Acoustics in green buildings, by Hassan Al-Ramadani
Over the last twenty years, there has been a remarkable surge in the construction industry’s adoption of green buildings. This has been due to public awareness of adopting sustainability and sustainable practices. Additionally, several studies have proposed that occupants of green buildings have a higher level of productivity and satisfaction than those of conventional buildings.
Green buildings are certified using green building rating schemes, such as BREEAM and LEED, which consider acoustics part of Indoor Environmental Quality (IEQ). implementing green building strategies may lead to poor acoustics in green buildings; the acoustics consultant may face many challenges in the green building’s design, including outdoor noise sources, noise control inside the building, daylight, natural ventilation, room acoustics problems, sound insulation, speech privacy, and practical problems related to the certification process.
Post Occupancy Survey and acoustic comfort
Green buildings aim to seize building impacts on occupants’ health and that is evaluated using IEQ criteria. IEQ is investigated using POE surveys. Office buildings were specifically investigated more than other buildings as they highly influence employee production.
POE survey regarding the acoustics comfort of office users has been performed in selected green-certified office buildings (BREEAM and LEED certification) and conventional office buildings in Finland. buildings categorized as following:
- BREEAM-certified buildings that have acoustics credits (BREEAM-AKU)
- BREEAM-certified buildings that have no acoustics credits (BREEAM-NO)
- LEED-certified buildings that have acoustics credits (LEED-AKU)
- LEED-certified buildings that have no acoustics credits (LEED-NO)
- Conventional Buildings, buildings with no green certification (CB)
The survey analysis demonstrated that users’ satisfaction with acoustics comfort varies among building categories, regardless of whether the building is green or conventional and its acquiring of acoustics credits or not. Also, there is no consistency in users’ responses within the same building category. However, The survey results indicated that green and conventional building users have a high level of satisfaction with noise from external sources; this could be because buildings in Finland are designed airtight to preserve heat inside the building. Additionally, survey results demonstrated high dissatisfaction with speech privacy in all building types as shown in Figure 1.
Figure 1: Users of all building categories are dissatisfied with speech privacy
Personal and Contextual variables influence
One study focusing on IEQ perception and acoustics comfort suggested that acoustic comfort in office spaces is influenced by acoustics parameters (such as sound insulation, noise levels, etc.) as well as many other variables, such as personal variables (including occupant age, gender, social conditions, lifestyle, worker position, social status, etc.) and contextual variables (include building automation, office layout, workstation location, privacy, tasks, and duration of working hours).
This survey considered personal and contextual variables, the finding was that personal and contextual variables influence users’ acoustic comfort, specifically gender, male users are significantly more satisfied with the acoustics comfort than female users see Figure 2.
Figure 2: Male users are more satisfied with acoustics then female users
Additionally, the research indicated a direct connection between visual privacy and acoustics comfort: users who are pleased with visual privacy are more satisfied with the acoustics comfort, see Figure 3.
Figure 3: The influence of visual privacy on overall acoustics comfort
Acoustic measurements
Acoustics measurements of the background noise level (LAeq), reverberation time (T), and sound insulation of each office space have been collected to determine whether the investigated buildings achieve the applicable acoustics criteria. Analyzing acoustics measurement data indicated that that acoustics measurements do not correlate with the survey results.
Accordingly, the study demonstrated that there are other considerations when evaluating acoustics performance in office buildings in addition to the criteria for acoustics parameters specified by authorities or organizations. Other considerations include personal and contextual variables, which shall be considered to achieve the best acoustics comfort for building users. This means that designers need to consider office layout, workstation conditions, visual privacy, and working culture, which may affect acoustics comfort and acoustics conditions when complying with BREEAM and LEED criteria.
For more information contact:
Hassan Al-Ramadani, M.Sc. (Tech) and B.Sc (Arch), at Akukon Oy, Helsinki, Finland
