3M 34, 36 Measurements

Tri-sensor Calculation and Remote Cable

Measurements

The QUESTemp° 34 & 36 data logging area heat stress m onitor directly senses the

four parameters: ambient or dry bulb temperature (DB), natural wet bulb t e mp erature

(WB), globe temperature (G), and relative humidity ( RH).

The QT° 34/ 36 compute the Wet Bulb Globe T emperature (WBGT), stay times for

three possible indices (QT° 36 only), and the Heat Index (HI) or the Canadian

Humidex. Using inputs on the side of the instru men t, tw o addit i onal sens or arr ays can

monitor up to three locations s i mu lt aneously.

On the QUESTempº 36 model, you can measure air flow, in meter s per sec ond, by

plugging an optional hot wire anemometer sensor into a side jack o n t h e un it.

Using Detection Management Software (DMS), you can determine the thermal comfort

indices, Predicted Mean Vote (P MV) and Predicted Percent Dissatisf ie d ( PP D) (with

the QUESTempº 36 model only).

The WBGT is a weighted average of the three temper at ur e sen sors , a gl obe

thermometer, a wet bulb thermometer, and a dry-bulb thermometer, using the

equations listed below.

The resulting WBGT values can then be compared to indices of work-rest regimens

(stay times) based upon work loads.

Stay times represent how long a worker should be able to safely work under heat

stress conditions (available on QUESTempº 36 only). Select one of the three

indices for displaying and printing from the unit: ACGIH Stay Times, NAVY PHEL’s,

or EPRI Action Limits. (For setup, please refer to “Setup” on pages 9 -10. For

detailed rest times please refer to charts in Appendix B.)

WBGT (indoor) = 0.7WB + 0.3G (denoted as “WBGTi” on the display)

WBGT (outdoor) = 0.7WB + 0.2G + 0.1DB (denoted as “WBGTo” on the display)