During the 1870s, the Parmelee Sprinkler Head was introduced in the United States. The heat from a fire opens the normally closed orifice releasing the water and the modern sprinkler head versions use a fusible link or a bulb containing chemicals, which breaks at about 160 F (70 C) to open the orifice.

The Sprinkler systems for fire protection consists of few overhead pipes which are fitted with sprinkler heads. Each head in the sprinkler is held closely independently by heat-sensitive seals. These heat seals prevent water flow until a design temperature is exceeded by the individual sprinkler heads. The seals may be broken by melting or fusing of the metals with a low melting point (often bismuth alloys), or may be glass bulbs that break from pressure differences when heated. The sprinkler bulbs are color-coded to indicate their operating temperature. The typical activation temperatures vary and correspond to the type of hazard the sprinkler system protects against. The life safety hazards such as residential occupancies use a lower (therefore quicker) activation temperature. The modern sprinkler heads are designed to direct a spray downward. When one fire sprinkler head goes off to fight a fire, the entire sprinkler system will not activate unless the system is a special deluge system. The sprinklers heads react to temperatures in individual rooms.

In order to select sprinkler heads for a system you will require investigating various sprinkler models to find one with the characteristics best suited for the site and watering needs. All important information for the selection includes the operating pressure, flow range, precipitation rate, and the radius and arc of coverage. This information can be found easily in the product catalogs provided by the sprinkler manufacturer and in addition, many sprinklers have special features such as angles of trajectory and nozzle options which may be important in the selection process.

Types of Sprinkler Heads

Various types of sprinklers includes the rotary heads, the bubblers and the spray heads. All these three general types of sprinklers are used for small residential irrigation projects. All three types are also suitable for traditional irrigation of potable water, but for irrigation with treated wastewater the first two should be avoided and the system should be designed by using rotary heads