Good afternoon!
Short: Is there a minimum temperature spec for sprinkler heads / bulbs in outdoor / freezing applications?
Long:
One of the condo communities I manage has 16-space garages under their buildings partially open to the air and they have had a couple dry pendant sprinklers break over the past couple years (in the same building).
The garage walls are poured concrete. North and East sides are solid with no openings to the outside. South side is the gate, and west side has two ~6 foot tall and ~10 foot wide openings. At these two openings sit three heat pump condensers each.
I can't speak to details about the first head that popped about 3 years ago, but the one in January this past year was a day or two after a little bit of snow. Temp was right about freezing and the morning had a misty kind of rain. Air was almost foggy. The pipe above the drop ceiling was fine, the heater in the space was working, the pendant was not cracked. We found the frame/deflector in two pieces like a broken wishbone.
The bulbs are JOB FX-3S and their website doesn't have any readily accessible info I could find, and engineers I've chatted about it with haven't pointed at anything in code I can bang on the table to have the sprinkler company modify the system.
My theory is that when the condenser kicks on, the sprinkler heads are getting intensely cooled. Add a high humidity and it can cause icing, breaks the bulb and creates a mess. The sprinkler estucheons in the three buildings with similar setups all show surface rusting in the vicinity of the heat pumps.
I can't imagine this is the first time sprinklers have been above an outdoor heat pump condenser.
Short: Is there a minimum temperature spec for sprinkler heads / bulbs in outdoor / freezing applications?
Long:
One of the condo communities I manage has 16-space garages under their buildings partially open to the air and they have had a couple dry pendant sprinklers break over the past couple years (in the same building).
The garage walls are poured concrete. North and East sides are solid with no openings to the outside. South side is the gate, and west side has two ~6 foot tall and ~10 foot wide openings. At these two openings sit three heat pump condensers each.
I can't speak to details about the first head that popped about 3 years ago, but the one in January this past year was a day or two after a little bit of snow. Temp was right about freezing and the morning had a misty kind of rain. Air was almost foggy. The pipe above the drop ceiling was fine, the heater in the space was working, the pendant was not cracked. We found the frame/deflector in two pieces like a broken wishbone.
The bulbs are JOB FX-3S and their website doesn't have any readily accessible info I could find, and engineers I've chatted about it with haven't pointed at anything in code I can bang on the table to have the sprinkler company modify the system.
My theory is that when the condenser kicks on, the sprinkler heads are getting intensely cooled. Add a high humidity and it can cause icing, breaks the bulb and creates a mess. The sprinkler estucheons in the three buildings with similar setups all show surface rusting in the vicinity of the heat pumps.
I can't imagine this is the first time sprinklers have been above an outdoor heat pump condenser.
