Clearances, Table 5 – clearance – grease duct – FloAire Non-Welded Grease Duct Systems User Manual
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CLEARANCES
This grease duct is primarily intended for use in non-combustible surroundings, when installed in a room
where enclosure is not required. Grease duct may be located at clearance to combustibles in accordance
with Table 5. Grease duct may be located in a corner formed by two combustible walls provided the
minimum clearance is maintained.
In all buildings more than one story in height and in buildings where the roof-ceiling assembly is required to
have a fire resistance rating, the duct must be enclosed in a continuous enclosure from the lowest fire-rated
ceiling or floor above the hood, through any concealed spaces, to or through the roof to maintain the integrity
of the fire separations required by the applicable building code provisions. If the building is less than 4
stories in height, the enclosure shall have a fire resistance rating of not less than 1 hour. If the building is 4
stories or more in height, the enclosure shall have a fire resistance rating of not less than 2 hours. The
clearance between the outside of the duct and the inside of the rated enclosure must be a minimum of 6
inches or required by code.
Combustible roofs or roof-ceiling assemblies may be penetrated using the vertical support assembly when
distance to combustible surfaces is maintained.
Table 5 – Clearance – Grease Duct
DIAMETER
CLEARANCE TO
COMBUSTIBLES
CLEARANCE TO
LIMITED
COMBUSTIBLES
CLEARANCE TO
NON
COMBUSTIBLES
8"
18"
3"
0"
10"
18"
3"
0"
12"
18"
3"
0"
14"
18"
3"
0"
16"
18"
3"
0"
18"
18"
3"
0"
20"
18"
3"
0"
24"
18"
3"
0"
The above figures represent air space, in inches, to surrounding
NOTE: See NFPA 96, 2004 EDITION, Chapter 3, Definition of Combustible, Limited Combustible and Non-
Combustible.