Natural Gas:
The composition of natural gas varies based on its source. Its major component is methane (CH4). The ratio of torch supplied oxygen to natural gas is 1.5 to 1 for a neutral flame. The flame temperature along with natural gas is lower than with acetylene. This is also more diffused and less intense. The characteristics of the flame for carburising, neutral, or oxidising conditions are not as different as with the oxyacetylene flame.
Due to the lower flame temperature and the resulting lower heating efficiency, considerably greater quantities of natural gas and oxygen are needed to produce heating rates equivalent to those of oxygen and acetylene. In order to compete with acetylene, the availability and cost of natural gas and oxygen, their higher gas consumptions, and their longer preheat times ought to be considered. The utilization of tips designed to provide a heavy preheat flame, or cutting machines that permit a high-low preheat setting, might compensate for deficiencies in the lower heat output of natural gas.
The tip designs and torch for natural gas are distinct from those for acetylene. The delivery pressure for natural gas is in general low and the combustion ratios are different.