag) Procedure. Report any electrical faults to Skudtek, and complete an equipment repair form
The use of double adaptors is prohibited. Power boards are a more practical and safe method of using single power points.
Never touch electrical equipment with wet hands or whilst standing on a wet surface.