Noise

Objectives

Understand effects of noiseIdentify at risk personnelIdentify ways to reduce noise exposureIdentify hearing protection devices

dBA chart

Noise Effects

Exposure to high levels of noise may cause hearing loss, create physical and psychological stress, reduce productivity, interfere with communication, and contribute to accidents and injuries by making it difficult to hear warning signals.

Noise Effects

Exposure to loud noise will inevitably cause hearing loss over time.Loud noise damages or destroys the hair cells in the inner ear.Another effect can be “tinnitus” or permanent ringing in the ear

Noise Effects

Damaged

Normal

At Risk

Noise - unwanted soundsPotentially hazardous noise

Continuous noise at >84 dBAImpact or Impulse Noise at ≥140 dBA

At Risk

Personnel who work in or around loud noise levels. Ex: Mechanics, Construction, Artillery, Firing Range, etc.

Noise Reduction

Preventive medicine should identify unwanted sounds and find a way to reduce or eliminate it

What is causing the noise?Can personnel working there be put on shifts to reduce exposure?Can the proper hearing devices be supplied?Can we engineer a way to reduce noise?

Noise Reduction

Engineering Control - Primary way to prevent noise (enclosing noise source, baffling, lubrication, acoustic barriers)

Protective devices - Secondary way to prevent noise (ear muffles and ear plugs)

Hearing Devices

There are many types of hearing deviceSemi-insert ear plugs which consist of two ear plugs held over the ends of the ear canal by a rigid headband. Ear muffs consist of sound-attenuating material and soft ear cushions that fit around the ear and hard outer cups. They are held together by a head band.

Ear plugs are inserted to block the ear canal. They may be premolded (preformed) or moldable (foam ear plugs). Ear plugs are sold as disposable products or reusable plugs. Custom molded ear plugs are also available.

Hearing Devices

Semi inserted Ear Plugs

Ear Muffs

Ear Plugs

Review Questions

1. What may happen if exposed to high levels of noise?

2. What is the at risk noise level?3. What is engineering controls?4. What are the three types of hearing devices?