Chimney Safety Institute of America (CSIA) Certification Practice Test

How does parging the smoke chamber improve flow?

1. By smoothing surfaces and increasing diameter

2. By reducing turbulence and eliminating corbeling

3. By adding insulation to the chamber

4. By increasing the height of the smoke stack

The correct answer is: By reducing turbulence and eliminating corbeling

Parging the smoke chamber enhances flow primarily by reducing turbulence and eliminating corbeling. When surfaces within the smoke chamber are rough or uneven, it can create turbulence as the flue gases move through. This turbulence can disrupt the smooth flow of gases, making it less efficient. By applying a parging material, the surfaces become smoother, which allows gases to travel more efficiently. Additionally, corbeling—the practice of supporting a structure with protruding blocks—can create unexpected obstacles in the smoke chamber. Removing or minimizing these corbeling structures streamlines the gas flow, further contributing to an effective and unobstructed path for smoke to exit. Both of these factors—reducing turbulence and addressing physical obstacles—play a crucial role in enhancing the performance of the smoke chamber.