4.3. SURFACE TEMPERATURE MEASUREMENTS
The temperature
of
surfaces such as windows, walls, radiators, etc., influence the envi-
ronment within a
building
or
vehicle. Hot
or
cold surfaces can cause air movement
or
draught and also cause asymmetry within the thermal environment (see also section 4.6).
Thus, although overall
or
mean values
of
temperature may lie within the
comfort
region,
hot
and/or
cold surfaces may be responsible
for
a
greater-than-expected
number
of
complaints from the individuals within that environment.
ISO 7730 recommends that
for
environments where people are engaged in light, mainly
sedentary activity, the surface temperature
of
the floor during winter conditions (heating
period)
should normally be between 19 and 26°C (66 and 79°F). However,
for
floor
heating systems the floor surface temperature may be designed up
to
29°C (84°F).
Fig. 4.3
illustrates the relationship between floor temperature and the percentage
of
peo-
ple dissatisfied.
%,-----------------------------------------------------------------------.
80
Cold and Warm Floors
60
40
20
"0
!!
iii
~
10
Ill
Ill
i5
8
6
4
2
1
5
10
15
20
25 30 35
40
Floor Temperature
841210
Fig. 4.3. Relationship between
Cold
and
Warm Floors
and
percentage
dissatisfied
4.3.1. Use of the Surface Temperature Transducer
Accurate measurements
of
surface temperature depend on a good contact between the
Transducer and the surface being measured.
It is also necessary
for
the surface to have
a high
thermal conductivity and
to
allow a sufficient length
of
time
to
elapse
for
equilib-
rium
to
be reached.
When measuring surface temperature
it
is good practice to take into account the reduc-
tion in temperature
of
the measurement surface caused by the absorbtion
of
heat by a
transducer. The usual procedure is
to
conduct three measurements very close to one
another,
allowing each to stabilize before moving the transducer, and taking the last
reading to be the true surface temperature.
33
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