Fire Alarm Question

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bcorbin

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Yeah, yeah...I know it's not an NEC issue, but the electricians end up installing it most times anyways, so I figured some of you guys might know.

I have some fire alarm audio-visual notification devices to put in a gymnasium. We need to put them on the wall where the collapsible bleachers are. We usually put the notification devices at 80" A.F.F., but in this case I am inclined to put them 80" above the top of the bleachers, since the bleachers are longer than the typical space between devices. I would think the spacing/candela rating would need to be altered as needed to be measured at the floor below.

Does this sound right? If anyone is familiar with a particular piece of NFPA 72 dealing with this, please let me know.
 
I can't help you with a nfpa section, but.
After the building is open (as you know) the fire marshall will take a walk through. And then again every year.
You might want to check with he or she.
 
You have two entities you are dealing with at this point. NFPA (requiring the devices and resulting light levels) and ADA (requiring mounting heights etc.) 80" is an ADA requirement.

80" above the top of the bleachers is a bit excessive ... but you don't want to be behind the bleachers for sure! A "couple" of feet above the bleachers would be fine. Being in a gym, don't forget the wire guards.

Talk with a fire alarm rep (or at least the company that created the drawings), they might have a specific height in mind. Is this a school? You can also talk with the school facilities person and see where they are mounted in their other buildings. Do they have issues with vandalism when in reach of the student population?

Also ... since it's higher than "normal" you might need a higher than normal candela device.

And, yes, contact the local fire marshal ... they've seen this before and know their preferred solution.

Good Luck!
 
Locations

Locations

If you can put them on the end walls and still reach accross the court, that is best. 110cd can reach up to 50', so from the end walls they can span 100'.
In the past when I still needed them above the bleachers in addition to the end walls, I put them at about 6' above the top of the bleachers, so if people were standing on the bleachers, the strobes would still be visible.
Gyms are a unique application and most AHJs understand this, and as long as you try to get it as close they will probably not have an issue with it.
 
MNWildcat said:
If you can put them on the end walls and still reach accross the court, that is best. 110cd can reach up to 50', so from the end walls they can span 100'.
Click to expand...

Wouldn't you know it? This gymnasium is 103' long. My luck, I tell you. :-?

But the ADA thing was a good point I didn't realize. I will also give the local fire marshall a call. Thanks, guys.
 
close?

close?

That is pretty close to 50'.
There is no way to get 100.000% coverage in a building with all the bends and nooks in the corridors. Strobe coverage has to be a realistic design. The 2002 version of 72 allows for a performance based alternative where a minimum illumination has to be met. With devices at boths ends, you would probably meet that.
You would probably have at least two on each end, then add one 6' above each bleacher in the middle. That should give enough coverage.

Also, there are higher cd rated strobes available, but they are not common.

Through equivalent facilitation (sp?), the ADA has basically defauled to NFPA requirements.

Coordinating with the AHJ is also good.
 
MNWildcat said:
That is pretty close to 50'.
There is no way to get 100.000% coverage in a building with all the bends and nooks in the corridors. Strobe coverage has to be a realistic design. The 2002 version of 72 allows for a performance based alternative where a minimum illumination has to be met. With devices at boths ends, you would probably meet that.
You would probably have at least two on each end, then add one 6' above each bleacher in the middle. That should give enough coverage.

Also, there are higher cd rated strobes available, but they are not common.

Through equivalent facilitation (sp?), the ADA has basically defauled to NFPA requirements.

Coordinating with the AHJ is also good.
Click to expand...

Agreed on all facets . though I thought the NFPA defaulted to ADA ... but which came first, the chicken or the egg?

I've wondered a lot recently ... all manufacturer's have ceiling mounted notification devices. I've had a building official suggest ceiling mounted devices in an open office area that I had. How in the world do ceiling mounted devices meet ADA requirements?
 
Ada

Ada

The ADAAG was revised in 94 and is in the process again. There is a 2004 draft verion out (which matches the current 72 criteria), but since it is changing so many parameters, not everyone can agree on the changes - so it sits there unchanged, still.
They did add the equivalent facilitation which allows for accpetance of equivant industry standards to be used. There is how NFPA 72 is now basically referenced from the ADAAG. NFPA 72 has a long history of updating to current technology and still maintaining good performance.

I was initially hesitant to use ceiling mounted devices until I understood the equiv. facil. So, do what you want for strobe and comply with 72 for mounting, but still comply with ADAAG for required locations.

And always reference any/all local codes and ammendments.
 
Open Area Design

Open Area Design

This is always a tough nut to crack. The appendix notes in NFPA-72 admit that the design criteria are fundamentally geared to an occupied space that has basically a standard 8-10' ceiling.

One of the key things to consider is where the occupant's field of vision naturally settles. If you're standing at one end of the gym and looking across to the other, you probably aren't focused 4" above the exit door. You're looking 1/3 to 1/2 up the opposite wall.

Placing the horn/strobes 6' or so above the bleachers is a good idea. System Sensor has readily available in their "H" series 135 to 185 candela. Skip the tanning salon! You may need a notification appliance circuit power booster to accomodate the current draw, which is up to 286 mA for the 185's. One thing that really helps is to sync the outputs. It will look like the whole space is flashing at once, and it's a requirement if you have 3 or more strobes in the same field of view. This should cover you from an ADA perspective, not that anyone really knows what's needed. Without knowing the particulars, if the space is rectangular and I wanted to be sure of coverage, I'd put one unit at each short end and two on each long wall at 110 candela and sync them. If it's square, put one on each wall but don't center them! See NFPA-72 (2002) chapter 7 annex notes for some guidance.

Ceiling mounted units are suitable for up to a 30' ceiling height. You have to reduce spacing for a given candela rating, but the tables are in NFPA-72 (2002) in chapter 7, Table 7.5.4.1.1(b). Maintenance can be a real pain if they're that high. Good luck!:grin:
 
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