PROCEEDINGS of the
23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

An investigation of room functions and acoustic demands inselected departments in three Danish Hospitals
Thea Mathilde LARSEN1; Cheol-Ho JEONG2; Mai-Britt BELDAM3, Jonas BRUNSKOG2, Christoffer
A. WEITZE4
1
2Henning Larsen Architects, Denmark

Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark, Denmark
3

Ecophon, Sweden
4

Niras, Denmark

ABSTRACT
Hospitals contain many different room types, each having its own contribution to the main functionof treating patients. Different room types with different functions demand different acoustics.
Currently only a few recommendations in terms of room acoustics are mentioned in the Danish
Building Code, BR18. Recommendations, only to a limited degree, fulfill the demand for a sufficient
acoustic environment for staff and patients. In this study different room types were investigated fromselected departments in Bispebjerg, Frederiksberg and Hvidovre hospitals. Four room types were
investigated; examination/treatment rooms, control rooms, nurse stations and lunch rooms. Frominterviews with staff and questionnaires, information about functions and acoustic demands wascollected for all four room types. Furthermore, acoustic parameters, T 20 , EDT, C 50 and STI were
measured in the rooms. Recommendations in BR18 were found to be insufficient to meet the acoustic
demands in several of the rooms. Future recommendations should be formulated to ensure asatisfactory acoustic environment, which meet the function demands in the rooms. A systematicinvestigation of room functions and use of facilities in hospitals in regards to noise is needed to be able
to make such recommendations.

Keywords: Room acoustics, hospital, staff

1. INTRODUCTION
Noise in hospitals is a well-known problem first mentioned in 1859 by Florence Nightingale in“Notes on nursing” (Nightingale, 1859). Since then and documented for the past 50 years, noise levels
have been excessive in hospitals (Busch-Vishniac, Barnhill, Hunter, Orellana, & Chivukula, 2005).
Increased noise levels influence patients and staff. Studies show that noise has negative in fluence on
the recovery and sleep quality of patients (Elbaz, et al., 2017), and therefore patients’ recovery time isincreased with exposure to noise (Fife & Rappaport, 1976). Reverberation has an impact on patients
sleep (Berg, 2001). Noise also has a negative effect on staff in hospitals. It has been found that noise
induces stress in nurses (Topf & Dillon, 1988), also influence hospital staff’s quality of work
(Mahmood, Chaudhury, & Valente, 2011), has an effect on communication in hospital staff(Woloshynowych, Davis, Brown , & Vincent, 2007). As noise is somewhat affected by the acoustic
environment, regulations and recommendations regarding the acoustic environment exist. The Danishbuilding code suggests a reverberation time of T ≤ 0.8 s. in patient rooms (this recommendation has,since this study was performed, been changed to T ≤ 0.6 s.) and T ≤ 0.6 s. in examination rooms.
However, the building code does not mention any other room types in hospitals such as control rooms,
1

tml@henninglarsen.com
chj@elektro.dtu.dk; jbr@elektro.dtu.dk
3
mai-britt.beldam@ecophon.se4
cawe@niras.dk
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surgery rooms, lunchrooms, nurse stations among other room types. This study investigates four
different room types, where only examination rooms are mentioned in the Danish building code, by
measuring room acoustics and interview and hand out questionnaires to staff. The objectives of thestudy are:
How does noise influence staff in three Danish hospitals?

How can we solve challenging acoustic/noise conditions in hospitals?

2. METHODS
Rooms in three different hospitals were investigated in 2017: two of the hospitals were built in the
beginning of the 20 th century, Bispebjerg hospital in 1914 and Frederiksberg hospital in 1903 and the
youngest one, Hvidovre hospital was built in 1976. Bispebjerg was furthermore listed.
In two of the hospitals, departments were contacted to report back whether the staff had reported
issues about noise and if they wished to participate in the project. Six departments reported back andparticipated in the project and made rooms, they found problematic, available for acoustic
measurements and filled out questionnaires. Later on the project another hospital, Hvidovre hospital,
participated with one department, because of lack of time and development in the project, thedepartment only participated by being group interviewed. List of departments and room types areshown below:
Table 1 – Abbreviations for departments and room types
Abbreviation

Department

Abbreviation

Room type

E

Emergency department

Ex

Examination roomD

Dermatological department

CR

Control roomP

Palliative Department

LR

Lunch roomR

Rehabilitation department

NS

Nurse station

W

Work and occupational
medical department

TR

Treatment room

X

X-ray department

M

MR-department

2.1 Questionnaires
Questionnaires were handed out to staff in departments in Bispebjerg and Frederiksberg hospitals.
The questionnaires included four major questions with five possible answers, the questions said:
Q1: “When you think back over the past six Months, how disturbed have you been by noise while you
have been at work?”
Q2: “When you think back over the past six Months, how often have you experienced that you could nothear or understand what a colleague and/or a patient said because of noise?”
Q3: “When thinking about the past six Months, how often have you experienced that you co uld not
speak confidentially with a patient without other patients hearing you? ”
Q4: “When thinking back over the past six Months, how often have you experienced that a patient said
that he/she could not hear or understand important information you were giving?”
For the four questions the participants were asked to answer in what rooms the issue occurred. The
questionnaire also contained a fifth question about noise sources, saying:Q5: “When thinking back over the past six Months, cross out up to five noise sources you founddisturbing at you work place.”
Finally the participants were asked about gender, age, hearing impairment and if they consideredthemselves as sensitive to noise.
2.2 Interviews
All representatives from the different departments were informally interviewed. A plannedinterview was performed with the staff at the MR-department at Hvidovre hospital about the7804

nurse/control room. The interview was performed right after the noise measurements were performed.
The interview was performed informal, as a group interview, unstructured, and as a receptive interview.
To the purpose an interview guide was produced in correspondence with (Kvale & Brinkmann, 2015),
see table 2:
Table 2 – Research questions and corresponding interview questions
Research question

Interview questions
1-1. What causes noise in the room?

1. What influence does noise have on
hospital staff?

1-2. In your own words how does
noise influence you and your work at
the hospital?

2. How can the working environment2-1. How do you think the noisy

be improved with design of rooms?

environment can be improved?

2.3 Measuring room acoustic parameters
The room acoustic parameters, early decay time (EDT), reverberation time (T20), clarity (C50) andspeech transmission index (STI) were measured with an omnidirectional speaker and B&K DIRAC
software with e-sweeps after (DS/EN-3382-2, 2009) using the engineering method.

3. RESULTS
3.1

Issues in measured room types and room functions of each room type (based oninterviews)
The interviews with staff revealed the following issues and functions of the measured rooms in thehospitals that were linked to noise and the acoustic environment. In general the work environment was
described as busy and noisy.
Examination/treatment rooms
The staff experienced that the acoustics environment in the examination rooms challenged themwhen communicating with patients. In some of the examination rooms staff had solved the problem byhaving patients wearing headphones and talk into a microphone.
One of the major functions of the examination rooms and treatment rooms is that important
information is passed from the patient to the staff and from the staff to the patient often in achallenging vocabulary. Many of the patients in the hospital are elderly people, who have a higher
chance of hearing impairment. Poor room acoustics challenge especially hearing impaired.
Examination rooms/treatment rooms are often small and have a high demand of cleaning.
Control rooms
The control rooms were perceived noisy and hectic by the staff. They explained how many different
people would come and go through the space furthermore the control rooms have a constant loudbackground noise from equipment (x-ray equipment and MR-scanners).
The investigated control rooms were in x-ray departments and MR-department. The
communication in the control rooms are mostly between staff individually and only short messages are
given to the patients. A lot of noise from equipment influences the control rooms and the staff told t hat
they easily can get filled up with noise and feeling tired and have headaches during/after work.
Nurse stations
The nurses described the nurse stations as noisy and sometimes also hectic because of constant run

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of nurses coming in shortly to write on medical journals and leaving again and sometimes talking
about work.
The nurse stations hold some of the same functions as the control rooms regarding communication
between staff, however without high background noise from equipment and normally nocommunication with patients. The nurses often need quietness to concentrate about writing in patient’s
medical journals. It was observed that the nurse stations tested in this project often were crowded.
Lunch rooms
The staff found the lunch rooms included in this paper as noisy and that noise would build up fromvoices making it a challenge to have conversation with their colleagues.
The functions of the lunchrooms are that it is a space where staff can have conversations with eachother and relax while taking a break. In general the impression was that the staff found the lunchrooms
noisy which may be a consequence of them missing a space where they can take a quiet break.
Overall this sorted the four room types into three types of acoustic issues: reverberant environment,
noisy/hectic environment and voices/noise building up. These issues were used later on to try and run
statistics to see if there was a tendency that staff were more unsatisfied with rooms with some issues
than others.
3.2 Room acoustics in room types
The room acoustic parameters EDT, T20, C50 and STI were measured to eval uate the acoustic
environment for the four different room types.

Reverberation time T 20
The reverberation time shows that special attention has been given to ensure a sufficient acoustic
environment in the control rooms and in two out of the three nurse stations. The lunchrooms showed
long reverberation time for the low frequencies which may be why staff is complaining about noisefrom voices building up in these rooms. The acoustic environment in all the examination rooms in
Bispebjerg and Frederiksberg hospital are not satisfying showed in (D) by too long reverberation time.

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BR15

REVERBERATION TIME T20 [S]

A

D.NS

E.NS

B

M.NS

1,4

1,4

1,2

1,2

1

1

0,8

0,8

0,6

0,6

0,4

0,4

0,2

0,2

0

0
125

250

500

1000

2000

4000

125

250

125

250

M.CR

X.CR

500

1000

2000

4000

500

1000

2000

4000

D

C
REVERBERATION TIME T20 [S]

BR15

2
1,8
1,6
1,4
1,2
1
0,8
0,6
0,4
0,2
0

1,4
1,2
1
0,8
0,6
0,4
0,2
0
125

250

500

1000

2000

4000

FREQUENCY BAND [HZ]
BR15

D.LR

P.LR

FREQUENCY BAND [HZ]
W.LR

BR15

D.Ex12

D.Ex18

W.Ex1

W.Ex3

W.Ex5

R.TR

Figure 1- Reverberation time T20 (A) nurse stations, (B) control rooms, (C) lunch rooms, (D) examination rooms.
Speech transmission index
STI is calculated from noise-free impulse responses, and it shows a similar trend to T20. STI isgenerally excellent in nurse stations, control rooms and lunchrooms, meaning that for a normal hearing
person the acoustic environment is proper for communication. Depending on the background noise,
STI in realistic occupied conditions could differ from these values.
STI values are generally lower in the examination rooms, where only two rooms have an excellent
STI, the resisting five have either a good or fair STI, which may lead to low speech intelligibility
especially for hearing impaired patients and patients who communicate in a foreign language.
Table 2 – Speech transmission index (STI)
Room

Nurse station

E.NS

0,79

D.NS
M.NS

Room

Control rooms

Room

Lunch room

Room

Examination rooms

Excellent M.CR

0,83

Excellent

D.LR

0,81

Excellent

D.Ex12

0,62

Good

0,82

Excellent X.CR

0,80

Excellent

P.LR

0,72

Good

D.Ex18

0,61

Good

0,8

Excellent

W.LR

0,74

Good

R.TR

0,53

Fair

W.Ex1

0,64

Good

W.Ex3

0,76

Excellent

W.Ex5

0,68

Good

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3.3 Staff perception of acoustics in room types (interview and questionnaires)
The answers to the questionnaires from staff show a normal distribution for Q1 and Q2 around“moderately/sometimes”, and a normal distribution for Q4 around “slightly”. For Q3 most participants
answered “considerably”. For Q5 regarding noise sources, the three different cases with talking scoredhighest. It is also noticeable that only 3% answered “Not at all” to Q1.
A one-way ANOVA was run between the questions and the issues to try and see if the staff
experienced one of the four questions more often than others for one of the three different issues. This
test revealed that for Q2 there was a weak effect of issue with a significance level of 0.05
(F(2.62)=3.723, p<0.0298), the significant difference was between Noisy/hectic environment andNoise/voices building up.
B

A
50

Talking in the corridors

45

Talking outside of room you are in

RESPONSES [%]40

Talking in room you are in

35

Trolleys in the corridors

30

Building installations

25

Other entertainment devices

20

TV

15

Office equipment

10

Alarms5

Medical equipment

0

0

5

10

15

20

25

VOTES PER NOISE SOURCE [%]Q1, n=64

Q2, n=64

Q3, n=61

Q4, n=19

Figure 2 - Results from questionnaires. (A) Answers to Q1-4 in percent, (B) answers to Q5 in percent.

4. DISCUSSION
The interviews and questionnaires revealed that noise is a problem in the three tested hospitals
according to staff. Only three percent answered “not at all” to Q1, about how disturbed the staff had
been by noise the past six Months, meaning that the remaining 97% have been disturbed by noise tosome degree. This result agrees with the findings in the group interview were the participants said thatthey were bothered by noise and that it coursed tiredness and sometimes headaches. Q3, regarding
talking confidentially with patients was experienced “often” by most participants; this indicates that
especially confidential conversations with patients is a challenge.
Of the sound sources, the participants found most disturbing, talking got the m ost votes. This tellsthat when designing hospitals architects, designers, engineers and acousticians should pay special
attention to designing hospitals to minimize disturbance from voices. This finding corresponds to thefindings of Buxton et. al, who found that the noise sources that had the greatest arousal effect onpatients’ sleep was alarms and voices, especially upset voices (Buxton, et al., 2015). A design toattenuate voices has been tested by Luertz et. al, who made a study where noise levels were compared
before and after a refurbishment of a hospital wing where focus was to bring down voices, leading toa significant reduction in noise levels (Luetz, et al., 2016).
The different rooms measured showed particular high reverberation time and low STI in
examination/treatment rooms in Bispebjerg and Frederiksberg hospital. This finding may be aconsequence of the two hospitals not being renovated to fulfill the functions of a modern hospital,
perhaps due to that Bispebjerg hospital is listed. It may also be a consequence of patients not being
able to speak out or not listened to when talking about the discomfort the acoustic environment iscausing. Long reverberation time and poor STI may especially be a challenge for hearing impaired

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patients, since a larger number of patients are elderly, and hearing impairment is increasing wi th age.
This may potentially cause loss of information for patients (Harris & Swenson, 1990) even for patientswearing a hearing aid (Reinhart, Souza, Srinivasan, & Gallun, 2015). Reverberation may even be a
problem for normal hearing patients as reverberation impairs listener’s ability to distinguish between
competing voices (Culling, Hodder, & Toh, 2003).
The acoustic environment in the nurse stations, control rooms and lunchrooms were found to begood with the exception of some of the lunchrooms having high reverberation time for the low
frequencies, which may cause voices to build up. Generally this means that for a normal hearing
person the acoustic environment is good for communication in these types of rooms. Therefore thesource to discomfort may be a consequence of too many noise sources and it should rather be lo oked
into the capacity of people in these types of rooms (Rindel, 2012) and (Svensson, Jeong, & Brunskog,2015).
The many complaints about lunchrooms may be an indication of staff needing a quiet place toretreat from the noisy working environment they experience, and they expect the room where they
have their breaks to be quiet, which is not the case. In the group interview the staff explained how they
had an office to withdraw to but with a window, so patients would tap on the window to ask questions.
They also told how often they are disturbed during their breaks to attend to a patient.
The control rooms were found to be very noisy although they were acoustically regulated,indicating that acoustic regulation cannot solve the noise problem in hospitals alone. Control rooms
and similar noisy rooms should be designed in such a way that staff feel less disturbed by noise, whenworking.
4.1 Future perspectives
This study is just one of the first steps in investigating noise and acoustic environment in hospitals.
More projects should be performed to investigate how the acoustic environment in each room typeinfluences their users staff as well as patients. Such studies will draw more attention to the acoustic
environment in hospitals and perhaps lead to more sufficient guidelines to regulate acoustics in
hospitals.

5. CONCLUSION
Staff is found to be very influenced by noise and experienced all four phenomenon asked in Q1-4
equally. Of noise sources they found voices most disturbing. The group interview revealed that someof the consequences were tiredness and sometimes headaches due to noise.
Room acoustic measurements showed especially poor room acoustics in examination/treatment
rooms, indicating that attention has especially been given to the working environment for staff than infavor of patients. Areas with a lot of noise, e.g., control rooms, were found to be well acousticallyregulated, indicating that we cannot minimize the disturbance in staff by acoustic regulation alone.
Lunchrooms and one nurse station showed poor acoustics for only the low frequencies which may still
be bothering staff as they in interviews especially pointed their lunchrooms out as rooms withespecially a lot of noise and uncomfortable acoustic environment. Which indicates that staff need aquieter place to retreat doing their breaks perhaps due to a general hectic and noisy work ing
environment.
More research is needed to come up with precise recommendations to design hospitals to minimize
noise and improve the sound environment both for patients and staff. The acoustics in the threemeasured hospitals were found to be not sufficient, though some of the room types did fulfill therecommendations in the Danish building code. This finding indicates that the recommendations in theDanish building code are not sufficient, but may also mean that the issue cannot be solved alone byrecommendations/requirements. Noise in hospitals must be reduced by considering the different room
functions carefully with the possibility of being flexible towards changes and new equipment andtreatment possibilities. Noise in hospitals is a large problem and it should be considered also from
authorities, that when changing the function of a room and when refurbishing, the room acoustics must
be considered. A change of a room could impact on noise levels adversely, causing the staff to be lesssatisfied at work, and patients to a slow recovery.
Acousticians should be included in the early design stages of hospitals to ensure good acoustic
conditions and sound environment in hospitals. Furthermore the acoustician has an important job in
understanding and knowing what functions the acoustics should support.

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ACKNOWLEDGEMENTS
The authors would like to thank Finnur Pind for discussions and advice, Danish Sound Innovation
Network for a financial support. Also thanks to Jens Hjortkjær, who cooperated from Hvidovre
hospital, and to all the representatives from Bispebjerg and Frederiksberg hospitals and theparticipants who participated in interviews and filled out questionnaires.

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