University Hospitals Strasbourg-Hautepierre

A noisy environment with peaks up to 100 dB

In the Neonatal Intensive Care Unit of Strasbourg University Hospital, the noise comes from equipment (respirators, syringe pumps etc.), staff going about their work, patients and relatives – all at the same time. As explained by Professor Kuhn, 80% of the noise generated within a unit of this type is artificial (noise generated by equipment) and only 20% is emitted by human voices.

The sound levels can range from 50 to 75 dB(A) (noise that is generally termed “intrusive”) with peaks that can reach 100 dB (painful noise).

Premature babies are sensitive to variations in sound, which can cause stress detrimental to their healthy development (reduction in their oxygen saturation, increase in heart rate). Furthermore, noise also has an effect on the medical and healthcare staff who work around the clock in this environment.

An environment to support the healthy development of young infants

As part of the NIDCAP programme, the Unit was looking to make changes to this environment so that it would be better suited to the healthy development of young infants. Noise was one of the parameters addressed by this project.

For this reason, Ms Cayeux, Unit Supervisor, proposed that acoustic enhancement for both patients and staff should be one of the priorities in the remedial work envisaged for the Neonatal Intensive Care Unit: “Noise was regarded as inevitable, something we just had to put up with. In actual fact, there are some easy ways of reducing it.”

An acoustic study to make the right choices

Acoustics specialist Joseph Flores was commissioned to undertake an acoustic study and oversee the remedial work inside a specimen room. This was the room where, in the opinion of the staff, acoustic discomfort was most pronounced. To raise staff awareness of the principles of acoustic correction, the resonance of various materials was demonstrated (sound in front of a glass pane or in front of absorbent materials) – a demonstration that was very well received by the staff.

The first calculations from the study showed that the reverberation time was greater than the 0.8 of a second required of providers of welfare accommodation in France⁽¹⁾. In actual fact, because the materials within the room were highly reverberant, they could not absorb the sounds generated in the Unit. When this happens, the net result is echo phenomena and amplification of the sound level.

An acoustic solution designed to meet hygiene requirements

A Hygiene Protec ceiling and Hygiene Advance Wall panels were installed in the room. These solutions enabled the reverberation time to be reduced by almost 50% ⁽²⁾. This naturally also resulted in a reduction of the global sound level within the room, from 55 dBA before the remedial work to 37.5 dBA once the work was completed.

In choosing this solution, full consideration was given to the requirements pertaining to healthcare facilities. Because a neonatal intensive care unit is an environment susceptible to major risk of infection, it was essential to use tailored materials that could be easily cleaned in accordance with various prescribed procedures. The Ecophon Hygiene range was able to meet all these needs.

A successful acoustic outcome for the Unit

The results for this room met with the full approval of the medical and healthcare teams. The difference was clear for all to hear: the room was quieter and calmer. Furthermore, this measure made the staff even more aware of potential noise sources and their impact on the healthy development of patients. As a result, all the rooms were given similar upgrades. Each room accommodates one to four patients.

Ms Cayeux on the acoustic changes: “You can't argue with the results – I’ve had nothing but positive feedback. Noise affects both patients and staff, so everyone wins.”

Our concept developer for Healthcare will be pleased to answer any questions you may have: anne.pollet@saint-gobain.com.

⁽¹⁾ Order of 25 April 2003 relating to noise control in healthcare facilities
⁽²⁾ Average calculated for frequencies of 500, 1000 and 2000 Hz