Typical applications - HPP272

HPP272 User Guide
Document code
M211972EN
Revision
G
Language
English
Product
HPP272
Document type
User guide

The probe is not intended for safety level measurement.

The probe is not intended to be used in vacuum applications.

Vaporized hydrogen peroxide is used for bio-decontamination in several applications from healthcare and pharmaceutics to food and beverage industry. Vaporized hydrogen peroxide is an easy-to-use and effective bio-decontaminating agent that destroys the full spectrum of biological contaminants including micro-organisms such as bacterial spores, mycobacteria, and non-enveloped, non-lipid viruses. Bio-decontamination with vaporized hydrogen peroxide is a low-temperature, environmentally friendly process that leaves no real residues, only water vapor and oxygen. One of the benefits also is that the bio-decontamination process can be validated.

Common vaporized H2O2 bio-decontamination applications include isolators, transfer hatches, closed Restricted Access Barrier Systems, and room bio-decontamination (for example, in hospital environments, cleanrooms, decontamination tents, aircrafts, ships, and shipping containers).

The bio-decontamination process typically has the following phases:
  1. Optional dehumidification, where relative humidity is decreased to a desired level, for example, by warming the space.
  2. Conditioning, where vaporized H2O2 mixture is introduced into the space to be bio-decontaminated.
  3. Decontamination, where H2O2 concentration is maintained at a desired level for a certain time.
  4. Aeration, where H2O2 is removed from the bio-decontaminated space.
Figure 1. Example behavior of H2O2 concentration, relative saturation (RS), and relative humidity (RH) in a vaporized H2O2 bio-decontamination cycle (non-condensing conditions)
In the non-condensing bio-decontamination cycle example shown in Figure 1:
  • In the dehumidification phase, RH (and RS) decreases.
  • When the conditioning phase starts, H2O2 concentration rises rapidly. There is also a rapid increase in RS, which indicates the humidity caused by both H2O2 vapor and water vapor. Because the generated H2O2 vapor is typically mixed with water vapor, RH also starts to rise.
  • In the decontamination phase, H2O2 concentration is steady. However, RS level rises slowly close to 100 %RS, i.e. condensation point, due to rising RH level.
  • In the aeration phase, H2O2 concentration, RS, and RH all decrease. When H2O2 concentration is zero, RS equals RH.

The way your bio-decontamination process is designed affects which parameters you want to measure in different phases.

Depending on your bio-decontamination process, you may also want to either create or avoid condensation during the conditioning and decontamination phases. In these phases, the air in the bio-decontaminated space always contains both water and H2O2 vapor, which both affect the possibility of condensation. To monitor and control whether and when condensation forms, it is useful to know the combined humidity level of water vapor and H2O2 vapor: relative saturation (RS). When relative saturation reaches 100 %RS, the vapor mixture starts to condense.

For condensation monitoring, choosing the right measurement location is very important. If the bio-decontaminated space has surfaces with a lower temperature than where RS is measured, condensation may start to form on those surfaces even before RS reaches 100 %RS in the exact measurement location. To monitor the possibility of condensation, consider installing the probe close to a surface where you suspect condensation may form.