Rules governing audible devices in stairwells

[mshields]

Specifically, I'm looking to find what the rule is for buildings that have horns (as opposed to speakers) and in MA. But even knowing where to find it in NFRPA 72 and or NFPA 1 would allow me to look up any ammendments in MA.

In any event, the question is where to find the rules governing audible devices in stairwells. I know that if its a high rise or a hospital and therefore you have a voice system, then you put them in but only use them for announcements. But what does this say about stairwells where the systems uses horns. Logice dictates that they should not be put in. But a code reference would be nice.

Much appreciated,

Mike

 

[steve66]

I've seen it in NFPA 72 somewhere, and you are correct - they are not required (and might not even be allowed in stairwells).

Loud horns in egress stairwells might discourage occupants from exiting the building.

 

[steve66]

I can't find the actual reference off hand.

The IBC does have an exception for visible appliances in exits (look under visual devices, and look at the definition of exit in chapter 2).

Not sure why this isn't also listed under audible devices, unless the intent is to have voice devices in stairwells where the system has voice capability.

 

[mshields]

I have since found if anyone is interested that 23.8.6.2.3 indicates that "the evacuation signal shall not be required to operate in exit stair enclosures and exit passageways. This makes perfect sense with a speaker based system where they are available for the FD to issue instructions. Not so much for horns. Where horns are concerned, if this is the only direction given, I note that it does not give cover for not providing horns, only that they may not operate. While it doesn't make sense that anyone would do that, if it's the intent, the wording is poor.

 

[gadfly56]

I have since found if anyone is interested that 23.8.6.2.3 indicates that "the evacuation signal shall not be required to operate in exit stair enclosures and exit passageways. This makes perfect sense with a speaker based system where they are available for the FD to issue instructions. Not so much for horns. Where horns are concerned, if this is the only direction given, I note that it does not give cover for not providing horns, only that they may not operate. While it doesn't make sense that anyone would do that, if it's the intent, the wording is poor.

Horn/strobes have a minimum setting of 90 dbA. That's at 10'. If you put them in a stair well, they are loud enough to cause disorientation, considering the highly reverberant nature of of the stair enclosure. Likewise, the visual signal can be a hazard to anyone trying to navigate the stairs. From a philosophical perspective, once the occupants have reached the stairwell they are on their way out of the building. No further evacuation signaling is required for those in the stairwell. See the Appendix A note for 23.8.6.2.