noise at workplace dr. noor hassim ismail. anatomy of ear 3 parts – outer ear – middle ear –...
TRANSCRIPT
Noise at Workplace
Dr. Noor Hassim Ismail
Anatomy of Ear
• 3 parts– Outer ear– Middle ear– Inner ear
• Cochlea- hearing apparatus• Vestibular- balancing of the body
Pathophysiology of hearing
• How we hear?– Air conduction– Bone conduction.– Conductive hearing loss– Sensorineural hearing loss
Effects of noise
• Noise definition- unwanted sound.• Noise unit- intensity –decibel (dB),
frequency(hertz –hz).• Type of sound based on frequency
– Infrasonic (0-20 Hz) ,– Audible (20-16,000)– Ultrasonic (> 16,000)
Factors contributing to noise hazard
• Noise spectrum• Overall noise exposure• Duration of exposure• Individual susceptibility.
Type of noise
• Steady state noise• Intermitent noise• Fluctuation noise• Impulse noise
Effect of noise
• Noise induced hearing loss– Temporary – permanent
• Rupture of ear drum• Dislocation os ossicle• Speech interference• Annoyance
• Other effect– Task performances– Intrusion of privacy– tinnitus’– Blood pressure– Fatique– Bood sugar– Gastric acid secretions
• Intermittent noise– Less effect than steady
state noise
• Impulse noise– Effect depend on
number of impulse exposed.
Hearing Conservation Programme
• Indication s for the ed of a HCP– Difficulty in communication– Tinnitus after workking– Temporay losss of hearing
Elements of HCP
• Assessment of noise exposure • Noise control• Audiometric testing programme• Medical evaluation and treatment• Health education and training• Provision of hearing protection• Establishment of proper record keeping.
Assessment of noise
• Competent person• To know the noise level• Mapping the noise level• >85 dB (action level) – do HCP• < 85 dB – no HCP
Noise Control
• Nose reduction activities to less than 85 dB• Engineering control• Administrative control• Both methods• Control strategies:
– Sources– At path– Receiver
Education programme
• To educate the workers• Training every 2 years• Teach them
– Effect of noise– Control– Personel protective equipment and maintenance– Audiomeric test – Noise regulations– etc
Audiomeric testing programme
• Baseline audiometric test• Periodic audiometric test• Objective the test:
– To establish the hearing status.– To monitor hearing loss during period of
employement– To identify worker who is secceptible to noise– To regulate noise hearing programme
Medical Evaluation and treatment
• Abnormal audiogram refer to doctor• Hearing problems refer to doctor
Povision of hearing protectors
• Ear plugs• Ear muffs• Factors deciding type of PPE.
– Sound reduction properties– Comfort of worker– Cost– Approved by DOSH.
Record Keeping
• Name• Job• Location of employee• Base line audiogram• Occupational history• Medical examination
• Keep record for 5years after stop work.