2015-0821 Pizza Hut type I hood revision - Alpine Fire and Safety.pdf
City of Edmonds
PLAN REVIEW COMMENTS
BUILDING DIVISION
(425) 771-0220
DATE: December 18, 2015
TO: Alpine Fire & Safety
steve@alpinefire.com
FROM: Chuck Miller, Plans Examiner
RE: Plan Check: BLD2015-0821
Project: Pizza Hut Type I Hood
Project Address: 23830 Highway 99, #118
The revised proposal to complete the installation of a type I hood under permit BLD2015-0821 without the
required clearance to combustible materials has been approved as allowed by International Building Code
(IBC) section 104.11 as follows:
The proposal to install the type I hood to a wall constructed of non-combustible framing (steel studs)
·
with a smooth, cleanable, nonabsorbent and noncombustible material between the hood and the
gypsum wallboard extending a minimum of 18 inches in all directions from the hood as an exception
to that required per International Mechanical Code (IMC) 507.9 was approved on August 31, 2015.
The approved plans were not followed and combustible framing (wood studs) was installed,
·
requiring a hood installation with a clearance to combustibles of not less than 18 inches per IMC
507.9.
A revised proposal to install the type I hood without the required minimum clearance to
·
combustibles as tested by Intertek ETL SEMKO Project No. 3183243 using fire tests based on
UL 710 was received on December 14, 2015.
The required clearance to combustibles per IMC 507.9 is not among those sections listed in IMC
·
507.1 as exempt from compliance for exhaust hoods listed and labeled in accordance with UL710.
Per the results of the tested assembly, a zero clearance to combustibles is allowed at the rear panel
·
only where a 1-inch layer of Owens Corning Type 475 or Johns Manville Type 475 insulation has
been factory installed to the inside surface of that panel. The installation of the insulation within the
3-inch standoff at the back of the hood appears to be equivalent to that achieved per National Fire
Protection Association (NFPA) 96. A minimum 18-inch clearance to combustibles must still be
maintained at the top, sides, and front of the hood per IMC 507.9.
A two-layered stainless steel backsplash with a 1-inch of Owens Corning Type 475 or Johns
·
Manville Type 475 insulation between the layers, spaced 1-inch off of the combustible wall is
required to be installed. It shall extend to the area behind the cooking appliance. While not attaining
the reduced 6-inch clearance to combustibles allowed per IMC Table 308.6, the installation of the
specific cooking appliance and associated cooking temperatures in this proposal appears to be
unlikely to result in pyrolysis of the wood framing. Concerns of re-use of the hood for other cooking
activities utilizing different appliances than that proposed under this installation are minimized by
the specific location and size of the hood installation.
In addition to the required clearance to combustibles noted in the cooking appliance manufacturers
·
installation requirements, a permanent means of maintaining the required cooking appliance
clearance of 6-inches from the rear wall per the results of the tested assembly shall be installed. In
addition, the required canopy size and location over the cooking appliance per IMC 507.12 shall be
maintained.
The conditional approval of the revision to permit BLD2015-0821 is specific to the installation as noted
above and to be verified by field inspection. It is not a precedent or an alternative for future proposals
required to comply with the provisions of IMC 507.9.
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