Autoclave FAQ

Frequently Asked Questions about Autoclaves

 

Q     What size autoclave do I need?
A    
This is determined by two factors:

  1. The size and quantity of your loads
  2. The space available in your lab

 

Q     Does one autocalve sterilise any type of product?
A
     Not necessarily. There are two major types of loads; liquids and non-liquids. Each must be processed in a different way, to ensure good sterilisation and safe handling of the product. Some autoclaves are only designed for non-liquids (instruments, tubing,glassware), and these typically have a vacuum stage during the cool down. These autoclaves must never be used for liquids, as the vacuum will cause the sterilised liquid to boil vigourously with significant liquid loss.

Many autoclaves are designed to cope with both types of product, but don't assume - ask first.

 

Q     How do I know if my product is sterilised?
A     There are two simple tests commonly used. The first uses a special indicator tape (looks like masking tape), which when heated for the required amount of time for full sterilisation to occur, will develop black diagonal stripes on the tape. The second test is abiological spore test using special strips. These indicate full sterilisation by a colour change from the original colour prior to being autoclaved.


Q     Can I put sealed waste bags in an autoclave?
A     No. As with bottles, all bags must be open to allow the steam to enter the bags and displace the air. This is especially important for kill cycles, as the biohazard material will not be destroyed if steam is unable to make contact with it during sterilisation.This is where pre-vacuum pulses are critically important, as they remove the air from all bags or flasks and allow steam to reach the product.

 

Q     How often should I replace the water in an autoclave which has a heating element in the chamber?
A     The water should be completely drained every week, and the chamber cleaned. Refill with demineralised water then recheck the water level before every run.

 

Q     What type of water should I use in the autoclave?
A     Always use demineralised or distilled water because this will reduce the amount of cleaning required to keep the autoclave in good condition.

 

Q     What should I do if the autoclave doesn't work correctly?
A     Take note of any error codes on the display panel. Check the User Manual to see if there is a simple resolution (such as add water). If the fault requires a service technician, record the type of run that was happening when the fault occurred, along with theerror code or message, and call us on 0800 ALPHATECH. Ask for a service engineer.

 

Q     What is so special about 121°C?
A      121°C is a historical value which equates to the steam pressure which will lift a 1kg weight. Sterilisation at this temperature and pressure will take 15 minutes.

 

Q     What about 134°C?
A     134°C is the temperature achieved when the pressure at 121°C is doubled (or lifts a 2kg weight). Sterilisation at this temperature is achieved in 4 minutes.

 

Q     Is 134°C better than 121°C?
A
     No. The sterilisation time is shorter, but the heat up and cool down times are longer.

 

Q     Are 100% of the bacteria killed during sterilisation?
A     No. Sterilisation is a statistical measure where is progressively gets harder and harder to kill the few remaining organisms. For this reason, steam sterilisation will claim to kill 99.999% of all organisms. If a manufacturer claims to kill 100% of allorganisms, they are making a false claim.

 

Q     Are autoclaves safe?
A     Yes, autoclaves are safe if used correctly by trained operators. Live steam combined with pressure can be very dangerous, and caution should always be used. Safety interlocks should never be bypassed, and the lid or door should never be opened while the chamberis either hot or under pressure.

 

Q     Do I need to have the autoclave inspected and if so, how often?
A     Your autoclave needs to be inspected annually by an approved steam inspector. It also needs to have the safety valves replaced or recertified every two years. It is recommended that the autoclave also be checked by a trained service engineer annually, to ensurethat there are no safety issues with any of the autoclave systems.