CSLB Class B General Contractor's License Practice Exam

When installing a low-heat appliance, the chimney must extend at least how many feet above the highest point where it penetrates the roof?

1. 2 feet

2. 10 feet

3. 15 feet

4. 5 feet

The correct answer is: 2 feet

The correct response to how far a chimney must extend above the highest point of the roof when installing a low-heat appliance is a minimum of 2 feet. This requirement is based on the need to ensure proper venting and draft for the appliance, which helps to safely expel combustion gases. Extending the chimney this distance above the roofline enhances ventilation, minimizes the risk of backdrafts, and helps prevent any potential hazards associated with poor exhaust flow. The 2-foot extension also assists in ensuring that the chimney terminates high enough to be clear of any nearby roof structures and to protect against potential obstruction from wind and weather. This is crucial for both safety and functionality, as a properly positioned chimney facilitates better airflow, reducing the likelihood of smoke or dangerous gases re-entering the home. Understanding the importance of this requirement helps in adhering to building codes and safety standards, which are set to protect inhabitants and the integrity of the structure.