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Published: January, 2009; Vol 5, Num 8

 

Audiograms Gauge Hearing, Guide Protection

Every construction Laborer should get a baseline audiogram and take strong action to ensure hearing loss prevention.

Following best-practice guidelines, workers who are exposed to noise in excess of 85 dB more than 30 days a year should get a baseline audiogram. For construction workers, this includes almost everyone on the worksite. Afterwards, they should get an annual audiogram so they can monitor their hearing and check the success of their protection program.

An audiogram typically returns a graph line that shows an individual’s hearing at various frequencies. Hearing loss may be greater at some frequencies than others. The broader and more extensive the damage, the greater the loss.

In the pictured sample, the hearing of four individuals is compared on one audiogram. The green line represents a person with normal hearing. Steady at around 15 dB, this individual can hear soft sounds across all frequencies.  In contrast, the orange and red lines show the impact of noise on hearing loss, regardless of age. In the milder (orange) case, the individual has lost hearing around the 4000 hertz (Hz) range, meaning hearing s’s, z’s, th’s, v’s and other soft, high frequency consonants is difficult. If it’s not noisy, this person has little trouble with normal conversation, but if it’s noisy, problems arise. For the person represented by the red line – severe noise-induced hearing loss – hearing is difficult along all the frequencies and, even in quiet conditions, following along with conversation is difficult.  

A number of companies offer onsite audiogram collection services. In one, demonstrated at the LIUNA Tri-Funds 20th Anniversary Conference last summer, up to four workers can be tested simultaneously and have their test results available within minutes for review and electronic storage. “All we need is a small, quiet, indoor space, and we can take audiometric readings for up to 25 workers an hour,” says Anthony J. Miltich, Ph.D., a former NIOSH researcher and the President of Digital Hearing Systems Corporation which provided the demonstration. 

For information on task-based noise protection, see Control Worksite Noise through Task Assessment in this issue of LIFELINES.