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• Doobtain n ew warning and instruction labels f rom Sears f or
placement ontheblanket directly o ver t heexisting l abels.
• Doinspect theinsulation blanket frequently tomake certain
itdoes notsag, t hereby o bstructing
combustion airflow.
Combustion
Air and Ventilation
for
A_0#liances
Located
in Unconfined
Spaces
UNCONFINED
SPACE
is space whose
volume
is not less than
50 cubic
feet per
1,000
Btu per hour
(4.8 m s per kW) 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.
Combustion
Air and Ventilation
for
A_0#liances
Located
in Confined
Spaces
CONFINED
SPACE
is a space
whose
volume
is less
than
50 cubic
feet per 1,0go
Btu per hour
(4.8 m s per kW)
of the
aggregate
input rating
of all appliances
installed
in that space.
A. ALLAIR
FROM
INSIDE
BUILDINGS:
(See Figure 9 on page
9 and Figure
10 below)
The
confined
space
shall
be provided
with
two
permanent
openings
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
gas utilization
equipment
installed
in the combined
space
shall
be considered
in making
this determination.
Each opening
shall
have a minimum
free area of one square
inch per 1,0O0 Btu per
hour (22 cm2/kW)
of the total input
rating
of all gas utilization
equipment
in the confined
space,
but not less than
100 square
inches (645 cm2). One opening
shall commence
within 12 inches
(30 cm) of the top and one commencing
within
12 inches
(30
cm) of the bottom
of the enclosures.
CHIMNEY OR GAS VENT
FIGURE
10.
B. ALL AIR FROM
OUTDOORS:
(See Figures
9, 11,12 and 13)
The
confined
space
shall
be provided
with
two permanent
openings,
one commencing
within
12 inches
(30 cm) of the top
and one commencing
within
12 inches
(30 cm) 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.
CHIMNEY OR
GAS VENT
VENTILATION
LOUVERS
OUTLET AIR
'WATER
HEATER
FURNACE
*INLET
AIR DUCT
ALT, INLETAIR
VENTILATION
LOUVERS
FIGURE 11.
When
directly communicating
with the outdoors,
each opening
shall
have
a minimum
free area of 1 square
inch per 4,000
Btu per hour (5.5 cm2/kW)
of total input rating of all equipment
in the enclosure.
See Figure
12.
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 (5.5 cm2/kW)
of total
input rating
of all equipment
in the enclosure.
See Figure
12.
CH'%O,t #O.C:,VER
s
TTIC)
11
FIGURE 12.
When
communicating
with the outdoors
through
horizontal
ducts,
each
opening
shall
have
a minimum
free area
of 1
square
inch per 2,000 BTU per hour (11 cm2/kW)
of total input
rating
of all equipment
in the enclosure.
See Figure
13.
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
(76.2 mm). See Figure
13.
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