Close-up of an adult gently holding a newborn baby's feet in their hands, with a soft background, conveying a sense of care, tenderness, and protection.

Investigating and optimising a birth ward at Randers Hospital, Denmark

Together with 4 students from DTU (Technical University of Denmark) Ecophon had the opportunity to investigate the sound environment in a maternity ward at Randers Hospital. 60 midwives work at the maternity ward and deliver approximately 2200 babies per year.

The project

In this project, all the measurements, questionnaires and data analysis were done by the students and measurements were done according to ISO 3382-2 utilising the Dirac software to analyze the impulse responses. A report ‘Analysis of Room Acoustics at Randers Hospital maternity ward’ was done by the four students: Ida Ørduk Hofmann, Sara Delagarde Jørgensen and Rojan Turan, as part of their course ‘Architectural Acoustics’.

Building regulation in Denmark

In Denmark there has been no building regulations in regards to acoustics but in 2018 a new guideline (BR18) was implemented.  BR18 divides hospital rooms into two categories:

  • patient bedroom

  • examination/treatment room

The regulation recommends a design value for the reverberation time of 0.6 s for both room types in the frequency range of 125-4000 Hz (with a liberation of 20 % for 125 Hz).

Speech clarity (C50) is not in the regulation but knowing that there is a lot of communication going on in such a ward we chose to investigate that together with reverberation time.

Delivery room

Measurements of a delivery room showed that the room actually lived up to the regulation and also that the midwives scored the acoustics of the room as ‘good’ or ‘neutral’.

Line graph showing T20 in seconds on the y-axis and frequency (Hz) on the x-axis. T20 decreases from 0.6 at 125 Hz to about 0.4 at 4000 Hz. Error bars are present for each data point.
Pie chart titled Q2: Acoustic in the DR showing approximately 70% labelled as Neutral (blue) and 30% as Good (light green).

Birth pool room

Unfortunately, not all rooms in the ward got so positive feedback and especially a birth pool room got really negative evaluations from the midwives. They said that they tried not to talk in the room, that the splash of water alone was noisy – and one told us that she tried not to have too much light in the room, since both sound and light were too much stimuli.

When looking at the acoustic measurements and the feedback from the midwives it was clear that the room had acoustic challenges. It was far from the regulation demands and half of the staff evaluated the room as either ‘bad’ or ‘very bad’.

A pie chart titled Q4: Acoustic in the BPR shows responses: Good (light green), Neutral (peach), Bad (blue), and Very bad (orange). Neutral is the largest portion, followed by Good, Bad, and Very bad.
Line graph showing T20 (in seconds) decreasing as frequency increases from 125 Hz to 1000 Hz, then stabilising from 1000 Hz to 4000 Hz; error bars are present at 125 Hz, 250 Hz, and 500 Hz.

Looking at the surfaces of the room it was very clear why the birth pool room had room acoustic challenges since all the surfaces were very hard. Traditionally hospitals are built with hard surfaces because the hygiene demands are high and unfortunately the acoustic performance of a surface is somehow ‘forgotten’.

Quick fix?

It was impossible for Ecophon to do what we normally would do in rooms with bad acoustics – change the ceiling tiles into class A and install sound absorbing wall panels. But with the help of duct tape and the students’ engineering skills a quick installation of wall panels was made to see what that alone could do. Below you can listen to the differences and to hear that it was quite remarkable change!

 

Measurement after the installation

After installing the wall panels, measurements showed that not only the reverberation dropped to a better level also the speech clarity went up! (NB. In this project there was also a focus on the background noise. Therefore, the C50 was converted to U50, which takes the background noise into consideration).

Line graph showing T20 reverberation time (y-axis) versus frequency (x-axis) from 125 Hz to 4000 Hz, comparing averages for “No absorbers” (higher, blue line) and “With absorbers” (lower, orange line).
Line graph comparing U50 [dB] values at various frequencies (125 Hz to 4000 Hz) for BPR with and without absorbers. The absorber line is consistently higher, peaking at 2000 Hz.

The panels that were used in the birth pool room can withstand disinfection and daily cleaning.