Autoclave

Today I studied about autoclaves and SOP of the autoclave, So I thought to write small article what I learn from the SOPs for any person who would like to study. 

Autoclave is a specialized equipment used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure temperature. Autoclaves are use in medical applications to perform sterilization. 

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Autoclave is use for Cultures and stocks of infectious material, Culture dishes and related devices, Discarded live and attenuated vaccines, Contaminated solid items such as: petri dishes, pipettes, gloves, paper towels, lab coats, solid and liquid waste, Items for sterilization such as: glassware, media, liquid solutions, Some equipment. But we cannot autoclave chemicals (includes most disinfectants, e.g. bleach), Radioactive material, Some plastics.

As autoclaves use high pressure and high temperature steam for sterilization, there are some risks we need to give attention. Those are,

1. Heat burns from hot materials and autoclave chamber walls and door.

2. Steam burns from residual steam coming out from autoclave and materials on completion of the cycle.

3. Hot fluid scalds from boiling liquids and spillage in autoclave and during transport of superheated materials.

4. Hand and arm injuries when closing the door.

5. Explosions can also occur when the seal of the autoclave door malfunctions or when autoclave is improperly loaded. If sealed containers are used they may explode during the autoclave process.

6. Autoclaving certain chemicals may cause an explosion.

7. Vapors and gases from the accidental autoclaving of volatile chemicals.

8. Broken glassware if the autoclave door is opened too quickly, and sufficient time is not provided for glassware to approach room temperature.

To ensure the health and safety of personnel using the autoclave, it is important to train user. Also the user need to supply equipment to protect against scalds and burns. The Protective equipments mainly used are, eye/face protection (safety goggles /face shield; worn if there is a possibility of ocular splash),  gloves for heat, lab coats (long sleeved and knee length), shoes (with closed toe and heel), long Pants or Skirt (covered legs). 

Autoclave Procedure

Prior to using an autoclave

Check that the autoclave has been functioning correctly

1.     previous cycle log recordings (time, temperature, and pressure)

2.     the results of efficacy testing with biological indicators if available

Loading an Autoclave

1.     Wear lab coat, eye protection, heat-insulating gloves, and closed-toe shoes.

2.      Place material in the autoclave. Do not mix incompatible materials.

3.      Do not overload; leave sufficient room for steam circulation.

a.     All autoclave pans and containers should be sitting flat and not be angled or leaning inside the autoclave.

4.      Close and latch the door firmly.

Operating an Autoclave

1.     Verify that the door is latched firmly.

2.     Choose the appropriate cycle (i.e., gravity, liquid, or dry cycle) for the material. .

3.   Start your cycle and fill out the autoclave user log with your contact information. A completed cycle usually takes between 0.5 - 1.5 hours, depending on the type of cycle.

4.      Do not attempt to open the door while the autoclave is still operating.

5.      If problems with your autoclave are perceived, abort the cycle and report it to your PI
and the individual responsible for the autoclave immediately.

Unloading an Autoclave

1.     Wear heat-insulating gloves, eye protection, lab coat, and closed-toe shoes.

2.      Ensure that the cycle has completed and both temperature and pressure have returned to
a safe range.

a.     Typically this means that the temperature is below 100C and the pressure is back to 0 psi.

3.     Wearing PPE, stand to the side of the autoclave (not directly in front of the door) and unlatch the door slowly, allowing extra steam to escape. Once the door is completely unlatched, carefully open the door no more than 1-2 inches. This will release the remaining steam upwards and allow pressure within liquids and containers to normalize.

4.     Allow autoclaved load to stand for a few minutes in the chamber. This will allow steam to clear and trapped air to escape from hot liquids, reducing risk to the operator.

5.     Do not agitate containers of superheated liquids or remove caps before unloading.

a.     Do not agitate or remove caps until the liquids have cooled to a safe level.

6.     Wearing heat-insulated gloves, remove items from the autoclave and place them on a stable structure to allow them to cool.

a.     This stable structure may be a water bath for liquids which need to remain molten.

7.     Shut the autoclave door and partially latch if necessary to keep the door closed.