Fire sprinklers can be open orifice or automatic. Automatic sprinklers are activated by heat that breaks the sensing device keeping the sprinkler closed. The water from the pipe comes through the sprinkler and hits the deflector and gives a water spray.
Fire sprinklers can be automatic or open orifice. Automatic fire sprinklers operate at a predetermined temperature, utilizing a fusible element, that either melts or breaks the glass bulb containing liquid, allowing the plug in the orifice to be pushed out by the water pressure. This results in a water flow from the orifice.
The water hits a deflector, which produces a specific spray pattern designed according to the sprinkler type. Most automatic fire sprinklers are activated individually by heat from a fire. Automatic fire sprinklers have glass bulbs, which comply to a standardized color coding indicating their activation temperature. Fire sprinklers are selected in accordance of the building hazard.
Design of the sprinklers are described by the fire standard authorities like NFPA and VdS etc.
Deluge fire sprinkler systems have open orifice sprinklers where all sprinklers operate at the same time. The open orifice sprinklers are similar to the automatic sprinklers but without the heat sensitive element.
A special sprinkler type for mainly residential occupancies, where a fast response is lifesaving, is the ESFR sprinkler – Early Suppression Fast Response. This sprinkler has a very fast response time and opens quickly compared to normal sprinklers.