Types Of Fire Sprinkler Systems
Fire sprinklers are one of those inventions that everyone takes for granted. They sit out of sight, and stay out of the way until they're needed—at which point they douse any potential inferno, saving lives and property with an incredibly-high success rate. In fact, over 99% of all indoor fires are extinguished by fire sprinkler systems alone. Due to the variety of materials and property being protected, there's a large variety of systems and methods in use to cater to various applications. The two major methods are based on both wet and dry systems, with some variants of both for more specific applications. While more obscure variations exist, we have summarized the three most common systems currently in use below.
Wet Pipe Systems
This is the most common fire sprinkler system in use for commercial buildings. Like the name suggests, this type consists of steel pipes that are always filled with a payload of pressurized water. Wet pipe systems are the most reliable and responsive systems available today, as well as the most inexpensive. Unfortunately, the design doesn't lend itself well to areas exposed to freezing temperatures, or places that are ultra-sensitive to potential leaks or excess moisture.
Dry Pipe Systems
Dry-Pipe Systems are Like with the wet-pipe systems, this type also maintains a constant pressure in the pipes. But unlike wet-pipe systems, dry pipe systems fill the pipes with pressurized air instead of pressurized water. When the system activates, it vents the pressurized air, which draws a high volume of water through the sprinkler heads in order to put out a fire. Such a system eliminates the risk of leaks and frozen pipes. However, they have a significantly longer lag before taking effect, and are generally more costly to install and maintain. It's important to note that some of these systems have the flexibility to be cycled between both wet and dry systems as necessary. They are filled with pressurized water during warmer seasons, and switched over to pressurized air during colder months. These bring together the best of both worlds for a higher installation cost due to the additional equipment involved.
These are a variant of the dry pipe system. Pre-action systems have two types of sensors that must be triggered before they put out a fire—such as a smoke or heat detectors. If the first sensor is triggered, an alarm will activate, but water will only flow from the sprinkler heads if the second trigger is also activated. This acts as a fail-safe to protect any accidental misfires that could pose a danger to moisture-sensitive equipment or environments, such as museums or archives.