US employers assessing occupational noise need to consider both sound level and duration. OSHA’s occupational-noise standard includes a permissible exposure limit of 90 dBA as an eight-hour time-weighted average for general industry and requires a hearing conservation program when employee exposure equals or exceeds an eight-hour time-weighted average of 85 dBA, calculated using OSHA’s methods.
NIOSH recommends an 85 dBA eight-hour exposure limit using a different exchange rate. The two frameworks should be labelled clearly; their figures cannot be mixed in one calculation.
A spot reading is not a daily exposure assessment
A phone app or one measurement at a desk cannot establish an employee’s time-weighted exposure. The assessment must consider changing levels, duration, work pattern, instrument suitability and calibration. Employers with potentially hazardous noise should use a competent occupational-noise professional and follow the requirements that apply to their industry and jurisdiction.
Office distraction is a separate question
Speech and calls can disrupt concentration at levels well below occupational hearing thresholds. That problem may require layout, source control, absorption, sound isolation, quiet rooms or operating rules. OSHA’s exposure limits should not be used as a comfort or productivity target.
