---
title: "MSHA Noise Limits: TWA / Noise Dose, Max Level | Aethair"
description: "MSHA Occupational Noise Exposure (30 CFR Part 62) limit values for TWA / Noise Dose and Max Level: every value and averaging period, who the standard…"
url: https://aethair.io/standards/msha_noise/
---

Compliance · US MSHA

# MSHA Occupational Noise Exposure (30 CFR Part 62)

Occupational: mines (USA), hearing conservation

The US Mine Safety and Health Administration's noise standard, **30 CFR Part 62**, protects miners' hearing. It sets a **permissible exposure level of 90 dBA as an 8-hour time-weighted average** (a dose of 100 %), an **action level of 85 dBA** (a dose of 50 %) that requires enrollment in a hearing conservation program, and a ceiling: **no miner may be exposed at any time to sound levels above 115 dBA**. Doses use a **5 dB exchange rate**.

[Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure MSHA noise Monitoring](https://aethair.io/build/?params=sound_twa,sound_lmax)

At a glance

**US MSHA** Occupational: mines (USA), hearing conservation

2 parameters · 3 limit values

[TWA / Noise Dose](https://aethair.io/parameters/sound_twa/) [Max Level (Lmax)](https://aethair.io/parameters/sound_lmax/)

1 device measures them all

- **Thiamis** TSI Noise Monitors

[Official text from US MSHA](https://www.ecfr.gov/current/title-30/chapter-I/subchapter-M/part-62)

Limit values

## MSHA noise Limit Values

Every value US MSHA publishes for the 2 parameters below, with its averaging period, as the standard states it.

[**TWA / Noise Dose** Noise](https://aethair.io/parameters/sound_twa/)

**90 dBA** *8-hour TWA (PEL)* 5 dB exchange rate; integrates 90 to at least 140 dBA

**85 dBA** *8-hour TWA (action level)* hearing conservation program; integrates 80 to at least 130 dBA

[**Max Level (Lmax)** Noise](https://aethair.io/parameters/sound_lmax/)

**115 dBA** *Ceiling (at any time)* without adjustment for hearing protectors

Who it applies to

## Who Must Comply

Operators of US coal and metal and nonmetal mines, for every miner exposed to noise on a work shift.

Monitoring

## How Monitoring Demonstrates Compliance

Exposure is determined with a dosimeter or sound level meter integrating the levels the standard specifies over the shift. Above the permissible exposure level the operator must use feasible engineering and administrative controls; continuous [noise monitoring](https://aethair.io/solutions/noise/) at fixed points shows where and when levels rise, which is where those controls go.

[Customize this configuration](https://aethair.io/build/?params=sound_twa,sound_lmax)

### Who measures each parameter

| Parameter | Aethair PRO | Aethair IAQ | External |
| - | - | - | - |
| [TWA / Noise Dose](https://aethair.io/parameters/sound_twa/) | — | — | [1 instrument](https://aethair.io/parameters/sound_twa/) via Thiamis |
| [Max Level (Lmax)](https://aethair.io/parameters/sound_lmax/) | — | — | [1 instrument](https://aethair.io/parameters/sound_lmax/) via Thiamis |

Devices

## Devices That Cover MSHA noise

How much of this standard one Aethair monitor covers, followed by the third-party instruments in the sensor catalog that measure its parameters. Each connects to Environet through a Thiamis gateway, which adds whatever the monitor leaves out.

Covers both on its own

[**TSI SoundPro** Noise Monitors](https://aethair.io/sensors/tsi-noise-monitors/)

Solutions

## Solutions Judged Against MSHA noise

### [Cabin Air Quality](https://aethair.io/solutions/cabin-air/)

Respirable dust, gases, and blast monitoring

[All solutions](https://aethair.io/solutions/)

Questions

## MSHA noise FAQ

What is the MSHA noise limit?

A permissible exposure level of 90 dBA as an 8-hour time-weighted average, with an action level of 85 dBA and no exposure at any time above 115 dBA.

How does MSHA's noise standard differ from OSHA's?

Both use a 90 dBA permissible level, an 85 dBA action level, and a 5 dB exchange rate; MSHA's applies to mines, OSHA's ([29 CFR 1910.95](https://aethair.io/standards/occupational_noise/)) to general industry.

What happens at the MSHA action level?

A miner whose exposure reaches the 85 dBA action level must be enrolled in a hearing conservation program.