Smoke Damper Connection to Emergency Power

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waj01

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I sent this off to the NFPA but would appreciate any input:

I work for a regulatory agency that has adopted the NEC and NFPA 99 and have the following technical questions in reference to NFPA 70 -2002: 517.30 and NFPA 99 - 2002: 4.4.2.2

1. For a Type 1 EES in a hospital, is it permissible to connect a smoke damper to the Emergency System-Critical Branch? ( The smoke damper protects a duct penetration in a smoke barrier wall and the damper is not part of an engineered smoke control system.)

2. Is the damper considered an auxiliary part of the fire alarm system and required to be connected to the Emergency System - Life Safety Branch?

3. Although not part of a engineered smoke control system, can the damper be connected to the Equipment System since it does serve to control smoke passage at the smoke barrier wall?
 
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Nick

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Re: Smoke Damper Connection to Emergency Power

I belive 517-34(a)(4) should answer your question.
 
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waj01

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Re: Smoke Damper Connection to Emergency Power

Only problem with 517.34(a)(4) is that (as per the NFPA 99 Handbook)this appears to apply to fans etc. that serve as part of an engineered smoke control system. I am refering to isolated smoke dampers that protect duct penetrations of smoke barrier walls. That was the reason for my question #3.
 
roger

roger

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Re: Smoke Damper Connection to Emergency Power

Like the NEC Handbook, the NFPA 99 Handbook commentary is only suggestions and is not all inclusive of every application.

I would agree with Nick.

If the dampers are sealing Smoke Walls which are architectural requirements for the facility, how is it that they are not part of an overall system? Just a question for my curiosity.

Roger
 
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bwilson

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Re: Smoke Damper Connection to Emergency Power

I don't see a problem if connected to normal power. The dammper is fail safe, it will close on loss of power. That is all a damper is for, to stop the flow of fire or smoke. If needed by spec. I would connect to the equip. branch.
 
roger

roger

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Re: Smoke Damper Connection to Emergency Power

Bwilson, one problem with closing any damper with out A/C shutdown occurring, is the possibility of exploding or collapsing the duct.

A hospital we are currently working on had this happen (collapse) in November, the Mech contractor had to stay until the duct was opened up again. This duct served an O.R. area.

Roger

[ April 16, 2004, 03:18 PM: Message edited by: roger ]
 
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brentp

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Re: Smoke Damper Connection to Emergency Power

My opinions:

1) No. 517.33(A) smoke dampers have nothing to do with "functions related to patient care".

2) No. 517.32(C) is for alarms and alerting systems only.

3) Yes. 517.34(B)(1) as the AHU is more than likely supplying air/heat to the areas listed.

Again, these are just my opinions based on what I've seen engineered on previous projects. I would like very much to hear further input.

Brent

edited as I read Roger's post wrong

[ April 16, 2004, 07:32 PM: Message edited by: brentp ]
 
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brentp

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Re: Smoke Damper Connection to Emergency Power

Roger,

Obviously for a duct to collapse the return air dampers closed. If the AHU served an O.R. area, AND the AHU is used for smoke evac, I see no reason for fire/smoke dampers in the return air duct. Do you have any further info regarding the incident you mentioned above?

Brent
 
roger

roger

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Re: Smoke Damper Connection to Emergency Power

Brent, in this case when the zone (O.R. suite) goes into alarm, the unit goes into Smoke Purge, the supply goes to 100% outside air, if any damper closes out of sequence with the unit running something will and did give.

The case above actually happened during a State inspection, design over site.

This would also happen if a damper fed from a source not connected with the A/C controls lost power.

Roger
 
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brentp

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Re: Smoke Damper Connection to Emergency Power

Roger,

I don't want to highjack this thread, or put you on the spot, but what dampers would close during smoke purge/evac? Supply and return dampers should be open with both supply and return fans at 100%.

Brent
 
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nvcape

Senior Member
Re: Smoke Damper Connection to Emergency Power

The answer to this is probably not with NFPA, but as already said, the mechanical designer needs to have the FSD work with the respective HVAC unit. If the HVAC is on the Essential-equipment ATS, then the FSD must be too. Also need to make sure duct detectors are correctly set up too, if they are 120V.
 
roger

roger

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Re: Smoke Damper Connection to Emergency Power

Originally posted by brentp:
Roger,

I don't want to highjack this thread, or put you on the spot, but what dampers would close during smoke purge/evac? Supply and return dampers should be open with both supply and return fans at 100%.

Brent
Click to expand...
Brent you're not putting me on the spot, I will be the first to say I have no idea as to the damper operation of Mechanical design and I don't claim to.

What I do know, is what happens if a damper closes at the wrong time.

I think Nvcape is on the money.

Roger
 
iwire

iwire

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Re: Smoke Damper Connection to Emergency Power

Originally posted by brentp:
I don't want to highjack this thread, or put you on the spot, but what dampers would close during smoke purge/evac? Supply and return dampers should be open with both supply and return fans at 100%.
Click to expand...
I have not done this work at Hospitals but I have been involved with smoke evac systems in large offices and retail stores.

What dampers open and close will depend on where they are trying to force the smoke.

In a large store at a mall for instance we put smoke detectors in the mall just outside the entrance of the large store.

If these smokes in the mall trip, all exhaust air dampers close and all fresh air supply dampers and fans go to 100% inside the large store, effectively pressurizing the large store keeping the smoke in the mall for the mall system to evac.

If we get a smoke trip in the store all fresh air supply dampers close and all exhaust fans and dampers go 100% creating a negative pressure in the store and keeping the smoke out of the mall.

I would imagine if there is smoke detected outside the O.R. suite you would want to pressurize the O.R. suite to keep the smoke from making it into the O.R. area, but I am just guessing now. :p

[ April 17, 2004, 12:33 PM: Message edited by: iwire ]
 
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a.wayne3@verizon.net

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Re: Smoke Damper Connection to Emergency Power

Brentp I side with you.Roger sounds like someone got paid to change what the engineer $$$$$$ got paid to but didn`t do.Common scense????????Lets suck 10,000 cu.ft. of air out a 1 cu.ft area, :p
 
iwire

iwire

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Re: Smoke Damper Connection to Emergency Power

Alan I agree someone messed up if they collapsed the duct work :D , I was just pointing out that you can not assume all dampers should be going to 100% open.

Some of the office building we do get fairly complicated smoke control panels beside the fire panel that allow the FD to pressurize certain areas, or they can leave it on auto and the smoke detectors control it.
 
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brentp

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Re: Smoke Damper Connection to Emergency Power

Originally posted by iwire:
[QB] I was just pointing out that you can not assume all dampers should be going to 100% open.

I didn't mean to imply that, as I never said "all".

I'm still not seeing the reason for return dampers in a smoke evac system, as the O.R. is already pressurized. :p
Click to expand...
 
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waj01

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Re: Smoke Damper Connection to Emergency Power

Clarification From Poster!

As I stated, the damper in question is not part of an engineered smoke control/purge system as defined in NFPA 92A. The damper protects a duct penetration of a smoke barrier wall. Dampers are required(in some cases) in duct penetrations ofsmoke barrier walls in Health Care Occupancies by NFPA 101.

After reading the input, I am leaning towards them being required to be connected to the Equipment Branch.
 
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waj01

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Re: Smoke Damper Connection to Emergency Power

I got an answer from the NFPA and am posting it below. In the specific case, the smoke damper is controlled by an automatic alarm initiating device ( required by NFPA 90A) so the damper is monitored by the fire alarm system and should not have been connected to the Emergency Sysyem - Critical Branch. We are going to ask the hospital to correct it.

NFPA Log # 23097

If the smoke damper is monitored by the fire alrm system it must be connected to the Emergency System - Life Safety Branch
 
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brentp

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Re: Smoke Damper Connection to Emergency Power

If the smoke damper is monitored by the fire alrm system it must be connected to the Emergency System - Life Safety Branch
Click to expand...
517.32(A) thru (G) does not allow smoke dampers to be connected to the life safety branch. Am I missing something?

Brent
 
roger

roger

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Re: Smoke Damper Connection to Emergency Power

Brent, everything that would be a functional part of the fire protection system (alarm system) would need to be covered under 517.32(C) or be a weak link in the chain.

I don't have my NFPA 101 here so I can't reference the FPN.

Roger
 
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