What percentage of the height of the chimney or vent may the horizontal run of a single-wall connector not exceed?

The correct answer is that the horizontal run of a single-wall connector may not exceed 75% of the height of the chimney or vent. This rule is established to ensure that venting systems operate efficiently and safely. When the horizontal run is kept to this limit, it helps maintain the necessary draft within the chimney or vent, which is crucial for the proper functioning of the appliance and for the safe evacuation of combustion gases.

If the horizontal run exceeds 75% of the chimney or vent height, it could lead to insufficient draft. Insufficient draft can cause backflow of combustion gases into the living space, increasing the risk of carbon monoxide poisoning and other hazardous conditions. Additionally, keeping the run within this limit helps prevent blockages and allows for proper airflow, enhancing overall system performance.

Understanding this regulation is important for ensuring compliance with the North Carolina Mechanical Code, as proper installation of venting systems is not only a matter of code adherence but also a critical aspect of building safety and performance.