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The Vaporized Peracetic Acid (VPA) Sterilization Cycle

Vaporized Peracetic Acid (VPA) Cycle Description

A REVOX® Sterilization Solutions VPA sterilization cycle encompasses the following steps to sterilize a chamber load of products and consists of multiple “blocks” and chamber ventilations.

A biocide cycle block consists of the following phases:

  1. Chamber evacuation
  2. Chemical injection (which is chemical injection via vaporization, plus hold time)
  3. Chamber dehumidification
  4. Chamber ventilation 

Depending on the complexity of a device, multiple injection blocks may be used to achieve a complete cycle.

routine REVOX peracetic acid (PAA) sterilization cycle image
This diagram shows chamber pressure variability over time surrounding one chemical injection. These pressure differentials aid in the chemical penetration into and evacuation from the product.

The chamber evacuation phase removes the air from within the chamber and the packaging of the product being sterilized. The chemical injection phase vaporizes the peracetic acid (PAA) sterilant, also known as VPA, while raising the pressure within the chamber.

The hold time is the time between chemical injection and dehumidification. This phase allows the chemical to remain in contact with the product for an amount of time sufficient to ensure sterilization.

The chamber dehumidification phase removes the chemical from the chamber. Finally, the ventilation phase removes any residual chemical from the chamber and product.