Lindab PC 410 - Option U-Value

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6.9 Option “U-value” The heat transfer coefficient (U value) describes the heat flow
W/m²k that flows through a building element.
Fig. 57: Application example with Special
Wall Temperature Probe
Fig. 58: Display during the measurement
of the U value
NOTE!
A Special Wall Temperature Probe is needed to measure the
heat transfer coefficient (see accessories). All temperatures
(also the inside air temperature tai and the outside air tem-
perature tao should be measured with the same sensor.
The temperature values measured by the Lindab PC 410 and
the Special Wall Temperature Probe are necessary for the
determination of the heat transfer coefficient. The u-value is
determined with the following equation according to the DIN
standard 4108.
α
i
· [t
Li
– t
Wi
]
[t
Li
– t
La
]
U
ist
=
U
current
U-value in W/(m²k), current value
t
AI
interior air temperature
t
WI
interior wall temperature
a
i
fix value, 7,69 W/(m²k)
All temperatures (also the interior air temperature tai and
the outside air temperature t
ao
should be measured with the
same sensor.