Smoke detector for stairwell pressurization

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dcushing

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I was told that I needed to put in smoke detectors within 5 feet of the stairwell doors to activate the stairwell pressurization. I can't find it anywhere in the IBC/NFPA etc where it says this. Does anyone know where this could have come from?

It's a non-residential high rise in MA.

Thanks
 
dcushing said:
I was told that I needed to put in smoke detectors within 5 feet of the stairwell doors to activate the stairwell pressurization. I can't find it anywhere in the IBC/NFPA etc where it says this. Does anyone know where this could have come from?

It's a non-residential high rise in MA.

Thanks
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I can't help you with a code citation, but since the likely source of smoke into the stairwell will be at one or more of the doors (even one which is closed at the time), it makes a lot of sense to detect that smoke as quickly as possible. Any air flow in the stairwell may dilute and carry away the smoke so that a sensor farther from the door will see a lower concentration.

Since this is MA, there may well be detailed local codes involved.
 
I would imagine it would be the combined logic and inputs from a fire command panel to activate stair well pressurization in a building much the same way a call for alarm will shunt trip AHU and the like. But, if there is such a code, it will be easy to find.
 
GoldDigger said:
I like the general background it supplies, but for the OP's question, the sequence for stairwell pressurization starts with "1. Any fire alarm initiates smoke control mode." That does not give us a lot of guidance on what inputs or combination of inputs the control system has to use, much less where detectors need to be mounted.
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I agree , there does not seem to be a good site available for this topic.
 
NFPA 92

NFPA 92

I don't have the latest edition of NFPA 92, but the only requirement I can find is that smoke be detected before it leaves the smoke zone and enters the protected zone (stairwell, in this case). If the stair case is in a blind corner of the building, you can probably use the corridor spacing for smoke detectors. If smoke can approach the stairwell from more than one direction, you probably want the detector as close to the stairwell door as possible. In fact, it might be wise to bracket the door with smoke detectors covering each approach. I'm thinking of a "T" corridor with the stairwell door in the run of the "T" opposite the bull. There would be three (3) approaches to the stairwell door in that case, each of which you might want to cover.
 
The building code requires the pressurization system which is designed by the mechanical code. The building code is going to require activation of the pressurization system upon activation of the fire alarm system, also required by the building code, and installed pursuant to NFPA 72.

Activation of the fire alarm system requires activation of the pressurization system.

I've never heard of smoke detectors within 5' of a stairwell door.

Where I have heard of 5' religiously is that a pull station is required within 5' of an entrance to an exit so that any person egressing in an emergency can manually activate the fire alarm system without slowing down or traveling in a direction other than their means of egress.

I think you've been misinformed, but I'm not up on Mass. amendments.
 
I found a section in the IBC relating to this:

909.20.6 Ventilating equipment:
The activation of ventilating equipment required by the alternatives in Sections 909.20.4 and 909.20.5 shall be by smoke detectors installed at each floor level at an approved location at the entrance to the smokeproof enclosure. When the closing device for the stair shaft and vestibule doors is activated by smoke detection or power failure, the mechanical equipment shall activate and operate at the required performance levels. Smoke detectors shall be installed in accordance with Section 907.3.


It doesn't say anything about 5', but it seems to me that this is a case of someone remembering a code and adding a specific number so they look like an expert.

Thanks everyone I appreciate all the input and additional information I got from this.
 
No magnetic door holders. I'm familiar with that code, but it's a good thought.

The IBC references NFPA 72 chapter 5 for smoke locations. It looks like that chapter is reserved.. any thoughts on that?
 
dcushing said:
No magnetic door holders. I'm familiar with that code, but it's a good thought.

The IBC references NFPA 72 chapter 5 for smoke locations. It looks like that chapter is reserved.. any thoughts on that?
Click to expand...

NFPA 72 has the locations for smoke detectors in article 17 and depending on wall height above door either requires one smoke or one on each side of door.

Looking at 2009 IBC 907.4.2.2 the location of manual pull stations is required within 5 feet of the entrance to each exit door.
 
IBC stipulates the smoke detector requirement for pressurized stairwells (note that the code excerpt below reads the detector must be in an "approved" location). There is a second part to 909.20.6 that stipulates if door closing devices are used, when they lose power or are activated by smoke detector, those conditions shall also activate ventilation equipment

NFPA 72 provides further direction on the detector location but bounces you around a few code excerpts while doing so. The end result when initiating action for a specific object or space is to locate the detector in close proximity to the object being protected. You'll learn something about elevator lobbies and ceiling heights reading this as well which can drive some elevator inspectors crazy.

IBC 2015 909.20.6 Ventilating Equipment: The activation of ventilating equipment required by the alternatives in Sections 909.20.4 and 909.20.5 (stair pressurization) shall be by smoke detectors installed at each floor level at an approved location at the entrance to the smoke proof enclosure.

NFPA 72 2013 17.4.10 If the intent is to initiate action when smoke/fire threatens a specific object or space, the detector shall be permitted to be installed in close proximity to that object or space.
NFPA 72 Annex A17.4.10 There are some applications that do not require full area protection, but do require detection, to initiate action when specific objects or spaces are threatened by smoke or fire, such as at elevator landings that have ceilings in excess of 15ft and for protection of fire alarm control units. In high ceiling areas, to achieve the desired initiation, such as for elevator recall and protection of fire alarm control units (FACUs), detection should be placed on the wall above and within 60 in from teh top of the elevator door(s) or FACU.
NFPA 72 21.3.5 A lobby smoke detector shall be located on the ceiling within 21ft of the centerline of each elevator door within the elevator bank under control of the detector
Exception: for lobby ceilin gconfigurations exceeding 15ft in height or that are other than flat and smooth, detector locations shall be determined in accordance with Chapter 17 (which gets us back to chapter 17 and some of the above applications)

Enjoy
 
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