Sound Protection Tips For Noisy Worksites

Of all the hazards faced by workers on the job, one of the most insidious is noise pollution.  Damage to an employee’s hearing can be so gradual that by the time it has been detected, either by a standard medical exam or by the individual who notices a drop off in their auditory acuity, it is often too late to mitigate the loss.  Hearing loss is cumulative, and it is irreparable.  This harsh reality makes it important for risk managers to take steps to protect the hearing of their workers right from the day they first set foot onto the job site.

The ‘loudness’ or intensity of sound is measured using decibels (dBa), with a figure of around 45 dBa representing what most individuals would consider a quiet level of background noise.  On a worksite where heavy machinery or even hand tools are in frequent use, it is not inconceivable for noise levels to start at around 90 dBa.  Given that decibels are a logarithmic unit, this indicates far more than a doubling of ambient sound levels – it in fact represents a much, much louder environment.

To demonstrate just how quickly a decibel increase can result in hearing damage, it is helpful to look at the permissible exposure lengths to specific levels of sound provided by the Occupational Safety and Health Administration (OSHA).  Workers can tolerate a constant 90 dBa of noise for up to 8 hours before there is any danger of permanent hearing loss.  However, increase that value by merely 2 dBa and the safe exposure length drops to 6 hours.  At 95 dBa, the time before injury occurs is halved to four hours.

Just as continual exposure to high levels of noise can cause permanent injury to an employee’s ears, a brief transient spike of loud sound can be equally scarring.  Exposure to sounds as loud as 139 dBa for more than just .11 seconds can cause significant damage.  To put that volume of sound into perspective, 139 dBa is approximately the auditory equivalent of a jet taking off or a gunshot.  There are plenty of chemical and other transformative processes that can produce this level of audio energy.  Those working in construction can also be exposed to sudden noise spikes caused by blasting and other explosives use.

It is clear that a simple and inexpensive investment in hearing protection can go a long way towards protecting the health of workers across a broad range of industries.  Hearing protection is generally divided into over-ear and in-ear categories, with the former providing up to 29 dBa of noise reduction (Optime 105 Series Earmuff) and the latter coming very close to that level (26 dBa for Moldex ear plugs).  It is even possible to purchase custom-molded earplugs that can block up to 40 dBa of sound.

Of course, some jobs require hearing protection that doesn’t interfere with communications between workers.  Products like the Peltor Push Earmuffs feature the ability to momentarily disable sound attenuation to the point where a conversation is possible.  It is important that any type of hearing protection that can be easily defeated always be accompanied by training that indicates when it is appropriate to do so without increasing the risk of permanent hearing damage.