What is the primary function of residential sprinklers?

The primary function of residential sprinklers is to stop flashover. Flashover is a rapid spread of fire that occurs when the temperature rises significantly and causes combustible materials in a room to ignite almost simultaneously. Residential sprinklers are designed to detect heat and release water when necessary, thereby cooling the space and reducing the heat that leads to flashover. By distributing water over the fire, sprinklers can control or even extinguish the flames before they escalate, enhancing the safety of occupants and limiting fire damage.

The other options do not directly relate to the primary function of sprinklers. While continuous water supply is essential for the operation of a sprinkler system, it is not the sprinkler's primary function. Enhancing fire alarm systems and improving air circulation are also not core functions of sprinklers; fire alarms serve to notify occupants of danger, and air circulation pertains to ventilation, neither of which specifically contribute to controlling or stopping a fire effectively like sprinklers do.