Noise is one of those topics that most of us have a bit of an idea about when the noise is hazardous or not, but we don’t really know for sure, unless we have some sort of system of knowing when it’s exceeded a certain threshold. In this video, Michael is going to discuss everything to do with workplace noise, and what you can do to manage this.
There is a bit of a rule of thumb when it comes to managing or identifying noise hazards, which is saying that if you have trouble hearing someone or conversing with someone from 1 metre away because of background noise, that’s a good indication that the noise is starting to get close to or exceeding the threshold for when it becomes hazardous.
That’s just a rule of thumb that has been used over the years. Now these days we can get a little bit better than that.
Oftentimes, to get a bit of a feel for whether noise is becoming hazardous, you can use smartphone apps . You never want to rely on those as the definitive noise assessment because there’s going to be a lot of variability and you can’t really rely on the microphone in a smartphone as your primary identifier of noise, but it does give you a nice idea of when you should proceed to the next level of proper noise identification.
Once you make the call that yes, this is getting too loud and you need to do an appropriate assessment, then you can go ahead and start doing proper assessments with the right equipment.
You need to make sure that if you’re doing a legitimate noise assessment or identifying the hazardous noise, that you use calibrated equipment to identify the actual decibel rating. If you are doing a comprehensive assessment, this is where you should probably use an expert. An occupational or industrial hygienist is usually the profession that will come around and do comprehensive noise mapping, noise assessments for your workplace.
When trying to work out what is excessive noise, you need to know firstly what the decibel rating of that noise is. This can sometimes get a bit tricky to understand. The workplace standard for noise is that you’re not allowed to be exposed to more than 85 decibels over an eight-hour period.
So, what does that mean for shorter periods of exposure for example?
As you can see from the video, what we’ve done is we’ve looked at the different exposure times for different decibel ratings. You’ll see that it goes in a bit of an odd scale, it’s a logarithmic scale, meaning that as the decibel rating goes up the exposure time goes down quite dramatically. The general rule here is that for every increase in 3 decibels we double the sound exposure.
The WHS Regulation states:
- 85 decibels over 8 hours
- 88 decibels over 4 hours
- 91 decibels over 2 hours
- 94 decibels over 1 hour
- 97 decibels over 30 minutes
- 100 decibels over 15 minutes
So, when it comes to risk assessment for noise, we can use a standard risk assessment, we don’t really need to do a comprehensive risk assessment. The noise level has been measured, it’s been determined as hazardous. Most of the time we can just skip straight towards noise control, because we know its excessive and we know what the appropriate controls are going to be.
When it comes to control, you want to use the hierarchy of control to ensure you reduce that noise at the source where appropriate.
You have to consider the type of equipment you’re using and try to either eliminate the use of that equipment or alternatively substitute it with a less noisy device.
For example, if you’re using an old, loud piece of equipment and you replace it with a nice new piece of equipment that does the same job but has a much lower noise rating, that’s a big advantage. The old one might have been working at say, 88 decibels, the new one might be working at 80. That’s a huge change there because all of a sudden, we don’t require noise control.
There’re some engineering options that you can use if the equipment can’t be replaced. You might use certain sound proofing items, such as mufflers to reduce the impact of the noise.
Administrative controls are going to be mostly looking at exposure times for workers. If you know that you’ve got something that’s 85 decibels, you can have it up to 8 hours. You need to ensure that workers are not working for more than 8 hours in that environment. It will be beneficial to use task rotation as an administrative control, and move workers through loud areas as much as possible.
At the end of the day, you’ve made your equipment as quiet as it can be, you’re rotating the workers and making sure your minimizing their exposure time, but there may still be excessive noise. Some equipment is just loud.
Once that happens, you need to make sure you’re using personal protective equipment. This is the bottom of the hierarchy of control but it is really important. Here we’re talking about earplugs or earmuffs (or a combination of both).
Personal Hearing Protection:
When it comes to personal hearing protection, you need to consider the rating that hearing protection has, and you need to make sure the rating is high enough to reduce the sound to a level where you’re working in a safe level of noise.
As you can see from the video, there are 5 classes for PPE. The higher the class, the higher the rating and the greater the sound level reduction is going to be. Class 5 has 26 or more decibels that will be reducing it by. That means that if you have a sound that is up around 100 to 105 decibels, you’re going to need to use something like a class 4 hearing protection device.
Other considerations that you need to take into account when selecting hearing protection are going to be things like hygiene. Earplugs tend to get a little bit dirty, messy and you’re not going to want to put them in your ears lots of times, so earmuffs tend to work a little bit better in that situation.
Another consideration is eye-ware or glasses. If people are using that and their using earmuffs, that can reduce the effectiveness, so we need to make sure that we are choosing the appropriate hearing protection for people that wear glasses as well.
- Noise becomes hazardous when it exceeds a certain exposure standard
- Use the hierarchy of control to reduce exposure to hazardous noise
- Use PPE when high order controls cannot reduce the noise adequately