A side-by-side room display set up at the Plymouth Massachusetts Fire Department. Sprinklers had been installed in only one of the rooms. Both rooms were set on fire. Home fire sprinklers are designed to activate when a certain degree of heat increase is reached, so as the temperature in the display went up, the sprinklers went off. As seen in this demonstration, the fire in the sprinklered room was controlled quickly by overhead sprinklers. In contrast, the fire in the room without sprinklers burned out of control until the fire department put out the fire.