QUESTemp QT-48N Portable Heat Stress Monitors

Offers Traditional Heat Stress Monitoring without the Aggravation of Maintaining a Wet Bulb.

The QUESTempº 48N offers traditional heat stress monitoring without the aggravation of maintaining a wet bulb. Through collaboration with Professor Dr. Thomas Bernard, from the College of Public Health at the University of South Florida, mathematical models were implemented to create a Waterless Wet Bulb calculation through a combination of dry bulb temperature, globe temperature, relative humidity, and air flow.
The QUESTempº 48N model was specifically engineered for the Department of Defense Ashore and Afloat Operations in which conditions require hand’s free monitoring, in-the-field user RH/WBGT sensor alignments, and snapshot measurement logging (called “event logging mode”).
The QT48N measures and calculates the dry bulb, wet bulb, globe, WBGT outdoors, and relative humidity with two different types of data logging modes – as a time history session or an event logging mode. You also have the capability to measure stay times in order to manage work/rest regimens. Guidance is based on the screening criteria for heat stress as defined in the ACGIH TLV Handbook, U.S. Navy PHEL charts, and Flag Conditions for U.S. Navy/Marine Corp. Ashore.

For more information on the QUESTemp QT-48N Portable Heat Stress Monitor, contact your local Air-Met office. 
  • Waterless wet bulb system
  • Ideal for athletic training facilities, military training, warehousing, occupational heat stress management, and risk analysis investigations
  • Measure and calculate dry bulb, wet bulb, and globe temperature, WBGT indoor/outdoor, relative humidity and heat index/humidex
  • Real-time clock provides accurate reporting with time stamping
  • Stay time measurement per ACGIH TLV Handbook, US Navy PHEL charts, US Marine Flag system, and EPRI action limits (QT46 only)
  • Compatible with 3M software for data storage, retrieval, analysis, reporting and charting
 Natural Wet Bulb ModelsWaterless Wet Bulb Models
Measurement Parameters: QT°32 QT°34 QT°36 QT°44 QT°46 QT°48N
Dry Bulb, Wet Bulb and Globe Temperatures, Relative Humidity
Air Velocity     option   option  
WBGT (indoor) Index  
WBGT (outdoor) Index
Heat Index/ HUMIDEX  
Temperature Reading: Celsius or Fahrenheit
Data Logging Intervals: 1, 2, 5, 10, 15, 30 or 60 minutes  
Event Logging Mode          
Display Languages: Choose from Chinese, Czech, English, French, German,
Italian, Japanese, Korean, Norwegian, Polish, Portuguese, Russian, Spanish, Swedish,
and Turkish
Time & Date Stamping with Clock and Calendar  
Displayed Stay Times: ACGIH TLV, U.S. Navy PHEL charts, U.S. Navy/Marine Corp. Ashore Flag Conditions, EPRI Action Limits (QT°48N excludes EPRI)      
Head-Torso-Ankle Weighted Average WBGT (optional with tri-sensors) option option option option option  
Dry Bulb Sensor - 1000 Ohm platinum RTD
Accuracy and Ranges: +/-0.5 from 0° C to 120° C (+/-0.9° F from 32° F to 248° F)
Wet Bulb Sensor - 1000 Ohm platinum RTD
Accuracy and Ranges: +/-0.5 from 0° C to 120° C (+/-0.9° F from 32° F to 248° F)
Waterless Wet Bulb (Humidity) sensor
Accuracy and Ranges: +/-1.1° C (k=2) between 0° C and 80° C (32° F and 176° F)
Globe Sensor - 1000 Ohm platinum RTD
Accuracy and Ranges: +/-0.5 from 0° C to 120° C (+/-0.9° F from 32° F to 248° F)
Relative Humidity Sensor
Accuracy and Ranges: +/-5% from 20 to 95% (non-condensing)
Air Velocity Probe - Omni-directional heated thermistor
Accuracy and Ranges: +/-(0.1 m/s + 4%) from 0 to 20 m/s
    option   option  
Operating Temperature Range:            
Sensor Assembly: -5° C to 100° C (23° F to 212° F)
Electronics: -5° C to 60° C (23° F to 140° F)
Data Management:            
Detection Management Software DMS
Thermal Comfort Indices in Accordance with ISO 7730
Predicted Mean Vote (PMV) and Predicted Percent Dissatisfied (PPD)
    option   option  
Output: RS-232 Serial Printer / Computer Interface; Parallel Printer Interface  
Power Source:            
9V Disposable Batteries; Hours of Battery Life 140 80
NiMH Rechargeable Battery; Hours of Battery Life 300 160
D-ring with Lanyard Attachment. Allows for Hands-Free Monitoring
Tripod Mount / Remote Sensor Bar.
Allows for up to 61 m (~200 ft) Long Distance Measurement
IP54 Water & Dust Ingress Protection Rating
Case Size (including mounted sensor assembly) 23.4 x 18.3 x 7.6 cm (9.2" x 7.2" x 3")
Weight: 1.2 kg (2.6 lb) with Mounted Sensor Assembly
Standards and Approvals: Intrinsic Safety, UL/CSA standards for Class I groups A, B, C & D,
Class II groups E, F & G, Class III temperature code T3 & ATEX
Electromagnetic Conformance: CE Mark
  • Air Flow in flume hoods
  • Military training facilities
  • Athletic training & events facilities
  • Warehousing & distribution centres
  • Manufacturing plants
  • Nuclear & fossil fuel power generation plants
  • Shipbuilding operations
  • Occupational heat stress management
  • Indoor air quality investigations
  • Thermal comfort monitoring
  • Risk analysis of job function or activity