MGM Grand, Las Vegas — Plenums and Seismic Joints Let Fire Climb 26 Floors

The MGM Grand Hotel on the Las Vegas Strip suffered the deadliest building fire in Nevada history on the morning of 21 November 1980, when an electrical ground-fault that ignited inside a concealed wall at a first-floor delicatessen killed 85 people and injured more than 600. The fire itself never left the ground floor. What killed the dead was smoke — carbon monoxide and combustion products that rose, almost unobstructed, the full 26 storeys of the tower. The proximate killer was not flame but a comprehensive failure of compartmentation.

This was not a structural collapse. The steel frame stood; the building was gutted at casino level and reopened eight months later. It belongs in the forensic record as the canonical demonstration that a high-rise can be lethal without failing structurally, simply by lacking the barriers that keep a single-floor fire from venting its smoke into every occupied room. Roughly four-fifths of the 85 dead died of smoke inhalation and carbon-monoxide poisoning, almost all on the upper floors between the 16th and 26th storeys, far above the fire.

The casino, restaurants and area of origin had no automatic sprinklers; a vast undivided return-air plenum above the casino let smoke cross the entire ground floor in seconds; and from there it rose through unsealed vertical paths — stairwells, elevator hoistways, impaired HVAC dampers and, most damningly, twelve-inch seismic expansion joints built as continuous open shafts from the plenum to the 26th floor. Investigators catalogued dozens of building-code violations and design flaws, and within a year Nevada had rewritten its codes to mandate retroactive sprinkler retrofit in high-rise hotels. The MGM Grand became the byword for compartmentation breach: proof that the question for a tall building is not only whether it will burn, but where its smoke can go.

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