I had a fitter question a seemingly similar situation and couldn't really come up with a logical answer.
#1 - It started with a light shelf. The self sticks out from the wall about 3'. It's about 10' long. This is in a very wide hallway. The top is more than 18" below the deflector. It's about 5" thick. I say '02-8.6.5.3 (obstructions more than 18" below) tells us we don't need a head under the shelf. The floor is covered from the overhead assuming the shelf didn't exist. #2 - Then we have about the same situation but the edge of the shelf returns to the ceiling creating a box. I think we'd call it a soffit. As I see it '02-8.6.5.3 doesn't apply anymore. We'd go back to 8.6.5.1.2 (beam rule). It's over 30" so that's not an option. In nearly all cases a head goes in. #3 - Or how about a closet with no doors recessed into the wall with just a header over the opening. In nearly all cases a head goes in. #4 - Or how about a shower with doors but the top 6"-8" of the door is missing. Really a drop soffit, 6" opening then the door below. In nearly all cases a head goes in. In all cases as I see it and our fitter sees it we have the exact same operation time of the head and the same wetting pattern on the floor assuming one doesn't put the lower head in. By that I mean there will be no water on the floor because of the obstruction. Again if the obstruction didn't exist the floor would be wet from the overhead. But in the first case we don't put a head under the obstruction but usually put one in the other three cases. Now example 3 and 4 could be argued as rooms but from a performance standard the issue is the same is it not. Now I say usually because with subtle dimension differences we might skip the head in the box or closet if we can meet the beam rule and distance from the wall. Any thoughts other than I know applying logic to the codes it dangerous. That's OK with me. I don't like it but will live with it. My fitter really doesn't like it. More of a black or white kind of guy. Chris Cahill, P.E. Fire Protection Engineer Sentry Fire Protection, Inc. 763-658-4483 763-658-4921 fax Email: [email protected] Mail: P.O. Box 69 Waverly, MN 55390 Location: 4439 Hwy 12 SW Waverly, MN 55390 _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
