Is this Sprinkler Obstructed by Light Fixture?

5/7/2019

In a residential dwelling unit of a high rise building, would a drum light fixture (7"h x 14"d) qualify as an obstruction?

It’s a concealed head in a residential unit of a senior living building.

The contractor – of course – doe not have exact dimensions because it wasn’t reflected on the plans and was added later as a lighting option and only caught by my inspectors during Rough-In. As it is installed, the head is a few inches from the fixture in some units and “a few feet” in others. They want to add a head on the other side of the light, approximately 3 feet -4 feet away citing NFPA 13 8.10.6.2.1.4.

I feel that the light, while an obstruction, doesn’t count as continuous nor does it meet the requirements of a baffle, so if they want to add another head it’d have to be at least 6 feet away to prevent cold solder.

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9 Comments

Clifford Schulze

5/7/2019 11:02:48 am

NFPA defines obstructions as both continuous and non-continuous. Can you relocate the sprinkler head to meet the obstruction criteria, in this case 2'-6" - 3'-0" off the fixture?

Rob Stewart

5/7/2019 11:08:17 am

If a residential sprinkler head - it is 8' minimum distance between sprinkler heads

pari

5/7/2019 11:19:49 am

NFPA13 D Section 8.2.5.1.1 Pendent sprinklers shall be located at least 3 ft away from obstructions such as ceiling fans and light fixtures.
Section 8.2.5.1.3 where the sprinkler cannot be located 3 ft away from the obstruction, an additional sprinkler shall be located on the other side of the obstruction.

5/7/2019 12:31:59 pm

He mentioned that this is a high rise building so 13D and 13R won't apply

PETE

5/7/2019 11:23:17 am

Echo what Clifford said. The inspector is correct. The scenario you described is a non-continuous obstruction to the discharge. Per §8.6.5.1.2 in NFPA 13, the sprinkler needs to either be spaced away from the obstruction based on the table. If you look at your concealed cut sheet and find that the deflector falls 1 1/2" out of the concealed head, you'd be 5 1/2" obstructed by the light (7"-1 1/2"). That would put your sprinkler 1'-6" to 2' away from the near edge of the light. That is to spray beneath it. The other option given under that section is to sprinkler on both sides of the light. Minimum spacing rules don't apply in this option because you're treating the obstruction like a wall. In other words, because of the obstruction the sprinklers won't spray on each other. The only requirement for the 2nd option is that the sprinklers are no more than the half distance of their maximum linear spacing from the center of the obstruction, again like it's a wall.

DaviD C

5/7/2019 02:48:58 pm

Pete well stated.

Just to expand on the cold soldering statement, if its treated as an obstruction or there is not the possibility of water from 1 head reaching the deflector of the other, it would not cold solder regardless of distance.

Cant tell you how many AHJ tried to state cold soldering when 1 head is 3 feet above another head in a different ceiling plane.

Jonathan Joseph

5/7/2019 12:25:43 pm

I would agree with Pari. You must be a minimum of 8 ' from the sprinkler or fixture in this case if you choose to add a sprinkler and keep the sprinkler that is obstructed.
I would try to re-locate if possible but it must be 3 feet away.
A light fixture cannot be considered a baffle because a tenant or owner can delete or change light fixtures at any time.

5/7/2019 12:45:07 pm

Anon did not state whether he was working per 13 or 13D, only that the space was a dwelling unit. Anon did state that the inspector objected to the placement per NFPA 13, so I assume it is an NFPA 13 job, not 13D.

5/7/2019 01:39:28 pm

It's a high-rise but the same rule applies to residential sprinklers.
NFPA 13 8.10.6.2.1.3(a) the four times rule or 3 feet away from light fixtures whichever works in the installers favor.

In this case the four times rule would be 4 foot 6 inches away and the obstruction table would be 4 foot to 4 foot 6 inches away if the deflector to obstruction vertical distance is 5 inches.

Is this Sprinkler Obstructed by Light Fixture?

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