The acronym WETT stands for Wood Energy Technology Transfer. WETT was established to train inspectors and installers to do their jobs properly and to ultimately save lives in the process. Most wood stoves today are EPA certified and have manufactures labels showing the minimum installation clearances. It is critical that the stove or fireplace and chimney maintain these clearances. The manufactures who design these wood burning products must submit the finished product for testing in a test laboratory. Once the stove is certified it can be sold to the public. There are minimum distances to combustibles that must be met and each unit is different depending upon how they preformed in the test enclosure. The B365 code applies to wood burning appliances and written in there are some other regulations that must be adhered to such as rules for shielding and so on. The big thing to remember is to be sure about the requirements before you attempt to install or use a wood burning appliance. Most insurance companies today will not insure a wood stove or fireplace unless it has been inspected by a WETT certified inspector. SGI has a 25% surcharge on their homeowner policies if there is a wood stove in the home. If the stove has been inspected by a WETT certified contractor and it meets the current code requirements as well as the manufactures requirements the surcharge is reduced to 10%, a significant reduction in insurance costs year after year.  I personally hold a WETT TECHNICIAN CERTIFICATE which means I can go beyond the basic visual inspection and make repairs etc. With over 300 installs I can say there is a lot to learn and I am still learning, You can never be too safe!