Interpretation #7471

Original Request

Code Version: 2007
Code: BUILDING
Code Description: Building
Chapter: 14
Section: 1406.3 Exception 3
Topic: Type 5A Underside of roof protection

Question

Is it the intent of the code to require the underside of the roof and columns that support these decks and roof to be protected by 1 hour assemblies if the construction type is type 5A and the sprinkler system is extended out to protect these exterior areas?

Answer Published 03/23/2015 at 3:56 PM

Yes, reductions in fire resistance rating are authorized
for NFPA 13 systems only; not NFPA 13 R systems. See Table
601 Note h.

Commentary

Note b could apply if every part of the roof construction is 20 feet or more above any floor immediately below, but sufficient information is not provided and this would be unusual in R-2 construction. Not sure what is meant by "the underside of the roof". This could mean the sheathing underside, metal deck, or something else. For Construction Type VA the roof assembly is required to be a one-hour fire resistant assembly which must be a documented and tested assembly installed in accordance with the testing.