Most commercial projects require two to three backflow preventers on each job site. You will generally need a backflow preventer for the irrigation system, another backflow preventer for domestic water, and yet another for the fire protection system. Often, one design engineer chooses the design and location of both the domestic and fire protection lines. They'll either specify them indoors, in a vault, or in an aboveground backflow enclosure as is best practice. Usually, the irrigation water piping is designed by a different discipline. It's most common for a civil engineer to specify a backflow enclosure for each device, but what about putting them both into only one aluminum enclosure? Many designers are choosing to do this with success and we recommend you try it as well. Some say there are disadvantages to designing both backflow devices in a single enclosure, and there are certainly benefits. Let's break it down.
