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Astell Autoclaves/Sterilisers – AMB220 | AMB230 | AMB240 | AMB420 | AMB430 | AMB440 | AMA240 | AMA440
STERILISATION CYCLES
NOTES AND ADVICE
This information is in addition to information on
sterilisation cycles given in the programming manual.
This machine is delivered with two basic types of cycle.
Other cycles may be entered based on either of these.
1.
Fluids cycle
2.
Dry cycle
FLUIDS CYCLE
This is suitable for processing media or other fluids in
unsealed containers.
DRY CYCLE
Suitable for instruments, dry glassware etc.
Note:
This is not intended for sterilizing fabrics or porous
loads. You may sterilize these loads however they may
come out wet.
SELECTING A FREESTEAM TIME
Free steaming times are between 3 and 20 minutes.
Longer than 15 minutes on an unloaded or lightly loaded
chamber may cause problems with boiling dry open load
containers without drain holes which can collect and trap
condensate from draining back down to the chamber
base – can retain water causing boiling dry .
Long free steaming times can mean excessive heating in
the condensate bottle and potential hazards from steam
and condensation.
Please ensure that the load and containers match the
selected cycle.
LOADING & PLASTIC BAGS
Note that the worst loads for air removal are loads in
plastic bags, loads with lots of small spaces like petri
dishes, small bottles etc. These will always need a longer
free steaming period. Best performance is obtained when
plastic bags are not used.
If it is in a plastic bag this should not be sealed and the
top must be opened up completely and ideally rolled
down so that the maximum area of the load is exposed to
the steam without the top of the bag getting in the way.
The container holding the bag must have large holes on
the sides to allow steam to enter the container sides and
the plastic bag must be slashed or cut with a knife through
these holes so that the steam can get into the bag.
A variety of different special containers are available from
Astell that contain the load and allow thorough air and
steam passage, whilst maintaining integrity and facilitating
pouring away liquid residue. Please consult your supplier.
SELECTING STERILIZE TEMPERATURE /
SELECTING STERILIZE TIME
The UK Medical Research Council recommended
the following time/temperature relationships for the
achievement of sterilising conditions:
Minimum
sterilize
temperature
Maximum
sterilize
temperature
Minimum
sterilize hold
time
134°C
138°C
3 min
126°C
129°C
10 min
121°C
124°C
15 min
115°C
118°C
30 min
Lower temperatures or shorter times may have to be used
to prevent degradation of bacterial growth media. This
may be adequate for culture purposes, but does may not
constitute full sterilization. The manufacturer of the media
will usually specify the sterilizing temperature.
Temperature Tolerance
Please note that during sterilizing the temperature will
normally cycle up and down over a range of approx.
±0.7°C around the set sterilise temperature.
Specified settings
Recommended cycle
settings
134°C -0+4
3 min
135°C or 136°C
3 min
126°C -0+3
10 min
128°C
10 min
121°C -0+3
15 min
123°C or 122°C
15 min
115°C -0+3
30 min
116°C
30 min
Load sensed timing
Allowance for extra sterilise time for load to reach sterilise
temperature.
Fluid loads normally require an allowance for extra time
for heat-up as they suffer from high thermal inertia. If the
load sensed timing option is not used an allowance is
needed for the time taken for the load to catch up with
the chamber temperature. Extra time should be added to
the sterilise time to compensate.