Where is the Smoke Chamber?
An important part of any fireplace is the smoke chamber. It’s the area of the chimney which provides support for the clay flue tiles that make up the chimney’s liner. Smoke chambers are often a tricky part of a chimney sweep’s job. Seeing that the design of any particular smoke chamber generally varies and maybe constructed that the smoke has a difficult time venting up through the flue system. Uneven inner surfaces cause the smoke to move in a circular motion over each of the uneven parts which decreases the chimney’s performance and may even cause issues like smoking problems.
According to NFPA 211, the walls of smoke chambers should be 6″ thick if lined with firebrick or 8″ thick. If no firebrick is present and the inside surface of the smoke chamber should be smooth.
This is important to note it is the heat, not flame and in which it is needed to ignite combustibles and if there is not sufficient clearance between the smoke chamber and combustibles, or any part of the chimney flue system and combustibles for that matter, if the chimney flue system gets too hot combustibles near the chimney can ignite.
Another problem surrounding smoke chambers is an over sized smoke chamber and in which creates problems as well. Smoke chambers which are too large for the firebox often cause a fireplace to smoke excessively. This is until the fire gets hot and a good draft is established. Hence, this makes it harder for a sweep to access and clean.
NFPA 211 states that the height of the smoke chamber should not be greater than the inside width of the fireplace’s front opening and that the depth of the smoke chamber should be less than the depth of the firebox. Keeping these codes in mind, some fireboxes are not as they should be.
Approximately 60% of chimney fires originate in the smoke chamber and using a video camera to inspect the interior of a flue system is often times the only way to see the entirety of a flue system or a smoke chamber for that matter. Hiring a sweep who uses video scans of the flue system is helpful to you as a homeowner and it’s also because the professional can then show you what he is talking about using pictures as opposed to words. 
You can find a reputable Chimney Sweep in your area by using this link to the National Chimney Sweep Guild locator : http://www.ncsg.org/search. Be sure and go online and read their customer reviews. Use websites like Google, BBB and AngiesList and you should never be impressed with those cheaper “Swab and Rob companies”
I hope that this information helps! Check out our YouTube Videos or our Blogs to learn more about water problems and more!
Burn Safe and Warm
Clay Lamb