GHM Delta OHM HD32.3TCA, Руководство по эксплуатации

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HD32.3TC
- 8 -
V1.1
•
directly reduce the thermal stress in the workplace under consideration;
•
proceed with a detailed analysis of the thermal stress.
Table 3.1 : limit values of the thermal stress WBGT indicated in the ISO 7243 standard
METABOLIC
RATE
CLASS
METABOLIC RATE, M WBGT LIMIT VALUE
RELATIVE TO A
UNIT AREA OF
SKIN SURFACE
(W/m
2
)
TOTAL
(FOR AN
AVERAGE AREA
OF SKIN
SURFACE OF
1.8 m
2
)
(W)
INDIVIDUAL ACCLIMATED
TO HEAT
(°C)
INDIVIDUAL
NON- ACCLIMATED TO
HEAT
(°C)
0
(RESTING)
M ≤ 65 M ≤ 117 33 32
1 65 < M ≤ 130 117 < M ≤ 234 30 29
2 130 < M ≤ 200 234 < M ≤ 360 28 26
3 200 < M ≤ 260 360 < M ≤ 468
STAGNANT
AIR
25
NON- STAG-
NANT AIR
26
STAGNANT
AIR
22
NON-STAG-
NANT AIR
23
4 M > 260 M > 468 23 25 18 20
NOTE: THE VALUES HAVE BEEN ESTABLISHED TAKING AS A REFERENCE A MAXIMUM RECTAL TEMPERA-
TURE OF 38 °C.
To calculate the WBGT index, the following probes must be connected:
•
HP3201.2
,
HP3201
or
TP3204S
natural ventilation wet bulb temperature probe.
•
TP3276.2
or
TP3275
globe thermometer probe.
•
TP3207.2 or TP3207 dry bulb temperature probe if the detection is made in presence of
solar irradiation.
For the measurement of the WBGT index, reference is made to the standards:
•
ISO 7726
•
ISO 7243
3.2 P
REDICTED MEAN VOTE
PMV
AND PREDICTED PERCENTAGE OF DISSATISFIED
PPD
The thermal comfort is defined by ASHRAE (American Society of Heating, Refrigerating and Air
Conditioning Engineers INC) as a condition of psycho-physical well-being of the individual with
reference to the environment in which he lives and works.
The evaluation of such subjective state can be objectified and calculated using integrated indices
that consider the ambient microclimatic parameters (Ta, Tr, Va, RH), the energetic waste (met-
abolic waste MET) associated with the working activity and the clothing typology (thermal insu-
lation CLO) usually used.
The index that more accurately reflects the influence of the physical and physiological variables
is the
PMV
(Predicted Mean Vote) index.
In summary, it comes from the equation of thermal balance whose result is related with a psy-
cho-physical well-being scale and expresses the mean vote (predicted mean vote) on the thermal
sensations of a sample of individuals that are in the same environment.
From the PMV index is derived a second index called
PPD
(Predicted Percentage of Dissatisfied)
which quantifies in percentage the “dissatisfied” individuals in relation to certain microclimatic
conditions.
ISO 7730 standard suggests the PMV index use in presence of the following ranges of variations
of the variables influencing the thermal balance: