How useful is manufacturer’s data on noise levels in a noise assessment?

Manufacturers of tools and equipment have an obligation to make data available on the expected noise level for their product. The HSE list this as a source of information which employers could use in deciding if there is a noise risk in the workplace, but is it actually any good or useful in a noise assessment?

There are two use-cases for manufacturer’s noise data - using it to decide if you need to do a noise assessment, and using it as the noise assessment / noise level itself.

Using manufacturer’s noise data to decide if you need a noise assessment

There is one good use case which is using manufacturers data to decide if you need to do a noise assessment. In this case, yes, it can be very useful.

If you have reason to believe noise levels are approaching 80 dB(A) then there is an obligation to get a noise assessment done, but how do you know noise may be reaching that 80 dB(A) level? That is where manufacturer’s noise level data can come in - if they say their tool or machine is over that 80 dB(A) point then that’s a good sign you need to go full-monty and get a decent noise assessment done to help assess the true risk.

Think of it as licking your finger and holding it up to see how windy it is. It kind of tells you if there is wind or not, but that’s it and that’s where manufacturer’s information on noise levels sit.

Using manufacturer’s noise data as the noise level in a noise assessment

How useful is the manufacturer’s noise data beyond that initial question once you get into a proper noise assessment? You will be unsurprised to hear ‘not at all’.

The noise level data is gathered by manufacturers under set controlled circumstances but those circumstances are not what happens in the real world and those real world changes can make a huge difference to the noise levels. For example:

New tools versus older ones

When a tool is new it is working exactly as designed but over time wear and tear can quite dramatically increase the noise level. Something as simple as a wearing bearing or an air leak on a compressed air line can significantly change the noise.

Tools are usually not used in isolation

When manufacturers generate their noise level data the tool is assessed in isolation and that is usually very unrealistic for actual use. The noise in an area is likely to be that tool, plus all the other machines or tools being used in the area at the time.

Positioning of machines can make a big difference

You have the more obvious issue where a machine placed close to a wall may have a higher noise level for the operator than a machine in the middle of the room as noise is coming from the machine to the person but also bouncing off the wall at them as well.

There are the less obvious ones as well as noise is weird and can change depending on things like the spacing of machines. Put two machines a couple of metres apart and their noise levels may multiply together and become larger than each individual one. Put those two machines three metres apart and their noise now starts to cancel each other out and the levels are below the noise emitted by each one. Where machines are put can make a huge difference to the noise levels and make manufacturer’s data rather fanciful.

As another example, I did a noise assessment in December 2025 where the noise from a massive panel saw was about 83 dB(A) for the operator over the entire cycle. However another person was working at a bench about five metres away, making no noise themselves, but their noise exposure was averaging around 87 dB(A) from the panel saw. The noise was kind of a ‘doughnut’ shape of loud at point of source, then a quieter band, then a louder band caused by reflections off the ceiling and walls, then getting quieter again.

This also is important with hand tools - using a drill in an open space can be a very different noise level to using the same drill in a small room or in a corner.

The Noise Regs are interested in noise received, not noise made

Manufacturer data relates to the noise of the machine but the Noise Regs are interested in the noise received by people and that is often entirely different. For example, a manufacturer may give a noise level for a CNC, but the operator doesn’t stand there for the entire cycle as there is nothing to do for large parts of it. Sometimes they run several CNCs at once. Their noise exposure is therefore not the same as the individual machine’s noise and will be a combination of their entire job which could be higher, or often lower, than the stated noise level from the manufacturer.

Maintenance and alteration over time

Ongoing use and maintenance of a machine may change its noise. For example, a panel could be removed for cleaning or maintenance and then replaced but it is not fasted quite as tightly as it was previously. Now you have the noise from the machine but also a rattle or vibration from the panel which is contributing to it.

Another issue I see quite often is a machine which jams quite frequently so the operators run it with panels open so they can see what is going on. There may be no physical risks for the panel to guard against so no issues there, but the panel was containing noise.

Summary on manufacturer’s noise level data used a means of identifying employee exposures

In an on-site noise assessment manufacturer’s data is not remotely useful and not something I would ever take into consideration as there are too many opportunities for it to be wrong.

What we are interested in during a noise assessment is the noise received by people, not the noise made by a machine. The two may indeed be the same, but often are entirely different. Generic noise levels from a manufacturer don’t add anything useful to the noise assessment process. That’s not a fault or failing of the manufacturers, they can’t account for every usage case.