How-To: How Do Chimneys Work?
How Do Chimneys Work?
Chimneys are important pieces of the structural puzzle. You can find them everywhere. They are a part of all kinds of buildings, from great to small, and dominate the skyline in most urban areas. Yet, most people have never spent even an idle moment contemplating how they work. So, as a fan of the chimney, I thought we would take a closer look at how a chimney functions.
Chimney professionals often describe the way a chimney works to their customers by comparing it to a common water hose found in your backyard garden. While this is a bit simplistic, it actually works very well to get the major points across, so we’ll use it here to illustrate the ways air and water are similar in their movement through the two systems.
A chimney that is filled with hot air from a fire pulls air in from the room through the firebox. This pulling in of air is known as draft, and is remarkably similar to the water pressure in a hose. One, the chimney, is negative air pressure, while the other, the hose, is positive water pressure. One pushes and the other pulls. Due to the negative air pressure it creates a chimney is known as a negative pressure system. The draft in your chimney, much like the water in your hose, can be increased by opening the source wider, so, for your fireplace, that means burning a hotter fire to lighten the air further. Chimney height also plays a part in increasing draft, but frictional effects hamper the benefits to increasing height.
Just as a larger water pipe can carry more water, a clean chimney has more area to pull air through thus an increased draft. There are many factors that can restrict the draft your chimney creates, so call McSweepy’s today to schedule an inspection!