In the past, there have been two viable options for sprinkler systems in spaces with freezing potential: you could use a dry system, or in small spaces, you could utilize a wet pipe system that contains a water-antifreeze solution. Wet pipe systems using an antifreeze solution were often preferred due to their lower cost and because they could be installed for smaller applications, such as systems containing 20 sprinklers or less. But, there have been recent issues with this practice that have resulted in changes to NFPA 13, the Standard for the Installation of Sprinkler Systems.
How NFPA 13, 2013 Edition, Will Impact Implementation of Antifreeze and Dry Systems
NFPA 13, 2013 Edition, requires antifreeze to be specifically listed for use in sprinkler systems. Unfortunately, there is no antifreeze on the market that currently meets this criteria. As a result, many designers will be steered toward dry pipe systems until the market adjusts.
Tips for Successful Implementation of a Dry Pipe System
Successful installation of a dry system begins with diligent design. We have seen a number of plans where the designer has indicated that the piping needs to be pitched without due consideration of how the right pitch will be properly achieved. The fire protection contractors installing the system are then left to find an impromptu solution during construction.
Dry pipe systems are required to have either a ¼-inch or ½-inch pitch for every 10 feet of pipe depending on the size of the pipe. To ensure the fire protection contractor will be able to accomplish the necessary angle during installation, designers need to consider the length of the hangers and whether the pipe may run into another structural member. To avoid installation mistakes, the fire protection contractor should be able to simply install the piping per the plans (shop drawings) and not have to make design decisions on the fly. In order to set up the contractors for installation success, all of those pitch questions need to be answered in the design phase.
When dry systems are not diligently mapped out, they can cause problems during and after installation, such as freeze failures. As a fire protection engineering design and consulting firm, we can give you advice on how to guard your buildings from future sprinkler problems.
By Jeff Harrington, CEO and Founder of Harrington Group, Inc.