During 2008 we were approached to review the PA announcement provision across twelve floors of a prestigious corporate headquarters building in the City of London.
The legacy system that we found installed was one which distributed general sound announcements around the building and also facilitated voice alarm or emergency announcements to be made throughout the building to enable evacuation action to be taken in a calm fashion and also for non emergency announcements to be made to selected floors and areas.
We were made aware of various aspects of performance which were proving unsatisfactory, largely centred around reliability issues and our first task was to carry out a detailed survey to establish what could be re-used and what needed to be replaced to achieve the required standard cost effectively.
There was an existing independent emergency evacuation system active throughout the building comprising of bells and beacons which was compliant with safety regulations and so, as the audio system would supplement this, the client could effectively draw up their own specification as to what the sound system was required to achieve.
Following many weeks of tracing and recording equipment location and condition we were in a position to re-specify the system and then following approval from the client, commence installation of the new equipment, integration and re-configuration.
Having identified that most of the reliability issues were arising from the old analogue user interface which routed signals around the building it was proposed that the upgrade would be based around a new control and paging system using a number of products from the Allen & Heath iDR series, supplemented by eight ARX Maxisplit line level distribution amplifiers.
To further enable consistency it was decided to include in the upgrade a system of pre-recorded messages intended to suit a number of possible situations.
The resulting system now offers 17 programmable presets; one for each floor and a master ‘All Calls’ preset with 32 separate balanced line level feeds to individual zones driving remote located amplifiers for each of the large floors.
In most cases we were able to re-use the existing ceiling speakers; in some cases more than 100 per floor driven by the existing multi-channel 100v line amplifiers; however, on one particularly important and busy space, where there was nothing suitable for re-use, we specified and installed a number of overhead mounted speakers offering a high degree of directivity driven by Crown CTS1200 power amplifiers and all new cabling.