The name comes from the hammering and seaming of sheet metal in the shop and on the job. Tin knockers lay out fittings, form seams, hang trunk lines and connect equipment, and they work side by side with pipefitters and refrigeration techs on mechanical jobs. The term is used with pride inside the trade and with mild teasing by other crafts.
Tell the tin knockers we need a 14 by 8 takeoff here before the ceiling grid goes in Monday.
Also heard as
- tinner
- sheet metal worker
Related terms
Ductulator
A slide-rule style duct sizing calculator that matches airflow and friction rate to round and rectangular duct sizes.
Mud
Duct mastic, the thick paste brushed over duct joints and seams to seal them airtight.
Duct leakage
Air lost from supply ducts or pulled into return ducts through gaps at joints, seams and connections.
Plenum
A box on the supply or return side of an air handler that feeds or collects several ducts, or a ceiling cavity used as a return path.