by Lori Greene, DAHC/CDC, CCPR, FDAI, FDHI
Door hardware specifications can be confusing and tedious. Just the thought of having to recall door hardware terminology, code requirements, and best practices is overwhelming. Then, transferring that knowledge to work when designing commercial or institutional facilities with hundreds to thousands of openings, each including five to 10 pieces of hardware, seems like a monumental task.
To help the process seem a little less daunting, here is a reference guide explaining common terminology and hardware. There are four main steps to follow when specifying door hardware:
- hang the door;
- secure the door;
- control the door; and
- protect the door.
Hang the door
Typically, hinges are used to hang the door. There are a few basic types. Five-knuckle or three-knuckle are the common choices. Continuous hinges run the entire length of the door and are often used on exterior doors. It is important to consider the door width, thickness, weight, and clearance when choosing a hinge.
Pivots reduce stress on the frame by distributing the door weight throughout the floor and structure. Pivots are used when the door is heavy, design requires pivots, or it is an aesthetic preference.
In the author’s experience, hinges causing the most confusion are wide throw, swing clear, raised barrel, and anchor hinges.
Wide throw hinges
These hinges are used when extra clearance is needed behind a door. These are commonly utilized when a door needs to open 180 degrees and sit parallel with the wall, held open on a magnetic holder.
Swing clear hinges
These hinges are used to swing the door out of the clear opening of the frame when the door is open approximately 90 to 95 degrees. Swing clear hinges are most commonly used in hospitals.
Raised barrel hinges
For these hinges, the barrel is offset to one side instead of centered between the hinge leaves. This type of hinge is fairly rare, but it is used when the barrel of a standard hinge would interfere with a special frame condition or trim.
These are used as the top hinge for high-use or heavy doors. In addition to the standard hinge leaves, flanges are attached to the top of the door and the underside of the frame head. These hinges require a special door and frame prep, and are handled.
Secure the door
Understanding how to secure openings is an important step with a lot of pieces to the puzzle.
It is easy to get overwhelmed when discussing lock functions as sometimes as many as 50 functions could be listed in a catalog. It is helpful to start with the following six basic functions that account for the vast majority of locks specified.
Passage sets are used where doors do not need to lock. A latch bolt can be operated by a lever from either side at all times.
Privacy sets are used for spaces like restrooms or dressing rooms. They can be locked from the inside with a thumb turn or with a push button/turn for privacy, and they are typically unlocked from the outside using a tool rather than a key. There are several variations.
Storeroom locks are used when the outside lever should be locked at all times. A key is used to retract the latch bolt and open the door; when the key is removed the door is locked on the outside.
These may be controlled by a key in the outside cylinder or by a thumb turn or push button/turn on the inside. The outside lever may be left in a locked or unlocked position.
Traditional classroom lock
Classroom locks are controlled by a key in the outside cylinder, which locks or unlocks the outside lever. The lock can be left in the locked or unlocked state by using the key, and there is no means of locking or unlocking the door from the inside. This function was originally designed for schools to prevent students from tampering with the lock, but most of the new institutions have classroom security locks, office function locks, storeroom locks, or electrified locks.
Classroom security lock
Classroom security locks allow control of the outside lever via key cylinders on both the inside and outside of the door. This allows a teacher to lock the classroom door during a lockdown without opening the door and possibly being exposed to an intruder in the corridor.
Tubular, cylindrical, mortise, deadbolt, and interconnected types of mechanical locks.
Tubular locks have a center spindle assembly extending through the center of the lock body and latch, allowing for retraction of the latch when the lever or knob is rotated. While this type of lock is very common on interior doors and in residential applications, they are considered the least secure lock type.
Cylindrical locks are sturdier and considered more secure than tubular locks. The latch bolt assembly interlocks with one side of the lock chassis, making it easier to install, replace, and rekey. Cylindrical locks are also available in different formats that provide various levels of security, all of which use the same type of key.
Mortise locks are stronger and heavier than cylindrical locks, making them ideal for use in hospitals and schools. They require a pocket—the mortise—to be cut into the door where the lock is fitted. Mortise locks also provide a wide variety of choices for function, trim, key systems, and finishes.
An interconnected lock comprises two locks that are connected together, so operating the lever handle will retract both the latch bolt and deadbolt simultaneously. The latch set is either a cylindrical or tubular lock with a deadbolt above it. These locks are most commonly employed on dwelling unit entrance doors in multifamily buildings.
Deadbolts are available with a single or double cylinder. The single-cylinder deadbolt operates by a key on the outside and a thumb turn on the inside. A double-cylinder deadbolt requires a key for unlocking on both sides of the door and cannot be used on doors required for egress, except in limited locations where specifically allowed by the adopted codes. In these cases, all criteria stated in the adopted code must be met.
Electrified hardware uses power to control the locking and unlocking of the door. Most electrified hardware is available in one of two functions: fail safe or fail secure. Fail safe and fail secure refers to the status of the secure side (key side, outside) of the door. Most electrified hardware allows free egress from the egress side (inside) of the door.