|
Posted by Abby Normal on November 17, 2006, 7:02 pm
gof...@gonefishin.net wrote:
>
> >NFPA 72 does not really differentiate between supply diiffusers and
> >return grilles or heat ing and cooling.
> >
> >They want a three foot clearance.
> >
> >The main reason being a supply in cooling could cool of the detector.
> >When the AC cycles off mositsure could condense inside of the detector.
> > Mositure can deflect light imilar to particles of smoke and cause
> >false alarms.
> >
> >Glenn wrote:
> >> What is the code for the distance between a smoke detector and a return
> >> from a forced hot air system?
>
>
> typically smoke detectors are installed in supply air plenums as close
> to the ac unit as possible, and in some cases in the return air
> compartment on package units. Some situations require SD's in both
> supply and return air plenums, for instance sometimes the fans are ran
> 24/7. typically sd's are not required on systems of 2000 cfm or less.
Those are duct mounted smoke detectors, designed to shut a unit down
when they begin to recirculate smoke. Some jurisdictions will want them
on fan coils under 2000 CFM if the fan coil serves an exit corridor.
I assumed the original poster was refering to ceiling mounted devices
montoring the space.
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap