How Doors Impact Access ControlAuthor: Brian Rhodes, Published on Feb 11, 2012
Assuming every door can be secured with either a maglock or an electric strike can be a painful assumption in the field. While those items can be applied flexibly with various openings, there are occasions where certain hardware cannot be used.
A common pitfall is inadequately or inaccurately describing the door resulting in a field mistake. In this note, we examine how to properly identify a type of opening including an explanation of terms including leafs, mullions, frames, lites, transorms and a review of steel, wood and glass doors.
A single door is often called a 'leaf'. Most commonly, a double-doored opening has two 'leaves'. Sometimes one of the 'leafs' is held stationary and is locked in place.
Sometimes 'leaves' are separated by a bar stop running vertically between them called a 'mullion'. Here's an example of leaves separated by a mullion
Mullions can be permanently affixed as part of the frame assembly or may be a removable type - typically locked into place to prevent unauthorized removal (and threaten the security of the opening).
'Mullion mount' card readers are common, named for the slim form factor they are designed to accomodate. Mullion mount readers are most commonly used on both frames and mullions. Be aware that mullion mounted devices will be subject to impacts and abuse.
Key elements of "Frames" include material used and its 'profile':
- Steel and Aluminum are common materials used to construct frames, although wooden frames can sometimes be found on older buildings.
- The 'profile' of the frame - or the shape in which it constructed is often dependent on aspects like the adjacent wall to which it is attached, the type of door it is intended to frame, the swing of that door, and the type of hinges it is designed to work with.
When specifying electronic strikes or hanging readers from frames, make sure that enough room for the device and the device wiring exists inside the frame.
Lites and Transoms
‘Lites’ and ‘transoms’ refer to the pieces of glass within or adjacent to the door leaf itself. It is a common feature to have a full-height glass sidelight adjoining an entry door. These features are important to note due to the impacts they may provide access control features like wire runs or the mounting options of items like maglocks.
Here's an example
Type of Doors
In general, care must be taken to understand the construction of the door and any special ratings it may possess (ie UL rated Fire doors, etc.).
For example, consider the distance between a card reader and the swing of a door upon a card read. Will the swing of the door make it awkward for the card holder to gain entry after scanning a card? Would a card reader located on the door frame itself or with a longer read range make the opening easier to use?
A low-level perspective is important during the design and installation phases of implementing an access control system, especially in how the access control system impacts the usability of the door.
In the commercial architectural market, 'hollow-core steel doors' and 'steel frames' are a mainstay product. Many access controlled doors fall into this category; the products are typically constructed of 16 - 22 gauge steel sheeting and then cut, formed, and welded into assemblies. ‘Hollow core’ indicates a steel shell with a fiber composition or polystyrene honeycomb core.
Here's an example of a steel door:
Steel doors provide a good rigid medium to hang a variety of security hardware upon. However, over time the perpetual hanging and rehanging of different types of hardware can damage the door and result in a structurally unsecureable opening. For example, make sure that maglocks are mounted with 'thru-bolts' and not only surface mounted.
While a steel door allows for mounting various accessories, this can result in awkward interaction of mechanical devices and access control systems. If the intent of an opening is to open upon a card read, make sure that no existing mechanical device (ie - deadlatching exit device) prevents this action.
'Wood veneer', or 'solid core wood' doors are also very common, especially in institutional and education buildings. The term is self-explanatory; instead of a hollow-core steel door, one composed of wood or wood veneer is used in its place. These types of doors are still commonly installed in steel frames.
Surface mounting hardware like maglocks to wood doors can sometimes be troublesome. Not only are those finishes especially sensitive to damage like tool marking and hole break-outs but the actual door itself will 'move' depending on environmental variables like heat and humidity. Because of that, special care should be taken to mount hardware so that it will always remained aligned, i.e. - a good electromagnetic bond is achieved.
Glass Doors, sometimes referred to generically by specific brand ‘Herculite’, are very common in architecturally significant openings like storefronts or main entries into highrise structures. These types of doors usually present cosmetic constraints to hardware specification, and due to the thin frame, or frameless, opening types great care must be taken to ensure the constraints of movement and interaction of hardware is well understood.
These types of doors are especially costly to modify in the field if improperly configured. Often times, the glass must be cut during manufacturing to accommodate for items like hardware and hinges. Making sure the build and action of these doors is understood will ensure cost controls when working with them.
Electromagnetic locks are most commonly used in glass doors rather than strikes. A variety of factors account for this: these doors see high traffic counts and strikes are more burdensome to maintain than electromagnetic locks, and it is difficult to 'hide' the strike in such a way that is aesthetically pleasing.
Though not traditionally within the domain of the 'security integrator', doors and openings remain a vital aspect for the integrator to understand. A good integrator or system designer should commit to understanding the different types of openings, how they are used, and how those factors influence selection of physical security devices.
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