Autoclave uses moist heat sterilization for sterilizing and decontaminating the equipments. Autoclave sterilizes the equipments by subjecting them to high pressure saturated steam at 121 degree C and 15 pounds of pressure per square inch depending for around 15-20 minutes on the size of the load and the contents.

As autoclave works by allowing steam to enter and maintaining extremely high pressure for at least 15 minutes therefore heat labile products cannot be sterilized using the autoclave such as plastics etc. Some materials present specific hazards when autoclaved such as production of toxic or noxious gases. There is a limit for the materials which can be autoclaved and which cannot. (As stated earlier heat labile articles cannot be autoclaved).

Certain equipment and material cannot tolerate the high temperatures of the autoclave. If you are unsure, do not put the items into the autoclave – always ask first!

Autoclave COMPATIBLE materials (OK to autoclave):

• Tissue Culture Flasks
• Surgical Instruments
• Glassware (see note below on glass before autoclaving)
• Pipette tips
• Media Solutions
• Animal food and bedding
• Waste
• Polypropylene (Secondary containers)
• Stainless steel
• Gloves

• Acids, bases and organic solvents
• Chlorides, sulphates
• Seawater
• Chlorine, hypochlorite, bleach
• Non-stainless steel
• Polystyrene (PS)
• Polyethylene (PE)
• Low density (LDPE) and High density polyethylene (HDPE)
• Polyurethane
• Polyvinyl chloride (PVC)
• Nylon
• Acrylic

• Flammable, reactive, corrosive, toxic or radioactive materials
• Household bleach
• Any liquid in a sealed container
• Any material contained in such a manner that it touches the interior surfaces of the autoclave
• Paraffin-embedded tissue

• Glass

Only Pyrex® or Type I borosilicate glass is autoclavable.

• Sterilizing liquids in glass bottles

When autoclaving liquids in Pyrex® containers, do not fill more than 2/3 full and do not seal the container (loosely tighten the lid if there is one).

• Plastic

Polypropylene is an inexpensive resin that can resist autoclave temperatures. Polypropylene containers are often used as secondary containers to hold materials that are autoclaved.  Polycarbonate can also withstand high temperatures.

Polystyrene (PS), polyvinyl chloride (PVC), nylon, acrylic, low-density polyethylene (LDPE), and high-density polyethylene (HDPE) lab ware and polyurethane tubing are not autoclavable under any conditions.

• Gloves

Gloves must be placed inside of an autoclavable biohazard bag and exposed to a steam setting; gloves will melt slightly but will not burn when autoclaved in this manner.

• Stainless steel

Most metals are designed for extreme conditions and are intended to be sterilized. Make sure to remove any plastics, liners and other items that may melt or combust.

• Paper

Paper is combustible and should not be placed directly inside an autoclave. It should be autoclaved in a waste bag on a biobag setting to prevent fire.

• Media Solution

No liquid should be sealed in a container and autoclaved. Fill 2/3 of the container and loosen caps. They should autoclaved in a steam producing cycle.

• Pipette tips

Most pipette tips are autoclavable. Some of these tips are plastic, some are high density polyethylene. In general, pipette tips should only enter the autoclave as waste inside of an approved biohazard bag and always sterilized on a steam-producing setting.