Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
Hearing loss from tools is not dramatic and that is the whole problem with it. There is no pain, no bruise, and no moment where you notice it happening — you notice it years later, in a restaurant, when you cannot follow a conversation. NIOSH puts lawn mowers, vacuums and power tools at around 85 to 90 dBA, and chain saws among the things that average 95 dBA or higher. Those are not exotic numbers reserved for a factory floor. They are a Saturday morning in the garden.
This page does three things. It gives you a way to estimate how loud your equipment is without a meter, using NIOSH's own published voice test. It sets out both federal exposure limits — NIOSH recommends 85 dBA over eight hours with a 3 dBA exchange rate, OSHA permits 90 dBA over eight hours with a 5 dBA exchange rate — and it does not merge them, because they are different by design and knowing which one you are working to is the point. And it shows what to do with the NRR printed on the package, using OSHA's published arithmetic rather than a rule of thumb, alongside NIOSH's own position that the printed rating often does not reflect the protection an individual person actually gets.
Necessary equipment
| Item | Note |
|---|---|
| Hearing protectors | Earmuffs and earplugs are the two usual types. |
| Documentation for your equipment | Some manufacturers give a sound level for the machine. |
| Clock or timer | The time of use decides the limit as much as the sound level does. |
| Sound level meter optional | A meter gives a measurement instead of an estimate. |
Find the sound level of the equipment
Estimated 11 min to 22 min
Source: Noise-Induced Hearing Loss · tier 1 · accessed 2026-07-29
Source: Noise-Induced Hearing Loss · tier 1 · accessed 2026-07-29
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
WEAR HEARING PROTECTION BEFORE YOU START A LOUD TOOL.
Noise injures the ear permanently. The ear does not repair itself.
- Find a sound level in the documentation for your equipment.4mReport a problem with step 1, Find the sound level of the equipment
- Some manufacturers give a sound level in dBA for the machine.
- Many manufacturers give no figure at all.
- If there is no figure, do the voice test that NIOSH gives.3mReport a problem with step 2, Find the sound level of the equipment
- Start the equipment.
- Ask a second person to stand three feet away.
- Speak to that person in your usual voice.
- If you must make your voice louder, the level is about 85 dBA.1mReport a problem with step 3, Find the sound level of the equipment
- NIOSH states that sounds at 85 dBA often need a louder voice at three feet.
- If you must shout, the level is 95 dBA or more.1mReport a problem with step 4, Find the sound level of the equipment
- NIOSH states that you likely have to shout at three feet at 95 dBA or more.
- NIOSH puts a chain saw and a bulldozer in this group.
- NIOSH puts a lawn mower, a vacuum and a power tool at about 85 to 90 dBA.
RECORD THE TIME OF USE EACH DAY.
The time decides the limit as much as the sound level does.
- Record the number of hours that you use the equipment each day.2mReport a problem with step 5, Find the sound level of the equipment
- Add the time from all the loud tools of the day.
- A limit is a level and a time together.
Compare the level with the two federal limits
Estimated 8 min to 12 min
Source: Understand Noise Exposure · tier 1 · accessed 2026-07-29
Source: Understand Noise Exposure · tier 1 · accessed 2026-07-29
Source: 29 CFR 1910.95 — Occupational noise exposure · tier 1 · accessed 2026-07-29
Source: 29 CFR 1910.95 — Occupational noise exposure · tier 1 · accessed 2026-07-29
Source: OSHA Technical Manual, Section III Chapter 5 — Noise · tier 1 · accessed 2026-07-29
- Compare your level with the NIOSH limit of 85 dBA.3mReport a problem with step 1, Compare the level with the two federal limits
- NIOSH gives 85 dBA over an eight-hour shift.
- NIOSH cuts the time by one half for each 3 dBA more.
- NIOSH calls this the exchange rate.
- Compare your level with the OSHA limit of 90 dBA.3mReport a problem with step 2, Compare the level with the two federal limits
- OSHA gives 90 dBA for eight hours in its Table G-16.
- OSHA uses an exchange rate of 5 dBA.
- OSHA starts a hearing conservation program at 85 dBA over eight hours.
- Use the lower limit if you are not sure about the correct limit.2mReport a problem with step 3, Compare the level with the two federal limits
- The two federal bodies do not agree, and the difference is deliberate.
- Do not use a number between the two limits.
- An employer in the United States must obey the OSHA limit.
Select the type of protector
Estimated 7 min to 17 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- Select earmuffs or earplugs.5mReport a problem with step 1, Select the type of protector
- NIOSH states that earplugs are often more comfortable than earmuffs.
- A person wears a comfortable protector for more of the time.
- A protector in your pocket gives no protection at all.
DO NOT USE THE NUMBER ON THE PACKAGE AS THE PROTECTION THAT YOU GET.
NIOSH states that the number often does not show the protection that a worker gets. Noise injures the ear if the protection is not enough.
- Read the noise reduction rating on the package.2mReport a problem with step 2, Select the type of protector
- Manufacturers put a noise reduction rating on the package.
- NIOSH states that this rating often does not show the protection that each worker gets.
Estimate the protection that you get
Estimated 7 min to 9 min
Source: 29 CFR 1910.95 Appendix B — Methods for Estimating the Adequacy of Hearing Protector Attenuation · tier 1 · accessed 2026-07-29
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- OSHA tells you to subtract 7 dB from the noise reduction rating.2mReport a problem with step 1, Estimate the protection that you get
- This step is the first half of the method in OSHA 1910.95 Appendix B.
- The method applies to a sound level meter set to the A scale.
- Subtract the remainder from your A-weighted level.3mReport a problem with step 2, Estimate the protection that you get
- This result is the level below the protector.
- Compare that result with the limit from the section above.
- Select a different protector if the result is above the limit.
MAKE SURE THAT YOU CAN HEAR AN ALARM OR A SHOUT.
A protector can hide a warning sound. You can then move into danger.
- Do not use the OSHA arithmetic with a NIOSH derating method.2mReport a problem with step 3, Estimate the protection that you get
- OSHA and NIOSH publish two different methods for the same question.
- NIOSH now gives a fit test and a personal attenuation rating.
- Select one method. Then keep that method.
Put the protector on correctly
Estimated 8 min to 10 min
- Read the instructions on the package of the protector.2mReport a problem with step 1, Put the protector on correctly
- An earplug that is not deep in the ear gives much less protection.
WEAR THE PROTECTOR BEFORE THE NOISE STARTS.
Injury from noise starts with the noise. There is no safe first minute.
- Put the protector on before you start the equipment.1mReport a problem with step 2, Put the protector on correctly
- Do this step outside the noise if you can.
DO NOT PUT A DIRTY EARPLUG IN YOUR EAR.
Dirt on an earplug can cause an ear infection.
- Roll a foam earplug into a thin rod with clean hands.2mReport a problem with step 3, Put the protector on correctly
- Pull the top of the ear up and back with the other hand.
- Push the earplug into the ear canal.
- Hold the earplug until the foam expands.
- Make sure that the earmuff cushion has a seal on the head.2mReport a problem with step 4, Put the protector on correctly
- Move the hair and the spectacle arms out of the cushion.
- A gap of one hair width decreases the protection.
KEEP THE PROTECTOR ON YOUR HEAD UNTIL THE TOOL STOPS.
Noise injures the ear during the time that the protector is off.
- Speak in your usual voice and listen to your own voice.1mReport a problem with step 5, Put the protector on correctly
- Your voice is louder in your head when the seal is good.
- Fit the protector again if your voice does not change.
Keep the protector in good condition
Estimated 6 min to 13 min
- Discard a used foam earplug.1mReport a problem with step 1, Keep the protector in good condition
- Wash a reusable earplug as its instructions tell you.
- Let the earplug become dry before you use it again.
REPLACE AN EARMUFF CUSHION THAT IS HARD OR THAT HAS A CRACK.
A cushion with no seal gives much less protection.
- Examine the earmuff cushions each month.2mReport a problem with step 2, Keep the protector in good condition
- Look for a hard cushion, a crack or a leak.
- Replace the cushions from the manufacturer of the earmuffs.
- Keep a protector at each place where you use a loud tool.3mReport a problem with step 3, Keep the protector in good condition
- A protector in the house is a protector that you do not use.
- Keep a spare pair in the vehicle.
Terminology
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
- hearing protector
- Also called: ear protection, ear defenders, ear muffs, earmuffs, ear plugs, earplugs, hearing protection, cans
- noise reduction rating
- Also called: NRR, NRR rating, decibel rating, db rating, noise rating, SNR
- A-weighted decibel
- Also called: dBA, dB, decibels, db level, how loud is it
- exchange rate
- Also called: doubling rate, trading ratio, how the time halves, 3 db rule, 5 db rule
- noise-induced hearing loss
- Also called: hearing damage, going deaf, tinnitus, ringing in the ears, industrial deafness
When to use a professional
Speak to a doctor if you have a ringing sound in the ear. Speak to a doctor also if sounds are not as loud as before. Noise injures the ear permanently and the injury does not repair itself.
Speak to your employer if you use loud equipment at work. An employer in the United States has duties under OSHA 1910.95. These duties include a hearing conservation program and hearing protectors at no cost to you.
This page gives an estimate and not a measurement. Speak to an occupational health service for a real measurement of your own exposure. Only a service with a meter and a dosimeter can give that measurement.
Do not put anything except a hearing protector into the ear canal. Speak to a doctor about pain, discharge or a blocked ear.
Common questions
What NRR do I actually need for a lawn mower or a circular saw?
Start from the level, not from the rating. NIOSH puts lawn mowers, vacuums and power tools at around 85 to 90 dBA, so you are already at or above the level NIOSH treats as hazardous before you have done anything. OSHA's published way of turning a rating into an expected result is to subtract 7 dB from the NRR and then subtract the remainder from your A-weighted exposure. Run your own number through that and see whether the result lands under the limit you are working to. What you should not do is buy the highest NRR on the shelf and stop thinking, because a protector you find uncomfortable is a protector you take off.
Why do NIOSH and OSHA give different limits? Is one of them wrong?
Neither is wrong, and the gap is deliberate. NIOSH's recommended exposure limit is 85 dBA over an eight-hour shift with a 3 dBA exchange rate — for every 3 dBA more, halve the time. OSHA's Table G-16 permits 90 dBA for eight hours and uses a 5 dBA exchange rate, and OSHA requires a hearing conservation program from 85 dBA upward. The NIOSH Science Bulletin explains the mechanism plainly: OSHA must consider cost and feasibility of implementation before it can adopt a NIOSH recommendation as a mandatory standard. A recommendation is health-based; a standard is health-based and enforceable. If you are working for yourself in your own garden, the lower one is the sensible target.
Is the number on the packet what I really get?
No, and NIOSH says so in its own words: manufacturers include a noise reduction rating on packaging, but this often does not reflect the actual protection provided for each worker. The rating comes from a laboratory test on people who have been fitted carefully. Real fit is worse — hair in the earmuff seal, spectacle arms, an earplug that was not rolled thin enough or pushed in far enough. That is exactly why OSHA publishes arithmetic that knocks the rating down before you use it, and why NIOSH now points at fit testing, which produces a Personal Attenuation Rating for one specific person wearing one specific protector.
I have seen a rule about derating by 25% or 50%. Should I use that?
That family of percentages is a real published NIOSH methodology, not folklore — but it lives in the NIOSH criteria document on occupational noise exposure, and we did not open that document for this page, so we are not printing the numbers from memory or from a second-hand copy. What we can point at is what NIOSH's current hearing protection page says: it notes that NIOSH has previously recommended derating the NRR as explained in that criteria document, and it now directs attention to fit testing and a Personal Attenuation Rating instead. If you want a derating percentage, take it from the criteria document itself. Do not take the front of OSHA's method and the back of NIOSH's — that produces a number neither agency stands behind.
How do I tell how loud something is without buying a meter?
NIOSH publishes a field test that costs nothing. Sounds that are 85 dBA often require you to raise your voice to be heard by someone 3 feet away, and as noise reaches 95 dBA or more you likely have to shout to be heard by someone 3 feet away. Stand a friend an arm's length or so away with the machine running and see which of those two describes you. It is an estimate and this page says so, but it is an estimate from the agency that sets the limit, which is a better starting point than a guess.
Earplugs or earmuffs — which is better?
The one you will keep wearing. NIOSH's own observation is that earplugs are often more comfortable than earmuffs, especially when worn for long periods of time or in hot environments, which matters more than most people expect on a hot afternoon with a blower. Earmuffs are faster on and off, which suits a job where the tool is running in bursts. Earplugs go deeper and are harder to get right, and a badly seated foam plug loses a great deal of its protection. If you are between the two, pick on comfort and then check the fit properly.
Does it matter if I take them off for a minute to hear someone?
Yes, and more than seems fair. Both agencies work in a currency where a small rise in level buys a large cut in allowed time — 3 dBA halves it for NIOSH, 5 dBA for OSHA — so unprotected minutes at 95 dBA are expensive against a budget set at 85. Stop the tool instead. If you need to hear people or alarms regularly, that is an argument for a protector you can lift quickly rather than for wearing nothing.
Can hearing protection be dangerous — will I miss a warning shout?
It is a real trade-off and worth planning for rather than ignoring. A protector that cuts the machine also cuts a shout, a reversing alarm, and a car coming up the drive. The answer is not to work unprotected but to change what you rely on: look before you move, agree hand signals with anyone helping, and do not work in traffic or near a moving vehicle while wearing high-attenuation muffs. Choosing more attenuation than you actually need makes this worse, which is another reason to do the arithmetic instead of buying the biggest number.
Related procedures
No related procedure is published yet. This section fills as the repository grows.
Sources
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
- Tier 129 CFR 1910.95 — Occupational noise exposure
- Tier 129 CFR 1910.95 Appendix B — Methods for Estimating the Adequacy of Hearing Protector Attenuation
- Tier 1OSHA Technical Manual, Section III Chapter 5 — Noise
- Tier 1Understand Noise Exposure
- Tier 1Provide Hearing Protection
- Tier 1Noise-Induced Hearing Loss
- Tier 1Understanding Noise Exposure Limits: Occupational vs. General Environmental Noise (NIOSH Science Bulletin, 2016)
Revision history
Current version 1 · updated 2026-07-29 · next review due 2027-07-29
- v1 · 2026-07-29First draft. Both federal exposure limits publish side by side and are not merged: NIOSH 85 dBA over eight hours with a 3 dBA exchange rate, OSHA Table G-16 90 dBA for eight hours with a 5 dBA exchange rate and an 85 dBA action level. The single derating method published is OSHA 1910.95 Appendix B method (iii), quoted from the regulation. The NIOSH derating percentages are deliberately NOT published: the criteria document that carries them was not opened for this record, so they publish as consult-the-source. NIOSH's current position — that the packaged NRR often does not reflect real protection, and that fit testing produces a Personal Attenuation Rating — is published alongside as the second method, and the record instructs the reader to use one method end to end. Equipment sound levels come from NIOSH and are quoted as ranges with the source named. The EPA labelling rule at 40 CFR 211 subpart B could not be read (ecfr.gov redirected to a block page) and is therefore not cited.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.