Figure 27 Room Measurement Example - Michell Instruments Optidew User Manual

Optidew User's Manual
The basic considerations for each measurement type are as follows:
In Situ:
1. Dew-Point Sensor position – will the sensor see an area of the environment that is
representative of what you want to measure? For example; you are looking to measure the
Relative Humidity of a room which is controlled by an HVAC vent at either end (see figure
25) you will get very different readings depending on whether the sensor is positioned at
point A, point B or point C. Point C provides the most representative sampling point given
that it won't be disturbed by the vent or the door.
2. Gas speed – if you are planning on installing the sensor in a duct, consider how fast the
sample gas is moving through it. Excessive flow speed will cause displacement of the
condensate layer on the mirror, leading to unstable measurement.
If this is the case, then a guard fitted over the sensor can mitigate the effects of excessive
gas speed by dissipating the sample throughout it's surface area. An appropriate guard can
be purchased from Michell Instruments, contact your local representative.
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Figure 27 Room Measurement Example

97551 Issue 4.1, October 2019