Condensation monitoring - HPP272

HPP272 User Guide

Document code
Document type
User guide

H2O+H2O2 vapor mixture starts to condense when relative saturation (RS) reaches 100 %RS.

RS level is strongly affected by temperature: decreasing the temperature increases RS. If there are temperature differences in the bio-decontaminated space, RS varies in different parts of that space even if the H2O+H2O2 vapor is evenly distributed.

Figure 1. Example: RS behavior in different temperatures when H2O2 concentration (500 ppm) and H2O concentration (8850 ppm) are constant

For condensation monitoring, this means that even if you measure < 100 %RS in one point, RS may be 100 %RS in another, cooler point. The following figure shows an example of how RS can vary in a decontaminated space according to temperature differences.

Figure 2. Decontaminated space with different temperatures and RS levels (H2O2 and H2O concentration evenly distributed)
Center of the decontaminated space. The center is warmer than the wall and the window, and the RS level is lower.
Wall of the decontaminated space. Because the wall is 0.5 °C cooler than the center of the space, RS level is higher than in the center.
Window of the decontaminated space. The window is 1 °C cooler than the center of the space, and RS = 100 %RS. Condensation starts to form on the window surface.
Condensation forms typically on surfaces, and first on surfaces that are cooler than the surrounding air, such as:
  • Walls
  • Windows
  • Supplies that have just been brought in the decontaminated space

To monitor the possibility of condensation by measuring RS, it is recommended to measure as close as possible to places where condensation might occur.