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.