Is Vertical Light Fixture a Sprinkler Obstruction?

4/10/2024

Good morning! Is there any NFPA 13 prescriptive option for this type of obstruction?

These are ceiling waves with a horizontal fall chain lighting system.

Thanks in advance.

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6 Comments

Dan Wilder

4/10/2024 07:27:18 am

If the fixtures are below the sprinklers >18", there isn't any additional requirements for sprinkler coverage, unless they are over 48" wide and solid top, but an "open" top gets more inventive. If they are attached to or start within that 18" zone, best bet is to place sprinklers on either side and treat the light as a vertical obstruction. This can be very instance specific so reviewing each design for impact is needed.

The top picture would likely have a sprinkler layout around the circumference of the lights as a whole (that rounded soffit area) with additional sprinklers located within the light fixture vertical stranding as needed (would need a plan view to place sprinklers). The bottom picture, I would not have any additional protection as the top of the lights look "open" in addition to the distance below the ceiling (may not be 70% open but there's a good argument for install effort vs result with this atrium setup - heat collection/spray pattern development).

One of my previous projects with a "3D trapezoid light fixture" that we dropped sprinklers inside (you can see the darker sprinkler plate at the bottom)

https://www.gannett-cdn.com/-mm-/c47227a8de36cdd28558e322e7e37b0ae829cf4c/c=0-185-3200-1993/local/-/media/2015/12/10/Phoenix/Phoenix/635853534323258491-West-Valley-Casino-5.jpg?width=3200&height=1680&fit=crop

or similarly, we had several vertical strung light fixtures over various bar areas, we ended up placing sprinklers behind and in front (picture left), but others that were not obstructions (picture right) received no additional sprinkler consideration.

https://www.enr.com/ext/resources/Issues/Southwest_Issues/2020/11-Nov/02-Nov/Best-Projects/desert-diamond-casino3_Interior.jpg?t=1603898914&width=1080

Anthony

4/10/2024 07:36:16 am

Most likely to be open above so you can treat it as a non obstruction as Dan says above.

Alternatively say this was attached to the ceiling you could surround the fixture with closely spaced sprinklers working with an FPE to define discharge criteria to isolate it from rest of the building. you'd need AHJ sign off, but I've seen this for art instilations in the past.

Pete H

4/10/2024 08:02:32 am

Second pic looks to be a corridor so I'd call a suspended obstruction in light hazard and use NFPA 13 (2016) Figure 8.6.5.2.2. You look well below 18" under where I'd expect the deflectors to be so this should get you out of the need to protect around that.

The first pic looks to be in a mercantile space and is no longer light hazard.

So then I'd say if I'm running this strictly by code it matters the width of the obstruction. If it's under 4'-0", treat it as such and use 8.6.5.3.3 to void the need for protection. If it's over, and it looks over.... you technically should have to protect underneath the obstruction.

Though I'd note and restate Dan's points about how open these things are at the top of the obstruction is also of major relevance.

I say technically because your case seems unique enough and "direct underneath the obstruction" protection seems like it'd be an eyesore as well as not provide necessary protection while being liable for false trips as lights tend to generate heat. Your best bet might be asking the AHJ if they'd be okay with tight protection in the circumference of the circle around the obstruction and a sprinkler dead set in the middle over it. As Anthony outlines, an FPE would be very useful for this.

Franck

4/10/2024 08:40:25 am

As indicated above, may be problematic only under some circumstances when the lateral side do present an. obstruction because located too close to ceiling sprinklers

Jesse

4/10/2024 12:07:14 pm

Is this fixture open at the top?

Glenn Berger

4/10/2024 06:32:06 pm

I just one of these scenarios in a Las Vegas showroom. The spacing of the verticals did not really look that close. In this case I would consider it a non-obstruction.

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Is Vertical Light Fixture a Sprinkler Obstruction?

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