What size Type B chimney is needed for a house with a 19 foot tall chimney and a total of 185,000 BTU input from one Category I natural draft vented appliance?

To determine the appropriate size for a Type B chimney based on the given inputs, we start by considering the height of the chimney and the BTU input of the appliance. In this case, a 19-foot tall chimney serves a Category I natural draft vented appliance with an input of 185,000 BTUs.

According to industry standards and guidelines regarding vent sizing, the diameter of the chimney must be sufficient to accommodate the flow of combustion gases while maintaining proper draft, especially for natural draft systems that rely on temperature differences to draw gases up through the chimney.

For Category I appliances, the vent size is often designated based on the output BTU of the appliance. In this scenario, the 185,000 BTUs input falls within a range typically requiring a 6-inch diameter vent. When calculating, we also consider factors such as the appliance type, the BTU input, and the height of the chimney. While certain larger sizes may also be acceptable for compliance with specific local codes or appliance specifications, standard sizing practices for this range indicate that a 6-inch diameter is generally adequate.

Thus, the choice of 6 inches is supported by the application's requirements, ensuring appropriate venting while adhering to safety standards and maintaining a proper chimney draft for optimal