These Semi-Automatic and Automatic Sterilizer is a stand alone, compact and fully automatic sterilizer, to cater to the needs of medium and large size hospitals. These can be fabricated in 4.0/4.5/5.0/8.0 cu.ft. or larger chamber volumes to suit customer requirements. These chamber volumes will work on 100% ethylene oxide disposable cartridges. The units have a flush, easy to operate door, a cartridge puncturing mechanism inside the chamber and state-of-the-art automation which is linked to sensors. All parameters can be set at startup and remain programmed as master cycle while the password facility ensures that these parameters, once set, cannot be changed by unauthorised persons.