pre-actionA pre-action sprinkler system is a combination of wet and dry pipe sprinkler systems. During normal circumstances, a pre-action sprinkler system is dry, with no water in the sprinkler pipes. When a fire is detected, the pre-action valve which holds the water back is released and water fills the sprinkler pipes. Then each sprinkler head is individually activated to discharge water onto the fire.

How Does a Pre-action Sprinkler System Work?

In order for a pre-action sprinkler system to discharge water onto the flames to control the fire, two important things must happen. First, the pre-action valve must be activated. In order for this to happen, heat, smoke, or flames are detected, and a signal is sent for the electrically operated pre-action valve to release the water. At this point the fire sprinkler system is like a traditional sprinkler with water filling the pipes.

The second step for water release is that each sprinkler head must be activated and opened individually for water to douse the affected area.

Some pre-action sprinkler systems are designed to have pressurized nitrogen or air to keep the water in place in the event of a valve failure or accidental opening. Having pressurized pipes is an added precaution to prevent accidental discharge.

Benefits of Pre-action Systems

The main benefit of installing a pre-action system is the prevention of accidental discharge of the fire sprinkler system. Since the system first needs to fill with water, then have each head individually opened, it is less likely to discharge accidentally. Pre-action systems can also be installed in cold spaces as they do not normally have water in the pipes so freezing is not a concern.

Common Applications for Pre-action Systems

Some places where pre-action systems may be found include:

  • Museums
  • Libraries
  • Freezer warehouses
  • Vaults
  • Data centers
  • Computer rooms

Davis-Ulmer Designs & Installs Pre-action Sprinklers

At Davis-Ulmer, we can design and install pre-action sprinkler systems for your facility. Our team will design a system for your application using the latest BIM technology and install the system in accordance with NFPA standards. Davis-Ulmer provides ongoing inspections and service for pre-action sprinklers to ensure that they are operating correctly and in proper condition. If you are interested in a pre-action system, contact us today!