How does higher altitude affect the function of an orifice?

Higher altitude impacts the function of an orifice primarily due to changes in atmospheric pressure, which in turn affects the availability of oxygen. As altitude increases, the atmospheric pressure decreases, leading to a reduction in the amount of oxygen in the air. This lower availability of oxygen requires adjustments to the gas supply to maintain optimal combustion and performance in gas appliances.

In this context, because there is less oxygen, the volume of gas must be reduced to achieve the appropriate mixture for efficient combustion. If the gas volume remains the same without accounting for the decreased oxygen levels, it can lead to incomplete combustion, causing the appliance to operate inefficiently or even produce harmful byproducts like carbon monoxide.

Understanding this relationship is crucial for technicians working with gas appliances at higher altitudes, as they must ensure that the gas supply is adjusted according to the specific altitude conditions for safety and efficiency. This adjustment is often accomplished by modifying or sizing the orifices appropriately to allow for the correct gas volume to mix with the reduced oxygen available at those heights.