Bakers Pride FC series, Design & Installation Manual

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IL FORNO CLASSICO OVEN DESIGN & INSTALLATION GUIDE
14
VENTILATION OF AN ARCHITECTURALLY ENCLOSED GAS FIRED OVEN
This applies to the FC series ovens initially, but also to
FC “stacks” as well as any other enclosed installations.
A four walled “room” around the oven is anticipated,
with a ventilation hood as the room’s “ceiling”.
(This four-walled room is selected for this discussion as
an easily defined, “worst case” scenario. A more ideal
installation is enclosed on only one, two or three sides,
which face the public space of the restaurant. The back
and one or two sides are open to the kitchen and/or
other working spaces).
Air Volume Required
The purpose of ventilation is to remove bi-products
of combustion, remove grease laden vapors, limit the
temperatures within the enclosure and to provide
fresh air for combustion. The combustion air volume is
included in the larger volume required for temperature
controlling the space, therefore only a single calculation
is required.
VOLUME REQUIRED (CFM) = RATED INPUT (BTUH) / 105
e.g. The air required for an FC-816 stacked with a Y-800
is 2,476 CFM ( = 260,000 BTUH / 105 ).
This assumes: (1) 70°F air entering the enclosure, (2)
the oven runs at an average of 70% of its rated input
during peak business hours and (3) 25% “stack losses”
are discharged directly to the top of the enclosure or are
removed from the enclosure by a chimney connection.
Air Openings To The Enclosure
At least three total openings must be provided in the
enclosure to allow the oven within the enclosure to
properly breathe. Additional openings are acceptable.
Louvers and grilles typically have free area ratings
provided by their manufacturer. If the ratings are not
known, assume 25% free area for wood louvers and
60% free area for metal louvers and grilles.
Top Opening(s)
At least one opening must be provided. The top
opening(s) prevents pressure differences from
developing over the height of the enclosure. Provide an
opening of one square inch free area per 1,000 BTUH
of Rated Input:
Top Opening Free Area(sq in)= Rated Input(BTUH)/ 1000.
e.g. The top opening for a FC-816 stacked with a Y-800
is 260 sq in (=260,000 BTUH / 1,000). The top edge of
this opening should be within (12”) twelve inches of the
bottom edge of the ventilation hood.
Bottom Opening(s)
At least one opening must be provided. The bottom
opening(s) provides the bulk of the ventilation air to
the space. Enough area must be provided to limit
the entering air velocity to five feet per second. The
calculation:
Bottom Opening Free Area (sq in) = Rated Input (BTUH) / 219
e.g. The bottom opening for an FC-816 stacked with a
Y-800 is 1,187 sq in (=260,000 BTUH / 219).
The same discussion regarding louvers and grilles
applies. The bottom opening, or openings, should be
planned to distribute air uniformly about the lower
portion of the enclosure. The bottom edge of the bottom
opening(s) should be within twelve inches of the floor of
the enclosure.
Clearances
Within the enclosure the normal clearances for safety
and service should be maintained. Additionally the floor
area of the enclosure should be at least equal to the
“footprint” area of the oven plus the bottom opening
free area. This limits the vertical air velocities inside the
enclosure to the same five feet per second.
e.g. FC-816 stacked with Y-800
51” deep x 84” wide = 4,284 sq in
Add the bottom free area:
1,187 sq in (Roughly 4 1/2” all around)
Total 5,471 sq in (38 sq ft) [Roughly 60” x 93”]