In an upcoming issue of PM, you will be able to read an article I wrote recapping the first 25 years of residential fire sprinklers. It is a somewhat bleak report, considering that less than 1 percent of all new single-family dwellings constructed in the United States have a residential sprinkler system.
NFPA 13D systems can be piped as multipurpose systems using the water distribution system to double as the sprinkler system. The connection to a sprinkler is the same as a connection to any other fixture in the house. You conveniently run the piping and connect a tee and sprinkler. Since it is an integral part of the potable water system, the only contractor I would want installing such a system is a plumbing contractor. I am sure all of you feel the same.