31
LOCAL HEATING VALUES FOR NATURAL GAS
ALTITUDE ABOVE
SEA LEVEL
BTU PER CUBIC FOOT
650
700
750
800
850
900
950
1,000
1,050
2,000 FT
LOW
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
3,000 FT
LOW
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
4,000 FT
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
5,000 FT
LOW
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
6,000 FT
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
7,000 FT
LOW
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
8,000 FT
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
9,000 FT
LOW
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
10,000 FT
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
Table 10. Natural Gas Heating Values
Table 11. Orifices for Natural Gas
High Heating Value
HIGH HEATING VALUE &
MANIFOLD PRESSURE = 3.5 in. W.C.
ALTITUDE ABOVE
SEA LEVEL
INPUT (BTU)
45,000
72,000
0 to 1,999 FT
49
47
2,000 to 2,999 FT
50
48
3,000 to 3,999 FT
50
48
4,000 to 4,999 FT
51
48
5,000 to 5,999 FT
51
49
6,000 to 6,999 FT
51
49
7,000 to 7,999 FT
52
50
8,000 to 8,999 FT
52
50
9,000 to 9,999 FT
52
50
LOW HEATING VALUE &
MANIFOLD PRESSURE = 3.5 in. W.C.
ALTITUDE ABOVE
SEA LEVEL
INPUT (BTU)
45,000
72,000
0 to 1,999 FT
49
47
2,000 to 2,999 FT
49
47
3,000 to 3,999 FT
49
47
4,000 to 4,999 FT
50
47
5,000 to 5,999 FT
50
47
6,000 to 6,999 FT
50
48
7,000 to 7,999 FT
51
48
8,000 to 8,999 FT
51
49
9,000 to 9,999 FT
51
49
Table 12. Orifices for Natural Gas
Low Heating Value
Table 9. Orifices for Propane Gas
ORIFICES FOR PROPANE GAS
MANIFOLD PRESSURE = 10 in. W.C.
ALTITUDE ABOVE
SEA LEVEL
INPUT (BTU)
45,000
72,000
0 to 1,999 FT
57
56
2,000 to 2,999 FT
57
56
3,000 to 3,999 FT
57
56
4,000 to 4,999 FT
57
56
5,000 to 5,999 FT
58
56
6,000 to 6,999 FT
59
57
7,000 to 7,999 FT
59
57
8,000 to 8,999 FT
60
57
9,000 to 9,999 FT
61
57