Vaisala HPP272 User Manual

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.
More Information
‣
Understanding Relative Humidity and Relative Saturation (page 10)
‣
Installation (page 20)
3.3 Condensation Monitoring
H
2
O+H
2
O
2
vapor mixture starts to condense when relative saturation (RS) reaches 100 %RS.
RS level is strongly aected by temperature: decreasing the temperature increases RS. If there
are temperature
dierences in the bio-decontaminated space, RS varies in dierent parts of
that space even if the H
2
O+H
2
O
2
vapor is evenly distributed.
Temperature
Relative saturation
21 21.5 22 22.5
100
95
85
90
H2O2 = 500 ppm
H2O = 8850 ppm
Figure 5 Example: RS behavior in dierent temperatures when H
2
O
2
concentration (500 ppm) and
H
2
O 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 dierences.
HPP272 User Guide M211972EN-B
18

Vaisala HPP272 Specifications

General

Brand	Vaisala
Model	HPP272
Category	Measuring Instruments
Language	English