Arkansas HVACR NewsMagazine September 2025

HVACR NewsMagazine September 2025

education News

Organ failure begins

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as core

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temperature soars. This isn’t just a theoretical limit: it is a physiological boundary of survival.

A Grim New Reality in the U.S.

For the first time in recorded history, parts of the United States have begun to see 95°F wet bulb temperatures . Traditionally, these deadly thresholds were confined to the hottest, most humid parts of South Asia or the Persian Gulf. But climate change is pushing these lethal combinations into new regions. As HVACR professionals, engineers, first responders, and educators, we must begin to treat Wet Bulb readings as essential data . They are more than academic — they are lifesaving. Teaching the Next Generation: Why Wet Bulb Belongs in the Classroom It’s time to make Wet Bulb Temperature part of every conversation about heat safety: • Measurement Skills : Teach students how to take wet bulb readings (psychrometers, sling thermometers, or digital sensors). • Interpreting Risks: Help learners understand humidity’s role in Heat Stress • Design Implications: Consider WBT in system sizing, building codes, and cooling strategies. • Survival Planning : Discuss community cooling centers, hydration, and early warning systems that use Wet Bulb Global Temperature forecasts. For educators looking to deepen this conversation, I highly recommend watching ️ Clifton Beck ️ , CSME and Jason Obrzut, CMHE 's informative

As our planet warms, conversations about heat waves often focus on air temperature alone. But a single number on a thermometer doesn’t tell the whole story of danger to human life. The Wet Bulb Temperature (WBT) may be the most important metric to understand and teach in this new era of escalating heat. Unlike dry air temperature, Wet Bulb Temperature accounts for both heat and humidity — the two factors that jointly determine how well our bodies can cool themselves through sweating. At a high enough Wet Bulb Temperature, even shade and fans stop helping, because sweat can no longer evaporate from skin. The Science: Why Wet Bulb Matters for Survival Humans (and other perspiring mammals like horses) rely on evaporation to shed excess body heat. But there is a hard limit: at a Wet Bulb Temperature around 95°F (35°C) , the body can no longer maintain a survivable core temperature, no matter how much you sweat. Sweating stops working – the air is too saturated to accept more moisture. • Internal temperatures rise unchecked – leading to heatstroke. Wet Bulb Temperature: The Most Important Metric in an Escalating Heating Cycle Above this threshold: •