for general medical supplies in health facilities with limited resources 

Second draft 10-12-2002

Intended use

The sterilizer should be suitable for sterilization of medical supplies:

• Porous loads
• Surgical instrument sets
• Rubber ware

Functional requirements

The processed load shall meet the requirements given in the European Standards EN556 in terms of Sterility Assurance Level. The manufacturer shall provide written confirmation of compliance to these requirements.

Compliance to these requirements implies:

• The presence of provisions for adequate pre-sterilization air removal
• The presence of provisions fro adequate drying
• Successfully passing the porous load test as per EN285 including the standard Bowie and Dick test pack
• Successfully passing the full porous load dryness test as per EN285
• Successfully passing the rubber load test as per EN285

Chamber

The chamber shall:

• Have a volume in the range of 50-150 litres.
• Preferably be fitted with a jacket.
• Be constructed of stainless steel.
• Provide an extra port for thermocouple entry.

Steam Generation

• Steam shall not be generated in the sterilizer chamber.
• Steam may be generated in the jacket or in a separate steam generator.

Control System

• Valves shall be operated mechanically (not by electric solenoid valves or pneumatic valves).
• It should be possible that relevant components (valves, locks etc) can be operated manually.
• It should be possible to step through the phases of the sterilization process manually.
• In order to reduce the chance of operator mistakes, single-knob operation for manual stepping through the sterilizer process preferred. An indicator shall display the current phase of the process.
• Where powered automatic or semi-automatic control systems are incorporated, it should be possible to commence through the process steps manually in case of a break down of the automatic control system or the failure of electrical power to the control system.
• Temperature control of the sterilization phase of the process can be through temperature or pressure. When controlled by pressure, it should be possible to compensate for the altitude of the location of installation. Adequate instructions shall be provided for calibrating the controller to correct temperature.

Instrumentation

The sterilizer shall be equipped with:

• Pressure gauge for jacket pressure, when fitted (preferred units in Bar or Pascals)
• Pressure gauge for chamber pressure (preferred units in Bar or Pascals)
• Thermometer indicating chamber temperature at the steam exhaust from the chamber (in ^oC and ^oF)
• Timer (either built-in or supplied as a separate item)
• If necessary the units on gauges can be adjusted to the requirements of the client

Mechanical and Electrical safety and quality

• Pressure vessels, piping and the safety devices should comply with the relevant international standards (prEN13445; unfired pressure vessels)
• Any electrical circuitry should comply with relevant international standards (IEC61010-2-045)
• When electrical heating is applied, the electrical heating system shall be 3-phase; suitable for the standard mains voltage of the country of destiny. (Usually 230/400VAC unless stated differently)
• Any electrical circuitry should allow voltage fluctuations of upto 254% above and below nominal voltage. If electronic components are used, the power supply to the electronic circuitry should incorporate a voltage stabilizer allowing voltage fluctuations of 30% and suppressing peak voltages and reducing the fluctuations to a maximum of 10%.
• The machines shall be designed for an operational lifespan of approximately 15 years of normal use.
• Kerosene burners shall meet minimum safety and performance requirements.
• All components shall be non-corrosive or protected such that corrosion will not occur.

Safety provisions

• Means shall be fitted to prevent the opening of the lid or door while the chamber is pressurized.
• The sterilizer shall have provisio0ns for the testing of the operation of the pressure safety devices.
• Where possible, the design shall reduce the chance on injuries caused by hot components.

Accessories

The sterilizer shall be provided with:

• 2 sets Grid baskets using the chamber space optimally
• Pieces of adequate tubing/piping for steam exhaust, cooling water (if applicable)
• Cable for electrical connection (if applicable)

Spare Parts

The sterilizer shall be provided with:

• A set of spare parts required for a period of 3 years of normal operation.
• Required spares will depend on the actual design. The following is a guideline:
• Lid/door gaskets
• Valves rings/seals
• Heating elements (if appropriate)
• Steam trap elements (if appropriate)
• Contractors for heating circuitry (if appropriate)
• Bulbs for indicator lights (if appropriate)
• Quantities of spare parts shall be recommended by the manufacturer, based on the expected lifespan of the specific parts.

The manufacturer shall ensure that spare parts are available for a period of atleast 15 years after commissioning of the sterilizer.

Maintenance

It shall be possible to perform all standard maintenance work with a basic, standard set of tools for mechanical/electrical engineering.

Documentation

The sterilizer shall be provided with

• Instructions for installation
• Instructions for the operator, regarding the processes for all types of loads, including a detailed description of the processes.
• Service manual, including instructions for maintenance and repair, planned preventative maintenance, full piping diagrams, electrical circuitry (if applicable)
• List of spare parts
• Documents, stating the compliance with the required standards on sterility and dryness for the specified loads, compliance with the relevant requirements related to pressure vessel and electrical installation.
• All documents shall be in the language as stated in the general conditions.