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Every minute of every day, noise – both welcome and unwanted – surrounds us. While most of the sounds experienced, such as being stuck in traffic, watching television or having a conversation with a family member have no adverse effects on a person’s hearing, when noises are too loud for too long, they can damage the delicate structures found within the inner ear and result in eventual hearing loss.
Noise is measured in decibels (dBA) and the louder the noise, the higher the dBA. For each jurisdiction across Canada there is a set occupational exposure limit to noise (generally accepted as an average of 85 dBA over the course of an eight-hour shift), referring to the maximum noise limit that most workers can be exposed to throughout the day without suffering adverse health problems.
“But there is some evidence out there that a portion of the population can experience hearing loss even at noise levels as low as 80 dBA,” said Michael Russo at the Infrastructure Health and Safety Association (IHSA). “A good rule of thumb is that if you need to shout for someone to hear you well at arm’s length, then the sound level is too loud and likely exceeds safe levels.”
Certainly then, a construction site can be a noisy work environment that far exceeds the ‘safe’ noise exposure limit of 85 dBA; something that is particularly true when foundation work is involved. According to IHSA, piling rig operators can be routinely exposed to noise levels of up to 125 dBA, which is louder than a thunderclap and at the point of inflicting physical pain. Compounding this, a shift for a construction worker will often last longer than eight hours, which only increases the duration of exposure to the harmful noise level.
Although the manufacturer may indicate the expected noise levels produced by its piling equipment, the decibels encountered in the field may actually deviate from what the manual says. When using the same piece of equipment within a new workspace or under differing conditions, there are a multitude of variables that may impact noise exposure, both for the operator and any other workers in the immediate area.
“With heavy equipment, especially newer heavy equipment, the operator in the cab tends to be better insulated to sound,” said Russo. “When we typically find a noise exposure issue, it is inside equipment where the insulation just isn’t there or has deteriorated over time, and the noise from outside can easily overexpose the operator. Something as simple as leaving the cab’s windows or doors open in the summer months can result in too much loud noise for the operator and lead to eventual hearing loss.”
The impact of noise on workers’ hearing will depend on a number of factors, including the type and intensity of noise, as well as the duration of time they were exposed to it. For most individuals, when they are exposed to really loud noise in a workday, there will be some degree of temporary hearing loss that will shortly return to normal. However, overexposure to high noise levels over time will inevitably lead to a gradual – yet significant – loss of hearing. Additionally, as the effect of high noise levels on hearing is so gradual, workers may not even be aware of the subtle signs of hearing loss until the symptoms become more pronounced.
“When you have chronic exposure to high noise levels, you may not be able to notice an impact on your hearing right away,” said Mathew MacLeod with the Canadian Centre for Occupational Health and Safety. “Rather it’s a slow progression of damage on your hearing and, by the time you find out that you’re starting to lose your hearing, it’s too late and irreversible.”
Some of the common warning signs of hearing loss to watch for are such things as the muffling of speech and other sounds, difficulty in understanding conversations, constantly turning up the volume on the radio to hear better or the need to ask others to speak more clearly. Another symptom that could indicate more advanced hearing loss is tinnitus, which is an incessant ringing or buzzing in the ears.
“More often than not, however, it will be your friends and family who first notice your loss of hearing, which leads to a visit to the doctor where the problem is diagnosed,” said Russo. “Your ability to hear others significantly impacts your quality of life, and there are many inconveniences linked to hearing loss, ranging from not hearing a warning horn at the work site to feeling frustrated and isolated because you might be uncomfortable participating in casual conversation.”
To determine if workers are being exposed to harmful levels of noise, employers should conduct a noise assessment of the workspace by trained and qualified individuals. If those assessments demonstrate that the level of noise exceeds the occupational exposure levels set for a particular jurisdiction, it is recommended that employers implement a hearing conservation program, including such items as routine noise assessments, noise mitigation efforts, hearing protector selection, employee training and education, scheduled audiograms and record keeping.
“Oftentimes there are simple things that can have dramatic impacts on reducing noise,” said Russo. “Even something like spacing workers further apart, cordoning off certain areas to keep back bystanders or routine equipment maintenance can significantly help. And then, only when it is determined that the noise cannot be reduced further, should hearing protection be required.”
“If you need to shout for someone to hear you well at arm’s length, then the sound level is too loud.”
– Michael Russo, Infrastructure Health and Safety Association
The choice of hearing protection depends on a number of factors, such as the level of noise, the suitability of the hearing protection for both the worker and the working environment and the desired noise reduction. The two most common kinds of hearing protection are earmuffs and earplugs, which can include pre-moulded, mouldable, push-to-fit, roll-down foam and semi-insert. In some circumstances, or under high noise conditions, workers may also be required to wear dual-hearing protection consisting of both an earmuff and earplug.
“Another important factor is comfort,” said MacLeod. “When the hearing protection is more comfortable and fits better for the individual worker, then compliance will certainly be better. Because of this, employers should always provide a choice in the number of different types of appropriate hearing protection that a worker can choose from to find what works best.”
“When the hearing protection is more comfortable and fits better for the individual worker, then compliance will certainly be better.”
– Mathew MacLeod, Canadian Centre for Occupational Health and Safety
The main standard governing hearing protection in Canada is the Canadian Standards Association Z94.2 Standard – “Hearing protection devices Performance, Selection, Care, and Use”, which provides performance requirements and the rating schemes that might help the user select hearing protection devices. In addition, the manufacturer may also offer additional information about the noise reducing capabilities of its hearing protection based on ideal conditions and provide a Noise Reducing Rating.
If an employee believes they are feeling any health effects from exposure to noise, they should seek out medical attention immediately and report their concerns to a manager, supervisor, health and safety committee representative or the union to address the potential hazard.
“They will be able to help and provide guidance to the worker, as well as investigate the issue,” said MacLeod. “And then, if you are not satisfied with the response you receive, you also have the option to contact the Occupational Health and Safety regulator or the Workers Compensation Board for further guidance.” 