Enter all but one of the volume, air-to-fuel ratio, temperature, pressure, gas constant, and compressibility factor into the calculator to determine the required combustion air.

## Combustion Air Formula

The following formula is used to calculate the required combustion air for a combustion process:

CA = (V * A * T) / (P * R * Z)

Variables:

- CA is the required combustion air
- V is the volume of the combustion process
- A is the air-to-fuel ratio
- T is the temperature of the combustion process
- P is the pressure of the combustion process
- R is the gas constant
- Z is the compressibility factor

To calculate the required combustion air, multiply the volume of the combustion process by the air-to-fuel ratio, then multiply the result by the temperature of the combustion process. Divide the product by the product of the pressure, gas constant, and compressibility factor.

## What is a Combustion Air?

Combustion air refers to the air that is necessary for the process of combustion to occur. Combustion is a chemical reaction that involves the combination of a substance (usually a fuel) with oxygen, resulting in the release of heat and light energy, often in the form of a flame. The combustion air provides the oxygen needed for this reaction. In a heating system, such as a furnace or boiler, combustion air is typically drawn from the surrounding environment and directed into the combustion chamber where it mixes with the fuel. The quality, temperature, and humidity of the combustion air can significantly affect the efficiency and performance of the combustion process. For instance, if the combustion air contains impurities or if it is not supplied in sufficient quantity, it can lead to incomplete combustion, resulting in lower heat output and higher emissions of pollutants.

## How to Calculate Combustion Air?

The following steps outline how to calculate the Combustion Air.

- First, determine the volume flow rate of the fuel gas (Qg) in cubic feet per hour (ft³/hr).
- Next, determine the volume flow rate of the combustion air (Qa) in cubic feet per hour (ft³/hr).
- Next, gather the formula from above = Combustion Air = Qg / AFR.
- Finally, calculate the Combustion Air.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

volume flow rate of the fuel gas (Qg) = 500 ft³/hr

volume flow rate of the combustion air (Qa) = 1000 ft³/hr