Installers and security managers should be thinking about incorporating door hardware and design that offers best support to access control systems and their electronic locking devices
One of the most important aspects of getting your electric locking solution right is ensuring that door furniture is strong enough to support the hardware. That means ensuring doors, hinges, closers, door surrounds and adjacent wall structures need to be designed to support electric locking devices.
When talking external timber doors you need to go for solid wood doors that are at least 50mm thick, and installed using at least 3 hinges. For highest security levels it’s recommended that external high security doors employ a minimum of glazing. A timber door with a window should limit that window to a size around 500 square centimetres.
It goes without saying the installers and security managers will more often than not be installing electronic locking solutions on external doors that are full glazed and have aluminium frame and aluminium surrounds. No glazed window – unless armoured – can ever be truly described as a security door. But your installation should still make the most of the door’s ability to delay or deny entry.
Some external security doors, even if fitted with electronic locking systems, will also incorporate mechanical keyways. Make sure any mechanical locking devices employed are high security numbers like mortise lever deadlocks or “unpickable” disc locks.
Some of things you want to avoid incorporating into your external access controlled door include double throw deadlocks, rising hinges, straps, hinges with open pins and locks with internal or external knob sets.
Things you want your access-controlled door to include are hinged 3-stage door-closing devices with a door stop or some sort of threshold that will stop doors from closing beyond 90 degrees. Nor do you want dead spots at the end of the closer’s arc where the door locks into a fully or slightly open position.
Something else that will require a bit of serious thought is closing mechanisms. Regardless of how good the electric locking solutions, door hardware and door surrounds, a door closer that routinely fails to shut doors will short circuit your site’s security, as well as creating false alarms that will have to be checked by security staff.
In order of preference you should go for a normally hinged door with an entirely separate mechanical closing device as a baseline. For better performance try a internally spring-loaded or flush, floor-mounted door closing device. Best of all is an automatic, electronically operated sliding door with a closing sensor.
It’s most likely that automatic sliding doors with sensors will be located on external doors, while internal access-controlled doors will have less expensive surface-mounted door closers. As a rule, this means there’ll be many more external door closers in an access system than there will be internal.
External closers will either be regular arm-mounted, top-jamb mounted or parallel mounted units. Of these 3, regular arm and top-jamb are the most common – the top-jamb type being the standard arm style mounted in an inverted position.
When making your decision, bear in mind that regular-arm and top-jamb closers are capable of handling the greatest amount of door movement while still functioning effectively – their tolerances are looser. Both these types are installed on the inside of the door to protect them from vandalism or weathering.
Meanwhile parallel-mounted doors have their closer arms sliding parallel to the door. Such a setup demands good door balance. It’s a door closer style most commonly used when the closer has to be installed on the jamb of the door.
A typical door closer is spring-loaded and there’s a fine balance between ensuring the closer will always get the door shut, and creating a force that’s so great the door can only be opened using a cardholder’s entire body weight.
If there’s one important thing with internal door closers, it’s the fact that if door is tough to handle and needs adjusting, an internal door closer are going to be harder to adjust or repair if something breaks.
Single Leaf Doors
The most common type of access barrier is a door – probably the single-leaf door, which does not offer particularly high security. Double doors are also a fiddle because of these will have to be bolted in order to give a fixed strike base for the electric locking device. Double doors are best secured with magnetic locks.
Next in line in terms of absolute security value is going to be an airlock style of entry, in which 2 doors in close proximity guide traffic into the sterile side of building. The idea with an airlock entry is that the second door can’t be opened until the first has closed.
The space between the doors is usually monitored by cameras or visible from a security post. In practice this sort of entry is usually only used in higher security areas where there’s a manned presence allowing every person entering or leaving the air lock to be checked.
You couldn’t use an air lock is a busy foyer, however. In locations like these, access control is more of a compromise with a series of layers designed to deny entry to unauthorized visitors. There might be a security post at the ground level, access to most floors could be denied to those without appropriate access credentials.
Proprietary access control systems will guard entries to the commercial suites, with management areas and computer rooms requiring another level of authorization again.
What this means is that while there’s a layering effect that weeds out unauthorized visitors, in some cases it might be difficult or impossible to deny entry to foyers, lifts and the reception areas of commercial suites. In this case an attacker might gain access to a premises by force after negotiating the foyer and lift well unchallenged. Once in the commercial suites it’s likely there will be only one door to get through in order to breach the company’s defences.
In this case security managers may need to come up with a solution that allows fast throughput but a significant psychological and physical barrier between the public foyer and the semi-sterile area allowing access to lifts and tenanted floors beyond them.
In large buildings which may house thousands of staff, you need something more efficient than a mantrap – the best solution is probably turnstiles, though in most cases they’re not going to completely deny entry to a committed attacker – it’s possible to jump over them.
The answer is to put the security point in a location in which it has surveillance of the turnstiles – security officers can then respond to any attempts they see to breach the barriers. This might include shutting down lifts or calling for police assistance.
Another benefit of turnstiles is that they prevent tailgating – this occurs when 2 people come through the same door using only one card. You can enhance the impact of turnstiles using a lane design which makes the access point more restrictive. Quality turnstiles will incorporate things like sensors which offer a delay function based on the time it takes a person to move through the lane. If there’s any variation from a norm, an alarm will be activated.
Obviously, the key with turnstiles in maintaining throughput. At peak times on a large site too few turnstiles can create a bottleneck so careful planning will be required to ensure the best possible performance for the least possible spend.
High security buildings and facilities may employ mantraps in their foyers, which are an extreme way of supporting the access control system. The mantrap may also be fitted with a metal detector that denies entry to any person carrying metal objects. These double vestibule hall portals are usually only seen in the highest security or highest risk locations.
Another way to reduce tailgating is to install revolving doors. Revolving doors can offer metal detection capabilities and it’s possible for them to be set up so that unless access credentials are authorized and there’s no presence of metal object, the revolving door will continue to turn through 360 degrees, opening only when its entry once again faces the pavement outside.
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