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Relcross Auto Equalizers Help Keep Library Accessible to All

24 November 2010

Relcross Auto Equalizer door operators are being used in the ongoing refurbishment of Edinburgh University Library.

The Auto Equalizer is unusual among automatic operators because it can be used as a conventional stand-alone overhead door closer with all the usual adjustments such as closing speed, latching speed and back-check as standard. But when required it can be pneumatically powered either manually, via an actuator such as a wall mounted switch, or automatically, via infra red sensors for example, creating a fully automatic door operator.

Edinburgh University Library is housed in an imposing building in George Square in the heart of the city near the Meadows. Although the library itself was founded as long ago as 1580 the current building that houses it was designed by Sir Basil Spence, J Hardie Glover and Andrew Merrylees in the 1960s. The style is typical 1960s sobriety but the interior features large amounts of timber with internal rhythms evoking thoughts of Alvar Aalto.

The building was formally opened by the Chancellor of the Edinburgh University, HRH The Prince Philip, Duke of Edinburgh, in 1968 and refurbished in 1999. By 2007 a more extensive refurbishment was needed but both the interior and exterior of the building had been ‘A’ listed in 2006 so any work would need to be done sympathetically and with respect to the original design.

Architects Lewis & Hickey were appointed by the University to mastermind the refurbishment. The £36m project commenced in 2008 and has progressed on a floor by floor basis to maintain constant usability while the work is in progress. Currently, four of the eight floors have been completed - good progress bearing in mind that each floor covers approximately one acre. When fully complete in 2012 the complex will contain staff accommodation, a café, information services, various student services and study areas and, naturally, a vast collection of books and other reference material.

One of the design requirements identified was to improve traffic flow through the building with particular regard to the DDA. Most of the doorsets are relatively small double doors rather than large singles and this creates particular problems for wheelchair users because even opening one door successfully would not create an space wide enough for a wheelchair. For a disabled person to open both doors unaided is a virtual impossibility. Similar problems are experienced by library staff with book trolleys even with their greater mobility.

Inevitably many of the doors are also fire doors and this adds further complications. Lewis & Hickey considered the options carefully. Floor mounted systems could not be used as there is insufficient space below floor level to house the mechanisms. Many standard door closers could not be fitted to doors this small or could not cope with the fire specifications. Eventually the use of a pneumatic system was suggested and some further research led them to the Relcross Auto Equalizer.

The system has three main components which vary in their capacity depending upon the number of doors within the system. Firstly there is one operator per door leaf, usually mounted to the frame above the door. The Relcross Auto Equalizer uses the REL.4000 series door closer with the addition of a bolt-on air cylinder. When the switch is actuated, air pressure is used to overcome the resistance of the spring to open the door. When the air is released the spring and hydraulics take over, closing the door in a controlled mechanical fashion. Secondly each system (or group of doors) has a separate controller incorporating one air valve per door or pair of doors. This enables both doors to be opened in unison and held open long enough to allow users through the entrance.

Controllers are custom built to give optimum performance for each installation. Thirdly, all Auto Equalizer systems are reliant upon a source of compressed air to power them. The capacity of the compressor is selected carefully at the specification stage to accommodate the likely traffic profile (i.e. frequency of use of doors) and the distances involved between the compressor and the doors to be controlled. Reserve tanks can be added where necessary.

An added advantage is reliability and ease of service. A lack of reliance upon micro-processors and (often) complicated electronics means the Relcross Auto Equalizer has much less opportunity for failure. It has been independently tested to over three million full load cycles and requires only occasional, minimal servicing of the compressor, usually with easily available proprietary components. And finally, vital in a library, the compressor is almost silent in operation with a noise level of dB (A)/1m 45 - equivalent to a ‘country quiet’ sound level.

Project Director Emily Forde is very happy with the installation. “Many of the Auto Equalizers are on double doors in a ‘hold open’ state, automatically released in the event of fire. Others are on single doors and all have push button actuators for disabled users, staff with trolleys or indeed anyone with their hands full” she said. “The installation has gone very well on the 4 floors we’ve completed so far. Traffic flow has increased by nearly 60% into and through the building and everything is still working very smoothly.” Relcross Sales and Marketing Director Stuart McMaster said “Auto Equalizers become more cost effective the more doors they control and a project like the Edinburgh University Library is an ideal showcase for their capabilities.” For further information call Relcross on 01380 729600, email or visit

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