Figure 177 Cinema with skylight in Cityplaza, Island East
9.4
Cinemas
9.4.1 Heating, ventilation and air-conditioning (HVAC) system
Due to high variations in the audience pattern, it is recommended that the fresh air supply to each cinema house be
equipped with a demand control system (such as CO
2
sensors and modulating dampers) to avoid over-supply, which will
lead to a saving of chiller energy for pre-cooling the fresh air.
In order to achieve an acceptable acoustical environment, the maximum permissible background noise level generated
by building services installations in a cinema is recommended to be a noise rating (NR) in the range of 25 to 30
1
.
9.4.2 Acoustical considerations in cinemas
Sound isolation
Care must be taken to avoid sounds from one cinema being heard in another within the same cinema complex, as well
as disruptive noise from the lobby area. It could be irritating to watch a movie while hearing a booming sound from the
movie next door.
• Sound isolation wall:
Walls between adjacent theaters must be well designed to ensure sufficient sound insulation. A typical weighted sound
reduction index (Rw) is required as follows:
1
Chartered Institution of Building Services Engineers (CIBSE) Guide A: Environmental design, January 2006, 7th Edition
9
Special topics
9.4
Cinemas
Location
Weighted sound reduction index (Rw)
Cinema to lobby/corridor
≥ 60
Cinema to cinema
≥ 70
There are a number of double wall and single concrete block wall constructions that satisfy these requirements.
Consult an acoustical engineer and consultants with a knowledge of these matters.
• Sound lobby:
The access area to a cinema is another location from where sound can leak into the cinemas. Doors to different cinemas
should be placed well away from each other to minimise any chance of noise contamination. Double doors and thick
curtains are usually provided to minimise indirect noise leakage through the foyer. Doors with a sound transmission class
(STC) of 45 is recommended.
192 Hong Kong Green Shop Guide
