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HD 32.3_2imagesHD 32.3_3HD 32.3_4em-people_energy_loadsHD 32.3_6EM-THERMIC BALANCE wbgt, pmv, ppd, confort, disconfort,HD 32.3_5images 3images 4IMAGES 2Immagine1

EM-HD32.3, EM-HD32.3A Instrument for the analysis of the INDICES: WBGT – PMV – PPD

EM-HD32.3 – WBGT – PMV Index is an instrument for:
• Analysis of hot environments using WBGT index (Wet Bulb Glob Temperature: wet bulb
temperature and Globe thermometer) in presence or absence of solar radiation.
• Analysis of the moderate warm environments using PMV index (Predicted Mean Vote)
and PPD index (Predicted Percentage of Dissatisfied).
Reference standards:
ISO 7243: Hot environments. Estimation of the heat stress on working man, based on
WBGT index (wet bulb globe Thermometer).
ISO 8996: Ergonomics of the thermal environment. Determination of metabolic rate.
ISO 7726: Ergonomics of the thermal environment – Instruments for measuring physical
quantities.
ISO 7730: Moderate thermal environments. Determination of PMV and PPD index and
specification of the condition for thermal comfort.

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Product Description

EM-HD32.3 – WBGT – PMV Index is an instrument for:
• Analysis of hot environments using WBGT index (Wet Bulb Glob Temperature: wet bulb
temperature and Globe thermometer) in presence or absence of solar radiation.
• Analysis of the moderate warm environments using PMV index (Predicted Mean Vote)
and PPD index (Predicted Percentage of Dissatisfied).
Reference standards:
ISO 7243: Hot environments. Estimation of the heat stress on working man, based on
WBGT index (wet bulb globe Thermometer).
ISO 8996: Ergonomics of the thermal environment. Determination of metabolic rate.
ISO 7726: Ergonomics of the thermal environment – Instruments for measuring physical
quantities.
ISO 7730: Moderate thermal environments. Determination of PMV and PPD index and
specification of the condition for thermal comfort.
The instrument is provided with three inputs for probes : the probe module is an interface between the instrument and connected sensor and communicates
the sensor parameters and calibration data to the instrument.
All probes can be plugged into any of the inputs: they are automatically recognized upon turning on the instrument.
The main features of the instrument are:
• Logging: data acquisition and logging in the internal instrument memory. Storage
capacity: 64 different logging sections, sample interval, user selectable.
• Start and stop can be set automatically with the auto-start function,
• Selectable measurement unit of the temperature: °C, °F, °K.
• The display of maximum, minimum, medium statistic parameters.
• The data transfer via RS232 or USB serial port.

EM-HD32.3 instrument can detect simultaneously the following quantities:
• Globe thermometer temperature Tg with TP3276.2 (or TP3275) probe.
• Natural wet bulb temperature Tn with HP3201.2 (or HP3201) probe.
• Environment temperature T with TP3207.2 probe (or TP3207).
• Relative humidity RH and environment temperature T with HP3217.2 (or HP3217R)
probe.
• Air speed Va with AP3203.2 (or AP3203) probe.
Starting from the measured values, HD32.3 can calculate and display, with TP3207.2
(or TP3207), TP3276.2 (or TP3275), and HP3201.2 (or HP3201) probes, the following
indexes:
• WBGT (in) Index (Wet Bulb Glob Temperature: wet bulb temperature and globe
thermometer) in absence of solar radiation.
• WBGT (out) Index (Wet Bulb Glob Temperature: wet bulb temperature and globe
thermometer) in presence of solar radiation.
Starting from the measured values, the HD32.3 instrument can calculate and display,
with HP3217.2R (or HP3217R), TP3276.2 (or TP3276 or TP3275), and AP3203.2 (or
AP3203) probes, the following indexes:
• Medium radiant temperature Tr.
• PMV Index (Predicted Mean Vote).
• PPD Index (Predicted Percentage of Dissatisfied).
WBGT index
WBGT (Wet Bulb Globe Temperature – wet bulb and globe temperature) is one of the
indexes used to determinate the occupational heat exposure.
It represents the value, related to the metabolic expenditure linked to a specific work
activity, that causes a thermal stress when exceeded.
WBGT index combines the measurement of wet bulb temperature tnw with natural
ventilation with the globe thermometer temperature tg and, in some situations, with the
air temperature ta.
The calculation formula is the following:
• inside and outside the buildings in absence of solar radiation:
WBGTclose environments = 0,7 tnw + 0,3 tg
• outside the buildings in presence of solar radiation:
WBGToutside environments= 0,7 tnw + 0,2 tg + 0,1 ta
where:
tnw = wet bulb temperature with natural ventilation;
tg = globe thermometer temperature;
ta = air temperature.
The measured data should be compared with the limit values prescribed by the
regulations;
when exceeded you have to:
• reduce directly the thermal stress on the examined work place;
• proceed to a detailed analysis of the thermal stress.
In order to measure the WBGT index, the following probes should be connected:
• Natural wet bulb HP3201.2 (or HP3201).
• TP3276.2 (or TP3275 or TP3276) Globe thermometer probe.
• TP3207.2 (or TP3207) Dry bulb temperature, of the measurement is performed in
presence of solar radiation.
In order to measure the WBGT index, you should refer to the following regulations:
• ISO 7726
• ISO 7243
• ISO 8996
PMV – PPD indexes
Human thermal comfort is defined by ASHRAE (American Society of Heating, Refrigerating
and Air Conditioning Engineers INC) as the state of mind that expresses satisfaction with
the surrounding living or working environment.
The evaluation of this subjective condition can be objectified and quantified using
integrated index that consider the micro climatic environment parameters (Ta, Tr, Va, RH),
and the work-related energy metabolic expenditure MET, and the typology of clothing
(thermal insulation CLO) commonly used.
Among these indexes, the most precise one reflecting the influence of the above
mentioned physical and physiological variables on thermal comfort is PMV (Predicted
Mean Vote).
Synthetically, it comes from the equation of the thermal balance whose result is compared
to a scale of psycho – physical health and expresses the average opinion (average
foreseen vote) about the thermal sensations of a group of subjects.
From PMV is derived a second index called PPD (Predicted Percentage of Dissatisfied)
that quantifies the percentage of subjects who will be dissatisfied with some micro
climatic conditions.
ISO 7730 regulations suggests PMV use in presence of following variables that influence
the thermal balance:
• Metabolic expenditure = 1 ÷ 4 met
• Thermal resistance of clothing = 0 ÷ 2 clo
• Dry bulb temperature = 10 ÷ 30°C
• Medium radiant temperature = 10 ÷ 40°C

Download

Manuals and Brochures here.  

HD32_3_WBGT_PMV_PPD.pdf

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