Autoclave tape is an
adhesive tape used in
autoclaving
An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform sterilizat ...
(heating under high pressure with steam to sterilise) to indicate whether a specific temperature has been reached.
Autoclave tape works by changing color after exposure to temperatures commonly used in sterilization processes, typically 121°C in a steam autoclave.
Small strips of the tape are applied to the items before they are placed into the autoclave. The tape is similar to
masking tape
Masking tape, also known as painter's tape, is a type of pressure-sensitive tape made of a thin and easy-to-tear paper, and an easily released pressure-sensitive adhesive. It is available in a variety of widths. It is used mainly in painting, to ...
but slightly more adhesive, to allow it to adhere under the hot, moist conditions of the autoclave. One such tape has diagonal markings containing an ink which changes colour (usually
beige
Beige is variously described as a pale sandy fawn color, a grayish tan, a light-grayish yellowish brown, or a pale to grayish yellow. It takes its name from French, where the word originally meant natural wool that has been neither bleached no ...
or
blue
Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The eye perceives blue when obs ...
to
black
Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have o ...
) upon heating.
It is important to note that the presence of autoclave tape that has changed color on an item does not ensure that the product is sterile, as the tape will change color upon exposure only. For steam sterilization to occur, the entire item must completely reach and maintain 121°C for 15–20 minutes with proper steam exposure to ensure sterilization.
The color-changing indicator of tape is usually
lead carbonate
Lead(II) carbonate is the chemical compound with the chemical formula . It is a white solid with several practical uses, despite its toxicity. It occurs naturally as the mineral cerussite.
Structure
Like all metal carbonates, lead(II) carbonate a ...
based, which decomposes to
lead(II) oxide
Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula Pb O. PbO occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern ap ...
. To protect users from lead -- and because this decomposition can occur at many moderate temperatures -- manufactures may protect the lead carbonate layer with a resin or polymer that is degraded under steam at high temperature.
References
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Laboratory equipment
Medical equipment
Medical hygiene
Microbiology equipment