Safe and sound

It is the largest terminal in the world’s busiest airport. When the first British Airways passengers enter Terminal 5 on 30 March 2008 they will be dwarfed by the 396 m-long, 176 m-wide, 40 m-high, glass-clad leviathan. The main terminal building, known to contractors as T5A, towers above its newly built sister satellite terminal, T5B. The main building is so large it could house 10 football pitches on each of its five floors.

The size of the terminal was also a huge challenge for designers, particularly when it came to specifying the fire alarm and public address systems. More than 30 million passengers will pass through the highly secure building every year, so the last thing airport operator BAA wants is to evacuate the entire terminal if there is a false alarm set off by a fire detection sensor.

Similarly, if a smoke detector sniffs out somebody having a puff on a cigarette in the level 3 toilets then again that needs to be dealt with as a local incident without closing the terminal. Likewise, passengers in departures need to be informed of a last minute change to a departure gate, but this information is of no interest to passengers in the arrivals hall.

It was these scenarios that Gent, part of the Honeywell group, set out to address when it developed the Epsilon system specifically for T5. Gent is one of BAA’s framework suppliers, so the manufacturer has worked with the airport operator on many of its terminals. The system the company developed for the giant new terminal combines fire detection, using its S-Quad units to sense heat, smoke and carbon monoxide, public address and voice alarm in the largest system of its type ever installed in the UK.

The system is highly adaptable. It integrates the firm’s Vigilon detection technology and an addressable voice alarm system, all controlled by a new panel. The combined public address/ voice alarm system can be used both for emergencies and also for passenger and flight announcements, background music and for security reminders.

The system is also capable of simultaneously relaying separate information to different parts of the complex, according to the needs of each particular area. “The same system manages all the public address, fire detection, gates and security,” says Simon Foulkes, product manager for Gent.

The innovation at the heart of the Epsilon system is that each speaker has an integrated amplifier. This allows every speaker to operate independently. It also permits separate sound pressure levels to be set for each speaker.

The speakers are connected in loops of up to 60 units. Each speaker is individually addressed and can be controlled independently from the rest of the speakers. This permits messages, live speech or background music to be routed to specific areas and set to specific volumes.

Another advantage of the addressable loop system is that because the cables are looped, the speakers can be driven from either end of the cable, so a fault or break in the circuit will not result in the loss of speakers.

Because each speaker is digitally addressed independently, the airport operator can programme delays into the speakers to enhance clarity of sound and prevent speaker echo or even sound waves cancelling each other out. A delay might be introduced into speakers serving a shopping outlet to ensure the message from the speakers in these venues is timed to exactly match the time it takes the message to reach these outlets from the main atrium speaker.

In addition, public address announcements in one area of the complex can be made independently and will not affect different announcements in other areas.

Specific parameters of the system can be quickly changed. For instance, a departure area can increase or decrease in size, dependent on the size of the plane that is docking at the gate. More passengers need to be reached, and this is achieved by simply changing the number of speakers on the loop that are used to convey the relevant passenger flight information.

There are two master panels for T5, networked to about 450 secondary panels using high speed Cobranet protocol, to manage and control data flow between panels and stream digital MP3 audio through the system. The network connects on a fault-tolerant ethernet fibre. The Epsilon network carries up to 64 channels at any one time to any of the panels.

The secondary panels have been developed to manage both the detection system and the addressable voice alarm system. These are connected on four loops – two for fire and two for voice.

The T5 system as a whole comprises 450 Epsilon panels, and the system manages 2,000 manual call points, 10,000 advanced detector devices and 3,000 sounder/strobes, all in addition to the 10,000 addressable speakers.

The Gent system will also communicate with the terminal’s BMS, using transmission control protocol/internet protocol ethernet, to control fans and fire dampers in air ducts and in air transfer openings in walls and partitions.

The patented addressable speaker technology developed by Gent for this project is claimed to be a world first, and promises further application in similar projects in the future. If the system’s first application is the largest fire detection, voice alarm and public address system ever to be installed in the UK, the question is, what will the next installation be?