Question

As altitude increases, the capacity of a furnace (decreases/increases) because there is less air, in which also means less ______. To compensate for less _______, a (bigger/smaller) orifice must be used in a gas burner so that (less/more) fuel is fed through the orifice. A burner orifice correction must be made when the altitude is over ___________ ___.

A. Decreases, oxygen, smaller, less, 2,500 feet
B. Decreases, oxygen, bigger, more, 5,000 feet
C. Increases, nitrogen, bigger, more, 7,500 feet
D. Increases, oxygen, smaller, less, 10,000 feet

Answer 1

As altitude increases, the capacity of a furnace decreases due to lower oxygen levels. To compensate, a larger orifice is required to allow more fuel to mix with the available oxygen. The correct altitude for making an orifice correction is over 2,500 feet.

Step-by-step explanation:

As altitude increases, the capacity of a furnace decreases because there is less air, which also means less oxygen. To compensate for less oxygen, a bigger orifice must be used in a gas burner so that more fuel is fed through the orifice. A burner orifice correction must be made when the altitude is over 2,500 feet. Therefore, the correct answer is A. Decreases, oxygen, bigger, more, 2,500 feet.

At higher altitudes, the air density decreases, and thus the concentration of oxygen decreases as well. This phenomenon affects combustion processes because the amount of oxygen available for the fuel to burn is reduced.

By increasing the size of the orifice, more fuel can be mixed with the available oxygen to maintain proper combustion. Mountain climbers experience similar effects of reduced oxygen levels with altitude as they may suffer from hypoxia, which is the inadequate supply of oxygen to the body.