×
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

Determining the Percent Reduction in Design Area - NFPA 13

Determining the Percent Reduction in Design Area - NFPA 13

Determining the Percent Reduction in Design Area - NFPA 13

(OP)
NFPA 13 11.2.3.2.3.3 “Where quick response sprinklers are used on a sloped ceiling or roof, the maximum ceiling or roof height shall be used for determining the percent reduction in design area.”

Its a light hazard occupancy building and has sloped ceilings, the maximum ceiling height is 19’-0”. NFPA 13 requires 1434 sq.ft. of system area of operation, including 30% for the sloped ceiling. The building also has a skylight (50 sq.ft approx.) , the maximum height on the skylight is 25’-0” above the finished floor. If this height is considered, the system area of operation requirement increases to 1950 sq.ft. One sprinkler head will provide coverage for the skylight.
So my question or confusion is- do I have to take into consideration the skylight height when calculating the design area reduction for quick response sprinklers? As the area of skylight is very small compared to rest of the room, I am not sure if this should dictate the system area of operation.

An interpretation on this code section would be appreciated.

Thank you !

RE: Determining the Percent Reduction in Design Area - NFPA 13

I have been told by one AHJ that skylight height is not ceiling or roof height. However, I went back and calculated it both ways in a scenario similar to yours just in case.

RE: Determining the Percent Reduction in Design Area - NFPA 13

(OP)
I have talked to few of the AHJs and pretty much this subject remains unclear. I have tried doing it both ways, but I'm trying to get a solid answer to make my self clear on this issue.
Thanks

RE: Determining the Percent Reduction in Design Area - NFPA 13

(OP)
Well got an answer to that .. It can be considered as a protected ceiling pocket and its height ignored while considering ceiling or roof height.

RE: Determining the Percent Reduction in Design Area - NFPA 13

Did you check the explanation section at the end of NFPA13? I don't have those NFPA codes anymore but I do remember those sections.

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