15
Table 6
Orifice Size* and Manifold Pressure (in. w.c.) for Gas Input Rate
(Tabulated data based on 21,000 btuh per burner, derated 4 percent for each 1000 ft. (305 M) above sea level)
ALTITUDE RANGE
FT. (M)
AVG. GAS
HEAT VALUE
AT ALTITUDE
(BTU/CU FT.)
SPECIFIC GRAVITY OF NATURAL GAS
0.58
0.60
0.62
0.64
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
Orifice
No.
Manifold
Pressure
U.S.A.
0 to 2000
(0 to 610)
900
42
3.2
42
3.3
42
3.4
42
3.5
925
43
3.7
43
3.8
42
3.2
42
3.3
950
43
3.5
43
3.6
43
3.7
43
3.8
975
43
3.3
43
3.4
43
3.5
43
3.7
1000
44
3.6
43
3.3
43
3.4
43
3.5
1025
44
3.4
44
3.6
43
3.2
43
3.3
1050
44
3.3
44
3.4
44
3.5
43
3.2
1075
45
3.8
44
3.2
44
3.3
44
3.4
1100
46
3.8
45
3.7
44
3.2
44
3.3
U.S.A.
2001 to
3000 (610
to 914)
800
43
3.8
42
3.2
42
3.3
42
3.4
825
43
3.5
43
3.7
43
3.8
42
3.2
850
43
3.3
43
3.5
43
3.6
43
3.7
875
43
3.2
43
3.3
43
3.4
43
3.5
900
43
3.0
43
3.1
43
3.2
43
3.3
925
43
2.8
43
2.9
43
3.0
43
3.1
950
43
2.7
43
2.8
43
2.9
43
2.9
975
43
2.5
43
2.6
43
2.7
43
2.8
1000
43
2.4
43
2.5
43
2.6
43
2.7
U.S.A.
3001 to
4000
(914 to
1219)
775
43
3.5
43
3.7
43
3.8
42
3.2
800
43
3.3
43
3.4
43
3.5
43
3.7
825
43
3.1
43
3.2
43
3.3
43
3.4
850
43
2.9
43
3.0
43
3.1
43
3.2
875
43
2.8
43
2.9
43
3.0
43
3.1
900
43
2.6
43
2.7
43
2.8
43
2.9
925
43
2.5
43
2.6
43
2.7
43
2.7
950
43
2.4
43
2.4
43
2.5
43
2.6
U.S.A.
4001 to
5000
(1219 to
1524)
750
43
3.3
43
3.4
43
3.5
43
3.6
775
43
3.1
43
3.2
43
3.3
43
3.4
800
43
2.9
43
3.0
43
3.1
43
3.2
825
43
2.7
43
2.8
43
2.9
43
3.0
850
43
2.6
43
2.7
43
2.8
43
2.8
875
43
2.4
43
2.5
43
2.6
43
2.7
900
43
2.3
43
2.4
43
2.5
43
2.5
925
43
2.2
43
2.2
43
2.3
43
2.4
U.S.A.
5001 to
6000
(1524 to
1829)
725
43
3.1
43
3.2
43
3.3
43
3.4
750
43
2.9
43
3.0
43
3.1
43
3.2
775
43
2.7
43
2.8
43
2.9
43
3.0
800
43
2.5
43
2.6
43
2.7
43
2.8
825
43
2.4
43
2.5
43
2.5
43
2.6
850
43
2.2
43
2.3
43
2.4
43
2.5
875
43
2.1
43
2.2
43
2.3
43
2.3
900
43
2.0
43
2.1
43
2.1
43
2.2
* Orifice number 43 is factory installed.
