Concrete ferrules are cast into the concrete panels to allow connections without drilling after installation. Threaded ferrules are often used for starter bars, steel connections and sometime props to hold the structures in place. The ferrules are cast in either face down or face up un the panel. If the ferrule is cast face down a ferrule locator will be required and if cast face up, a ferrule support chair will be normally used.
Concrete ferrules can be broken down into several key characteristics.
The material of the ferrule is made from solid steel or tube steel, solid steel offering the greater strength.
Solid ferrules have a thread that is drilled and then tapped where the tube ferrule is just tapped tube. There is also a course threaded ferrule that accepts a coil bolt which reduces the chance of clogged threads and increases installation time.
The solid ferrule can have a foot on the bottom of the ferrule to increase pull out loads where the tube ferrule can have a bent end. The footed ferrules have names like Qwikfoot (the old Klikfoot ferrule), Elephants foot and Big foot.
Coatings are zinc plated and hot dipped galvanised, the hot dip galvanised ferrule needs to be tapped after the plating process to clear the thread, so no coating on the inside of the ferrule. The galvanised ferrule will also have an oversized thread in most cases to accept a gal bolt.
Materials include mild steel, high tensile steel and stainless steel in several grades such as SS304 and SS316.