Effects of Noise and Hearing Disability

Transcription

1 Effects of Noise and Hearing Disabiity Compied by : J. L. Lad It is a we known fact that different kinds of sound are detected by our ears. The human ear can be divided into three parts : Externa, midde & interna. When the sound waves hit the externa ear, they are transmitted to the midde ear through a pipe caed externa ear cana which is approximatey 3 cms. in ength. The midde part has the eardrum (1.5 to 2 cms in diameter) which starts vibrating when these sound waves hit it. Just behind the eardrum there are three sma bones caed hammer, anvi & stirrup. As the eardrum vibrates these bones aso start vibrating. These vibrations are transmitted to the cochea which act ike a spring and is surrounded by a fuid which has nerve endings. The activation of the nerve endings produce the impuses which are taken to the brain by the auditory nerve & are decoded at the tempora obe in the brain and we hear the sound. In order to keep the ears heathy, it is essentia to cean them reguary. A waxy substance is produced in it which gets deposited on the eardrum. If this wax accumuates it can ead to deafness. Therefore we shoud take care of our ears and consut the ENT experts as soon as there is an ache in the ears. Outer Ear Midde Ear Inner Ear Semi-Circuar Canas (Baance) Maeus (Hammer) Vertibuar Nerve Brain Utrice Saccue Bone Posture Cochea (hearing) Auditory Nerve Pinna Musce Bony Cana Incus (Anvi) Ear-Drum Stapes (Stirrup) Eustachan tube Ova Window Round Window Cochea Nerve Indoymph (Fuid) A newborn baby (infant) does not receive message in the womb. A sma infant can pick up a sound of a high frequency. The infant s brain understands the word Mamma and Papa in the eary stage of ife. 36

2 Noise is unwanted sound. It is measured in db (Decibes) the pitch or frequency (hertz). Noise is a sound eve above 90 db. Noise may be continuous or intermittent and may be of high frequency or ow frequency. There are a variety of noises ike - Low noises, Whispers, medium noises, high noises, noises from the back, noises from side, high pitched noises etc. There are some noise eves measured as foows: 1. Rusting of eaves db 2. Quiet room db 3. Whispers db. 4. Subdued Music db 5. Quiet Office db 6. Conversation to 75 db 7. Motor car db 8. Noisy office db 9. Heavy vehice, scrapper db 10. Chainsaw, Excavator db 11. DISCO music db 12. Propeer Aircraft db 13. Revetting work Rock music & Jet Aircraft db. The person fees irritated at 0 db eve noise for one hour. Minimum 20 db noise is required for a person to ive happiy and comfortaby. I Effects of Noise : Noise affects hearing and causes deafness in the ong run. Exposure to excessive noise eves for an extended period of time can damage the inner ear in such a way that the abiity to hear high frequency sound is diminished or ost atogether. Additiona exposure can increase the damage unti even ower frequency sounds cannot be heard. 37

3 Besides causing deafness, it affects the other systems of the body. Irritation pain, ringing in the ears, feeing tired, ack of concentration, seepessness, speaking in a oud voice and high bood pressure, may aso be caused due to excess noise exposure. Noise reduces working efficiency Noise Induced Hearing Loss (NIHL) is a reportabe and compensabe disease. NIHL is not curabe but can be prevented. How to spot the noisy areas & reduce the noise eve! Look for steam & air eakages, oose mounting of machines, oose machines parts, eakage from the siencer, missing covers, meta to meta striking etc. Noise can be decreased with the foowing methods. 1. Partition provision around the high noise generating machines. 2. Mechanica moving parts provided with ba bearings shoud be reguary maintained by oiing & greasing. 3. Riveting process substituted by sodering / weding. 4. Doube doors with the vacuum in between for the noise isoation. 5. Foors shoud be provided with rugs, coir matting, rubber sheets for the absorption of noise. Noise Meter 6. Roof & was shoud be provided with thermoco, sound absorbing materia or hard boards. 7. Designing the buiding position and wa position. 8. Provision of rubber shoes. 9. Use of persona protective equipment ike earmuffs or ear pugs is a must in noisy work paces. In many paces it is difficut to bring down the noise eve very much. Hence suitabe type of ear protection is a must. 10. Stop a the eakages. 11. Educate the empoyees on i effects of noise and importance of use of hearing protection. 38

4 Audiometry is a simpe painess test conducted with the hep of an audiometer for measuring the hearing capacity. The test takes a few minutes but can detect the hearing oss very eary. The foowing points shoud be taken care of for the correct resut through the audiometry test. This examination is required to be done every year. I. There shoud be no acohoic drinks prior to the examination. 2. A person shoud not hear any kind of music at the time of the examination. 3. A person shoud be away from work for 3 days before the examination. 4. A person shoud not suffer from any sickness such as cod, fever. Audometry test in progress 5. Drugs / Chemicas may cause deafness hence it shoud be avoided. Age reated deafness : This is due to the nerves becoming weak. The sound waves take time and are not abe to give the correct information to the brain. The high vibration noise enters the ear at a high frequency. A very young person can hear Vibrations/ Second from a 3 foot distance. The common deafness occurs at 3000 to 5000 Vibration frequency. The vibration noise aso creates eary deafness. Vibration hazards : Vibration hazards are cosey associated with noise hazards because toos that produce vibrations typicay aso produce excessive eves of noise. Vibrations can cause physica probems ranging from motion sickness to spina injury to handarm vibration syndrome. The physica damage associated with this may be irreversibe Prevention is especiay important. This incudes purchasing ow vibration toos, imiting empoyee s exposure and changing empoyee s work habits. 39

5 Seective Deafness : Temporary Deafness occurs during exposure for 4 to 5 hours at 100dB. At 110 db. it takes 2 to 3 days to recover from temporary deafness. At 120 db. it takes 7 days to recover from temporary deafness. At 130 db. The empoyee does not recover from deafness up to 6 months. After continuous noise of 6 months the deafness become amost permanent. It occurs to 20% of peope who are working in the area for a minimum of 10 years. Permanent deafness at 4000 to 5000 vibrations - the person wi not be abe to hear at 80 db. Deafness is a compensatabe disease. In USA the compensation is 3 months eave with fu saary paid. Before giving the compensation the empoyee is tested by using audiometry tests. Deafness & Dumbness is due to a nerve probem. To minimise impact on an eardrum, it is advisabe to open the mouth now and then when the noise is high. Perforation of the ear is ikey. The echo can be magnified to increase the noise. Vertigo : It is a disease which may be caused because of high bood pressure. If such a person works in a high noise area for more than 8 hours he may suffer from vertigo. This is due to semicircuar cana not functioning propery. Noise irritates a person. Due to the irritation the musce contracts and the bood suppy becomes ess to the brain. Due to the constriction of bood vesses, the judgment of the person may go wrong. The bood vesses shrink in the ear too. The body becomes unsteady. The person suffers from vertigo and gets a ringing sound in the ears. Deafness is aso caused due to 1. Concussion 2. Venera disease 3. Vira infection 4. Vertigo 5. Extreme Heat 6. Ten years of working in a noisy area 7. Use of mobie phones continuousy for more than 10 years. 40

6 The instrument used as a hearing aid wi magnify the sound at the inner ear above 100 db so as to enabe hearing. Protect your hearing off the job, too Decibe eves of 120 db have been recorded at popuar concerts, and many peope pay their radios and stereos far ouder than is good for their hearing - or anyone ese s! Protect your ears now so you ALWAYS be abe to enjoy the atest sounds. Masking noise means that the sound we want to hear is drowned by other sounds. This can cause accidents because warning shouts and other signas are not heard. The ear can toerate ow tones more easiy than high tones. Consequenty if the ear is damaged, it is the perception of high tones which disappear first. We must not notice this because we can hear norma speech. It takes severa years before the damage becomes so apparent that we have difficuty in understanding what other peope say. 41

7 100% wear time - the ony sure way to prevent damage to your hearing. It foows ogicay that once a hearing protector which gives the correct attenuation has been chosen, it must be checked for maximum comfort. If the hearing protector is not comfortabe enough to wear a the time, the predicted protective effect wi not appy. Even 99% wear time (five minutes of careessness each day) reduces the protective effect dramaticay. And at 90% wear time you can no onger be sure of effective protection eves. Stricty speaking, if you take a break from the hearing protector for about an hour during the working day, there is itte use in wearing it the rest of the time - the over exposure or the overdose has aready occurred. Use of Persona Protective Equipments It costs 10 times more to rehabiitate a hearing impaired person than to prevent injury in the first pace. 42

8 The moment you are in tension you wi ose your attention then you are in tota confusion and you fee irritation then you spoi persona reation utimatey, you won t get cooperation then you make things compication then your BP may aso rise caution and you may have to take medication instead, understand the situation and try to think about the soution many probems wi be soved by discussion which wi work out better in your profession don t think its my free suggestion it is ony for your prevention if you understand my intention you never come again to tension!! 43