44
TABLE 13—ORIFICE SIZE* AND MANIFOLD PRESSURE FOR GAS INPUT RATE
(TABULATED DATA BASED ON 21,000 BTUH PER BURNER, DERATED 4 PERCENT FOR EACH 1000 FT. ABOVE SEA
LEVEL)
ALTITUDE RANGE (FT.)
SPECIFIC GRAVITY OF NATURAL GAS
AVG. GAS
HEAT VALUE
(BTU/CU FT.)
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. and
Canada
0 to 2000
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
ALTITUDE RANGE (FT.)
AVG. GAS
HEAT VALUE
(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. and
Canada
U.S.A.
Altitudes
2001 to
3000 or
Canada
Altitudes
2000 to
4500
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
ALTITUDE RANGE (FT.)
SPECIFIC GRAVITY OF NATURAL GAS
AVG. GAS
HEAT VALUE
(BTU/CU FT.)
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. Only
3001 to
4000
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
SPECIFIC GRAVITY OF NATURAL GAS
ALTITUDE RANGE (FT.)
AVG. GAS
HEAT VALUE
(BTU/CU FT.)
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. Only
4001 to
5000
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
58ST