×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Sprinkler proximity to AC diffuser etc

Sprinkler proximity to AC diffuser etc

Sprinkler proximity to AC diffuser etc

(OP)
I'm having trouble finding anything in NFPA13 regarding heat zones etc. for QR or SR SSP pendants
Any help would be appreciated, thanks   

RE: Sprinkler proximity to AC diffuser etc

Table 8.3.2.5(a)  Temperature Ratings of Sprinklers Based on Distance from Heat Sources

RE: Sprinkler proximity to AC diffuser etc

I know there is a minimum spacing for smoke detectors from diffusers (so the air flow doesn't affect their opperation), but I've never heard of a similar requirement for sprinklers.

I don't think there is any rule that stops you from putting a sprinkler next to a diffuser (although it will likely take longer to go of in a fire with cold air being blown on it).

RE: Sprinkler proximity to AC diffuser etc

I dont think anyone here is talking about cold air being blown on the sprinkler. The original comment is reference to heat zones.
Then sprinklerdesigner2 referred his comment to NFPA 13:
Distance from sprinkler to heat sources

AZsprink needs to elaborate a little more so we can properly comment on his question.

   

RE: Sprinkler proximity to AC diffuser etc

(OP)
Sorry for not being more clear, My original question was referring to the minimum distance a sprinkler can be placed next to a ceiling heat diffuser.

I know that most tyco residential heads have to be at least 2 ft. from vertical AC diffusers and 3 ft. from the front and 2ft. from the side of horizontal diffusers (according to the TYCO residential design guide)

I wasn't sure if the requirements are  different for commercial heads, looks like they are, for commercial heads you can be 1 ft. from vert. diffuser. "maybe residential heads are more sensitive to temp. changes than commercial heads"

Thanks    

RE: Sprinkler proximity to AC diffuser etc

I think in practice you will be 2' from a heating outlet unless you want to use intermediate temperature (yellow or green) heads next to outlets.  For convenience, you probably want red bulb sprinklers throughout.  

 

 

RE: Sprinkler proximity to AC diffuser etc

AZsprink:

I suspect (and this is purely my opinion) the increased distance is necessary because residential sprinklers have an RTI <= 50. Most likely the manufacturers are concerned with HVAC air flow interrupting the hot gas plume and ceiling gas layer during the fire's growth from incipent to pre-flashover.

RE: Sprinkler proximity to AC diffuser etc

Be aware that the more restrictive requirements (2'-0" from ceiling diffuser instead of 1'-0", etc.) found in table 8.3.2.5(c) apply to ALL types of sprinklers installed in residential areas, not just to residential sprinklers.

RE: Sprinkler proximity to AC diffuser etc

@Stookey,

Perhaps NFPA should be concerned about interupting the gas plume the way you described, however the way NFPA 13 is written, the requirement only addresses diffusers used for heating not for cooling.  

The requirement seems to address unwanted discharge of sprinklers caused by overheat, but doesn seem to address reduced response time caused by blowing cold air on a sprinkler as diffusers that only have cold air are exempt.     

RE: Sprinkler proximity to AC diffuser etc

So what would you  do about a 20000 sq ft freezer storage room and delay in sprinkler response???

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources