I could use some help with sprinkler obstructions.
Generally, I’m looking at piping and ductwork, that is installed within 18” below the plane of the standard upright sprinkler deflector. Light or ordinary occupancies.
I called NFPA 13 and got an interpretation that these would be considered a sprinkler obstruction, and I would need sprinklers on either side, regardless of the size of the duct/pipe (no rule here about only being over 4’). This was per Section 10.2.7.2 in the 2019 edition.
I didn’t think to ask, but could I still apply the three times rule of 10.2.7.2.1.3, even though these aren’t structural members? As long as I was three times, or 24-inches away, it wouldn’t be an obstruction, right?
I’ve seen these close configurations all over the place in many different peoples’ designs, so I’m wondering if I’m missing some allowance.
Most recently, I observed a 14” wide (horizontally) x 6” deep duct (vertically), with a sprinkler installed directly above with the deflector 5” above the top of the duct. The next sprinkler head is approximately 12 feet away. Also observed in the same room, was a 5” diameter pipe about 8” diagonally down from a deflector, measured at a 45-degree angle. If I’m understanding NFPA 13 correctly, these would both be considered obstructed. I have a question into NFPA 13, but would appreciate others’ opinions as well.
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