5 Proven Strategies for Reducing Industrial Noise and Meeting OSHA Compliance

Highlights

Understand the Law: OSHA’s Noise Standard (29 CFR 1910.95) mandates action when noise exposure exceeds an 8-hour time-weighted average of 85 dBA.
Use a Proven Framework: The most effective strategies for reducing industrial noise follow the NIOSH Hierarchy of Controls, which prioritizes solutions from most to least effective.
Prioritize Engineering Controls: Modifying equipment and installing barriers or enclosures are the most durable and reliable methods for long-term noise reduction and compliance.
Combine Strategies: A successful noise control program often uses a combination of engineering controls, administrative changes, and personal protective equipment (PPE).
Compliance is Key: Implementing these strategies is essential for protecting employee hearing, improving productivity, and avoiding costly OSHA citations.

Understanding the OSHA Noise Standard

Industrial facilities are often loud environments. The sound from machinery, processes, and equipment is a common part of daily operations. However, when noise levels become too high, they stop being a simple byproduct and become a serious workplace hazard. Exposure to excessive noise can cause permanent hearing loss, increase employee stress, and contribute to workplace accidents. For facility managers and safety professionals, reducing industrial noise is a critical responsibility for both employee well-being and legal compliance.

The U.S. Occupational Safety and Health Administration (OSHA) has strict regulations for protecting workers from noise. Meeting these standards requires a clear and effective strategy. This article outlines five proven strategies for reducing industrial noise in your facility. These methods are based on the Hierarchy of Controls, a framework developed by the National Institute for Occupational Safety and Health (NIOSH) that ranks safety solutions from most to least effective. Following this guide will help you create a safer, quieter workplace and ensure you meet your OSHA compliance obligations.

Before implementing any noise control strategy, it is important to understand the legal requirements. OSHA’s Occupational Noise Exposure standard sets the rules for workplace noise. The standard establishes two critical thresholds: 

  1. 1. The Action Level: An 8-hour time-weighted average (TWA) exposure of 85 decibels (dBA). When employee exposure reaches this level, the employer must implement a formal Hearing Conservation Program.

  2. 2. The Permissible Exposure Limit (PEL): An 8-hour TWA exposure of 90 dBA. Employers must use feasible engineering or administrative controls to keep exposures below this limit. 

A Hearing Conservation Program is a comprehensive effort that includes noise monitoring, employee training, hearing protection, and annual hearing tests (audiograms) to track employee hearing health over time. 

The Framework: The NIOSH Hierarchy of Controls

The most effective way to approach any workplace hazard, including noise, is by using the hierarchy of controls. This framework prioritizes control methods in five levels, from most effective to least effective. The strategies for reducing industrial noise should always be considered in this order.

Elimination: Physically remove the noise source.
Substitution: Replace the noise source with something quieter.
Engineering Controls: Isolate people from the noise.
Administrative Controls: Change the way people work.
Personal Protective Equipment (PPE): Protect the worker with hearing protection.

The following five strategies are based directly on this proven model.

Hierarchy of Controls
Source: CDC (NIOSH)*

Strategy 1: Elimination (Most Effective)

For many applications, certain STC levels are considered standard. For example, the International Building Code (IBC) requires a minimum STC rating of 50 for wall and floor assemblies separating different dwelling units (e.g., in apartment buildings or hotels). This is considered the threshold for providing good sound isolation and minimizing noise complaints between neighbors. For more sensitive spaces, like conference rooms or executive offices, an STC of 55 or higher is often specified.

Examples of Elimination:

Process Redesign: Can a manufacturing process be changed to eliminate a noisy step? For example, can parts be welded instead of being joined with loud riveting machines?
Removing Redundant Equipment: Decommissioning and removing old, loud machinery that is no longer essential to operations.
“Buy Quiet” Programs: Implementing a company policy to purchase quieter machinery and tools from the start. Organizations like NASA have promoted “Buy Quiet” initiatives to encourage this proactive approach.
Elimination is the ideal solution because it is permanent and does not require ongoing employee action to be effective.

Strategy 2: Substitution

For many applications, certain STC levels are considered standard. For example, the International Building Code (IBC) requires a minimum STC rating of 50 for wall and floor assemblies separating different dwelling units (e.g., in apartment buildings or hotels). This is considered the threshold for providing good sound isolation and minimizing noise complaints between neighbors. For more sensitive spaces, like conference rooms or executive offices, an STC of 55 or higher is often specified.

Examples of Elimination:

Process Redesign: Can a manufacturing process be changed to eliminate a noisy step? For example, can parts be welded instead of being joined with loud riveting machines?
Removing Redundant Equipment: Decommissioning and removing old, loud machinery that is no longer essential to operations.
“Buy Quiet” Programs: Implementing a company policy to purchase quieter machinery and tools from the start. Organizations like NASA have promoted “Buy Quiet” initiatives to encourage this proactive approach.
Elimination is the ideal solution because it is permanent and does not require ongoing employee action to be effective.

Strategy 3: Engineering Controls (The Technical Solution)

Engineering controls are physical changes to the workplace that reduce noise levels at the source or along the path to the worker. This strategy is the core of technical noise control and is often the most durable and reliable long-term solution for existing facilities. Our work in Industrial Noise & Vibration Control focuses heavily on these solutions.

Engineering controls can be broken down into three main categories:

Control at the Source: This involves modifying the noisy machine itself to make it quieter.

Install Mufflers or Silencers: Adding mufflers to engine exhausts or silencers to compressed air releases can dramatically reduce noise.
Modify Fan Blades: Changing the shape, size, or angle of fan blades can reduce aerodynamic noise.
Improve Lubrication: Proper maintenance and lubrication of bearings and gears reduces noise from friction and wear. This is a key part of any predictive maintenance program.

Control Along the Path: This involves placing a barrier between the noise source and the employee.

Acoustic Barriers: Constructing walls or partitions made from sound-absorbing materials between a noisy machine and a worker’s station.
Acoustic Enclosures: Building a full enclosure around a piece of equipment to contain the noise. A properly engineered solution must balance sound reduction with the machine’s need for ventilation and operator access. For more information, see our guide on designing high-performance acoustic enclosures.

Control at the Receiver: This is less common but can involve creating a quiet space for the worker.

Operator Booths: Placing an operator who monitors a loud process inside a soundproof control room or booth.

The NIOSH Engineering Controls Database is an excellent resource for exploring proven solutions for specific industries and equipment.

Strategy 4: Administrative Controls

Administrative controls change how and when employees work to limit their noise exposure. These controls do not reduce the noise itself but reduce the dose of noise an employee receives over a shift. They are often used in combination with engineering controls.

Examples of Administrative Controls:

Job Rotation: Rotating employees between quiet and noisy tasks to ensure their 8-hour TWA exposure remains below the 85 dBA Action Level.
Time Limits: Restricting the amount of time an employee can spend in a high-noise area.
Scheduling: Running the noisiest operations during shifts with the fewest number of employees present.
Increasing Distance: Moving workers farther away from a noise source. For every doubling of distance from a source, the noise level decreases by approximately 6 dBA.
These controls require careful management and supervision to be effective.

Strategy 5: Personal Protective Equipment (PPE)

Personal Protective Equipment (PPE) is the last line of defense against hazardous noise. PPE for noise includes earplugs and earmuffs. When engineering and administrative controls cannot reduce noise exposure to safe levels, employers must provide PPE to their employees.

While necessary, PPE is considered the least effective control method for several reasons:

It relies on consistent and correct use by the employee.
If not fitted properly, its effectiveness is greatly reduced.
It can introduce other hazards by making it difficult to hear warning signals or communicate.
When selecting PPE, you must consider its Noise Reduction Rating (NRR). The NRR is a laboratory-derived number that indicates how much noise the device can block. However, OSHA requires employers to de-rate the NRR to estimate its real-world performance. For example, when estimating the protection from an A-weighted noise measurement, you must first subtract 7 from the NRR before subtracting the result from the noise level.

The Framework: The NIOSH Hierarchy of Controls

Reducing industrial noise is a critical part of any effective safety program. By using the NIOSH Hierarchy of Controls as a guide, facility managers can move beyond simply handing out earplugs and implement more durable and effective solutions.

While all five strategies have their place, a focus on engineering controls provides the most reliable protection for employees and the most dependable path to long-term OSHA compliance. A well-designed acoustic enclosure or a properly silenced machine protects every worker in the area, every shift, without requiring individual action.

If your facility is facing challenges with hazardous noise, a professional assessment is the best first step. To discuss your specific needs for noise monitoring or engineering control design, please contact us for a consultation.