NFPA 13 Temperature Ratings

[964]

Hi

For the purpose of this post I am using NFPA 13 2010 Edition as it was the one on my desk and within reach.

I was wondering if anyone could clarify for me when Table 8.3.2.5(c) "Ratings of Sprinklers in Specified Residential Areas" applys. My confusion stems from the fact that some items appear in both Table 8.3.2.5(a) and (c), but the requirements are different.

For example per Table 8.3.2.5(a) intermediate temperature heads are required within a 1' radius of a downward discharging diffuser or 2'6" semicylinder of a horizontal diffuser. Table 8.3.2.5(c) requires intermediate temperature sprinklers within 24" of any hot air diffuser.

Consider this question in the context of a multiple "residential" unit building, such as a condo high-rise or a college dorm, where you have multiple dwelling units and common/areas. The individual units could be protected with either commercial or residential sprinkler heads depending on room size and available water, halls and common areas are protected with commercial heads.

Does Table 8.3.2.5(a) apply to the commercial heads and Table 8.3.2.5(c) apply to the residential heads? Or does Table 8.3.2.5(a) apply in the common areas and Table 8.3.2.5(c) apply in the dwelling units regardless of head type? I haven't gotten a strong opinion from the more senior designers that I have asked so far, and my web searches tend to return hits for write ups about specific individual temperature requirements rather than a higher level view of when to apply each table. Thought I would come here for another opinion.

Thank You
Huey

 

[skdesigner]

Looking at the 2013 handbook (the closest edition at hand), it contains the following:

FAQ

Is any guidance for temperature selection for residential sprinklers available?

Paragraph 8.3.2.5(8) provides technical guidance when selecting the temperature rating of sprinklers protecting residential areas. The requirements of 8.3.2.5(8) and Table 8.3.2.5(c) provide guidance for all sprinklers utilized in residential areas, including residential sprinklers.

So, your second interpretation appears correct.

 

[964]

sk

That is the way I was leaning, I guess it just irked me that items which appear in both tables have different requirements based on the setting. In my mind if a 1' radius from a diffuser defines the need for intermediate temperature in an office, why would the requirements change in a condo or dorm room. The differences probably have more to do with how each table was developed for the code than the actual conditions.

Thanks for the confirmation.

Huey

 

[cdafd]

Above my pay grade,,,


May have something to do with the type of sprinkler

 

[MGXFP]

I think the difference has to do with residential sprinklers being fast response and commercial sprinklers being quick response.

I think the solution is to just use intermediate temp sprinklers throughout.

EDIT: meant to say intermediate not ordinary temp sprinklers.

 

[TravisMack]

I'm actually seeing a trend with my customers to use intermediate temp sprinklers throughout. It is permitted in the 2010 and newer editions of NFPA 13, 13D and 13R.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692

 

[cdafd]

Have seen that recently but mainly in kitchen and bathroom areas or adjoining them.

Had to read the book the first time someone proposed it

 

[TravisMack]

You can use intermediate in all areas of a building designed per NFPA 13, unless the standard requires a higher temperature rating. It used to be that you could only use ordinary temp throughout. Now you can use intermediate or ordinary temp throughout.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

"Follow" us at

https://www.facebook.com/pages/MFP-Design-LLC/92218417692

 

[MatthewJWillis]

Be aware of that pesky Chapter 6. It sill lists max ceiling temps.

R/
Matt

 

[964]

I am starting to provide intermediate temperature heads throughout even if the customer doesn't ask for it. That way I don't have to worry when supply diffusers start moving around. Most of my work is in CT and the CT State Building Code recently went from 2005 to 2016, so until last year I was still designing to NFPA 13 2002...

Got to be careful with residential heads since plenty of models are not available in intermediate temperatures, I've run into this with ECLH heads recently as well.

 

[Ehendrix]

Travis,

I agree I am starting to see the use of Intermediate heads in commercial office space. I kept wondering why I kept seeing this, at first I thought someone was using spare heads off a shelf.

Last year I saw a nursing home that another company did and all the sprinklers were 200°. I really struggled with why you want to do that but as I read and study more into it perhaps it can cover you in the future from any additional heat sources and changes.

But if you look in NFPA 13 chapter 6 will you have a ceiling temp near 150 deg???

Thanks,



Eric Hendrix, SET
NICET Certified
Design Manager