What is the maximum horizontal length of a single-wall vent connector as a percentage of chimney or vent height?

The maximum horizontal length of a single-wall vent connector is limited to 75 percent of the chimney or vent height. This guideline is established to ensure proper drafting and venting efficiency, allowing combustion gases to exit efficiently while minimizing the risk of backdraft or obstruction.

In practical terms, if a vent connector is too long relative to the vertical height of the chimney, the flow of exhaust gases can be impeded. This can lead to inadequate venting, resulting in the gases potentially entering living spaces, which poses safety hazards, including the risk of carbon monoxide buildup.

The value of 75 percent allows for a balance between horizontal run lengths and vertical chimney heights, facilitating effective venting while adhering to safety standards. It's essential to follow these guidelines to ensure optimal performance of the heating system and safety of the structure.