Heat stress: NIOSH criteria
CHST video lesson, 6:48. CHST Domain 2: Emergency Preparedness, Incident Investigation, and Response
Narrated with an AI-generated voice. The script is AI-drafted from the cited rules and fact-checked against them.
NIOSH heat criteria for the CHST exam: RAL vs REL, acclimatization, the 1-hour TWA, WBGT calculation, administrative controls, medical monitoring and the 1.5% body weight limit.
Included with every CHST pass, with captions, chapters and the full transcript. Every rule and number is cited on screen to its primary source.
What this lesson covers
In this lesson, you'll learn to: define heat stress and heat strain, tell the RAL from the REL, calculate indoor and outdoor WBGT, and choose controls and medical monitoring steps. Start with definitions, because the exam loves them. Heat stress is the load placed on the body. Heat strain is how the body responds. Total heat stress is metabolic heat, plus environmental heat, minus heat lost to the environment.
- Intro
- Learning objectives
- Key definitions
- Exposure limits
- WBGT index
- Worked example
- Controls
- Medical and hydration
- On the job
- Common exam traps
- Recap quiz
The video, captions and full transcript are included with every CHST pass. See passes
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