Dublin ready for take-off

AUTHOR: Inavate

Ireland’s Dublin airport now boasts a brand new terminal building as part of the ongoing redevelopment plan. The award-winning facility posed considerable acoustic challenges solved by Arup Acoustics and the project’s engineering team.

The parlous state of the Republic of Ireland’s public finances means that Dublin Airport’s Terminal 2 will be the last major capital project it funds for a while. It is therefore fitting that it should be such an impressive looking building.

The building itself has already won a Structural Steel Design Award for architect Pascall + Watson, whilst Arup took the role of lead consultant and design engineers. Boasting a steel and glass façade, the new terminal building makes use of natural light to create a modern and comfortable space for both departing and arriving passengers.

However, with great architecture often come significant acoustic challenges. Especially when that architecture involves many hard, reflective surfaces. Arup acoustics was charged with overcoming these.

The company’s Pierpaolo Pilla outlined the scale of the problem. “The most acoustically challenging spaces in the terminal were in the landside. The very big volumes in this part of the terminal only allowed a certain degree of control of reverberation. However these big areas were free of obstacles and the use of active phased arrays was the only viable option. Satisfactory architectural integration was achieved by the use of active phased arrays at check in, landside arrivals and landside departures, and by the use of passive phased arrays at security.”

The arrays in question are Duran Audio Intellivox units including DSX480, DSX280 and DS115 active models and V90 passive units. These were supplied by the company’s Irish distributor Sound Productions, selected as supplier and systems house by the main electrical contractor Mercury International.

Sound Productions’ project manager Peadar Carley commented: “We’ve worked with Mercury on a number of projects so we have a good relationship.”

The terminal building is divided into 55 paging zones and ten evacuation zones. “The master evacuation zones are for evacuation only, so an evacuation zone could cover several paging zones. For example, the check-in area is open plan, so it’s just one evacuation zone, but there are several paging zones within it. By the same token there are 25 paging zones for the individual gates, and a single evacuation zone for that area,” explained Carley.

Audio reinforcement outside of the open plan space is provided by Penton loudspeakers. Corridors with low ceilings are served with 6W ceiling speakers and larger areas by 20 and 40W column speakers. The paging and distribution system behind the speakers was supplied by Current Thinking. Seven rack positions are linked by fire-proof fibre cables in a loop system providing standards compliance via dual redundancy.

Amplification comes from Current Thinking Perma 4 and LSA120 amplifiers, while DCD16 digital audio routing matrix controllers govern the routing of messages to the appropriate zone. The rack positions are all provided with battery backup sufficient to provide 24 hours of standby power or two hours under full load, in accordance with the requirements laid out in BS-5839-8.

Current thinking microphones are located throughout the building, for departure gates, check in desks and in the master control rooms located in both Terminal 2 and Terminal 1. The latter room governing the entire site.

Terminal 1’s PA and fire systems are currently run via a Peavey MediaMatrix solution over Cobranet, and therefore to allow the two systems to communicate, a Cobranet bridge was established into the Current Thinking network. Overall installation time was two years, with the Sound Productions team supervising onsite rack builds and installation of cable and speakers, installation work was carried out by Mercury International engineers.

According to Carley, one of the key points of contention was the siting of the Duran Intellivox units.

“There was a lot of debate over the design of the columns to house the Duran speakers. The architect didn’t want them at all.” In the end, the solution was to conceal the speakers in stainless steel uprights. The speakers’ own standard issue grills were removed before being concealed in architectural columns.

These columns are located at ground level in the check-in area, and also in the first floor café and restaurant mezzanine level. Also in the seating and check-in areas, Arup specified the use of induction loops to assist the hard of hearing and these too were supplied by Current Thinking.

Having visited the site for three or four hours, and therefore listened to a number of announcements, I feel slightly qualified to comment on its efficacy. On the face of it Arup appear to have done an excellent job of the acoustic design. Announcements in the busy terminal were clear, intelligible and not deafening and even in the Aer Lingus lounge, with its complex lay out and hidden corners. Negotiations are currently underway with the DAA (Dublin Airport Authority) for a refresh of Terminal 1’s systems to bring them in line with its younger sibling.