I'm not sure if the efficacy of the model of a smoke detector inside the 
(assault resistant) grill from each cell. 

But this doesn't pass a laugh test. Back calculate the from the high 
sensitivity setting from the detector manual, then multiply that number by Ed's 
30 times dilution comment, and you are starting to get an idea of smoke level 
in the cells. 

You haven't added a safety factor for dilution prior to smoke entering the duct 
system, or that the self monitoring detector may be out of specs. And all based 
on one detector?

I can't imagine the system operating before the turnkeys in the control booth 
opened the manual control valve.

They did specify a second manual override to trip the valve in the control 
booth, didn't they?

Best




Sent from my iPhone
> On Sep 20, 2016, at 09:39, michael G <m...@keyfps.com> wrote:
> 
> Absolutly, what we have been saying the entire time.  the return air is drawn 
> at roughly 75 cfm if im not mistaken, the entire draw for the unit was in the 
> range of 6500-8500 cfm.
>  
> From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] 
> On Behalf Of Ed Vining
> Sent: Tuesday, September 20, 2016 12:32 PM
> To: sprinklerforum@lists.firesprinkler.org
> Subject: Re: Pre-action detection
>  
> The need is to detect fire in a pod. Fire in a pod generates smoke. Air comes 
> back from all pods.  The ventilation system dilutes the smoke from the fire 
> pod.  By a factor of 30?  The concentration of smoke hitting the detector 
> could be close to 3% of the concentration at the pod. Lack of  detector 
> listing is insignificant compared to the effect of dilution.
>  
> Wouldn't a wet system be nice? 
>  
> On Tue, Sep 20, 2016 at 8:14 AM, michael G <m...@keyfps.com> wrote:
> No, they are back at the main return, that is it. just one duct detector, 
> that covers about 30 cell pods.   They do not have any detectors in the 
> grilles in the cell pods.   that’s our main concern.
>  
> From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] 
> On Behalf Of rongreenman .
> Sent: Tuesday, September 20, 2016 11:07 AM
> 
> To: sprinklerforum@lists.firesprinkler.org
> Subject: Re: Pre-action detection
>  
> I am presuming the duct detectors are just inside the return air from the 
> cells and the day rooms  and other common areas are high ceilinged with 
> normal detectors or where ceilings are low the access is limited.
>  
> On Tue, Sep 20, 2016 at 7:54 AM, <craig.pr...@ch2m.com> wrote:
> Where a fire alarm system is installed, duct detectors are an initiating 
> device attached to and powered by the FACP system just as any other room 
> detector.  It’s essentially a regular detector head with tubes placed in an 
> enclosure. 
>  
> Here’s a quote to chew on from the book, Operation of Fire Protection Systems:
> “The detection of duct smoke is made difficult by its dilution with return 
> air from other spaces (away from the fire) and possibly with outside fresh 
> air.  Also, when the HVAC system fan is not running, smoke may not reach the 
> duct detector. For these reasons, air duct smoke detectors must never be 
> considered as a substitute for open area protection.”
>  
>  
>  
>  
> 
> Craig L. Prahl 
> Fire Protection Group Lead/SME
> CH2M
> 200 Verdae Blvd. 
> Greenville, SC  29607
> Direct - 864.920.7540
> Fax - 864.920.7129
> CH2MHILL Extension  77540
> craig.pr...@ch2m.com
> 
>  
> From: Sprinklerforum [mailto:sprinklerforum-boun...@lists.firesprinkler.org] 
> On Behalf Of Parsley Consulting
> Sent: Tuesday, September 20, 2016 10:22 AM
> To: sprinklerforum@lists.firesprinkler.org
> Subject: Re: Pre-action detection [EXTERNAL]
>  
> Greg,
>     The first issue that came to my mind was that the duct detector is 
> frequently provided with power from the HVAC system and not from the FACU or 
> releasing panel.  I don't know the logistics of what you're dealing with or 
> whether that issue might have some impact however that might be worth looking 
> into.  I have to admit I'd never heard of something like this.  That by 
> itself doesn't mean it's outside the listing or the guidance in -72 or -13, 
> just that I've never run across this configuration.
> Ken Wagoner, SET
> Parsley Consulting
> 350 West 9th Avenue, Suite 206
> Escondido, California 92025
> Phone 760-745-6181
> Visit our website
> On 09/20/2016 6:28 AM, Gregg Key wrote:
> Greetings,
>  
>                               First of all, what a great convention. Good 
> speakers and fellowship. Nashville was awesome as well. I am in serious need 
> of some technical assistance. I have posted this a few times with some 
> response but this has become a three ring circus between the architect ,fire 
> marshal and us . The Architect specified a double interlock pre-action system 
> with the detection being provided with a duct detector in the return duct at 
> the unit. We have refused to certify the system due the fact that the 
> detector not being listed for this application. State is asking me to hang a 
> partial certification ( yellow tag) . has anyone else dealt with this 
> detection being used for a pre-action system in a detention center?   Any 
> help would be appreciated  
>  
> Gregg Key
> General Manager
> Key Fire Protection Enterprises,LLC
> 3200 Mike Padgett Hwy
> Augusta GA, 30906
> O-706-790-3473
> C- 706-220-8821
> F- 706-738-2119
> gr...@keyfps.com
>  
>  
>  
> 
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> 
>  
> --
> Ron Greenman
> 
> 4110 Olson Dr., NW
> Gig Harbor, WA 98335
> 
> rongreen...@gmail.com
> 
> 253.576.9700
>  
> The Universe is monstrously indifferent to the presence of man. -Werner 
> Herzog, screenwriter, film director, author, actor and opera director (1942-)
>  
> 
> 
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> --
> Ed Vining
> 4819 John Muir Rd
> Martinez CA 94553
> 925-228-8792
> Cell 925-787-0465
>  
> 
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