Thread: How much dust is too much

That is pretty scary.
I thought my extraction was reasonable with the dusty under the floor, but I still get a fine film of dust around the shop.
However I no longer get an dust in my "snot" so must be some improvement

That is an eye opener. I usually judge it by how much dust collects on the cobwebs in my shed

Cheers

So can you explain the recommendation in laymans terms?

Is that like the total amount of dust that should collect in a shed of that size in a give time period?

Forty three years ago, when I started my apprenticeship as a carpenter on high rise stuff in Sydney, was about the time friction discs started to be used extensively. We all though it was great to wack a disc in a 9 1/2" Black and Decker and cut into concrete, brick and....fibro. The method was that you would get set up take a deep breath and keep sawing until either you finished the cut or you stopped because you could not see the line you were cutting due to the cloud of dust. You would put down the saw and run to get a gulp of clean air. Don't laugh, this is the way we would do it. No dustmask/respirator, no eye protection and definitely no noise protection!
Is it any wonder now that my hearing is impaired? I also developed asthma which hung around for 10 or more years but has now gone (thank goodness).
I used to shoot brick ties on to concrete walls for the brick layers with an Omark explosive charge gun. There again no eye protection and no noise protection.
Thankfully things have changed in the work place.
I am now wondering if the fibro cutting experiences will show up. They say it takes 40 years to affect you
The latter part of my working life was spent in a white board kitchen manufacturing business (16 years) where you often had your head and snoz close to a screeming router putting profiles on Pyneboard and MDF, while wearing head phones and those white paper dust masks. Ummmmwhat is around the corner for me?
My set up at home is serviced by a 2Hp dusty mounted on a Bill Penze inspired cyclone that I am slowly trying to get connerted to all my machines. When I first got the DE I just had it hooked up to the table saw and I could not believe just how it kept so much dust off every thing in the workshop. The cyclone is such an improvement over the plain dusty. I do have to make it a priority to get it to all the machines though

Originally Posted by HeadScratcher

So can you explain the recommendation in laymans terms?

Is that like the total amount of dust that should collect in a shed of that size in a give time period?

The Australian standard is that at any time there are workers present the air should not contain more than 5 mg/m^3 of softwood or 1 mg/m^3 of hardwood dust (0.5 mg/m^3 of WRC)

A 6 x 4 x 2.4 m shed has a volume of ~60 m^3 so it should not contain more than 60 mg of hardwood dust in the air at any instance in time. That's less than about 1/4 of whats in that cap.

If the dust is in large particle sizes such as is produced by a hand saw or chisels it will most settle out immediately. A much more dangerous problem happens with power tools especially something like a power sanders where the majority of dust particles generated can be invisible and they will hang around for hours or even days.

Originally Posted by chambezio

My set up at home is serviced by a 2Hp dusty mounted on a Bill Penze inspired cyclone that I am slowly trying to get connerted to all my machines. When I first got the DE I just had it hooked up to the table saw and I could not believe just how it kept so much dust off every thing in the workshop. The cyclone is such an improvement over the plain dusty. I do have to make it a priority to get it to all the machines though

Even better still if you can would be to get the DC venting outside the shed. This is the biggest single improvement most people can do to existing system.

Originally Posted by BobL

The Australian standard is that at any time there are workers present the air should not contain more than 5 mg/m^3 of softwood or 1 mg/m^3 of hardwood dust (0.5 mg/m^3 of WRC)

A 6 x 4 x 2.4 m shed has a volume of ~60 m^3 so it should not contain more than 60 mg of hardwood dust in the air at any instance in time. That's less than about 1/4 of whats in that cap.

If the dust is in large particle sizes such as is produced by a hand saw or chisels it will most settle out immediately. A much more dangerous problem happens with power tools especially something like a power sanders where the majority of dust particles generated can be invisible and they will hang around for hours or even days.

I see why the very large volumes of air is required to try grab it all before it becomes air born.

Originally Posted by HeadScratcher

I see why the very large volumes of air is required to try grab it all before it becomes air born.

Yep it is very hard to grab it all at source unless a powerful DC is used. And it also demonstrates that apart from specifically designed well shrouded power tools why vacuum cleaners are not up to the job.

The next best thing to grabbing it all is to run the DC for some time after the last dust making activity

Of course the less air/dust grabbed at source the much longer the DC needs to be run for after the last dust making activity.

A 1HP grabs so little of the invisible dust that the best it can do for the operator is to keep it running until the operator leaves the shed.

A 2HP can under some circumstances grab the dust but most setups I have seen would require it to run for about 20-40 minutes after the last dust making activity.

Depending on specific setups a 3HP should be able to grab the dust at source but even so it should still be run for 5 - 10 minutes after the last dust making activity.

The only way to be reasonable confident of grabbing the dust is using a 4-5 HP DC but not everyone has the readies for this.