The method
Before using the result
- Geometric internal area only. Equal cross-sectional area does not establish equivalent flue performance, venting capacity or appliance compatibility.
Worked examples
These original training examples illustrate the method for CSIA Certified Chimney Sweep. Use the matching “Load example” button above to explore a variation; example values are not equipment settings or prescribed criteria.
1. Worked example
Compare the internal geometric areas of circular and rectangular passages. Equal area alone does not make two flues equivalent for appliance venting.
- Passage shape
- Circular
- Internal diameter
- 0.2 m
- Circular passage; internal area = 0.031415926535897934 m².
- Internal cross-sectional area: 0.03141593 m²
2. Comparison example
Compare a different supplied condition using the same method. For Chimney Exam, the important check is that the input meaning, units and method assumptions still match the problem.
- Passage shape
- Rectangular
- Internal width
- 0.15 m
- Internal height
- 0.25 m
- Rectangular passage; internal area = 0.0375 m².
- Internal cross-sectional area: 0.0375 m²
Check your understanding
1. Which relationship is used?
Circular internal area = πD²/4; rectangular internal area = width × height.
2. Which assumption should you check first?
Geometric internal area only. Equal cross-sectional area does not establish equivalent flue performance, venting capacity or appliance compatibility.
3. How should you verify a different unit system?
Convert every input to the displayed calculation units first. Equivalent physical inputs must give equivalent results; a unit label alone does not convert a number.
Continue with the matching exam topic
This tool connects to CSIA Certified Chimney Sweep free practice. Work through a question independently, then use the calculation steps to identify where your method differs. The tool stays free whether or not you choose paid preparation.