63. Physical hazards in the workplace – noise.

What is the definition of noise?

Unwanted sound audible to the human ear, typically between 16 Hz and 20,000 Hz.

What are the thresholds for ultrasound and infrasound?

Ultrasound > 20,000 Hz; Infrasound < 16 Hz.

Name common sources of environmental noise.

Cars, industry, aircraft, public areas (e.g. railway stations, airports), domestic appliances.

What variables influence risk of noise exposure?

Frequency composition, amplitude, and continuousness.

What unit is used to measure occupational noise exposure?

Decibel (dB), representing sound pressure level.

What is the threshold of pain in dB?

140 dB.

At what dB level does noise become harmful?

Above 85 dB.

List factors that affect noise exposure in the workplace.

Intensity, type of noise, period of exposure, work duration, age, susceptibility, hearing disease, surroundings, distance, and ear position.

What is the most serious auditory effect of noise?

Permanent hearing loss.

Name auditory effects of noise.

Hearing fatigue, temporary and permanent threshold shift, tinnitus, acute acoustic trauma.

Name non-auditory effects of noise.

Speech interference, annoyance, decreased efficiency, headache, irritability, high BP, increased heart rate and sweating.

How can workplace noise exposure be controlled?

Reduce noise at source, block transmission path, limit exposure time, use administrative controls, provide ear protection.

When is a hearing conservation program required?

When noise exposure exceeds 8-hour time-weighted average of 85 dB/A.

What are key components of a hearing conservation program?

Exposure monitoring, audiometric testing, hearing protection, training, and record keeping.

How can city planning help control noise?

Zoning, green belts, wider streets, separating residential from industrial areas.

What vehicle-related strategies reduce city noise?

Restrict heavy vehicles from narrow/residential streets and reduce traffic in quiet zones.

What building strategies reduce noise exposure?

Acoustic insulation and constructing detached rather than large shared buildings.

How can industry-related noise be controlled in cities?

Use of green belts to separate residential areas from industrial and railway zones.