What does the term "draft" refer to in the context of gas appliances?

In the context of gas appliances, the term "draft" specifically refers to the flow of flue gases up the venting system. Draft is crucial for ensuring that combustion gases produced by gas-burning appliances are safely expelled from the living space, thus preventing potential hazards such as carbon monoxide buildup. A proper draft facilitates the efficient functioning of venting systems, maintains appliance performance, and ensures compliance with safety standards.

Having a good draft means that there is adequate upward movement of flue gases, which is essential for creating the necessary pressure difference that allows these gases to exit the system effectively. Insufficient draft can lead to backdrafts, where gases are drawn back into the home, posing serious health risks. This flow is influenced by factors such as temperature, atmospheric pressure, and vent design, all of which play a role in the safe operation of gas appliances.