During 2008 we were approached by almost certainly the most famous organisation in the world of insurance; The Corporation of Lloyd’s, to review the PA announcement provision on and to all twelve floors of the prestigious Lime Street building in the City of London.
The existing system that we found distributed around the building was, whilst not exclusively a voice alarm system, originally intended to provide emergency announcements if required throughout the building and also ‘Broker Calling’ announcements on the three floors occupied by the insurance brokers.
We were made aware of various areas which were proving unsatisfactory, largely centred on an old and very heavily used paging control point situated on one of the floors.
The system had become unreliable 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.
As there is an independent emergency evacuation system active throughout the building comprising of bells, Lloyd’s 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.
It was decided 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.
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 for each of the large floors.
In many 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 the huge and extremely important Ground Floor ‘Room’ 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.
All floors have benefited from the processing power of the Allen & Heath iDR system by enabling us to set a different equalisation curve in addition to other aspects of signal processing for each of the different types of loudspeaker in use and the prevailing environment; all measured and configured using our computerised Smart Real Time Analyser.
The numerous digital programmable presets enable paging announcements to be made from more than one location with a full graphic display being available to the operators so that total control is always possible as well as monitoring of other paging stations.
Following commissioning we were able to issue a report of speech intelligibility achieved for each floor by taking measurements using a calibrated Speech Transmission Index meter and with this data recorded in the client’s system manual it is now possible to monitor the system for continuity and stability of performance at each scheduled maintenance visit.
So, our works which were completed by mid 2009, have resulted in Lloyd’s having a system capable of making announcements to all floors of the building to a measurable standard of speech intelligibility and naturalness of sound not previously achievable and with a level of control which meets their current requirements but with the development potential aimed at taking account of future aspirations.