ICC Commercial Mechanical Practice Exam

Can an 80,000 BTU per hour input appliance with a 4-inch-diameter draft hood outlet be vented using a 4-inch-diameter vent?

1. Yes

2. No

3. Only with a larger vent

4. Only if local codes allow

The correct answer is: Yes

For appliances with an 80,000 BTU per hour input, it is essential to ensure proper venting to prevent hazardous conditions like backdrafting. The connection between the appliance and the vent must be appropriately sized to allow for safe exhaust of combustion gases. In this scenario, a 4-inch-diameter draft hood outlet is designed to create a specific draft that allows for proper venting of combustion gases from the appliance. If the vent has the same diameter of 4 inches, it generally maintains the correct air flow and pressure required for efficient exhaust. The installation aligns with typical mechanical codes that allow for the same diameter to be used for the venting system as that of the draft hood outlet. Therefore, venting an 80,000 BTU per hour input appliance using a 4-inch-diameter vent is permissible, as long as it meets the guidelines set forth by relevant codes and standards. This compatibility helps ensure that the vent operates efficiently, which is critical for the appliance’s safety and performance.