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L.P. AND NATURAL GAS ORIFICES
The actual size and configuration of each orifice depends on several factors. The most important
factor, however, is the type of gas that will be used by the gas range system. The two most
frequently used types are:
liquefied petroleum (L.P.)
gas, and
natural
gas.
L.P. gas is generally heavier than natural gas and has a higher heat output.
For example, when one cubic foot of L.P. gas is burned, it gives off approximately 2,500 B.T.U. of
heat, while one cubic foot of natural gas will yield only 1,000 B.T.U. Since the heat density of L.P.
gas is higher than natural gas, it takes less cubic feet of L.P. gas to produce the same amount of
heat. An L.P. orifice will always be smaller than a natural gas orifice with an equivalent B.T.U. rating
(see the following “Orifice Specifications Chart” ). It is also important to remember that much more
air is needed with the L.P. gas system (24 cu. ft.) than with the natural gas system (10 cu. ft.). The
identification color location on the valve is shown in Figure 3-6.
SUGGESTED IDENT.
DRILL SIZE COLOR STAMPING BTU RATING
1.45 MM BRASS NAT 9,500
#65 BRASS L.P. 8,500
#55 BLACK NAT 7,500
#68 BLACK L.P. 6,500
1.2 MM NICKEL NAT 6,500
.7 MM NICKEL L.P. 5,500
#54 BRASS NAT 9,000
#66 BRASS L.P. 8,000
1.85 MM – NAT 12,500
#60 – L.P. 11,500
Identification
Color
Figure 3-6
Orifice Specifications Chart