For the use of acoustic assessment of machinery, a global index of acoustic quality has been developed. Acoustic quality index is considered as a product of the following partial indices: sound power index, index of distance between the workstation and the machine, radiation directivity index, impulse and impact noise index and noise spectrum index. Each partial index always assumes positive value. If the value of global index does not exceed 1, the noise of the assessed machine will not exceed the admissible value of A-weighted sound pressure level at the workstation.
Experimental tests were carried out in order to determine the values of global indices for a group of engine-generators, with the use of inversion method allowing for the determination of sound power level. The correctness of the determined values of indices was confirmed by the results of A-weighted sound pressure level measurements, at the hypothetically assumed workstations in simulated in situ conditions.
In 2010, the Central Institute for Labour Protection - National Research Institute celebrated the 60th anniversary of its activity. Primary objectives of the Institute have been and continue to be the protection of employees against any hazards at work stations. Among the numerous hazards, vibroacoustic ones are becoming prevailing. Therefore, one can now dare to say that the 60 years of activity of the Central Institute for Labour Protection have also meant 60 years of preventing noise and vibration in the working environment. For those 60 years of activity, Central Institute for Labour Protection has been associated with outstanding acousticians and vibration specialists. The first chairperson of the Scientific Council of the Central Institute for Labour Protection was Professor Ignacy Malecki, one of the most outstanding Polish scientists. Chairpersons of the Council have also included Professor Adam Lipowczan and Professor Zbigniew Engel and the members of the Council have included Professor Stefan Ziemba and Professor Jerzy Sadowski.