Wet Pipe Water Sprinkler System
The Wet System is an installation where the sprinkler pipes are constantly charged with water under pressure. It is the simplest and most widely used system, and because the water can be available immediately a sprinkler operates, it is the speediest system to come into action.

For this reason it is only suitable for use where there is no danger of frost, i.e. in climates where freezing never occurs or in buildings which are constantly heated during cold periods. Being equalled only by the pre-action system in this respect. The layout of the controlling valves of a typical wet system is shown and it includes the alarm valve, the combined drain and test valve, test valve, pressure gauges and alarm motor isolating valve, strainer, alarm motor and gong.

The Wet System is an installation where the sprinkler pipes are constantly charged with water under pressure. It is the simplest and most widely used system, and because the water can be available immediately a sprinkler operates, it is the speediest system to come into action.

For this reason it is only suitable for use where there is no danger of frost, i.e. in climates where freezing never occurs or in buildings which are constantly heated during cold periods. Being equalled only by the pre-action system in this respect. The layout of the controlling valves of a typical wet system is shown and it includes the alarm valve, the combined drain and test valve, test valve, pressure gauges and alarm motor isolating valve, strainer, alarm motor and gong.

This type of system is the easiest to design and install and the simplest to maintain. Wet-pipe systems contain water under pressure at all times and utilize a series of closed sprinklers.

When a fire occurs and produces a sufficient amount of heat to activate one or more sprinklers, beacuse an automatic water supply is mandated, water immediately discharges from the open sprinklers.

A Wet-pipe system should be the first choice of designers and installers because they are more inherently reliable and less costly to maintain. However, wet-pipe systems should not be considered when temperatures to which the system could be exposed fall below 4°C (40°F). Refer to the animation above for a description of how a Wet-pipe system operates.