9
Obstructions
Obstructions to Attic Sprinkler differ from standard sprinklers and the following criteria shall be used.
There can be up to a 6"
(152,4mm)
obstruction, measured vertically, as long as it is 36"
(914,4mm)
, measured
vertically, below the Attic Sprinkler. If the obstruction is closer or larger, there must be a sprinkler on the other
side of the obstruction. See figure A & B. This does not limit the top cord of the trusses or the depth of the rafter,
but rather obstructions that run across the trusses or rafters.
Figure B
Figure A
6" (152,4 mm) max.
No
Sprinkler
Required
36" min.
(914,4 mm)
If the obstruction is below the sprinkler, there must be 6"
(152,4mm)
clearance over the top of the obstruction to
allow water to pass both over and under the obstruction. The 6"
(152,4mm)
is measured perpendicular to the slope
from the bottom of the joist. If there is not 6"
(152,4mm)
clearance, a sprinkler must be added on the opposite side
of the obstruction.
Figure C
over 6" (152,4 mm)
Sprinkler
For Vertical Obstruction, See Table 1 on Page 10.
The maximum dimension of the obstruction is the
width of the obstruction and the horizontal distance
away from the obstruction is measured flat.
See Table 1
Figure E
36" min.
(914,4 mm)
≤
4'-0" (1,2 m)
No Sprinkler
Required
Ducts, as per NFPA 13, require a sprinkler under them
if they are over 4'-0"
(1,2m)
wide. If they are not, then
no sprinkler underneath is required.
6" (152,4 mm) min.
36" min.
(914,4 mm)
Figure D
less than 6" (152,4 mm)
36" min.
(914,4 mm)
Figure F
OBSOLETE
