Cornish boiler: typical shell diameter range Recall the common dimensions used in a single-flue Cornish fire-tube boiler. Choose the correct diameter range for the boiler shell.

Concept
Cornish boilers are horizontal, fire-tube, single large-flue units. Typical shells have diameters around 1–2 m and lengths around 4–7 m. Lancashire boilers are larger (often 2–3 m diameter) with two flues.

Elimination
0.5–1 m is too small for a practical Cornish shell; 2–3 m is typical of Lancashire, not Cornish. 1.25–2.5 m overlaps but the standard textbook range is 1–2 m.

Final Answer
1 to 2 m