Measuring Dry Heads

Spring is finally upon us! The snow is melting, flowers are blooming, and the service department is sleeping with one eye open, as previously frozen sprinkler pipe begins to fully rot away. With the sudden temperature swings of sunny and 80° one day and snow two days later, comes the very real risk of condensation forming in, on, and around our pipe. Condensation happens when water vapor cools from a gas, back into a liquid. If that liquid gets cooled down to a freezing temperature, you get ice. And I don’t care if it’s sprinkler pipe, your basement walls, or Audrey Griswold’s eyes at Christmas time… Ice always wins.

Every 10 years, a sampling of installed dry heads needs to be taken out and sent in for testing to ensure functionality. Sometimes the seats get damaged from ice and begin leaking. Existing sprinkler
heads get damaged. Heads need to be ordered for new construction jobs. And on rare occasion, we’re heroes and the head activates to put out a fire. In all of these situations, new dry heads need to
be ordered. It is imperative that these are measured and ordered correctly.

Whenever you talk about measuring dry heads, someone will inevitably use the phrase “Face to Finish”. But what does this mean? We usually measure to “make up” on a fitting, which is taking into
account the 1/4″(ish) that the pipe is going to thread into the fitting. With dry heads: Don’t Do That. You measure from the closest part, or “face” of the fitting to you. *See pictures below for visual reference. Then you measure to the finished ceiling height for pendants, finished wall dimension for sidewall heads, and top of the deflector for uprights; keeping in mind how far down your deflector
needs to be on an upright head, depending on the application (usually 1″-12″). Each dry sprinkler head is custom made to length upon ordering, costing $10 or more PER inch! They take weeks, sometimes months, to get. What does that do to your job’s schedule and budget if they weren’t measured correctly and need to be reordered? This one mistake can be the difference between making money or you metaphorically buying a shovel to go bury that job. Measure twice. Order Once.