OSHA Permissible Noise Exposure Chart (Table G-16)

What it is

Table G-16 in 29 CFR 1910.95(b)(1) lists how long a worker may be exposed each day at a given sound level, measured in dBA on a sound level meter set to slow response. The table starts at 90 dBA for 8 hours and uses a 5 dB exchange rate: every 5 dB increase cuts the allowed time in half. When exposures exceed these limits, OSHA requires feasible engineering or administrative controls, and hearing protection if those controls do not bring exposure within the table.

How to read it

1. Find the sound level in the left column.
2. Read the maximum duration per day in the right column.
3. For a day with several different levels, add up each fraction of time spent divided by time allowed (C1/T1 + C2/T2 + ...). If the total is more than 1, the mixed exposure exceeds the limit.

Table G-16 permissible noise exposures

Key points

• Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level (footnote to Table G-16).
• OSHA uses a 5 dB exchange rate. NIOSH recommends a stricter limit (85 dBA for 8 hours with a 3 dB exchange rate). Do not mix the two systems on one chart.
• The hearing conservation program is triggered at a lower level, the 85 dBA 8-hour TWA action level in 1910.95(c).
• Appendix A of 1910.95 gives the formula for durations between table values: T = 8 / 2 raised to the power (L minus 90) / 5.
• Construction work is covered by 29 CFR 1926.52, which has its own table.

Common mistakes

• Reading the table as a protector rating chart. It sets exposure limits, not NRRs.
• Applying the 3 dB NIOSH rule when explaining an OSHA requirement, or the reverse.
• Adding sound levels in decibels arithmetically. Decibels add logarithmically; use the dose fraction method.
• Ignoring short, very loud tasks that push the daily dose over 1.

Governing standards: 29 CFR 1910.95(b)(1), Table G-16; 29 CFR 1910.95 Appendix A.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.