Table of Contents
Advertisement
Installation
Instructions
(cont'd)
Combustion
Air and Ventilation
for Appliances
Located
in
Unconfined
Spaces
Unconfined
Space
is a space whose volume
is not less than 50
cubic feet per 1,000 Btu per hour of the aggregate input rating
of all appliances installed in that space. Rooms communicating
directly
with
the space in which
the appliances
are installed,
through
openings
not furnished
with doors, are considered
a
part of the unconfined
space
In unconfined
spaces in buildings,
infiltration
may be adequate
to provide
air for combustion,
ventilation
and dilution
of flue
gases. However,
in buildings
of tight construction
(for example,
weather stripping,
heavily insulated,
caulked, vapor barrier, etc.),
additional
air may need
to be provided
using
the methods
described
in Combustion
Air and Ventilation
for Appliances
Located in Confined
Spaces, b.
Combustion
Air and Ventilation
for Appliances Located in
Confined Spaces
Confined
Space is a space whose volume is less than 50 cubic
feet per 1,000 Btu per hour of the aggregate input rating of all
appliances
installed in that space.
a. ALL AIR FROM
INSIDE
BUILDINGS:
(See Page 9 Figure 1, and Figure 2 below)
The confined
space shall be provided
with two permanent
openi_ngs communicating
directly
with an additional
room(s)
of sufficient
volume
so that
the combined
volume
of all
spaces meets the criteria for an unconfined
space. The total
input
of all _as utilization
equipment
installed
in the com-
bined space shall be considered
in making this determination.
Each opening
shall have a minimum
free area of one square
inch per 1,000 BTU per hour of the total input rating of all
gas utilization
equipment
in the confined
space, but not less
than 100 square inches. One opening
shall commence
within
12 inches of the top and one commencing
within
12 inches
of the bottom of the enclosure.
b. ALL AIR FROM OUTDOORS:
(see Figures 3-5)
The confined
space shall be provided
with two permanent
openings,
one commencing
within
12 inches of the top and
one commencing
within
12 inches from the bottom
of the
enclosure.
The openings
shall communicate
directly,
or by
ducts, with the outdoors
or spaces (crawl or attic) that freely
communicate
with the outdoors.
I Figure 3 ]
10
I. When directly communicating
with the outdoors,
each open-
ing shall have a minimum
free area of 1 square inch per 4,000
BTU per hour of total input
rating of all equipment
in the
enclosure.
(See Figure 3.)
2. When
communicating
with the outdoors
through
vertical
ducts,
each opening
shall have a minimum
free area of 1
square inch per 4,000
BTU per hour of total input rating of
all equipment
in the enclosure.
(See Figure 4.)
Figure 4 ]
3. When
communicating
with the outdoors
through
horizontal
ducts,
each opening
shall have a minimum
free area of 1
sguare inch per 2,000 BTU per hour of total input
rating of
all equipment
in the enclosure. (See Figure 5.)
_
CHbM_EY O_ GA_ VEN_
_
___UrLEr
A_n OUCh.
[
Figure
5
]
..........
4,
When ducts are used, they shall be of the same cross-sectional
area as the free area of the openings
to which they connect.
The minimum
short side dimension
of rectangular
air ducts
shall not be less than 3 inches. (See Figure 5.)
5.
Louvers
and Grilles:
In calculating
free area, consideration
shall be given to the blocking
effect of louvers,
grilles or
screens protectin_
openings.
Screens used shall not be smaller
than ¼ inch mesh. If the free area through
a design of louver
or grille is known,
it should
be used in calculating
the size
opening
required
to provide
the free area specified.
If the
design and free area is not known,
it may be assumed
that
wood louvers will be 20-25 percent free area and metal louvers
and grilles will have 60-75
percent
free area. Louvers
and
grilles shall be fixed in the open position or interlocked
with
the equipment
so that they are opened automatically
during
equipment
operation.
6. Special
Conditions
Created
by Mechanical
Exhausting
or
Fireplaces:
Operation
of exhaust
fans, ventilation
systems,
clothes
dryers or fireplaces
may create conditions
requiring
special attention
to avoid unsatisfactory
operation
of installed
gas utilization
equipment.
Hide quick links:
Advertisement
Table of Contents
