Workplace Noise Management: Acoustic Environment & Worker Safety

Acoustic Environment: Managing Workplace Noise

Key Concepts of Workplace Noise

• Noise is a particularly annoying and unpleasant sound that can be harmful to health.
• Sound can be defined as a set of mechanical waves transmitted through a medium.
• Auditory capacity is the processing of sound into nerve signals that are interpreted by the brain.

Characteristics of Sound and Noise

• Frequency: The number of pressure variations of a sound wave per second. It characterizes the tone we perceive. The human ear can typically perceive 20 - 20,000 Hz, but the most common range for speech is 500 - 3,000 Hz.
• Intensity (Sound Pressure Level): The sound pressure capable of being perceived by the human ear. Levels above 120 dB can cause severe pain; prolonged exposure can lead to chronic pain.

Noise Exposure Rate Types

• Stable: Difference between maximum and minimum values is less than 5 dB.
• Random: Variation exceeds 5 dB and fluctuates randomly over time.
• Pulse: Lasts less than one second and decreases exponentially over time.

Health Effects of Noise Exposure

Auditory Effects of Noise

• Temporary Hearing Loss
• Permanent Hearing Loss
• Acoustic Trauma
• Noise-Induced Hearing Loss (NIHL)

Noise Level Risk Thresholds

• Risk Level: Exposure above 80 dB

Non-Auditory Physiological Effects

• Increased Blood Pressure
• Increased Respiratory Rate
• Stomach Ulcers
• Sleep Disorders
• Difficulty in Spoken Communication
• Difficulty Concentrating
• Nuisance and Irritation
• Decreased Performance
• Increased Accident Risk

Noise Evaluation and Measurement

Noise Measuring Instruments

• Sound Level Meters: For stable noise levels.
• Acoustic Dosimeters: For fluctuating noise levels.
• Frequency Analyzers

Noise Level Estimation Guidelines

• 45 dB: Threshold of Discomfort
• Equivalent Daily Level: 90 dB
• Peak Level: 140 dB

Hearing Assessment Methods

• Audiometer
• Audiogram

Protecting Workers from Noise Exposure

Workplace Noise Exposure Limits

• Daily Equivalent Level: 87 dB
• Peak Level: 140 dB

Setting Exposure Control Levels

Employer Obligations for Noise Safety

• Hygienic Evaluation of Workplaces
• Health Monitoring of Workers
• Provision of Hearing Protectors
• Delimitation of Noise Zones and Signposting
• Information and Training for Workers