Reusing foam ear plugs multiple times
Despite ear plugs having quite a low per-pair cost, that cost can soon mount up and it is tempting for employers to limit how many pairs people can use in a given period, or the employees themselves choose to reuse them, but this is not always a good approach and can also be a false economy.
A review of why disposable foam ear plugs cannot be reused, covering both hygiene and performance issues.
Ear plug dispenser
I have seen employers set limits on how many ear plugs people can use, such as this site where they were limiting the disposable foam plugs to one pair per person per day, but this cannot be done.
There are good reasons for this, both in terms of hygiene and also effectiveness of the ear plug.
Why limit the use of ear plugs?
I do understand why employers do it - ear plugs can be expensive. If we take a basic standard ear plug of the Laser Lite, the foam ones which look like pear drops. They cost around 15p per pair. An average full time person works about 220 days a year, and if we assume a pair of plugs in the morning and another after the lunch break, that’s 440 pairs of plugs per person per year.
The cost mounts up and for those 15p disposable foam ones that’s about £66 per person per year. If you have 50 staff that becomes a not-inconsiderable cost of around £3,300 every year.
Hygiene issues with reusing foam ear plugs
When you take an ear plug out to go on a break you need somewhere to put them and a pocket or a table are simply not clean enough. Any dirt or bacteria in your pocket will then be on the ear plug, and when you put it back in the ear the bacteria are now in a warm moist place, it is inviting ear infections.
A basic principle is that ear plugs do not cause ear infections, dirty ear plugs on the other hand, or indeed dirty hands when handling the ear plugs, that can certainly cause an infection.
Add to that, foam ear plugs are simply not designed to be washed and then worn, they don’t work that way - you cannot adequately wash them and then put them back in.
Performance of foam ear plugs degrades with reuse
Foam ear plugs work by the slight expansion power forming a good seal in the ear canal and to do that they are designed to be rolled up, inserted and then allowed to expand but the more you do that, the less effect there is of that expansion and the less protection is received.
To test that I had a little play. As I have an audiometer I got a new pair of ear plugs, (EARSoft FX - yellow squishy ones) and put them in. I then did a hearing test while wearing them. I then took them out and let them recover, then I rolled them up and inserted them again. I repeated that ‘roll up, allow to expand, remove’ process three times and then put them in and did another hearing test while wearing them. This was the result:
Hearing test result for new and worn ear plugs.
In a hearing test, the lower down that chart the result is, the more protection is being given.
The red line was my result while wearing a brand new set of ear plugs.
The black line is the result after wearing them three times, there is consistently less protection across the entire frequency range. It is at least 10 dB worse in some areas, increasing to 15 and even 20 dB less protection at the lower frequencies.
Repeatedly wearing the protectors has taken away a lot of the protection they would have had when new. These plugs when new have an SNR of 37 dB but at least 10 dB of that protection has been taken away by reusing them, and even more at the lower frequencies.
Solutions for it - buy reusable ear plugs
Moldex Rockets and case
It is quite easy to deal with this. Either stipulate foam ear plugs are use-once only, but more usefully you can get reusable ear plugs instead.
For example, the Moldex Rockets come in their own little case.
The plug itself is silicone so it can be washed, as can the case itself, and the case gives somewhere clean to store them when not being worn.
They cost a little more, for these it is about £1.68 for a pair but they can be reused for a long time.
For disposable foam plugs, that same £1.68 is only about eleven days of using disposable plugs so by day twelve the employer is saving money, and these Rockets can be reused much much longer than that.
So, if you want to save money on hearing protection, the solution is not to limit how many pairs of disposable ear plugs a person can use in any one day but to instead buy ear plugs which are designed for reuse, can be washed and have a case. It quickly works out much cheaper than disposable ones and avoids any infection risks from poor hygiene.
