A chimney for residential-type gas appliances must extend at least how many feet above the roof where it passes through?

The correct answer is based on the guidelines established for gas appliance venting systems. A chimney for residential-type gas appliances is required to extend at least three feet above the point where it passes through the roof. This height is critical for safety reasons, as it ensures that the combustion gases are adequately dispersed above the building structure, reducing the risk of them entering living areas.

In addition to meeting the required height, extending the chimney further helps to mitigate backdrafts and provides sufficient clearance from potential obstructions, such as trees or nearby structures, which could interfere with proper ventilation. This extension plays a vital role in maintaining the efficiency of the appliance and safeguarding the health of occupants by preventing the risk of carbon monoxide or other harmful gases accumulating near the roof line or being drawn back into the home.

Overall, adherence to this chimney height specification is an essential aspect of propane gas safety and installation practices, ensuring that residential gas appliances operate safely and efficiently. The other choices do not meet the established safety standards for chimney height and therefore would not provide the necessary clearance for safe ventilation.