I don't know if you will like this answer or not. The topic of noise, its measurment, and the calculation of what constitues a hazadous level of exposure to noise, is quite a technical topic. Here are 3 ways of knowing that you are being over-exposed to a hazardous level of noise: 1 Two people stand in the noisy area approximately 3 feet (1metre) apart. They speak in a normal voice (normal speaking volume). If they cannot hear each other clearly, the noise level is too high and if a person is exposed to this level 8 hours per day and 5 days per week they are likely to suffer hearing loss. 2 If your ears are ringing or buzzing after you leave work, then you may be over-exposed at work. 3 Before you go into work, set the car radio volume as low as you can while still hearing th sound. After work listen to the radio again. If you cannot hear the sound from the radio, you may be over-exposed to noise in the workplace. Now, a more technical answer is: the noise level, 8 hour average should not exceed 85 dBA (decibels measured on the A-weighted scale of a noise level meter). No one should ever be exposed to more than 115 dBA, even for a second. Here in Canada we have legislation that tells us how to evaluate a worker's exposure to noise. The following is a direct excerpt from my province's Health and Safety Regulations: “dBA” means a measure of sound level in decibels using a reference sound pressure of 20 micropascals when measured on the A-weighting network of a sound level meter; “decibel” means a unit of measurement of sound pressure level that is equal to 20 times the logarithm to the base 10 of the ratio of the pressure of a sound, divided by the reference pressure of 20 micropascals; “equivalent sound exposure level” is the steady sound level in dBA which, if present in a workplace for eight hours in a day, would contain the same total energy as that generated by the actual and varying sound levels to which a worker is exposed in his or her total work day, determined in accordance with the formula set out in subsection (2). O. Reg. 565/06, s. 2. (2) The formula for determining the equivalent sound exposure level is as follows: [NOTE from Richard: The formula is a logarithmic equation which I could not copy and paste here (because it's a graphic file, i.e. jpg). To see the equation please look at section 139. (2) in the following website: http://www.e-laws.gov.on.ca/html/regs/english/elaws_regs_900851_e.htm#BK19] where, Lex,8 is the equivalent sound exposure level in 8 hours, Σ is the sum of the values in the enclosed expression for all activities from i = 1 to i = n, i is a discrete activity of a worker exposed to a sound level, ti is the duration in hours of I, SPLi is the sound level of i in dBA, n is the total number of discrete activities in the worker’s total workday. _____________________________________________________________

holy cow richard! How long did it take you to write that?! lol

Thanks to all of you !! SPECIAL THANKS TO MR, Richard Sir. Little!