#tenability

Evacuation test in a shopping mall atrium seen from a mezzanine — a thin grey smoke layer hangs flat under the glass roof while the air below stays clear, shoppers walk toward a green-lit exit and bunch up at the doors, red strobe beacons flash on the concrete columns, and a fire engineer in a navy jacket in the foreground holds a tablet showing two coloured bars labelled ASET and RSET

🛡️ Fire Safety Engineering September 4, 2026 · 19 min read

ASET vs RSET: The Inequality Behind Every Evacuation Plan

ASET vs RSET decides whether a building passes. Here come the timeline, the tenability limits, the equations, and the one term that swings the answer most.

A dark living room early in a house fire, seen from floor level: a thick black smoke layer presses down from the ceiling and glows orange, while a thin band of clearer air remains near the floor over a sofa, coffee table, and doorway — showing why smoke inhalation strikes before the flames reach you.

🔥 Fire Fundamentals June 26, 2026 · 15 min read

Smoke Inhalation: Why the Upper Layer Kills You First

Smoke inhalation kills more fire victims than flame does. Here is the toxic upper layer, the CO and HCN dose, and the FED clock that times your escape.