By Lilia Chen, MS, CIH, Scott E. Brueck, MS, CIH, and Maureen T. Niemeier, BBA
The National Institute for Occupational Safety and Health (NIOSH), part of the Centers for Disease Control and Prevention (CDC), was recently asked to evaluate a high school band director’s noise exposure during music classes and band rehearsals (see “The Health Hazard Evaluation (HHE) Program”). The band director was concerned about hearing loss from loud noise while teaching music classes, and during band rehearsals and performances. Music classes included fifth and sixth grade band, music arts, and marching band rehearsal. Most classes had 15-30 students. The marching band had about 90 students and band rehearsal lasted 50 minutes each day. Music classes were held in the 1,700-square foot band room. The marching band rehearsed in the band room or in the 6,000-square foot cafeteria. The band director sometimes taught lessons after school which contributed to his overall noise exposure.
Noise-induced Hearing Loss (NIHL)
NIHL is a permanent condition caused by damage to the nerve cells of the inner ear; it cannot be treated medically.1 In most cases, NIHL develops slowly from repeated noise exposure over time, but the amount of hearing loss is usually greatest during the first several years of noise exposure. NIHL can also result from exposure to very loud noise for short periods of time, or even from a single exposure to an impulse noise or continuous noise, depending on the intensity of the noise and the person’s susceptibility to hearing loss.1 Noise-exposed employees can develop substantial NIHL before they realize it.
Hearing often worsens with age, but exposure to loud noise can increase how quickly hearing loss occurs. Even mild hearing losses can interfere with a person’s ability to understand speech and hear important sounds. Some people with NIHL develop tinnitus, a condition in which a person hears sound in one or both ears (often described as ringing, hissing, buzzing, whistling, clicking, or chirping like crickets), but no external sound is present. Tinnitus can be occasional or constant, and the volume can range from soft to loud. Currently, there is no cure for tinnitus.
One study of 104 music educators found evidence that being a high school band director carried a slight risk for NIHL.2 However, fewer than 20 percent of the high school band directors had NIHL, and the degree of loss was highly variable. In another study, 45 percent of student musicians aged 18 to 25 years had NIHL, compared to 11.5 percent of people in the same age range in the general population.3
A study of university music students indicates that how close the band director and students are to specific groups of instruments can affect noise exposure levels.4 The study found that brass instrument players had significantly higher average noise exposure levels (95.2 dBA) compared to woodwind players (90.4 dBA), percussion players (90.1 dBA), vocalists (88.4 dBA), or string players (87.0 dBA) (see “Noise Exposure Limits” for an explanation of noise measurements). Since music teachers and students may also be exposed to loud music outside of the classroom, it is important to educate them about the risk of hearing loss from excessive noise exposures and inform them about ways to protect and preserve hearing (see “Recommendations”).
Noise Exposure Limits
Occupational noise exposure limits in the United States have been developed by NIOSH, the Occupational Safety and Health Administration (OSHA), and safety and health organizations. Employers are encouraged to follow the more protective NIOSH recommended exposure limit (REL),5 but the law requires them to adhere to the OSHA permissible exposure limit (PEL) and Action Level (AL).6 When employees’ noise exposure levels exceed the AL, employers must institute a hearing conservation program which includes noise monitoring, audiometric testing, providing hearing protectors, training and education, and record keeping. When noise exposures are greater than the PEL, employees are required to wear hearing protection.
Noise measurements are reported in units of A-weighted decibels (dBA). The decibel (dB) scale is logarithmic, so increases of 3 dB, 10 dB, and 20 dB represent a doubling, tenfold, and hundredfold increase of sound energy, respectively. A whisper is 30 dB, a normal speaking voice is 60 dB, a powered lawn mower is 90 dB, an ambulance siren is 120 dB, and a jet engine during take-off is 140 dB.
Noise Exposure Measurements and Results
We measured the band director’s noise exposure during marching band rehearsal in the cafeteria, and we measured his noise exposure in the band room for an entire school day. Because the band director was the only employee who taught music classes and rehearsals, we also measured noise on each side of the band room. We measured the dimensions of the band room and cafeteria and calculated reverberation times (the time it takes for a sound to decrease 60 dB from its original intensity) for these areas.
The band director’s full work day noise exposure did not exceed the OSHA PEL of 90 dBA, but reached the OSHA AL of 85 dBA and was above the NIOSH REL of 85 dBA. Noise exposures were the highest during marching band rehearsals and averaged 97 dBA when rehearsal was in the band room and 95 dBA when rehearsal was in the cafeteria. Noise levels exceeded 100 dBA numerous times during rehearsals. Noise levels on each side of the band room were below the OSHA AL or PEL. Our results showed that increasing the distance between the band director and the students decreased noise exposure. Reverberation times in the cafeteria and band room were appropriate for teaching music classes (and within ranges recommended by other researchers), but the band room was too small for the number of students in the marching band.
We evaluated the band director’s noise exposure, but not the students. Students are likely to have lower noise exposures from school-related activities, because they spend less time in music classes and rehearsals. However, for the range of the noise levels we measured during rehearsals, overexposures could occur in 30-60 minutes. We recommend administrators educate teachers, students, and parents involved with music (especially with the marching band) about NIHL symptoms (see “Noise-induced Hearing Loss (NIHL)” and prevention (see “Recommendations”).
Recommendations
We provided the following recommendations to reduce noise exposures during music classes and marching band rehearsals. The recommendations are based on basic principles that are also applicable in other schools.
- Hold marching band rehearsal outside or in a room appropriately sized for the number of band students and acoustically designed for musical rehearsals and performances. Until an acoustically-designed space for musical rehearsals and performances is available, hold marching band rehearsals in other spaces such as the cafeteria or a larger room with sound absorbent materials. If rehearsals must be in the current band room, all students should be asked to play softly and focus on technique. They should practice louder dynamics when rehearsals are outside or in a larger rehearsal area. One organization recommended that a high school band room for 60 to 75 musicians have a floor space of 2,500 square feet and a ceiling height of 18-22 feet.7
- Stand away from surfaces off which sound can bounce, such as blackboards, when leading music classes and marching band rehearsal. If this is not possible, then cover such surfaces with sound absorbent material.
- Move the students farther back in the classroom to create more distance from the band director.
- Provide the band director with flat attenuation “musician” ear plugs until an acoustically appropriate space for musical rehearsals and performances is available and noise levels are below occupational exposure limits. These hearing protectors reduce sound levels evenly across frequencies to maintain sound quality. Administrators should provide training for the proper fit, use, and care of the ear plugs.
- Establish a hearing conservation program for the band director and other music teachers in accordance with the OSHA hearing conservation standard [29 CFR 1910.95] and NIOSH recommendations (see “Resources and Links”). This program should provide guidelines for reducing the risk of hearing loss, include annual audiometric testing and follow-up, and include training on using hearing protectors. Audiometric testing allows for the early detection of hearing loss and provides opportunities for interventions.
- Share information on the symptoms and prevention of NIHL with band students and their parents (see “Resources and Links”).
Resources and Links
NIOSH HHE Program information: www.cdc.gov/niosh/hhe/HHEprogram.html
OSHA hearing conservation program information: www.osha.gov/dts/osta/otm/noise/hcp/index.html and www.osha.gov/Publications/osha3074.pdf
NIHL information: National Institutes of Health, National Institute on Deafness and Other Communication Disorders WISE EARS!® campaign at: www.nidcd.nih.gov/health/wise/Pages/Default.aspx.
For more detailed information on the methods, results, and recommendations of this evaluation, see www.cdc.gov/niosh/hhe/reports/pdfs/2011-0129-3160.pdf.
Footnotes
- Berger [2003]. Berger EH, Royster LH, Royster JD, Driscoll DP, Layne M, eds. “The noise manual.” 5th rev. ed. Fairfax, VA: American Industrial Hygiene Association.
- Cutietta RA, Klich RJ, Royse D, Rainbolt H [1994]. “The incidence of noise-induced hearing loss among music teachers.” J Res Music Ed 42(4):318–330.
- Phillips SL, Henrich VC, Mace ST [2010]. “Prevalence of noise-induced hearing loss in student musicians.” Int J Aud 49(4):309–316.
- Phillips SL, Mace S [2008]. “Sound level measurements in music practice rooms.” Mus Per Research 2:36–47.
- NIOSH [1998]. “Criteria for a recommended standard: occupational noise exposure” (revised criteria 1998). Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 98-126.
- 29 CFR 1910.95. Code of Federal Regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.
- Wenger Corporation [2001]. “Planning guide for secondary school music facilities.” Owatonna, MN: Wenger Corporation.
Lilia Chen, MS, CIH, is an industrial hygienist for the Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH), Health Hazard Evaluation (HHE) Program in Cincinnati, OH.
Scott E. Brueck, MS, CIH, is an industrial hygienist for the Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH), Health Hazard Evaluation (HHE) Program in Cincinnati, OH.
Maureen T. Niemeier, BBA, is a freelance technical writer/editor in Cincinnati, Ohio. She has written and edited public health documents for the Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH), and other clients since 2002.
Mention of company or product names does not imply endorsement by the National Institute for Occupational Safety and Health.