Testing of infrasonic noise annoyance when performing precicion work and conceptual work requires great concentration of attention

"In this research project are presented the results of tests concerning the analysis of annoyance of infrasonic noise that occurs at the work station located in offices. The tests covered measurements of acoustic parameters specific for this type of noise and a survey conducted in the working environment and experiment in laboratory conditions at a model of a work station.The selected group of volunteers (60 persons: 30 women and 30 men) had different properties of the nervous system. From the selected group 30 persons (including 15 women and 15 men) were defined as low-reactive LR and 30 persons (including 15 women and 15 men) were defined as high-reactive HR. The subjects (60 persons) participated in an experiment which consisted in using computerized psychological tests (efficiency of performing intellectual tasks - ALS test, and cognitive processes: observation ability and focus DAUF test) which were completed by the survey participants under three different acoustic conditions: broadband noise (reference noise) at 35 dB (A) and 62dB (G), LFN of about 53dB (A) and 62 dB (G), infrasonic noise of about 53dB (A) and 90 dB (G).Generally, different noise levels used in individual types of experiments did not influence the objective measurements of psychophysical fitness of surveyed persons. The annoyance of infrasonic noise and LFN was rated higher than that of the reference noise. Significant result differentiation can be found in the subjective assessment of noise annoyance Infrasonic noise is perceived as more annoying by women. Persons HR reported higher annoyance due to infrasonic noise in comparison persons LR. We did not observe any significant diversification in the assessment of infrasonic noise (in the LGeq 62 - 90 dB range) with groups of persons with the same reactivity level.The results of survey on the tiresomeness of noise in office facilities showed that most subjects complained about problems with concentration (50,7%),discomfort (49%), fatigue(40%) (percentage of answers in relation to n =150). The surveyed persons were exposed to noise with equivalent sound pressure level corrected by the frequency characteristic: G from 56 to 83dB and A from 39 to 68 dB.Proposed admissible value for workplaces when performing conceptual work that requires especially attention; equivalent G-weighted sound pressure level LGeq,Te over duration Te (Te ? 8h) can not exceeded 86 dB. Additionally equivalent continuous A-weighted sound pressure level LAeq,Te over duration Te (Te ? 8h) shouldn't exceed 35-45 dB."