ملف:Seven-flue Stack 1834.png

English: A seven-flue stack, showing how it would be cleaned by climbing boys, or with little modification by a human cleaning machine (a brush). In the diagram:

• A is a hearth served by vertical flue, a horizontal flue, and then a vertical rise having two right-angled bends that were difficult for brushes.
• B is a long straight flue (14in by 9in) being climbed by a boy using back elbows and knees.
• C is a short flue from a second floor hearth. The climbing boy has reached the chimney pot, which has a diametre too small for him to exit that way.
• D (omitted) is a short flue from the third floor.
• E shows a disaster. The climbing boy is stuck in the flue, his knees jammed against his chin. The master sweep will have to cut away the chimney to remove him. First he will try to persuade him to move: sticking pins in the feet, lighting a small fire under him. Another boy could climb up behind him and try to pull him out with a rope tied around his legs - it would be hours before he suffocated.
• F (omitted)
• G How a flue could be straightened to make it sweepable by mechanical means
• H A dead climbing boy, suffocated in a fall of soot that accumulated at the cant of the flue

Comments might be influenced by:

Strange, K.H. (1982). Climbing Boys: A Study of Sweeps' Apprentices 1772–1875 (PDF). London/Busby: Allison & Busby. ISBN 0-85031-431-3. Retrieved 6 May 2011.