Tough Talk— Hear, Hear… Wear That Ear Protection

The Hearing Loss Association of America (www.hearingloss.org) reports that one in ten people have some sort of hearing loss. After age 60, that figure rises to one in four. Hearing loss can be represented as a loss in hearing volume (conductive hearing loss) or a combination of loudness hearing loss and clarity (sensorineural hearing loss). The former can be caused by otosclerosis (boney growths on the inner ear), a buildup of fluids due to infection, or something as simple as the accumulation of earwax. All of these causes can be remediated with medical and/or surgical intervention. Sensorineural hearing loss (SNHL) is typically caused by excessive exposure to loud and repetitive noise.

Conductive hearing loss is organic and is relatively unpreventable, but can be corrected. Sensorineural hearing loss is nearly always caused by conditions that can be avoided or mitigated. Specifically, you can protect your hearing from excessive exposure to loud noises. SNHL makes it difficult to hear high frequency sounds such as birds chirping, young children and voices from another room. In addition it can make it difficult to hear conversations when background noise is present such as at meetings, parties, and in bars.

Unfortunately, it is rather difficult to fix SNHL after the damage has been inflicted. Conventional hearing aid technology gives us devices that can increase volume; however, SNHL usually affects only a range of hearing typically in the higher frequency ranges and simple amplification doesn’t help. Technology is advancing and some of the newer devices allow the user to “tune” the amplification to specific frequency ranges.

As powder coating technologists, where do we encounter hearing damaging noise? Well it’s a combination of workplace and the common noise in everyday life. In the lab or shop we are exposed to air compressors, grinding machines, media blasters, and even industrial vacuum cleaners. Back home, the most common assaults involve lawn care equipment, including lawn mowers and leaf blowers.

So how does one protect their hearing? The most common means are squishy ear plugs (foam types), Christmas trees (molded types), and ear muffs.

All hearing protective devices are required to indicate the device’s noise reduction rating (NRR), which is quoted as the decibel difference between open and occluded hearing thresholds. These values are measured in a laboratory with trained subjects. The CDC (Center for Disease Control) recommends that the values stated from these lab tests are overestimated compared to real life situations and should be de-rated. Typical values are listed in Table 1.

It is imperative for you to protect your hearing sooner than later if you are not already doing so. Any protection is better than none, but the CDC recommends a combination of either foam or molded ear plugs with a well-fitted set of ear muffs. This is especially important when exposed to loud sound over a long period of time. Table 2 provides OSHA recommendations for time-weighted exposure of damaging noise levels. All manufacturing plants, application systems, and laboratories should have hearing protection programs, easily available protection equipment, and regular training programs to limit exposure to loud noise. It’s better to be safe now so you can enjoy your hearing later on.