Sterilization is a process which achieves the complete destruction or killing of all
microorganisms, including bacterial spores.
Sterilization is principally accomplished by:
• Steam under pressure (Autoclaving)
• Dry heat (Hot Air Oven)
• The use of chemicals such as ethylene oxide gas (which is mainly used in
industry) or other low temperature methods (e.g. hydrogen peroxide gas
• Boiling and flaming are not effective sterilization techniques because they do
not effectively kill all microorganisms.
• Large health care facilities should have more than one type of sterilization
system in case of power outage, equipment failure, or shortage of supplies.
Pressure Steam Sterilization (Autoclaving)
Steam sterilization is the most common and most preferred method employed for
sterilization of all items that penetrate the skin and mucosa if they are heat
stable. Steam sterilization is dependable, non toxic, inexpensive, sporicidal, and
has rapid heating and good penetration of fabrics.
The steam must be applied for a specified time so that the items reach a
specified temperature. For unwrapped items:
• 121 °C for 20 min. at 1.036 Bar (15.03 psi) above atmospheric pressure.
• 134 °C for 3-4 minutes at 2.026 Bar (29.41 psi) above atmospheric pressure.
Astell03 BioClave mini autoclave Autoclave 3000
Types of steam sterilizers
1. Small table-top sterilizers
• Sometimes used in physicians’ and dentists’ offices and clinics.
• Are essentially horizontal pressure cookers.
• Holding temperature for unwrapped items:
• 121ºC for 20 minutes or 134 °C for 3-4 minutes.
2. Portable steam sterilizer
These can be adapted for processing critical devices in low resource settings.
In addition, pressure cookers can provide adequate steam sterilization in
situations where conditions and resources are severely limited.
3. Gravity downward-displacement sterilizers
• Larger than tabletop sterilizers with addition of more automatic controls.
• The chamber fills with steam, displacing the air downward and forcing it out of
the drain valve.
• Holding temperature for unwrapped items: 121ºC for 20 minutes or 134 °C for 3-4 minutes.
4. High-speed prevacuum vacuum sterilizers (Porous load autoclaves)
• Similar to downward-displacement sterilizers, with the addition of a vacuum
• Vacuum pump removes the air from the chamber before the steam is
admitted, reducing the penetration time and total cycle time.
• Holding temperature 134ºC for 3-4 minutes for wrapped items.
• Ideally used for wrapped items and porous loads (fabrics, swabs, instruments
we are in Technotronics company repair many boards and models of sterilizers such as :-
ü FUJI steam sterilizer.
ü ELITE steam sterilizer.
ü Hirayama steam sterilizer (HA series – HL series )
ü TAU sterilizer.
ü Astell sterilizer.
ü Prestige sterilizer
ü MIDMARK sterilizer.
Validator - original autoclave
CISA sterilization system
Astell Large Frontload