Gas Fitter Practice Test

What is the minimum allowable distance to be maintained from a 50,000 Btuh water heater flue outlet to grade level?

1. 6" (150mm)

2. 12" (300mm)

3. 18" (450mm)

4. 24" (600mm)

The correct answer is: 12" (300mm)

The correct answer is a minimum allowable distance of 12" (300mm) from a 50,000 Btuh water heater flue outlet to grade level. This distance is established to ensure safe venting of combustion gases and to minimize the risk of those gases re-entering the building. Maintaining this distance helps prevent issues related to combustion air and allows for proper dispersion of exhaust gases, which is critical in preventing carbon monoxide buildup and ensuring the appliance operates efficiently. Local codes and regulations may specify this distance to promote safety in residential installations. Other distances may not provide sufficient clearance, potentially leading to dangerous conditions or non-compliance with safety regulations.