What is Pittsburghh joint in HAVC duct work?

Refer to the SMACNA reference for metal duct construction. The Pittsburg joint is used for most commonly fabricated metal retangular ducts. Most modern sheetmetal fabrication shops use a mechanized piece of equipment to create the Pittsbugh joint on one edge of the sheet metal that is being formed into a retangular duct. The Pittburgh joint is basically a series of bends in the sheetmetal that create a female joint that will accept the male end of the rectangular duct. The female joint includes an extended section of sheet metal that is mechanically or manually hammered over the male edge of the sheet metal once it is positioned within the Pittsburgh joint. It is much easier to understand when viewing a piece of flat piece of sheet metal that is being formed into a section of duct with a mechanized piece of equipment found in most sheet metal shops. I have created a Pittsburgh joint with a manual hand break for specialized duct fittings.

I hope the information has been helpful.

Ralph Pimentel C.B.O.

Member ICC ICBO IAMPO

Member Sheet Metal Workers Local #77

National Building Consultants

Member State of Kansas Home Inspector Board, Vice Chairman