Vaisala HPP272 User Manual

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Cycle Phase
Aeration Decontamination Conditioning Dehumidification
CONDENSATION POINT
RELATIVE
SATURATION (RS)
RELATIVE HUMIDITY (RH)
VAPORIZED HYDROGEN
PEROXIDE CONCENTRATION
Humidity
H
2
O
2
Concentration
Figure 4 Example behavior of H
2
O
2
concentration, relative saturation (RS), and relative humidity
(RH) in a vaporized H
2
O
2
bio-decontamination cycle (non-condensing conditions)
In the non-condensing bio-decontamination cycle example shown in Figure 4 (page 17):
• In the dehumidification phase, RH (and RS) decreases.
• When the conditioning phase starts, H
2
O
2
concentration rises rapidly. There is also a rapid
increase in RS, which indicates the humidity caused by both H
2
O
2
vapor and water vapor.
Because the generated H
2
O
2
vapor is typically mixed with water vapor, RH also starts to
rise.
• In the decontamination phase, H
2
O
2
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, H
2
O
2
concentration, RS, and RH all decrease. When H
2
O
2
concentration is zero, RS equals RH.
The way your bio-decontamination process is designed
aects which parameters you want to
measure in dierent 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 H
2
O
2
vapor, which both
aect
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 H
2
O
2
vapor: relative
saturation (RS). When relative saturation reaches 100 %RS, the vapor mixture starts to
condense.
Chapter 3 – H2O2 Measurement
17

Vaisala HPP272 Specifications

General

Brand	Vaisala
Model	HPP272
Category	Measuring Instruments
Language	English