Glossary
Standards and regulations
OSHA 29 CFR 1910.95
Also known as OSHA noise standard, 29 CFR 1910.95, OSHA Occupational Noise Exposure.
OSHA 29 CFR 1910.95 is the US Occupational Safety and Health Administration's standard for occupational noise exposure in general industry. Two thresholds matter:
- Action level — 85 dBA TWA (time-weighted average over an 8-hour shift) — triggers a hearing-conservation programme
- Permissible exposure limit (PEL) — 90 dBA TWA — at which engineering controls or hearing protection are mandatory
How it interacts with sonic-horn installations
A sonic horn at the work area can exceed 130 dBA SPL at close range. Operators within ear-shot of firing horns require hearing protection; permanent personnel exposure must be calculated as time-weighted average given the horn duty cycle and operator distance.
Mitigation options:
- Sound-attenuation enclosures at the bell
- Operator-station relocation outside the near-field
- Hearing-protection requirements during horn operation
- Acoustic monitoring during operator-presence audits
Related terms
Related terms
- Sound pressure levelSPL is the logarithmic measure of sound pressure in decibels relative to a 20 µPa reference. Industrial sonic horns operate at 140–180 dB SPL.
- EU Directive 2003/10/ECEU Directive 2003/10/EC sets noise-exposure limits for EU workplaces. Lower action 80 dBA, upper action 85 dBA, exposure limit 87 dBA, all daily averages.
- Sound-attenuation enclosure (sonic horn)A sound-attenuation enclosure surrounds the sonic horn to reduce SPL at the operator station. Typical 10–25 dB reduction; required where horn proximity exceeds OSHA / EU action levels.