When obtaining combustion air from indoors on the same story, what is the minimum number of openings required?

When obtaining combustion air from indoors on the same story, the requirement for a minimum of two openings ensures sufficient airflow for the safe and efficient operation of combustion appliances. This setup allows for proper air circulation, which is crucial for the combustion process. Having one opening may not provide the necessary draft and could potentially lead to backdraft or insufficient air supply, which can negatively impact appliance performance and could even pose a safety hazard.

The two openings, typically designed to allow air to enter and exit the space, help to create a balanced environment for combustion. One opening acts as an intake for fresh air, while the other can serve as an exit for combustion gases. This configuration also mitigates the risk of creating a vacuum that can pull in harmful gases from other parts of the home, promoting better air quality and safety.

Regulatory codes often stipulate such measures, emphasizing the importance of maintaining adequate ventilation when appliances are located in enclosed spaces.