4
Table 3
Orifice Size and Manifold Pressure (in.w.c.) for Gas Input Rate
S
A
G
L
A
R
U
T
A
N
F
O
Y
T
I
V
A
R
G
C
I
F
I
C
E
P
S
S
A
G
.
G
V
A
HEAT VALUE
0.58
0.60
0.62
0.64
AT ALTITUDE
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
Orifice
Manifold
(Btu/cu ft)
No.
Pressure
No.
Pressure
No.
Pressure
No.
Pressure
900
43
3.8
42
3.2
42
3.3
42
3.4
0
925
43
3.6
43
3.7
43
3.8
42
3.2
(0)
950
43
3.4
43
3.5
43
3.6
43
3.7
975
44
3.7
44
3.8
43
3.4
43
3.6
to
1000
44
3.5
44
3.6
44
3.8
43
3.4
1025
44
3.3
44
3.5
44
3.6
44
3.7
2000
1050
44
3.2
44
3.3
44
3.4
44
3.5
(610)
1075
45
3.7
45
3.8
44
3.3
44
3.4
1100
46
3.7
46
3.8
45
3.8
44
3.2
U.S.A.
800
42
3.4
42
3.5
42
3.6
42
3.7
2001 (611)
825
43
3.8
42
3.3
42
3.4
42
3.5
to
850
43
3.6
43
3.7
42
3.2
42
3.3
3000 (914)
875
43
3.4
43
3.5
43
3.7
43
3.8
900
44
3.7
44
3.8
43
3.5
43
3.6
Canada
925
44
3.5
44
3.6
44
3.8
43
3.4
2001 (611)
950
44
3.3
44
3.4
44
3.6
44
3.7
to
975
44
3.2
44
3.3
44
3.4
44
3.5
4500 (1372)
1000
44
3.0
44
3.1
44
3.2
44
3.3
775
42
3.3
42
3.4
42
3.5
42
3.6
3001
800
43
3.8
42
3.2
42
3.3
42
3.4
(915)
825
43
3.6
43
3.7
43
3.8
42
3.2
850
44
3.8
43
3.5
43
3.6
43
3.7
875
44
3.6
44
3.7
43
3.4
43
3.5
4000
900
44
3.4
44
3.5
44
3.7
44
3.8
(1219)
925
44
3.2
44
3.4
44
3.5
44
3.6
950
44
3.1
44
3.2
44
3.3
44
3.4
750
42
3.3
42
3.4
42
3.5
42
3.6
4001
775
43
3.7
43
3.8
42
3.3
42
3.4
(1220)
800
43
3.5
43
3.6
43
3.7
43
3.8
825
44
3.8
43
3.4
43
3.5
43
3.6
850
44
3.5
44
3.7
44
3.8
43
3.4
5000
875
44
3.3
44
3.5
44
3.6
44
3.7
(1524)
900
44
3.2
44
3.3
44
3.4
44
3.5
925
44
3.0
44
3.1
44
3.2
44
3.3
725
42
3.2
42
3.3
42
3.4
42
3.5
5001
750
43
3.7
43
3.8
42
3.2
42
3.3
(1525)
775
43
3.4
43
3.5
43
3.7
43
3.8
800
44
3.7
44
3.8
43
3.4
43
3.5
825
44
3.5
44
3.6
44
3.7
44
3.8
6000
850
44
3.3
44
3.4
44
3.5
44
3.6
(1829)
875
44
3.1
44
3.2
44
3.3
44
3.4
900
44
2.9
44
3.0
44
3.1
44
3.2
675
42
3.4
42
3.5
42
3.6
42
3.8
6001
700
42
3.2
42
3.3
42
3.4
42
3.5
(1830)
725
43
3.6
43
3.7
43
3.8
42
3.3
750
43
3.4
43
3.5
43
3.6
43
3.7
775
44
3.6
44
3.7
43
3.4
43
3.5
7000
800
44
3.4
44
3.5
44
3.6
44
3.7
(2133)
825
44
3.2
44
3.3
44
3.4
44
3.5
850
44
3.0
44
3.1
44
3.2
44
3.3
to
to
to
to
ALTITUDE
RANGE
ft (m)
U
.S
.A
.
an
d
C
an
ad
a
SINGLE-STAGE FURNACE
(TABULATED DATA BASED ON 20,000 BTUH PER BURNER, DERATED 2%/1000 FT (305M) ABOVE SEA LEVEL)
U
.S.A
.
O
n
ly
U.
S
.A
.
O
n
ly
U.
S
.A
.
O
n
ly
U
.S.A
.
O
nly
U
.S.A
.
a
nd
C
a
na
da
A11253A
