M 3196 Hearing Conservation Leader s Guide
HEARING CONSERVATION AND SAFETY This easy-to-use Leader s Guide is provided to assist in conducting a successful presentation. Featured are: INTRODUCTION: A brief description of the program and the subject that it addresses. PROGRAM OUTLINE: Summarizes the program content. If the program outline is discussed before the video is presented, the entire program will be more meaningful and successful. PREPARING FOR AND CONDUCTING THE PRESENTATION: These sections will help you set up the training environment, help you relate the program to site-specific incidents, and provide program objectives for focusing your presentation. REVIEW QUESTIONS AND ANSWERS: Questions may be copied and given to participants to document how well they understood the information that was presented. Answers to the review questions are provided separately. ATTENDANCE RECORD: Document the date of your presentation as well as identify the program participants. The attendance record may be copied as needed. INTRODUCTION Many industries have work areas where employees are exposed to harmful noise levels. Nearly 10 million people in the U.S. suffer from some sort of hearing loss caused by loud noise. To protect workers from high levels of noise, OSHA created the Occupational Noise Exposure Standard. The regulation requires employees to be trained on how to protect their hearing while working in areas with harmful noise levels. This video provides viewers with the training that they need to work in areas with high noise levels safely. Topics include dangerous characteristics of noise, how the ear works, how hearing is damaged, types of hearing protection and hearing tests. PROGRAM OUTLINE DANGEROUS CHARACTERISTICS OF NOISE Noise has often been called any unwanted sound, but harmful noise is much more than that. While noise has many characteristics, there are three that can be dangerous. Frequency is measured in Hertz, which is the number of cycles per second a sound has. The higher the number of cycles per second a sound has, the higher the frequency of the sound. The frequency of a noise is a concern because higher frequencies are more damaging to our hearing. The second source of potential trouble for your hearing is a sound s volume. Sound volume is measured on a mathematical scale of units known as decibels. Each of these increments represents a significant increase in the power of a noise. For example a three-decibel increase is a doubling of sound energy. The third potentially harmful characteristic of sound is the length of time you remain within a noisy area. This duration of sound is defined by three categories. Continuous noise is a steady sound with little or no change over time. Constantly running machinery is a good example of a continuous noise level. Intermittent noise levels occur for significant time spans, but are separated by relatively quiet pauses. Impulsive noise lasts for less than a second, but is generally very loud. A hydraulic punch press or a stamping machine often produces this type of noise each time it is activated.
Noise that is loud and continuous is especially dangerous to your hearing. When loudness levels reach an average of 90 decibels over an eight-hour time frame, your hearing is in jeopardy. OSHA s Noise Exposure regulation says you must take steps to protect your ability to hear at this level. HOW THE EAR WORKS The outer ear collects sound waves as they come into the area and funnels them down the ear canal toward a tight membrane called the ear drum. When the sound waves strike the ear drum, it vibrates. These vibrations are then transmitted to the middle ear. Three small bones within the middle ear amplify the power of the sound about 1000 times greater than that of the original sound wave. This intensified sound vibration is then transmitted to the fluid-filled inner ear or cochlea. As this happens, it stirs thousands of hairs within the cochlea. Finally, the movement of these hairs sends electrical signals to the brain, which interprets them as sound. HOW HEARING IS DAMAGED Hearing loss most often occurs when the hairs within the cochlea are harmed. Loud noise can easily injure these fragile hairs and their associated nerve cells. Once harm is done to your cochlea, there is no medical treatment that can bring your hearing back. This makes it especially important to protect yourself. To be safe, we have to maintain an awareness of how the noise we encounter on a daily basis can threaten our hearing. PROTECTION FROM NOISE Most facilities use a system of controls to protect workers from this noise. Often the first thing that is done is to limit the amount of time an employee spends in a noisy area. At other times, it s possible to use sound muffling equipment on the source of the noise. When neither of these work, hearing protection is used. A variety of hearing devices are available for just about every situation. Hearing protection is designed to reduce the sound that reaches your ear. This ability is expressed as the Noise Reduction Rating (NRR). This number helps to indicate how well the device can reduce noise, but these ratings may not be accurate for your working environment. During testing, the manufacturer assigns an NRR based upon a best-case scenario. Since this rarely matches the conditions found in a workplace, OSHA recommends that the NRR be reduced by half when you are determining which type protection you should use. When calculating the amount of protection you need, first ask your supervisor what the noise level is in your area. Then subtract 90 decibels from the figure they give and multiply the resulting number by two. That number is the minimum Noise Reduction Rating your hearing protection should have. CHOOSING PROTECTION Once you know how much noise reduction you need, you also have to choose the type of protection that is best for your working conditions.
Adequate protection is the first selection concern. The equipment must lower the noise exposure below the legal limit of 90 decibels. Proper fit is also important. An inadequate fit allows noise to enter your ear. You may be tempted to remove equipment that s not comfortable. You also need to choose a protector that is practical. It should not interfere with doing your job or you may again be tempted to remove it. You should be aware that each piece of equipment has its own advantages and disadvantages as well as specific instructions for use and care. EARMUFFS Earmuffs feature cups filled with sound-dampening material, generally joined together by a headband. Cap-mounted earmuffs attach to safety helmets. They are used in places where multiple personal protective equipment is necessary and both the head and ears need protection. Muffs are popular because they are easy to use and designed to fit anyone. They aren t easily lost or misplaced and don t irritate infections or other ear conditions. Muffs can t be worn in all situations. Some of their disadvantages include being heavy and uncomfortable in hot working conditions. A muff s protection can also be reduced through an inadequate seal caused by glasses, facial hair and other personal protective equipment. Also, because they are bulky, they can make working in confined spaces difficult. If you decide to wear earmuffs, you need to follow some basic guidelines to ensure top performance. Place the cups over your ears and make sure the cuffs provide a secure seal with your head. The headband should be tight enough to provide a proper seal, but not so tight that it becomes uncomfortable. Never remove your muffs while you are still in a noisy environment. Follow all of the manufacturer s instructions for care of your muffs. Inspect your muffs regularly for wear and tear. Don t use them if they are defective in any way. Wash the cups and headband with a mild detergent. Be careful not to get the sound-reducing material wet. Keep ear cushions clean by using a soft brush to remove oil and dirt that can harden the cushioning material. Replace the cushions when they get stiff or brittle. EAR PLUGS If earmuffs aren t right for your situation, ear plugs might be a good alternative. These are designed to fit inside the ear canal and come in both reusable and disposable models. Some of the good reasons for using plugs include the fact that they are small and lightweight as well as inexpensive and easily to replace if lost. In hot or humid conditions, they can be more comfortable than other types of ear protection. They don t interfere with other personal protective equipment.
Just like all hearing protection, plugs are not ideal in every instance. For some people, plugs may irritate the ear canal. Plugs are easily lost, so you may need to carry extra pairs with you. Also, they don t provide adequate protection for high levels of noise. Always wash your hands before handling plugs. When using foam-type plugs, first shape them between your thumb and forefinger for easy insertion. Use your opposite hand to pull the ear outward and upward to enlarge and straighten the ear canal. Insert the plug. For foam plugs, allow a little extra time so the foam can expand to form the proper seal against the canal walls. Release your ear and make sure that the plug is fully inserted and will not fall out. Caring for your plugs is just as easy as using them. Always follow the guidelines from the manufacturer. The only care required for disposable plugs is that you throw them away. Never use disposable plugs more than once. Regularly inspect reusable plugs for torn flanges or other signs of wear. Don t use plugs that are weakened because they won t protect you. Keep reusable plugs clean to avoid infection and to ensure a proper fit. Wash them with a toothbrush in a mild detergent. Rinse the detergent off and allow them to air dry on a clean surface. Once they are completely dry, store them in their own plastic container. CANAL CAPS In locations where noise levels are intermittent, ear plugs can be bothersome. For these circumstances, canal caps may be more useful. Canal caps, sometimes called pods, consist of two ear plugs held in place by a rigid band. These are easy to remove when sound levels decrease. Keep in mind that canal caps offer less protection than either muffs or individual plugs. Ask your supervisor if this type of protection is suitable for your work area. HEARING TESTS Hearing tests provide an accurate measure of your hearing ability. They also make it possible to start early medical treatment if your test shows a hearing loss. Your employer will provide these tests free of charge each year that you work in an area where the noise level averages 85 decibels or higher during an eight-hour period. The first test establishes a starting point, or baseline, of your hearing. A health professional will compare the results of the tests you take each year to see if any change has occurred. The goal of OSHA s Noise Exposure Standard is to preserve your ability to hear human speech. Since the human voice is made up of many frequencies of sound, a hearing test is designed to measure your ability to hear at frequencies between 500 and 6,000 Hertz. The results of your hearing test are plotted on a graph called an audiogram. This is your hearing record.
If a 10 decibel reduction in your ability to hear is detected at the 2,000, 3,000 or 4,000 Hertz frequencies, you will be notified. This kind of hearing change is known as a Standard Threshold Shift. It means that sound has to be 10 decibels louder for you to hear it than was necessary in previous years. If the test shows you have experienced this type of hearing loss, you may be asked to take the test again. This is to make sure the first test was accurate or that the change was not a temporary one. The hearing loss could also be the result of an ear infection or some other reason. To rule these out, you may be referred to another physician for a medical exam.
PREPARE FOR THE SAFETY MEETING OR TRAINING SESSION Review each section of this Leader's Guide as well as the videotape. Here are a few suggestions for using the program: Make everyone aware of the importance the company places on health and safety and how each person must be an active member of the safety team. Introduce the videotape program. Play the videotape without interruption. Review the program content by presenting the information in the program outline. Copy the review questions included in this Leader's Guide and ask each participant to complete them. Copy the attendance record as needed and have each participant sign the form. Maintain the attendance record and each participant's test paper as written documentation of the training performed. Here are some suggestions for preparing your videotape equipment and the room or area you use: Check the room or area for quietness, adequate ventilation and temperature, lighting and unobstructed access. Check the seating arrangement and the audiovisual equipment to ensure that all participants will be able to see and hear the videotape program. Place or secure extension cords to prevent them from becoming a tripping hazard. CONDUCTING THE PRESENTATION Begin the meeting by welcoming the participants. Introduce yourself and give each person the opportunity to become acquainted if there are new people joining the training session. Explain that the primary purpose of the program is to show employees the types of harmful noises that exist in the workplace and how they can prevent these noises from permanently damaging their hearing. Introduce the videotape program. Play the videotape without interruption. Review the program content by presenting the information in the program outline. Lead discussions about specific work areas at your facility that have harmful noise levels and the proper protection required for work in these locations. Use the review questions to check how well the participants understood the information. After watching the videotape program, the viewer will be able to explain the following: How the ear and system of hearing is constructed and how it works; The most common types of hearing damage and their potential effects; How to choose, use and maintain the different types of hearing protection; Why hearing tests are important in preventing hearing loss.
HEARING CONSERVATION AND SAFETY REVIEW QUESTIONS Name Date The following questions are provided to check how well you understand the information presented during this program. 1. Which type of noise usually lasts for less than a second but is very loud? a. continuous b. intermittent c. impulsive d. none of the above 2. No medical treatment is available to repair damage done to the cochlea that results in hearing loss. a. true b. false 3. When determining whether a certain protective device is adequate for your work environment, you should reduce the Noise Reduction Rating by to make sure you have enough protection. a. one-tenth b. one-eighth c. one-fourth d. one-half 4. In general, which type of protection provides the best protection? a. ear muffs b. canal caps c. disposable ear plugs d. reusable ear plugs 5. The goal of OSHA s Noise Exposure Standard is to preserve your ability to hear machines and alarms on the job. a. true b. false 6. What is the average decibel level where you must wear protection if exposed for an entire eight-hour day? a. 60 b. 90 c. 105 d. 120 7. Often hearing loss is only temporary and will return in a few hours. a. true b. false 8. The hearing record on which the results of your annual hearing tests are plotted on a graph is known as a. a. baseline b. threshold c. audiogram
ANSWERS TO THE REVIEW QUESTIONS 1. c 2. a 3. d 4. a 5. b 6. b 7. a 8. c