Indoor environment in a digital future - Master thesis - s154397 - s153767 (1)

2.5 Acoustic Comfort
Acoustic comfort is often understood as an acceptable level of noise. However, the perception of
sound is more complex, and often it depends not only on the sound level, but also on factors such
as reverberation time, sound insulation and absorption. In an office building, acoustic comfort is the
capacity to protect occupants from indoor and outdoor noise and provide a good acoustic working
environment [39].
Noise
Noise is defined as unwanted sound [19]. An office can have two noise sources: external and internal.
External sources include noise from outside, such as traffic, machinery and the public. Internal
sources include noise from within the office, such as co-workers conversations, machine sounds, telephones
and office equipment.
Noise and poor acoustics can lead to a decrease in productivity, stress, fatigue, headache and
lack of concentration [43]. Studies have shown that occupants exposed to continuous external
noise, such as traffic noise, have higher levels of blood pressure and stress hormones. One study
showed a 66% decreased in performance within memory tasks when the occupants were exposed
to different types of background noises [19]. The Danish Standard Association’s recommendations
for continuous sounds levels from sounds generated by building service systems, also referred to as
background noise, are presented in Table 2.7. The Danish Working Environment Authority recommends
that sound-levels do not exceed 70 dB in a furnished office room.
Small office ≤ 35
Landscape office ≤ 40
Conference room ≤ 40
Table 2.7: Continuous sound levels from background noise [15]
2.6 Visual Comfort
Visual comfort in offices includes daylight, illuminance, glare and colour temperature. Studies have
shown daylight to have as a positive effect on health and glare as one of the most reported complaints
[39]. To enable occupants to perform visual tasks efficiently and accurately, appropriate
lighting at work spaces is essential. Appropriate light levels are achieved by both natural and/or
artificial light [25] [48].
The Danish Working Environment Authority states, that in addition with sufficient lighting from daylight
and artificial lighting, the outdoor surroundings should be visible [48]. Regarding the intensity
of artificial lighting, a study concerning the association of sick building syndrome with indoor air parameters
showed that the light intensity was significantly correlated to symptoms such as skin dryness,
eye irritation and fatigue [43].
16 INDOOR ENVIRONMENT IN A DIGITAL FUTURE