PA-system at Dubai Metro station
The first two lines of the Dubai Metro comprise 74.5 km of track, 10 underground stations, 34 above-ground stations, three maintenance depots, three car parks and 4 km of bridges and entry pods all of which required acoustic studies. Atkins specialist acoustics division played a major role in the design and implementation of the station and depot design elements of the project.
Digital modelling and simulation of various station entrances, platforms and concourse areas throughout the system allowed for accurate PA/voice alarm system design to be integrated.
A key concept in the acoustic design was the “intelligibility” prediction which involves a synthesis of inter-related factors. The key elements of success to the design of the PA system were achieving appropriate reverberation times, speaker coverage, sound pressure level, speech intelligibility and selection and placement of absorbing materials.
Contract compliant performance values for speech intelligibility were required to be achieved throughout all areas. To reach the requirements, it was important that ceiling materials and coverage were correctly specified in order to maintain appropriate reverberation times, sound pressure levels, and consequently, speech intelligibility levels. Sound pressure level coverage was also a major consideration in the selection and locating of speakers.
Outputs from the digital models included material performances, area coverage, locations and quantities of speakers, directivity patterns and tapping settings.