Our trade is slow to change. Many of the items we utilize today were developed in one fashion or another many years ago. The deluge system was really the first sprinkler system where an open piping network was supplied with water and water discharged through open outlets on the system piping. As time passed, the automatic sprinkler was developed and our basic wet system came into being, water-filled pipe with water at a sprinkler head held closed with a heat activated device. When the heat actuates the device, the sprinkler’s water way is opened and water discharges through the outlet.

Deluge valves and deluge systems are most often thought of as flooding systems as all the discharge devices are open on the piping network. These systems are designed to discharge water through each outlet on the piping network relatively at the same time, creating a flood of water. The most basic deluge system is open discharge devices on a piping network, controlled through a water shut-off valve, such as an OS&Y that is opened manually. Deluge systems are normally installed in high-hazard areas, so it is desirable not to be near the system when there is a fire. That’s where the deluge valve and its release system come into play.

One of the oldest deluge valves you may come upon is an Automatic Model A deluge valve. By most accounts, its time of production started in 1919 and lasted until 1931. This valve was an angle-style valve, meaning the water inlet into the valve was in the vertical plane and its water discharge was on the horizontal plane. The valve had a standard clapper on a hinge with a large cavity that a weighted cam fell into when the release system operated. The valve had a clapper latch that held the clapper open once the system operated and had to be manually released to reset the valve, much like many dry-pipe valves.

In 1931, Automatic released the Model C Deluge valve that was used in Automatic’s Suprotex system, for some time in Grinnell’s Multitrol System, and Rockwood’s Dualguard system. Each of these systems utilized a modified check valve with a hydraulic side differential mechanism that had a rod that pushed on a latch that held the clapper closed. The release system was relatively complicated as each used a mercury check manifold and a system of Heat Actuating Devices, (HADs.) These HADs were pneumatic chambers that were connected in zones with 1/8-in. OD copper tubing. When heat built higher pressure in the pneumatic chamber, pressure was pushed back to the mercury check. when the pressure could not be compensated through a vent on the mercury check, pressure overcame the mercury pool and activated the valve through a relief of water pressure that was controlling the water pressure in the side differential mechanism. So, in basic terms, the water pushing against the rod was relieved, which took pressure away from the clapper latch, allowing the clapper to open and flow water into the system piping.

In 1936, Viking introduced an angle-style deluge valve, that utilized a diaphragm and surface area differential in lieu of a side differential piston, latch, and clapper design. The diaphragm design simplified the operation of deluge valves, as there were three (3) chambers – a priming chamber, an inlet chamber, and an outlet chamber – but only one moving part. The simplicity of the design was such that the priming chamber was filled with water, then the control valve was opened and the system was in service. The priming chamber had a surface area about two times greater than the inlet chamber, so the valve was held closed with the same water pressure without additional levers or latches. The Viking deluge valve was a Model D from 1936 through the early 1980s. In the early 1980s, the valve model changed to a Model E, which indicated some material changes in the body and clapper. In 2000, Viking added a straight-through version of the diaphragm valve to respond to market requests for an in-line valve in lieu of the perennial angle style diaphragm valve.

So, the birth of the modern deluge valve occurred in the 1930s, either as a modified check valve with a side differential or a diaphragm valve. I’d like to say that we’ve made great strides in developing new valves over the years, but I’m not sure we have. There are three (3) deluge valve styles found throughout the world today: a modified check valve with a side differential, a diaphragm valve – either angle-style or straight-through, and a sleeve valve that was borrowed from the process industry and is sometimes used as a deluge valve.
Deluge valves provided opportunity to develop special systems, the most prevalent being a preaction system. Development of preaction systems occurred in the late 1940s and early 1950s. Some of the first preaction systems required two different types of valves, a deluge valve with a dry-pipe valve placed shortly after it. A release system would activate the deluge valve, placing water to the inlet of the dry-pipe valve. Then, when a sprinkler operated, the dry-pipe valve would open and supply water to the sprinklers that opened due to heat. In theory, this was a good idea, in practice, not so great. If a hydraulic cushion was not provided between the deluge valve and the dry-pipe valve, many times the dry valve would open when the deluge valve opened. Not an ideal situation if you were protecting a freezer.

When we speak of preaction systems, we are generally referring to two types, either single-interlocked or double-interlocked. Single-interlocked systems fill the system piping with water upon activation of the release system or supplemental detection system. Double-interlock systems flow water into the system piping when the supplemental detection system operates and a sprinkler on the system has activated. Conservative fire protection would direct you to almost always use a single-interlock preaction system. Double-interlocked preaction systems should only be installed when water entering the system piping could harm the sprinkler system, such as in a freezer. Not everyone agrees with that outlook so we find many double-interlocked preaction systems protecting areas that probably don’t need them, such as data centers, computer rooms, gymnasiums, museums, etc. The development of dependable release systems, such as electric releases and pneumatic actuators with a single moving part allowed for the removal of the dry-pipe valve over the deluge valve and permitted a check valve after the deluge valve to maintain air pressure in the system piping. So, as the trade progressed things started to get simplified.

The future of these systems is simplicity and ease of installation. To simplify a special system installation today, manufacturers offer either integrated systems, a deluge or preaction system in a cabinet, or pre-trimmed riser valves. The trend in the future is to eliminate loose trim on a valve as a product offering by having the valve trimmed at the manufacturer. This trend is in not to limit anyone’s right to work but rather to increase the dependability of sprinkler systems, which we all have a responsibility to steward.

ABOUT THE AUTHOR: Martin Workman has been involved in the fire sprinkler industry for more than 20 years. He is product manager for the Viking Corporation. Workman is a principal member of the NFPA 30 committee. He is NICET certified and is a member of AFSA, ASPE, NFPA and the Society of Military Engineers.