Keep the noise down
February 1, 2008
To prevent noise-induced hearing loss (NIHL), it has long been thought that one must render employees nearly deaf through the use of earplugs or earmuffs. Pick the highest Noise Reduction Rating (NRR) available, distribute to employees, and that should do it.
But while the highest attenuating hearing protection devices (HPDs) may be appropriate for employees exposed to high levels of hazardous noise over extended periods of time, they most likely are not suitable for most of the workforce. Overprotection, or providing too much attenuation, is a challenge for hearing conservation program managers. When employees utilize high attenuating earplugs or earmuffs in marginal noise environments, they are put at additional workplace risk. Too much protection may isolate employees from important communications, including co-workers’ voices, machine sounds, alarms and signals that could prevent workplace accidents. No wonder Bob didn’t hear that forklift backing up, or why John never reset the pressure gauge and the pipe burst; they couldn’t hear the signals or commands!
Quite often overprotection occurs in facilities where a variety of manufacturing processes and operations emit a wide range of noise levels. Laura Kauth, an occupational audiologist with Audiology Consultants, P.C., sees this firsthand when evaluating hearing conservation programs.
“A lot of companies seem to have the idea that when OSHA requires ‘a variety of suitable hearing protectors,’ it means ‘two different colors of foam earplugs.’ That’s just not adequate for a range of employees and noise levels. While some employees may need a high level of protection, for others, it is overkill,” said Kauth. In fact, overprotection is one of the most frequent reasons employees compromise their protection by not wearing their HPDs properly or not wearing them at all when exposed to hazardous noise. Some may remove their protectors in order to have a conversation. These employees place a higher perceived value on their ability to understand communications than on their overall hearing health.
Like overprotective mothers, safety managers often cause hearing overprotection. They want to do the right thing to protect staff from hazardous noise, but distrust their employees’ ability to insert their earplugs properly. They think that the highest NRR will cover everyone. But this approach often confuses employees who are ready, willing and able to do the right thing when it comes to their personal hearing safety.
So what is considered an “acceptable noise exposure”? The International Standards Organization recommends that protected noise levels â€” that is, the noise level under the earplug or earmuff â€” should fall within a manageable 70-85 dB range (ISO Guideline EN-458). Protected noise levels over 85 dB indicate exposures that put the worker at risk for hearing damage. Protected noise levels under 70 dB may indicate overprotection, and workers may feel isolated from their work environment.
Tom Huntebrinker, industrial hygiene manager at Shaw Industries, a flooring manufacturer, aims to keep his workers within this range. “We require employees exposed to 85 dBA for 8 hours TWA to be in the hearing conservation program, including wearing required hearing protection,” said Huntebrinker. “We have a lot of employees who work 12-hour shifts, so we, of course, lower the hearing conservation requirement to 82 dBA for these persons. Our goal with hearing protectors or noise control is to lower the employee’s effective exposure below these levels where possible.”
There are several measures that safety managers can take throughout their hearing conservation programs to ensure appropriate protection for their employees without compromise.
Offer a true variety of HPDs
While OSHA mandates a “variety of suitable hearing protectors” be provided to employees at no cost, Kauth believes this should be a well-rounded offering. “At the very least, there needs to be a comprehensive variety offered. That means several moldable foam and pre-formed reusable earplugs; earmuffs; and in fairly quiet settings, canal caps, all in different sizes and attenuation levels,” said Kauth. This allows employees to match their HPDs to their real noise level and to accommodate their personal comfort preference. As the adage goes, the best hearing protector is the one that is properly worn 100 percent of the time when exposed to hazardous noise.
Companies need to address the problem of employees who already have a hearing loss and can’t hear with their HPDs. “When we review test results, I try to make certain the safety personnel are aware of employees who have problems with overprotection due to their hearing loss, and offer options for that scenario,” said Kauth. Also, know your current noise level. Update your noise map when you update machinery or change processes.
Don’t derate â€” innovate
While derating schemes are occasionally applied to NRRs to determine approximate “real world” attenuation, new technologies can immediately identify the specific personal attenuation rating (PAR) an employee achieves with each fit of his or her earplug. Such field verification technologies can determine an individual PAR on earplugs, providing the program manager with an opportunity to evaluate the employee’s earplug efficacy. This evaluation can determine if an employee is achieving ideal fit and attenuation or should take the opportunity to select a more appropriate HPD. Studies have shown that this personalized attention, timed with the annual audiogram, has a positive impact on employee motivation in the hearing conservation program.
At Shaw Industries, Huntebrinker uses various methods to ensure both intelligible communication and overall worker safety.
“We have several locations where we implemented special hearing protectors, including earmuffs combined with two-way radio communication, that allow for verbal communication between employees. These are areas with very high noise levels where we require dual hearing protectors,” Huntebrinker said.
Shaw Industries also incorporates visual indicators to alert hearing protected employees of additional hazards. “In some noisy areas, we adjust our communication method where necessary,” said Huntebrinker. “We use flashing lights as warning devices instead of sound.”
Train the trainer
While most companies are compliant in administering their hearing conservation programs and place a high emphasis on employee training, there is another person who requires a higher level of training â€” the hearing conservation program manager. Many mid- to large-sized companies have trained safety managers on staff, but in smaller companies, the role of program manager may not be that person’s first, or only, role. They may also be the operations manager, shipping supervisor, purchasing clerk or human resources specialist. These people may not realize they are overprotecting employees who would be better suited to lower attenuating protectors.
Program managers who wear multiple hats should look into taking a course offered by the Council for Accreditation in Occupational Hearing Conservation (CAOHC) to become certified in administering certain portions of a hearing conservation program.
Like the success of any hearing conservation program, preventing overprotection is dependent on both management and employee participation and motivation.