REHS Noise Lecture Vocabulary

Vocabulary flashcards covering key terms and regulations from the REHS Noise lecture.

Sound

Oscillations in pressure that convey useful communication or pleasant audible signals.

Noise

Unwanted or unpleasant sound that can cause negative effects depending on level, frequency, duration, and individual susceptibility.

Amplitude

Magnitude of sound pressure, perceived as loudness and reported on the decibel scale.

Frequency

Rate of vibration of a sound wave measured in hertz (Hz); perceived as pitch.

Time Pattern

Predictable pattern or fluctuation of noise over time.

Decibel (dB)

Unit that measures sound intensity (sound-pressure level).

dBA Scale

A-weighted decibel scale that reflects human hearing sensitivity in normal settings.

dBC Scale

C-weighted decibel scale used for measuring loudness in very noisy settings.

dBD Scale

D-weighted decibel scale designed for assessing aircraft noise impact on the human ear.

Hertz (Hz)

Unit of frequency equal to one cycle per second.

Noise Control Act of 1972

First U.S. federal law targeting environmental noise control; still in effect but unfunded since 1982.

Quiet Communities Act of 1978

Expanded federal anti-noise efforts; remains unfunded since 1982.

OSHA Permissible Exposure Limit (PEL)

90 dBA for an 8-hour workday for all U.S. workers.

NIOSH Recommended Exposure Limit (REL)

85 dBA over an 8-hour time-weighted average.

Cal/OSHA Noise Limit

85 dBA over an 8-hour workday; triggers required hearing conservation program.

Sone

Unit of perceived loudness; 40 phons at 1 kHz equals 1 sone.

Phon

Loudness level of a 1 kHz tone at a given dB; 40 dB equals 40 phons.

Sabin

Unit measuring a surface’s sound absorption ability.

Transverse Wave

Wave in which particles move perpendicular to the direction of wave travel (e.g., ripples on water).

Longitudinal Wave

Wave in which particles move parallel to wave travel; sound waves are longitudinal.

Sound Level Meter

Instrument that measures environmental sound intensity and elapsed time.

Noise Dosimeter

Device worn near a worker’s ear that records cumulative noise exposure over time (8-hour TWA).

Sensorineural Hearing Loss

Hearing impairment from damage to inner ear or nerve pathways, often affecting low frequencies.

Conductive Hearing Loss

Hearing loss caused by trauma or infection that impedes sound conduction to the inner ear.

Tinnitus

Perception of ringing or buzzing in the ears, often linked to hearing loss.

Loud-Noise Threshold

Sound levels above 120 dB that can cause immediate ear damage.

Combining Sound Sources Rule

When two sounds differ by >10 dB, the lower adds insignificantly; smaller differences add 0–3 dB to the total level.

Same-Sound Axioms

Two equal sounds add 3 dB; removing one subtracts 3 dB; three equal sounds add 4.8 dB.

Source-Path-Receiver Model

Noise control strategy focusing on modifying the source, disrupting the transmission path, or protecting the receiver.

Hearing Conservation Program

Employer-administered plan to monitor exposure and protect workers when noise equals or exceeds an 8-hour TWA of 85 dBA.