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Wide cinematic cutaway photograph of a tall office tower at night under a deep-blue winter sky with snow blowing past lit windows; inside, a single illuminated emergency stairwell runs the full height of the building like a glowing vertical spine, with faint pale arrows of rising air suggesting stack effect drawing upward through the shaft — calm, architectural documentary framing that shows why a stairwell pressurization system behaves so differently on the coldest night of the year

Fire Safety Engineering

Stack Effect: Why Stairwell Pressurization Fails in Winter

On the coldest night of the year, stack effect can reverse a stairwell pressurization system and pull smoke into the stairs occupants flee through.

May 29, 2026 · 15 min read