While this option is not referenced directly in the BCE, Provincial authorities have declared that F.B. chimneys tested by a private testing agency to U.L.C. Standards are deemed to be acceptable. Comparison of FR, Chimneys to Masonry Chimneys Historically, well built masonry chimneys have served society well. evs in all buildings, the F.B. chimneys do provide a more economical methed of construction in some instances. The cost differences between a masonry chimney and a F.B. chimney are relatively small for small buildings. Quality and Safety Considerations of F.B. Chimneys meanest U.L.C. $629 F.B. Chimneys While the quality of this chimney was improved in 1981, there are still some concerns tegarding the ability to assess damage caused by chimney fires and the long-term assurance of quality. A Yecent report (attached) from the Fire Commissioner's office states the number of fires has tripled over the last 10 years that relate to the use of solid fuel.