Airflow: the Pipe's Smoke Channel Debate

Airflow refers to the cross-section of the smoke channel running from the base of the chamber to the tip of the mouthpiece in a pipe, and to how that cross-section affects the smoke. The term is also the name of a debate that has run through the community since the late 1990s: how wide should the channel be, and should the user later alter this measurement?

The subject is considered the detail of pipe anatomy most directly tied to the smoking experience.

The Geometry of the Channel

Smoke enters the shank through the hole at the base of the chamber, passes the mortise-tenon junction where the shank meets the mouthpiece, travels through the channel inside the mouthpiece, and exits through the slot at the bit end. Along this path, any narrowing of the cross-section or any sharp corner disrupts the flow. The measurement has not stayed constant through history: in clay pipe records the shank-hole diameter is about 3.6 millimeters at the end of the 16th and start of the 17th century, dropping to 1.6 millimeters by the end of the 18th century. Archaeologists use this narrowing as a criterion for dating clay pipes.