Objective: To identify and measure the main sources of noise, to determine the levels of ambient noise and to know the perception of employees about noise in a Neonatal Unit.
Material and method: A quantitative study developed in a Neonatal Unit School Hospital, Paraná, Brazil, conducted in three steps: identification of the main sources of noise and subsequent measure; interview with the multidisciplinary team about the perception of noise in the unit; and dimensioning noise ambient for two non-consecutive weeks.
Results: The main sources of noise were: monitor and equipment alarms, open water faucets, trash can lids, among others. The mean) of the two weeks period was: Leq 44.4 dB, Lmax 104.5 dB, Lmin 40 dB and Lpeak 144.8 dB. Employees acknowledged that intense noise is prejudicial to them and to babies.
Conclusion: It was found that the mean value of the noise is within the recommended, but with very high levels of Lpeak and Lmax.