Fire hydrant connects firefighters to water supply for active fire protection. Underground hydrants used since 18th century, above-ground pillars in 19th century. Water pressure typically around 350 kilopascals (51 psi)
Sir William Congreve patented manual sprinkler system in 1812. Hiram Stevens Maxim invented first automatic fire sprinkler in 1813. Henry S. Parmelee created first automatic sprinkler system in 1874. Frederick Grinnell improved Parmelee system with self-closing valve
Backdraft occurs when oxygen rapidly enters hot, oxygen-depleted environment. Material breaks down into hydrocarbons through pyrolysis without oxygen. Oxygen concentration decreases when compartment fire has little ventilation. When oxygen reintroduced, combustion restarts explosively
Smoke is airborne particulates and gases emitted during combustion. Combustion conditions determine smoke composition: oxygen-rich fires produce ash, others toxic compounds. Particles range from 2.5 nm to micrometers in size. Smoke contains various chemicals including carbon monoxide, sulfur oxides, and hydrocarbons
Atrium was central court in Roman domus with enclosed rooms on all sides. Central impluvium pool collected rainwater for passive cooling. Wealthier houses featured marble cartibulum and lararium chapel. Atrium provided shelter while maintaining visual connection to environment
First fire safety regulations issued between 1940s-1960s for 50-150 seat aircraft. 1983 DC-9 accident led to FAA updates and expanded testing requirements. Aircraft cabins made from lightweight polymers pose significant fire risk