The Microtherm WBGT is an ergonomically designed, compact and rugged instrument designed to monitor heat stress potential of personnel in hot working environments in accordance with ISO 7243. It is the first heat stress meter that offers real time graphical display of data and also features an audible/visual alarm which allows the operator to make rapid decisions if required. PC software for retrospective data analysis is included.
Workers exposed to hot working environments can be susceptible to heat stress when the core body temperature rises to dangerous or hazardous levels. This can result in physiological symptoms like heat cramps, nausea, palpitations, stroke and possibly death. An overall estimation of heat stress levels on the body can be measured by utilizing the Wet Bulb Gold Temperature Index (WBGT). This combines the measurement of three parameters; natural wet bulb temperature (tnw), globe temperature (tg) and air temperature (ta), applied to the following formula for both indoor and outdoor environments:
WBGT (Indoor) = 0.7tnw + 0.3 tg
WBGT (Outdoor) = 0.7 tnw + 0.2 tg + 0.1 ta
The data collected for these values are compared to reference values (as defined by the standard and appropriate "work rest" regimes) can then be adopted in the workplace or more detailed medical analysis undertaken.
Applications
- Power stations
- Foundries
- Steel works
- Bakeries
- Glass manufacturing
- Routine monitoring
- Medical surveillance testing
Features
- Large LCD screen
- Real time display of changing levels
- Data logging as standard
- Low water level alarm
- Audible & visual warning for WBGT levels
- RH% and dewpoint calculation
- Windows PC software for setup and download of results from memory
- Automatic calculation of work/rest regimes with included PC software
- Tripod mounting for extended surveys
- Meets the requirements of ISO 7243
The WBGT meter measures simultaneously from three PRTD sensors for Wet Bulb, Dry Bulb and Globe Temperatures. Sensors are manufactured to high accuracy standards: BS EN60571 and DIN 43760.
Processed data values include:
- WBGT (indoor and outdoor)
- 1 hour (TWA0 WBGT values
- Relative humidity (%)
- Dewpoint
Sensors can be used either attached directly on the body of the unit or remotely via 10M extension cables. Both the electronic unit and sensor array can be tripod mounted.
The Microtherm WBGT incorporates a large 128 x 64 pixel graphics LCD with backlight, capable of displaying data in two modes:
- Graphical Representation - The Microtherm WBGt is the first area heat stress instrument to offer real time scrolling graph of the temperature parameters being measured. This display can be shown over variable time bases of 15, 30, 60 & 120 minutes. This allows the user to assess how the environment is changing over time, without having to download to a PC.
- Numerical Values - Instantaneous values for all parameters are displayed, combined with the hourly rolling average values.
- Alarm - An adjustable alarm threshold may be defined for one selected data channel: WBGTwa, WBGT, Ta or Off. An audible alarm and flashing visual message on the display screen provides warning of excedence of the threshold.
The Microtherm WBGT has been designed with a simple, easy to use menu structure for the displaying of information, instrument configuration and retrieval of data. The access of this menu via the tough keypad and screen prompts, ensures ease of use for the operator.
The software provides an interface for data collection to PC for retrospective analysis. It produces graphical and tabular reports which can easily be imported into other applications. Summary and WBGT Heat Stress Index reports can also be generated. Work rest regimes are calculated, Clothing (CLo) correction factors, and metabolic rates can be entered in accordance with OSHA and ISO 7243. Data can also be viewed "live" by selection of the real time option while connected to a PC.
Calibration of the Microtherm WBGT is performed against an internal reference prior to every single measurement. This ensures a high accuracy for each of the temperature sensors and eliminates the need for annual recalibration. Sensor arrays are also interchangeable without the need for recalibration.
Specifications
| Sensing Technique |
Platinum resistance temperature detectors (PRTD), 100 elements 0.1% using 4 wire cable up to 30' |
| TA, Dry Bulb, Air |
Range: 50 - 140ºF
Accuracy: ±2.0ºF |
| TG, Globe |
Range: 68 - 248ºF
Accuracy: ±2.0ºF |
| TNW, Natural Wet |
Range: 41 - 104ºF
Accuracy: ±1.0ºF |
| Resolution |
0.1% for temperature & humidity |
| Battery |
4 x AA, alkaline or rechargeable NiCad |
| Battery Life |
Alkaline: 85 hours
NiCad: 20 hours |
| Displayed & Stored Values |
Wet Bulb Globe Temperature Indoors & Outdoors
Wet Bulb Globe Temperature Indoors & Outdoors TWA, Ta, dry bulb, air, Tg, globe, Tnw, natural wet, dew point, relative humidity |
| Datalogging |
49,100 records at 30, 60 seconds, 1, 2, 3, 4, 5, 6, 10, 15, 20, 30, or 60 minutes, record and stop when memory full or overwrite oldest results |
| Software |
MS Windows, RS232 port, 8 Mb Ram, FDD & HDD, VGA graphics card |
| Battery Charging |
Internal NiCad fast charger circuitry, with time out protection |
| Keypad |
7 key tactile membrane |
| Weight |
26.5 ounces |
| Dimensions |
10 H x 3.7 W x 2.0" D |
Ordering Information
Each MicroTherm Heat Stress meter includes tri-temp sensor array, 10 spare wicks, distilled water, RS-232 cable, software, rechargeable batteries, power supply & charger and case. For pricing, please call AFC International at 1-800-952-3293, 219-987-6825 or fax 219-987-6826 or email sales@afcintl.com.
| Description |
Catalog No. |
| Microtherm Heat Stress Meter with accessories & calibration certificate |
180042A |
| Sensor Extension Lead, 30 feet |
180043B |
| In Car Charger |
176086B |
| Replacement Tri-Temp Sensor |
180036C
|
| Spare Wicks, pk/10 |
107039A
|
| Spare Download Cable |
151099B
|
Downloads
Mircotherm product literature