Wet Bulb Globe Temperature (WBGT) Monitoring

Talking points

1. The heat index only accounts for temperature and humidity. WBGT also factors in sun exposure, wind speed, and radiant heat — making it a more accurate measure of heat stress on a jobsite.
2. WBGT monitors are available as portable devices for under $200. Place them in the work area, not in the shade, to get a reading that reflects actual conditions.
3. OSHA and ACGIH use WBGT to set work/rest cycles. At a WBGT of 86-89°F for moderate work, the recommendation is 45 minutes of work followed by 15 minutes of rest each hour.
4. Take rest breaks in a shaded or air-conditioned area — state heat rules like California's require shade once it tops 80°F, and OSHA's national heat guidance says the same thing. Sitting in the sun is not a rest break — your body cannot cool effectively without shade and airflow.
5. Document your WBGT readings throughout the day. Conditions change — 10 AM measurements do not represent 2 PM exposure. Monitor and adjust your work/rest cycle accordingly.

Ask the crew

Are we monitoring heat conditions with a WBGT meter or just going by the weather forecast — and which is more accurate?

Standards this talk is built on

• Section 5(a)(1)

A toolbox talk is a short safety briefing. It supports the training a standard requires; it does not replace it.

Sign-in sheet

Print this page to collect signatures, or run the talk in Jobsite and workers sign in on their phones.

© Jobsite. Free to read aloud, print and use in your own crew's safety meetings. Republishing, reselling or bulk-copying these talks is not permitted.