What must be installed when CAZ depressurization limits are exceeded?

When combustion appliance zone (CAZ) depressurization limits are exceeded, it is crucial to install make-up air. This is necessary because significant depressurization can lead to a situation where the combustion appliances cannot draw the required amount of air for proper combustion, which can subsequently cause backdrafting. Backdrafting can allow harmful combustion gases, including carbon monoxide, to enter the dwelling rather than being expelled through the venting system.

Make-up air provides a controlled source of outside air, ensuring that the combustion appliances have adequate air for combustion. This helps maintain safe operation and reduces the risk of hazardous situations arising from insufficient air supply. The installation of make-up air systems can greatly enhance safety and efficiency by balancing the air pressure within the space.

Other options, while potentially beneficial in different contexts, do not address the immediate need created by exceeding CAZ depressurization limits. Additional vents might help with airflow, but they do not specifically ensure adequate air supply for combustion. Air filters serve to clean the air but do not affect the supply of air for combustion processes. Carbon monoxide detectors are essential for safety but do not address the root cause of the depressurization issue.