Class 2 vs Class 3 vs foam: which ear plugs a workplace actually needs
Most sites buy hearing protection the way they buy gloves: the strongest thing on the shelf, by the carton. With ear plugs that backfires. The class has to match the measured noise, and the plug has to still be in the ear at the end of the shift. This page covers how the AS/NZS classes map to a noise level, what foam costs over a year against a reusable corded pair, and three sites where the answer comes out differently.
- What the classes mean
- Why more attenuation is often worse
- SLC(80) 14 dB on a 90 dB floor
- What foam costs over a year
- Three sites, three answers
- Choosing, in four questions
- Sources
What the classes mean
AS/NZS 1270:2002 is the test standard for hearing protectors. It produces one number, SLC(80): the decibels of reduction the protector achieves for at least 80% of wearers. That number puts the product in a class from 1 to 5.
AS/NZS 1269.3:2005 is the selection standard. Its classification method works from the worker's measured eight-hour exposure (LAeq,8h) and gives the class to buy for it:
| Class | SLC(80) | 8-hour exposure, dB(A) |
|---|---|---|
| Class 1 | 10 to 13 | less than 90 |
| Class 2 | 14 to 17 | 90 to less than 95 |
| Class 3 | 18 to 21 | 95 to less than 100 |
| Class 4 | 22 to 25 | 100 to less than 105 |
| Class 5 | 26 or more | 105 to less than 110 |
The workplace exposure standard is 85 dB(A) averaged over eight hours, with a peak of 140 dB(C). Exposure is measured without counting any hearing protection, so the class comes from a measured figure, not from what the floor sounds like.
Hearing protection is also the last control on the list. Removing the noise, swapping in quieter plant, isolating it and changing how the work is done all come first. Plugs cover what is left after that.
Why more attenuation is often worse
WorkSafe Victoria's guidance is that hearing protectors should not bring exposure much below 75 dB(A), because of over-protection. A worker who is cut off from the floor stops hearing the things that keep them safe on it:
- a reversing forklift or a siren,
- a shout from the next aisle,
- the radio, so the plug comes out every time it goes off.
And a plug that comes out stops protecting straight away. The same guidance shows what short breaks do to a protector rated at 30 dB:
| Worn for | Out of an 8-hour shift | Effective protection |
|---|---|---|
| 100% | never out | 30 dB |
| 98.6% | about 7 minutes out | 18 dB |
| 84% | about 77 minutes out | 8 dB |
Seven minutes out of the ear costs 12 dB. So a plug that is comfortable enough to stay in all shift protects more than a stronger one that keeps coming out. That is the whole case for matching the class to the noise instead of buying the top of the range.
SLC(80) 14 dB on a 90 dB floor
Take a floor with a measured eight-hour exposure of 90 dB(A). That is the bottom of the Class 2 band. Using the simple SLC(80) method, the level at the ear is the exposure minus the protector's SLC(80). Taking the lowest SLC(80) in each class:
| Protection | SLC(80) | At the ear | Against 85 and 75 dB(A) |
|---|---|---|---|
| None | 0 dB | 90 dB(A) | Over the 85 dB(A) standard. |
| Class 2 | 14 dB | 76 dB(A) | Under 85, not below 75. |
| Class 3 | 18 dB | 72 dB(A) | Under 85, below 75. |
| Class 5 | 26 dB | 64 dB(A) | Well below 75. The over-protection case. |
At the top of the band it still holds: 94 dB(A) less 14 dB leaves 80 dB(A) at the ear. At 95 and above, Class 2 no longer covers it and the table moves to Class 3.
This is the simplified single-number method. Where one frequency dominates, such as a particular machine's whine, the octave band method in AS/NZS 1269.3 is the better tool, and it needs measured data for the site.
What foam costs over a year
Foam looks cheap because it is priced per pair. The cost arrives per shift. A disposable pair is worn once and, more often than not, it is lost by the end of the shift. They turn up across the site and in the car park.
Here is one year costed both ways, using the same assumptions as the calculator on our home page: foam at 30 cents a pair, one pair per person per shift, 260 shifts a year. EarGuard at four pairs per person per year, priced at the tier each quantity earns.
| Team size | Foam pairs a year | Foam cost | EarGuard pairs a year | EarGuard cost | Difference |
|---|---|---|---|---|---|
| 1 worker | 260 | $78.00 | 4 | $11.96 | $66.04 |
| 10 workers | 2,600 | $780.00 | 40 | $111.60 | $668.40 |
| 50 workers | 13,000 | $3,900.00 | 200 | $500.00 | $3,400.00 |
EarGuard prices as listed: $2.99 a pair, $2.79 a pair from 10, $2.50 a pair from 100. The 10-worker row is 40 pairs at $2.79; the 50-worker row is 200 pairs at $2.50. Shipping is not included: Standard is $9.95 and free on orders over $65, so the 10- and 50-worker orders ship free. A pair lasts two to three months depending on use and care, and the table uses three. At two months it is six pairs a person a year, and the 10-worker figure becomes $167.40 instead of $111.60.
For your own headcount, the cost calculator on the home page runs the same comparison on a slider. It prices every pair at $2.99, so for a team it comes out a little higher than the table above.
Three sites, three answers
Anonymised. The first is a site that has already switched from foam. The other two turn on a measurement, and one of them is not ours to sell.
A Brisbane cold-store distribution centre
- Environment
- Docks, loaders and general machinery.
- Was using
- Disposable foam.
The foam was worn once and lost by the end of the shift. Used pairs turned up across the site and out in the car park.
A corded pair changes that. When a plug comes out so someone can talk, it hangs on the cord instead of going on the floor, and it goes back in. Washed and looked after, one pair lasts two to three months depending on use.
Class 2 corded. Most of the team preferred them over foam. Docks, loaders and general machinery is the kind of floor Class 2 is made for, provided the measured eight-hour figure sits between 90 and 95 dB(A).
An aged-care facility
- The question
- Whether any area measures over the exposure standard at all, and how long staff spend in it.
- Constraint
- Staff have to hear call bells and residents. That is the job, not a preference.
Most of an aged-care building is not a noise workplace. If anywhere is, it will be back of house: a commercial laundry, the kitchen, a plant room. Those are the areas to measure, not the whole building.
If a room measures under 90 dB(A), the table points to Class 1: at 88 dB(A), a Class 2 plug leaves 74 at the ear, which is over-protection. If it measures 90 to 95, Class 2 fits, worn in that room only. The cord helps here: plugs come out at the door and hang round the neck on the way back to residents.
Class 1 or Class 2, depending on the measurement, and only in the rooms that need it. When to wear them matters as much as which ones to buy.
A Melbourne coffee roastery
- The question
- A roaster, a grinder and a packing line are different machines. They can land in different classes in the same building.
Measure each area separately. Where the eight-hour figure is 90 to 95 dB(A), Class 2 covers it. Where any area is 95 or over, the selection table moves to Class 3. At the top of that band the reason is plain: 99 dB(A) less 14 dB leaves 85 at the ear, which is on the standard, not under it.
Possibly two classes under one roof. Class 2 where the figure is 90 to 95. Anywhere 95 or over needs Class 3, and we do not sell a Class 3 plug, so buy that from someone who does.
Choosing, in four questions
- What does the area actually measure? A measured eight-hour figure, per area, is the input to everything below. Without it, every other answer is a guess.
- Does the class bring it under 85 dB(A) without going much below 75? Under 85 is required. Far under 75 is how plugs end up in pockets.
- Does the job depend on hearing something? Reversing alarms, call bells, radios, shouted instructions. If it does, that limits how much attenuation will actually get worn.
- Will the format last the shift? A cord keeps a removed plug on the worker instead of on the floor. A washable pair that lasts a quarter is a reorder every few months, not a dispenser to refill every week.
Where we fit. EarGuard sells one product: an AS/NZS 1270:2002 Class 2 reusable corded plug, SLC(80) 14 dB, under a current StandardsMark licence. It is the right plug for a 90 to 95 dB(A) exposure and the wrong one above that. The certificate is public (PDF).
Sources
- WorkSafe Victoria, Hearing protection: the class table from AS/NZS 1269.3, the 75 dB(A) over-protection guidance, and the wear-time table.
- Safe Work Australia, Managing noise and preventing hearing loss at work: Code of Practice (PDF).
- AS/NZS 1270:2002 Acoustics: Hearing protectors. AS/NZS 1269.3:2005 Occupational noise management, Part 3: Hearing protector program.
Class 2 reusable corded ear plugs, $2.99 a pair, bulk pricing from 10.
See the product and pricingStandardising across a site? Ask for a bulk quote. WHS documentation for procurement and audit can be supplied with the order.