Comfort Level - Pmv / Ppd (En 7730 / Ashrae 55) - TESTO 400 Instruction Manual

8 Click on Stop.

Values currently being measured are displayed. You now have three
options to proceed
Start: start another measurement.
9
Or:
New: launch a new measurement. The current measurement will be
deleted along with all readings (a warning is displayed).
Or:
Save: exit the current measurement and save all readings on the testo
400 (see Section 9.6).
Comfort level – PMV / PPD (EN 7730 /
9.4.9
ASHRAE 55)
The PMV/PPD measurement determines the comfort level (PMV = Predicted
Mean Vote) and the relative discomfort (PPD = Predicted Percentage
Dissatisfied) e.g. at workstations (described in the standard ISO 7730).
The mean radiation temperature required for determining PMV/PPD is
calculated in the testo 400 from the measurement parameters of globe
temperature, ambient temperature and air velocity. The formula is based on
forced convection and applies to standard bulbs 150 mm in diameter in
accordance with DIN EN ISO 7726.
Necessary measurement parameters
• Mean radiation temperature in °C = t
• Globe temperature in °C = t
• Ambient temperature in °C = t
• Air velocity in m/s = v
t = [(t
r
For the PMV/PPD calculation, we use the measured temperature of the
humidity probe for the ambient temperature. At low flow velocities < 0.2
m/s, the temperature of the turbulence probe cannot be used because a
slightly increased temperature is indicated due to the thermal effect of
the hot wire.
g
a
a
+273) 4 +2.5*10
g
r
8 *v 0.6 *(t -t )]
a g a
9 Operation
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