Lock close

There are several ways to secure a door with an access control system, but are you specifying and fitting the most suitable?

Installers need to know the main methods of electronic locking and their pros and cons … so here they are:

Electromagnets

Used by virtually every installation company to secure a variety of doors, electromagnets fall into two main categories – shear and pull locking.

The standard overhead magnet, fixed to the doorframe with the armature mounted on the face of the door is probably the most widely used method of locking. Easy to fit, with very low maintenance requirements, they are available in various holding forces, sizes and voltages. But care is needed when specifying them, as they will reduce the clear head height of the door opening leading to the possibility of an injury to the door user. Building Regulations require a 2 metre clear height on all escape routes and, as most doorways are only just 2 metres high, hanging a 50-75mm magnet will cause an obstruction.

Shear magnets are concealed in the head of the door and frame but require more fitting expertise to achieve a quality installation. They are sensitive to door/frame movement, leading to more maintenance. There can also be a delay on opening whilst the armature drops away. Any side pressure could stop the armature dropping so care is required before specifying shear magnets on fire escape routes.

Be careful when specifying magnets for doors with glass panels as, because the magnet is usually holding at the top of the door, problems can occur with flexing of the top joints of the door. This is particularly true of cheap mass produced doors where the joint is doweled, but the problem can occur on almost every door. The standard means of releasing a magnet is by a wall/frame-mounted push button. Care needs to be taken in public areas as this may lead to confusion on trying to exit. How many times have you seen people standing by a door scratching their heads because they haven’t seen the button?

PROS: Easy fit with low maintenance. Varied price range.

CONS: Reduced head height (standard magnet). Heavy current draw compared to a release/ solenoid lock. Require large battery back up or secondary locking. Shear magnet prone to locking problems, in particular side pressure will prevent release. Damage to door joints. Requires push button to exit. Unattractive installations, particularly when used with Z&L brackets on inward opening doors.

Electric releases

Probably the second most common form of locking is the electric release. Used in conjunction with either a mortise (fitted in the edge of the door), or a rim (surface mounted on the back of the door) nightlatch, the electric release can offer cost effective locking.

Quality is everything in electric releases. The budget releases look cheap and, in the mortise fitting, show the cut away frame. The ANSI style release offers a more attractive installation, but is more time consuming to install. Just as important is the lock fitted to the door – specifiers should consider several points about the type of nightlatch being used. For example, is it deadlocking? Particularly important on outward opening doors, deadlocking prevents the sprung loaded bolt being pushed back by a plastic card or piece of wire. Mortise nightlatches can be fitted with lever handles for egress. Beware of fitting just a thumbturn on fire escape doors.

PROS: Variety of qualities to suit all budgets. Available to suit most door/frame configurations. Can be used in conjunction with lever handles for emergency escape.

CONS: Difficult to achieve a good fit. Budget units can be easy to force. Frame considerably weakened. Regular maintenance required.

Solenoid locks

Solenoid locks generally offer higher security as they fit like a normal mortise lock, therefore the frame is not weakened as much by cutting most of it away. The lock can be positioned on the door to give maximum resistance to attack.

There are various options available to suit wood, aluminium and steel doors and most are available with a lever or paddle handle for egress.

Fitted with a concealed door loop and wired through the door, solenoid locks can be the most attractive option, particularly if the door furniture matches any existing handles etc. If you are fitting a lock to a fire escape door then the new range of solenoid locks from Abloy Security meet the requirements of BS EN179 when fitted with the correct lever handles and can meet BS EN1125 if used with the JPM panic bar.

PROS: Attractive installation. Easy, single-handed operation. Good resistance to physical attack. Can meet the European Standards for fire exit hardware.
CONS: Fitting not for the faint hearted!

Other methods

There are some other methods of securing the door I haven’t covered in this article, such as solenoid bolts, but these tend to be specialist requirements rather than general installations.

Don’t forget that as part of the specification process you will need to check the door closers and hinges for proper operation. This is particu-larly true on aluminium doors where wear in the closer and pivots will prevent the door from clos-ing properly. If it’s a wooden door you are fitting a new closer to, it may be necessary to upgrade the hinges to stainless steel ball bearing hinges as door closers put a tremendous strain on hinges, particularly when the back check action is used.

Particular consideration should always be given to how exit is to be achieved – in the light of the new European Standards for fire escape hardware and the draft Standard for electro-mechanical locking letting someone out of a building is as important as stopping them getting in! And the Disability Discrimination Act comes into force in October, so you will need to look at the overall installation, such as how easy is that push button to operate, or at what height should it be fitted?

If your company has reservations about fitting solenoid locks or mortise nightlatches and releases why not call in an Approved Master Locksmiths’ Association Company to do the work for you?

* Call the MLA’s Head Office on 01327 262255 for your nearest member.

* Simon Griffiths has been a locksmith for 25 years and is a member of the British Locksmiths’ Institute. He is also a partner in Holdfast Security Systems of Crewe.