History of Fire Sprinkler Systems

The following text relies upon extracts from the writings of Sir John Wormald which are reproduced here by kind permission of Marcel Boschi and David Drew-Smythe from their History of Mather & Platt (U.K.) Ltd. web site.

Fire sprinkler systems were developed to protect buildings from fire by producing a discharge of water. The sprinkler piping is usually run near the ceiling directing the water down on the flames.

The first automatic sprinkler system was created in England in the 1806 by John Carey. It was made up of a pipe with several valves held closed by counterweights attached by string. When flames burned through the string the counterweight dropped to the floor, which opened the valve that released the water and extinguished the fire.

In 1864 Major Stewart Harrison of the 1st Engineer (London) Volunteers invented the first Automatic Sprinkler Head. Manually operated systems were developed around the turn of the nineteenth century as well. Manual systems consisted of a number of perforated pipes fed by a main riser, which was activated from an adjacent area. Manual systems were effective at dousing fires. However, water damage to the building and the contents not effected by the flames were often more costly than the fire damage.

Variable Pressure Alarm Valve Invented by John Taylor - Image used by permission of Marcel Boschi

Henry Parmelee of Newhaven, Conn. and Frederick Grinnell of Providence, R.I., must be awarded the credit for giving to the Automatic Sprinkler its practical application and laying the foundation of what is now a worldwide industry. The Parmelee sprinkler head developed in the United States, in the 1870s, provided a way to control which heads discharged water. The newly designed head incorporated a heat-sensing device that only opened the valve when a predetermined temperature was reached. The heat of the flames activated specific heads, leaving areas unaffected by the fire dry. Modern sprinkler heads use a bulb containing chemicals or a fusible link, that breaks at around 160° F, opening the valve, releasing the water.

The "Simplex" was a sealed or non-valve device of the Parmelee type, though much more sensitive in its operation, and had the great advantage of being placed on the market in conjunction with the well-known Variable Pressure Alarm Valve invented by John Taylor. This valve is operated by the flow of the water, and is constructed so as to prevent false alarms being given by any variations of pressure in the main supply pipes. When the water pressure has achieved an equilibrium above and below the valve, the clack, which is of differential area, drops by its own weight upon a seating on which is grooved an annular chamber with an outlet pipe to a small water motor, to the spindle of which are attached revolving hammers that strike a loud sounding gong. In practice the opening of a Sprinkler Head reduces the pressure above the Valve, which is lifted by the upward flow from the main supplies, and so long as this continues, water passes to the motor and the gong sounds a continuous alarm. In the clack of the Valve there is a small compensating valve which takes up any violent Fluctuation of pressure without lifting the valve itself, thus obviating false alarms.

First Grinnell Sprinkler - Image used by permission of Marcel Boschi

Frederick Grinnell worked to improve upon Henry Parmelee's invention and eventually evolved the well known "Grinnell" Sprinkler, in which he secured greatly increased sensitiveness by removing the fusible joint from all contact with the water, and, by the ingenious method of seating a valve in the center of a flexible diaphragm, relieved the low fusing soldered joint of the strain of water pressure or hammer. By this means the valve seat was forced against the valve by the water pressure, producing a self-closing action, so that the greater the water pressure, the tighter the valve. The flexible diaphragm had a further and most important function, viz; that it caused the valve and its seat to move outwards simultaneously until the solder joint was completely severed. The invention of Mr Grinnell's which was entirely novel in the field of Hydraulics, was destined to revolutionize the whole sphere of fire protection.

Next to Mr Grinnell's invention this ingenious valve of Mr Taylor's remains the most important step in advance in the development and practice of Automatic Fire Extinction. Previously there was nothing better than a rude and clumsy clockwork arrangement consisting of a copper cord wound around a drum with a weight attached which, when released, caused a hammer to strike a gong just as in an 8-day clock. When the weight reached the ground the alarm ceased. Mr Taylor's new valve was speedily adopted by Mr Grinnell himself and applied all over America. It is still an integral part of every Sprinkler Installation.

From the days when fire sprinklers randomly sprayed water to systems that can regulate the discharge covering an area of a few square feet, automatic fire sprinkler systems protect property saving millions of dollars annually. Most importantly they save lives!

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