58CV
Table
2
-
Minimum
Free
Area
Required
for
Each
Combustion
Air
opening
of
Duct
to
Outdoors
TWO
HORIZONTAL
DUCTS
SINGLE
DUCT
OR
OPENING
TWO
OPENINGS
OR
VERTICAL
DUCTS
FURNACE
|
(1
SG.
IN/2,000
BTUR)
(1,100
SG.
MM/KW)
|
(1
SQ.
IN./3,000
BTUR)
(734
SG.
MM/KW)
(1
$0.
IN/4,000
BTUH)
(550
SG.
MIM/KW)
INPUT
Free
Area
of
Opening
Round
Duct
Free
Area
of
Opening
Round
Duct
Free
Area
of
Opening
Round
Duct
(BTUH)
and Duct
Dia.
and Duct
Dia.
and Duct
Dia.
Sq.
In.
(Sq.
mm)
In.
(mm)
Sq.
In.
(Sq.
mm)
In.
(mm)
Sq.
In.
(Sq.
mm)
In.
(mm)
44,000
22
(14194)
6
(152)
147
(9484)
5
(127)
11
(7096)
4
(102)
66,000
33
(21290)
7
(178)
22
(14193)
6
(152)
16.5
(10645)
5
(127)
88,000
44
(28387)
8
(203)
29.3
(18903)
7
(178)
22
(14193)
6
(152)
110,000
55
(35484)
9
(229)
36.7
(23677)
7
(178)
27.5
(17742)
6
(152)
132,000
66
(42580)
10
(254)
44
(28387)
8
(203)
33
(21290)
7
(178)
154,000
77
(49677)
10
(254)
51.3
(83096)
9
(229)
38.5
(24839)
8
(203)
EXAMPLES:
Determining
Free
Area
FURNACE
WATER
HEATER
TOTAL
INPUT
410,000
+
30,000
=
(140,000
divided
by
4,000)
=
35.0
Sq.
In.
for
each
two
Vertical
Ducts
or
Openings
66,000
+
40,000
=
(106,000
divided
by
3,000)
=
35.3
Sq.
In.
for
a
Single
Duct
or
Opening
88,000
+
30,000
=
(118,000
divided
by
2,000)
=
59.0
Sq.
In.
for
each
of
two
Horizontal
Ducts
Table
3
-
Minimum
Space
Volumes
for
100%
Combustion,
Ventilation,
and
Dilution
from
Indoors
OTHER
THAN
FAN-ASSISTED
TOTAL
FAN-ASSISTED
TOTAL
(1,000’S
BTUH
GAS
INPUT
RATE)
(1,000’S
BTUH
GAS
INPUT
RATE)
ACH
30
|
40
|
50
44
|
66
|
88
|
110
|
i32
|
ss
Space
Volume
Ft?
(M*)
0.60
1,050
1.400 1,750
1,100
1,650
2,200 2,750 3,300 3,850
.
(29.7) (39.6) (49,5) (31.1) (46.7)
(62.2) (77.8)
(93.4)
(109.0)
0.50
1,260 1,680
2,100
1.320 1,980
2,640 3,300 3,960 4,620
.
(35.6) (47.5) (59.4) (37.3) (56.0) (74.7)
(93.4)
(112.1)
(130.8)
0.40
1,575
2,100
2,625
1,650
2,475
3,300
4,125
4,950
5,775
,
(44.5) (59.4) (74.3) (46.7) (70.0)
(93.4)
(116.8)
(140.1) (163.5)
0.30
2,100 2,800 3,500 2,200 3,300 4,400 5,500 6,600 7,700
‘
(59.4) (79.2) (99,1) (62.2) (93.4)
(124.5) (155.7)
(186.8) (218.0)
3,150 4,200 3,300 4,950 6,600 8,250 9,900
11,550
9.20
(89.1)
(118.9)
|
3-250
148.6)
(93.4)
(140.1)
(186.8) (233.6) (280.3)
(327.0)
0.10
6,300 8,400
10,500
6,600 9,900
13,200 16,500 19,800
23,100
.
(178.3) (237.8) (297.3) (186.8) (280.3) (373.7) (467.2) (560.6)
(654.1)
0.00
NP NP NP NP NP NP NP NP NP
NP
=
Not
Permitted
AIR
FOR
COMBUSTION
AND
VENTILATION
4&
WARNING
Provisions
for
adequate
combustion,
ventilation,
and
dilution
air
CARBON
MONOXIDE
POISONING
HAZARD
must
be
provided
in
accordance
with:
.
;
. . .
Failure
to
follow
this
warning
could
result
in
personal
injury
or
death.
©
USS.
Installations:
Section
9.3
of
the
NFPA
54/ANSI
2223.1-2009
,
Air
for
Combustion
and
Ventilation
and
applicable
provisions
of
the
local
building
codes.
The
operation
of
exhaust
fans,
kitchen
ventilation
fans,
clothes
dryers,
attic
exhaust
fans
or
fireplaces
could
create
a
NEGATIVE
PRESSURE
CONDITION
at
the
furnace.
Make-up
air
MUST
be
provided
for
the
ventilation
devices,
in
addition
to
that
required
by
the
furnace.
Refer
to
the
FURNACE
CORROSION
HAZARD
Carbon
Monoxide
Poisoning
Hazard
warning
in
the
venting
section
of
these
instructions
to
determine
if
an
adequate
amount
of
make-up
air
is
available.
Failure
to
follow
this
caution
may
result
in
furnace
damage.
Air
for
combustion
must
not
be
contaminated
by
halogen
compounds,
which
include
fluoride,
chloride,
bromide,
and
iodide.
These
elements
can
corrode
heat
exchangers
and
The
requirements
for
combustion
and
ventilation
air
depend
upon
shorten
furnace
life.
Air
contaminants
are
found
in
aerosol
whether
or
not
the
furnace
is
located
in
a
space
having
a
volume
sprays,
detergents,
bleaches,
cleaning
solvents,
salts,
air
of
at
least
50
cubic
feet
per
1,000
Btuh
input
rating
for
all
gas
fresheners,
and
other
household
products.
appliances
installed
in
the
space.
©
—
Spaces
having
less
than
50
cubic
feet
per
1,000
Btuh
require
the
OUTDOOR
COMBUSTION
AIR
METHOD.
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