For safety reasons, why must combustion air openings be located at different heights in confined spaces?

Combustion air openings in confined spaces are strategically positioned at different heights to facilitate airflow separation. This design ensures that fresh air can enter the space efficiently while allowing for the proper mixing of combustion gases. When combustion air openings are set at different levels, it promotes better circulation and prevents the stagnation of air, which is crucial for maintaining a safe and effective combustion process.

Additionally, separating the air intake openings helps reduce the risk of backdrafts, where combustion gases or smoke can be inadvertently drawn back into the combustion zone. This configuration protects the overall efficiency of the heating system and minimizes hazards associated with improper ventilation.

In contrast, other options do not address the specific safety and operational concerns related to airflow and combustion processes in confined spaces. Factors such as construction costs, aesthetics, or smoke detection are not directly related to the critical function of ensuring sufficient and safe airflow for combustion.