The Ideal Monitors to Comply with the OSHA NEP for Heat Stress
Heat Shield Wireless Wet Bulb Globe Temperature (WBGT) Meters
April 12, 2022
OSHA announces first ever National Emphasis Program (NEP) to protect workers from indoor and outdoor heat hazards.
WASHINGTON – For the first time, the U.S. Department of Labor’s Occupational Safety and Health Administration has launched a National Emphasis Program to protect millions of workers from heat illness and injuries. Through the program, OSHA will conduct heat-related workplace inspections before workers suffer completely preventable injuries, illnesses or, even worse, fatalities.
» Read more
What entities need to implement Heat Stress Monitoring?
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- Industrial Hygiene consultants
- Construction
- Agriculture, Horticulture
- Foundries, power plants
- Utility companies, linemen, road crew
- Military training establishments
- Sports facilities and event locations
- Firefighters
- Bakeries, warehouses, shops, offices, cold rooms
» Download OSHA's complete list of 76 "High Hazard Industries" by NAICS Code
Heat Shield Monitoring Solutions
The LSI Heat Shield system measures heat stress in WBGT, a more comprehensive measurement than Heat Index. In a compact and rugged system, Heat Shield integrates dry bulb/wet bulb/globe temperatures and relative humidity sensors to display and store on-line WBGT indoor & outdoor index, Heat Index, and Humidex measurements. HeatShield is available with either a 2 inch (5cm) or 6 inch (15 cm) globe. The Heat Shield is a vital heat stress monitoring tool for Health & Safety professionals across the Occupational Health, Environmental Safety, and Industrial Hygiene realms.
What is WBGT? [1]
Environmental heat is more than just temperature. Four factors contribute to heat stress in workers:
- Air temperature.
- Humidity. High relative humidity makes it difficult for the body to cool itself through sweating.
- Radiant heat from sunlight or artificial heat sources such as furnaces.
- Air movement. In most situations, wind helps workers cool off.
An environmental heat assessment should account for all of these factors. OSHA recommends the use of wet bulb globe temperature (WBGT) monitor to measure workplace environmental heat.
WBGT devices contain three different thermometers:
- A dry bulb thermometer to measure the ambient air temperature.
- A natural wet bulb thermometer to measure the potential for evaporative cooling.
- A black globe thermometer to measure radiant heat.
WBGT vs Heat Index[1]
WBGT has important advantages over other environmental heat measurements. One major advantage is that WBGT accounts for all four major environmental heat factors — temperature, humidity, radiant heat, and wind. In contrast, standard thermometers only assess one factor (air temperature). Heat Index is another common way to measure heat stress. It is measured in the shade and combines air temperature and relative humidity to represent how hot the conditions feel at rest. The heat index does not account for the effects of wind, sunlight, radiant heat sources, or workload. Air (dry bulb) temperature also ignore relative humidity. All these factors can influence the total heat stress experienced by workers.
Workplace environmental heat should be measured on-site using WBGT meters. Use of heat index is a less desirable substitute. While local weather reports based on meteorological data from observation stations can be useful, the readings from these stations may not reflect the conditions at the specific worksite. Heat conditions at the worksite may be different for multiple reasons, from cloud cover and humidity to local heat sinks. The potential error increases with distance from the weather station.
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Reference:
1."Heat Hazard Recognition, Environmental Heat," US Department of Labor, Occupational Safety and Health Administration. Retrieved May 9, 2022 from: https://www.osha.gov/heat-exposure/hazards
» Download the OSHA NEP 1-page Fact Sheet
» Download the entire OSHA NEP document (41 pages)
Calculations
Heat Shield calculates on-line and displays the following indexes:
WBGT indoor & outdoor index (ISO7243)
Head-Torso-Ankle Weighted Average WBGT (ISO7243)
Heat index According to 1990 National Weather Service (NWS) Technical Attachment (SR 90-23)
Humidex According to J.M. Masterton and F.A. Richardson of Canada’s Atmospheric Environment Service equation
Easy to Operate
Heat Shield is very stable when placed on any horizontal surface but it can be also hand held or mounted on standard photographic tripod. With its power-on-and-play philosophy, measurements can be displayed in just a few instants from power on. No configuration is required by PC. Rechargeable batteries assure up to 400 hrs of measurement.
Heat Shield has a large on-board memory to store measurements and calculations performed during every survey. Included software makes it easy for users to generate custom or standard reports. and perform analysis of the measurement results to evaluate working limits.
Wireless Remote Modules for Heat Stress
Heat Shield can be supplied as a single base unit or with two additional wireless satellite modules. The satellite units are used to measure environmental conditions at three levels and calculate Head-Torso-Ankle Weighted Average WBGT as required by the ISO 7243. Alternatively, the satellite modules can be used in different locations, performing three simultaneous measurements saving the user precious working time. Heat Shield radio can cover up to 300 m (line-of-sight; actual range in indoors conditions may vary).
Webinar: July 14, 2022
The OSHA NEP FOR HEAT STRESS and HEAT STRESS MONITORING SOLUTIONS.
Webinar topics presented and discussed:
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The OSHA National Emphasis Program (NEP) for Heat Stress Monitoring
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Who needs to comply?
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What is WBGT temperature measurement?
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WBGT vs Heat Index measurement
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Our WBGT Heat Stress monitoring solutions
FEATURED CO-HOSTS:
Aaron Apostolico, CIH, CSP, CIEC
Sensidyne
Product Line Manager
Dr. Stephanie Lynch
OHD
Senior Technology & Research Manager
Base Modules |
Satellite Modules |
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Instrument Comparison |
ELR610M 2” Globe |
ELR615M 6” Globe |
ELR610S 2” Globe |
ELR615S 6” Globe |
|
Wet bulb temperature sensor |
Y |
Y |
Y |
Y |
|
Radiant temperature sensor |
Y |
Y |
Y |
Y |
|
Dry temperature sensor (including radiant shield) |
Y |
Y |
Y |
Y |
|
Anemometer. Indoor use (optional) |
Y |
Y |
Y |
Y |
|
Air velocity / Air flow |
O |
O |
- |
- |
|
Measurement Capabilities |
|||||
WBGT (indoor) index |
Y |
Y |
Y |
Y |
|
WBGT (outdoor) index |
Y |
Y |
Y |
Y |
|
Heat index / HUMIDEX |
Y |
Y |
Y |
Y |
|
PMV-PPD |
Y* |
Y* |
Y* |
Y* |
|
Predicted Heat Strain (PHS) |
Y* |
Y* |
Y* |
Y* |
|
Insulation Required (IREQ) |
Y* |
Y* |
Y* |
Y* |
|
Duration Limit of the Exposure (Dlim) |
Y* |
Y* |
Y* |
Y* |
|
Temperature reading: Celsius or Fahrenheit |
Y |
Y |
- |
- |
|
Data logging intervals |
1-min |
1-min |
1-min |
1-min |
|
Languages: English, Spanish, Portuguese, Italian |
Y |
Y |
- |
- |
|
Measures stay times viewable in computer software |
Y |
Y |
Y |
Y |
|
Head-Torso-Ankle Weighted Average WBGT (Requires satellite modules) |
Y |
Y |
- |
- |
|
Sensors |
|||||
Wet bulb temperature sensor |
Range: -20 – 60°C. Accuracy: ± 0.3°C |
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Radiant temperature sensor (Globe) |
Range: -20 – 60°C. Accuracy: ± 0.3°C |
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Dry temperature sensor (including radiant shield) |
Range: -20 – 60°C. Accuracy: ± 0.8°C, ±0.4 °C (10-40°C) |
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Anemometer. Indoor use (optional) |
Range: 0.01 – 20 m/s. Accuracy: ±10 cm/s (0,5 – 1,5 m/s) 4% (>1,5 m/s) |
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Anemometer. Outdoor use (optional) |
Range: 0 – 75 m/s. Accuracy: 2,5% |
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WBGT (indoor) index |
According to ISO7243 |
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WBGT (outdoor) index |
For up to 3 locations simultaneously (Requires Satellite units) |
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Head-Torso-Ankle Weighted Average WBGT |
According to ISO7243 (Requires Satellite units) |
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Heat index |
According to 1990 National Weather Service (NWS) Technical Attachment (SR 90-23) |
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Humidex |
According to J.M. Masterton and F.A. Richardson of Canada's Atmospheric Environment Service equation (1979) |
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PMV-PPD** |
According to ISO7730 |
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Predicted Heat Strain (PHS)** |
According to ISO7933 |
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Insulation Required (IREQ), Duration Limit of the exposure (Dlim)** |
According to ISO11079 |
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Instrument |
|||||
Acquisition rate |
1 sec – 12hrs |
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Compatibility |
HS Manager (included), Gidas TEA (optional) |
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Power supply |
8 – 14 Vdc |
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Battery |
2 A (4.2 V) Lithium rechargeable |
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Battery life |
Standby: 9 months, Radio OFF: 400 hrs, Radio ON: 24 hrs |
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Environmental limits |
-20 – 60 °C |
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Protection |
IP 54 |
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Standards / Approvals |
CE Mark |
Click on a file below to open. Visit our Technical Library for further documents and resources.
Filename | Filesize |
Presentation_Introducing The LSI Heat Stress System_2022.pdf | 2.36 MB |
Sensidyne_LSI-Heat-Shield_Brochure_4C_051622.pdf | 3.78 MB |
Sensidyne_LSI-Heat-Shield_User-Manual.pdf | 1.88 MB |
Sensidyne_OSHA-heat-stress-NEP-factsheet-en.pdf | 177.23 kB |
Sensidyne_OSHA-NEP-on-Heat Stress_040822.pdf | 608.6 kB |
Sensidyne_OSHA NEP on HeatStress_AppendixA_04082022.pdf | 250.53 kB |