Gas Fitter Practice Test

In a room with two gas appliances, what is the required combustion air opening size for specific inputs?

1. 0 square inches

2. 7 square inches

3. 9 square inches

4. 11 square inches

The correct answer is: 9 square inches

The required combustion air opening size for gas appliances is determined based on the total input of the appliances and specific codes or standards relevant to gas installations. In situations where two gas appliances are present in a room, the sum of their input ratings directly impacts the necessary combustion air opening sizes. An opening of 9 square inches likely aligns with the guidelines set forth by many building codes for rooms where two appliances are installed. These guidelines consider factors like room volume, combustion air requirements, and the efficiency of the appliances, ensuring that adequate air is supplied for safe and complete combustion, which in turn helps prevent hazards such as carbon monoxide buildup. In this instance, the selection of 9 square inches is often based on the total BTU input of the appliances, along with standard engineering practices for ensuring proper ventilation. This consideration underscores the importance of maintaining sufficient air for combustion to facilitate optimal functioning of gas appliances while adhering to safety regulations.