Would a glass atrium with steel mullions on steel beams be considered "smooth ceiling?"
What is the depth and spacing of the mullions?What is the depth and spacing of the beams?Is there slope associated with the entire assembly?
What is the context of the question? Are you going for a spacing, deflector distance, remote area increase...?
Mullions are a nominal 5” deep, ±7’-3” on center.
Majority of beams are 24”. A few are twice that.
Slope is less than 3 in 12.
Context is for spacing, deflector distance and determining if sidewalls are an option.
Check out the NFSA E TECH ALERT JUNE 20 2006 for some guidance. Your picture leads me to think the glass isn't flat but rises up and down (so the glass to top of beam is greater than 5" at the peaks). This would point me to a heat collection issue with using sidewalls.
Pan decks greater than 3" deep (similar construction profile) require the top of the pan deck (or in this case the bottom of glass) as the start point for deflector distance measurements...leaving a sprinkler that needs to be listed in the 6"-12" range IF they can even be utilized.
Lots of yellow flags and AHJ interpretations to be had. What is the occupancy below?
I would say per NFPA 13 no not a smooth ceiling
You can send the question to NFSA EOD and see what they think:::
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