An offset pivot operates similarly to a traditional hinge. It consists of at least two separate pieces. A top pivot fastens to the top of the door and the head of the frame, and a bottom pivot connects to the bottom of the door. The bottom pivot may be built into a concrete floor or attached to the floor after it is complete. Offset pivots come in 3/4 inch and 1-1/2 inch varieties, which represent the measurement between the centerline of the door and how far away the pivot is installed. A 3/4-inch offset is standard, while a 1-1/2 inch offset accommodates doors and frames covered with trim or cladding.
A center-hung pivot installs directly at the centerline of the door. It consists of a top and bottom component, used to connect the door to the floor and frame. A center-hung pivot is almost completely concealed when it is installed with the exception of the floor plate. Center hung pivots cannot be used on fire-rated doors but can be used on double acting (Eliason) doors.
An intermediate pivot, similar to a barrel hinge, is placed on the edge of the door at mid-height. These pivots are non-load bearing and are used to keep tall or heavy doors properly aligned. They are only used in conjunction with top and bottom pivots, whether offset or center hung. All fire-rated doors hung using pivots must have at least one intermediate pivot if they are more than 5 feet tall.
A side jamb pivot is designed for applications where the pivot cannot be fastened to the head of the frame. It is used to hang frameless doors or those set in frames that are not solid enough to support the weight of the door. It may also be used on a frame with wires or other objects placed in or near the head. The side jamb pivot fastens to the top and bottom of the door jamb and to the edge of the door. If there is no door frame, it can be fastened directly to wall studs or framing members.
Asylum pivots are used in detention and institutional facilities to reduce the risk of hanging. They have a sloped top pivot rather than a traditional squared edge. Lead-lined pivots are designed for use in hospitals and other buildings where X-rays and MRI machines are operating. These pivots have specially placed screw holes to allow installers to fasten them around the lead panels in a lead-lined door. A traditional pivot will not work with lead doors because it is too difficult to drill into the lead.