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NFPA 13 8.15.1.2 Concealed Spaces Not Requiring Sprinkler Protection

Question asked by mcamire on Apr 5, 2017
Latest reply on Apr 11, 2017 by maasaicontracting

We have a old presbytery (1900)- wood construction- 3 story high- unsprinklered

 

The owner want to  install sprinklers in it.  In the rooms, all the piping will be visually apparent under the ceiling. For the the sprinkers in the rooms, no problem.  The question is for the concealed space over the room (floor structure between storey).

 

We have two types of floor detail :

See detail #1 and picture- Floor on wood planks (1'' x 1½'') on 2'' concrete slab supported by 2''x 10'' wood spaced à 24''.  Ceiling (plaster below 1/2'' wood base) attached to the 2'' x 10'' structure by pieces of 1.5''x1.5'' installed perpendicular to the 2x 10''.  So between the 2'' x 10'', we have free-empty space (24'' x 10'' height each) and under the 2 x 10'' (1.5'' height).

 

Question #1:  Do we need to installed sprinkled in the concealed space (between or under  the 2'' x 10'') ?

 

 

See detail #2- More complex- 2 levels of concealed spaces.-Floor on wood planks (1'' x 1½'') supported by 2''x 6'' wood spaced à 24''. So between the 2'' x 6'', we have free-empty space (24'' x 6'' height each).

 

Under the 2''x6'', 1,5 x 1,5'' wood plank slab supported on 2''x 11'' wood spaced à 24''.  Ceiling (plaster below 1/2'' wood base) attached to the 2'' x 11'' structure by pieces of 1.5''x1.5'' (18'' spaced) installed perpendicular to the 2x 11''.  So between the 2'' x 11'', we have free-empty space (24'' x 10'' height each) and under the 2 x 11'' (1.5'' height).

 

Question #2a:  Do we need to installed sprinkled in the concealed spaces (between or below  the 2'' x 11'') and (between or the 2'' x6'') ?

 

Question 2b:In the Handbook 2007 "Paragraph 8.15.1.2.5 applies to sheahed joist construction or similar narrow spaces formed by the attachement of a ceiling to, or within, 6in. of joists.  This exception is intended to apply only to joists with no openings in the members and within a nominal depth of up to 14 in."  For the 2 levels of concealed space, (1'' +6'' depth), what to do to have less then 14'' depth?

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