November 6, 2021
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 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 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 in the overall design and specification process.
It is easy to get overwhelmed when discussing lock functions as sometimes as many as 50 functions could be listed in a product 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 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 used 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.
An electronic lock is controlled by a reader, such as a keypad, card reader, or biometric terminal. There are two main types of electronic locks.
Standalone locks and readers
Standalone electronic locks use the same credential as networked locks. However, they are not connected to access control software, so they require the user to physically go to each lock to administer access rights and retrieve tracking information.
Networked electronic locks are connected to an access control system. They allow the system manager to easily change access rights and track movement throughout the facility from anywhere they are connected to the network.
An electromechanical lock is an electrified lockset that can be controlled by a card reader, remote release, or other access control device. Most electromechanical locksets allow free egress at all times.
An electromagnetic lock is an electromagnet that mounts on the frame, with a steel armature mounted on the door. When power is applied to the magnet, it bonds to the armature, securing the door. Electromagnetic locks are only available in fail-safe mode. They unlock when power is removed.
An electric strike replaces the regular strike for a lockset or panic hardware. It is used as part of an access control system to provide added security and convenience such as traffic control and remote release. An electric strike is typically paired with a storeroom function lockset or panic hardware, so access is controlled by the electric strike but egress is unaffected.
Fail safe versus fail secure
Fail-safe products are unlocked when power is removed. Power is applied to lock the door. Fail-secure products are locked when power is removed. Power is applied to unlock the door.
Here are some tips to keep in mind:
• Fail-safe locks should be used on stairwell doors requiring re-entry and any other doors that must allow free access upon fire alarm or power failure;
• Fail-safe electric strikes cannot be used for stairwell re-entry because fire door assemblies require fail-secure electric strikes for positive latching (fire doors do not require fail-secure electric locks, only fail-secure electric strikes);
• Be aware when a fail-safe product is used, the door will be unlocked when power is removed (e.g. it would be removed during a power outage and, in some systems, during a fire alarm);
• Electric latch retraction panic hardware is only available fail secure;
• Fail-secure products are more common than fail safe due to security concerns, as they provide security when power is not applied; and
• Most electrified products, with the exception of electromagnetic locks, allow free egress at all times, regardless of whether they are fail safe or fail secure.
Just as a key fits a lock, a card, biometric, fob, or phone requires a reader. There are a number of options to choose from. In some cases, the lock and reader are combined into one unit. Readers can be contact-based, which requires the credential to be swiped or touched by the reader. They can also be contactless, requiring only a certain proximity or range to communicate. Biometric readers are also an option. These use unique human characteristics as the credential, such as the size or shape of the hand. The most secure reader options on the market, biometrics are more common in high-security applications, such as data centres, airports, banks, and government buildings.
When specifying a card reader, it is advisable to ensure it has the capacity to read all types of cards: smart, proximity, and mag stripe. Specifying a multi-technology reader can eliminate the expense of installing new readers should credentials change down the road. In today’s market, it is also important to make sure the specified product is able to read mobile credentials.
Panic hardware—also known as exit devices, crash bars, panic bars, panic devices, or push bars—is designed to provide fast and easy egress to allow building occupants to exit safely in an emergency. These devices allow the exterior side of the door to be locked, while ensuring people can always exit from the interior. Consisting of a spring-loaded metal bar or touchpad mechanism fixed horizontally to the inside of an out-swinging door, it activates a mechanism that unlatches the door, allowing occupants to leave quickly.
Dogging is a feature used in panic hardware to hold the touchpad or crossbar in a retracted position, thus allowing a door to operate in push/pull mode without latching. Mechanical dogging is not allowed for fire doors, so fire exit hardware will not have the ability to be mechanically dogged. Fire doors may be dogged electrically, as long as the latches project upon fire alarm to positively latch the door.
There are several types of panic hardware.
Touchpad panic hardware is mounted on the inside of the door and features an enclosed mechanism case with a touchpad to allow egress.
Crossbar panic hardware may be used for doors with large glass lites or where there is an esthetic preference for the crossbar style. Available for both wide and narrow stile doors, they are ideal for environments demanding a traditional look that is durable enough to withstand rugged applications.
Recessed panic hardware is embedded into the door to maintain a low profile with sloped end caps to deflect objects away from the door. This hardware is close to being totally flush with the door when depressed.
Rods versus cables
Vertical rod panic hardware has historically been manufactured with rods and latches to secure the door at the top and bottom. Recently introduced exit devices use a concealed vertical cable instead of rods. Concealed vertical cable panic devices are more esthetic and easier to install and maintain than traditional vertical rod devices.
Control the door
Controlling the door is the job of a door closer. The function of a door closer is not just to close the door, but also control the door in both the opening and closing cycles to prevent damage and injury caused by abuse, wind, or other factors.
Choosing a door closer involves the consideration of a variety of criteria. In addition to the closer’s performance in fire situations, other factors may include resistance to opening forces, control over the rate of closing, safety, durability, risk of vandalism, and esthetics. Many codes and standards contain requirements for door closers, so it is important to reference all accessibility, fire, and life-safety requirements before specifying.
There are five basic types of door closers.
These closers mount at the top of the door and frame—either parallel arm mount (push side), regular arm mount (pull side), or top jamb mount (push side).
These closers mount in the floor, and the door is typically hung on pivots. Floor closers must be carefully co-ordinated with the floor construction and finish flooring for proper installation.
Concealed closers are mounted in the frame head, or in the top rail of the door, when esthetics are a concern.
High-security closers feature a vandal-resistant design for use where closers may be exposed to abuse or vandalism.
Fire doors may not be held open mechanically, but electronic closers may be used on fire doors to hold the door open and automatically close the door when a signal is received from the fire alarm or smoke detector. A door with this type of closer is called automatic-closing, while a door closing each time it is opened is called self-closing.
Low-energy automatic operators are used where a knowing act, such as a push button, is used to automatically open the door. They are required by code to open the door slowly and with a limited amount of force.
These are designed for manual opening applications where there is occasional need for automating the door to allow easier access for building occupants or to meet code requirements. Electro-hydraulic operators combine a conventional heavy-duty door closer with a low-energy automatic operator.
Designed for more frequent automatic use, these operators are often used on cross-corridor doors and other often-used openings in hospitals. These operators are designed for applications where automatic operation is the primary need.
Pneumatically powered systems
These are great for use in areas where electrically operated devices are not convenient or permitted. The pneumatic operator consists of a heavy-duty door closer for manual operation and a pneumatic automatic operator to power the door when required. Power for the operator comes from the in-house air supply or a compressor furnished with the operators. These operators are silent when the compressor is installed in a remote location, making them ideal for use in libraries, churches, hospitals, and laboratories.
Protect the door
Many products are available to protect the door, an important step in the specification process.
Protection plates, including mop plates, kick plates, stretcher plates, and armor plates, are used to protect a door from wear and tear. In institutional or high-abuse and high-use applications, it is best to specify the proper plates to help prevent damage.
Stops and holders
Door stops prevent doors from coming into direct contact with walls or other adjacent surfaces. Common stops include wall stops, floor stops, and overhead stops.
Overhead stops and holders should be used in locations where wall stops and floor stops are unsuitable. Some door closers are available with built-in stops, which work well for some applications, but the backcheck feature of a door closer is not a substitute for an auxiliary stop.
Gasketing and thresholds
Gasketing and thresholds may be used to restrict airflow, smoke infiltration, sound, light, and temperature. Gasketing is installed at the head and jambs of the door opening. Thresholds and sweeps are installed at the bottom of the door.
In the author’s experience, some architects and specifiers enjoy writing hardware specifications. Others are overwhelmed by the amount of products, code requirements, and terminology that come with the territory. Whether one writes their own specifications or work with an architectural hardware consultant, knowing the jargon for door hardware will help ensure the next project is safe and secure.
Lori Greene, DAHC/CDC, CCPR, FDAI, FDHI, is the manager of codes and resources for Allegion. She has worked in the industry for more than 30 years, including more than 20 years as a hardware consultant writing specifications. Greene is a member of CSI, the Door and Hardware Institute (DHI), the International Code Council (ICC), the National Fire Protection Association (NFPA), and the Builders Hardware Manufacturers Association (BHMA) Codes and Government Affairs Committee. Greene blogs at www.iDigHardware.com and can be reached via email at firstname.lastname@example.org.
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