Why fit test hearing protection?
February 9, 2009
New technologies allowing individual fit testing of hearing protection devices (HPD) are becoming increasingly available in today’s market (ISHN November 2008). This is excellent news because many workers have been using their HPDs improperly for years with no awareness of whether or not they are protecting their hearing.
How can you ensure that your employees are getting optimal performance from their hearing protection? The following seven steps, all centered around one-on-one training, will help you build a program that produces results.
1â€” Train the trainer
Most people issuing HPDs have no training in selection, fitting, and use of the devices. The effect of small differences in rolling down foam earplugs, for example, or pulling the pinna prior to insertion can be clearly demonstrated with a quick feedback fit testing system. Trainers need to learn what a good fit looks like and understand the importance of appropriate HPD selection by seeing the personal attenuation rating (PAR) â€” the actual performance of HPD â€” in various ears.
2 â€” Insist on individual fit testing
Even if the trainer is effective, how can you be sure the trainee “gets it”? While workers may be able to give appropriate responses on a written test, individual fit testing provides a superior performance test of the effectiveness of HPD training. The trainer can instruct and demonstrate, but being able to measure how well the trainee actually performs the fitting is the best indicator that he understands the use of the HPD, will use it properly and will be protected from the effects of workplace noise.
It is common to hear workers say during individual fit testings, “Oh, is that how it’s supposed to work? Is that what it’s supposed to feel like?” This immediate feedback on what a good fit feels and sounds like is an excellent motivator.
Using PAR findings to show the measurable difference between a good fit and a bad fit allows you to quantify HPD fit in a single number, thus challenging the idea that “in the ear is good enough.” The ability to effectively demonstrate the difference between a “normal” insertion providing 6 dB of protection, and a tightly rolled foam earplug, pinna pull, and deep insertion resulting in 30 dB PAR is powerful indeed.
3â€” Assign/select HPDs
In most cases, HPD selection decisions are made on the fly by workers with little or no oversight and with no consideration of HPD performance other than the flawed, laboratory-based noise reduction rating (NRR). But every ear is different in size and shape, and each worker’s noise exposure is different. Individual fit testing allows you to select the HPD most appropriate for worker physiology and exposure conditions.
Fit testing is the only process that enables effective selection by quantifying individual performance. A worker may think a certain plug is more comfortable, but if a test can demonstrate the need for different kind of plug, the HPD selection can be made on a more practical and rational basis when individual comfort and preference decisions are coupled with quantifiable data.
4â€” Provide “standard-thresholdshift” follow-up
When workers show standard-threshold-shift (STS), OSHA requires specific follow-up actions. One of those is determining whether the HPD is providing insufficient protection in the noise environment. Currently, review of the NRR of the HPD is the only option employed, but this is not a reliable means of estimating protection.
Individual fit testing can assess the effectiveness of the worker-specific HPD system, including the protector itself, the training provided for its use, and the individual workers’ insertion/use habits. By identifying deficiencies in the HPD system at the time of STS determination (or earlier), fit testing can promote intervention before hearing loss starts to approach the impairment or recordability stages. Getting the exposed worker into the right HPD â€” and ensuring that they use the devices properly â€” is essential in preventing hearing loss.
5â€” Determine HPD adequacy/sufficiency
How can you know if workers are sufficiently protected from noise? De-rating or devaluation of the NRR is difficult, as workers will achieve a range of protection from any given HPD depending on the variables described above.
In critical noise environments, reliance on NRR to determine HPD sufficiency has proven problematic. Many workplaces with high noise exposures have defaulted to extremely conservative policies, such as requiring dual HPD (earmuffs over earplugs) in noise conditions of 95 to 100 dB.
The difficulty here lies in overprotection. If a worker in 95 dB uses a foam earplug properly, he will likely achieve somewhere in the range of 25 to 30 dB of protection. Add an earmuff to the equation, and the total protection will be 30 dB or more, making the “net” noise exposure (taking HPD into account) 65 dB or less. Given a target protected level of 75 to 80 dB, in this situation, most workers will lift the earmuff cup or pull an earplug out of their ear in order to communicate. A system that requires workers to defeat their PPE to do their job effectively is doomed to fail.
6â€” Audit departments
The reason for differences in hearing loss rates between plants or departments can be bewildering. If these groups are functioning under the same hearing conservation program, why the variability?
Fit testing can help identify these variables. Is it selection of HPD? Training in HPD use? Age of the workers, with the accompanying challenges in using some types of HPD? The HPD trainer? Noise conditions and HPD sufficiency?
Whatever the case, quantifying HPD performance enables you to find and fix the weak spots in your hearing conservation program performance.
7â€” Provide documentation
HPD performance has long been the missing link in determining work-relatedness of hearing loss. We understand noise and noise measurement. We understand how to assess hearing. We know that HPD is certainly capable of protecting workers. But the NRR on the label is pretty much meaningless when it comes to determining individual protection. So how can we make a reasonable call about the work-relatedness of any given hearing loss?
Enter individual fit testing. Today’s systems typically provide documentation that identifies the worker, the HPD on which they were tested and the PAR or other measure of HPD performance. This documentation can be useful to the physician or audiologist making determinations about hearing loss. Documentation over time that indicates the level of protection an individual worker receives from their HPD can be a useful tool in determining if a given hearing loss is related to workplace noise exposure.
Most of the fit-testing systems available today are point tests â€” that is, they test a specific worker on a specific HPD with a specific fit at a specific time. Conducting fit testing over an extended period of time, perhaps by integrating it with annual hearing testing, provides a “paper trail” that can help the supervising professional determine if the recorded hearing losses are truly due to workplace noise exposure.