Thread: Guess the dust level

this is a rhetorical question, right BobL ?

I'm guessing over 250. There's good evidence of settled dust (the broom) but they also have a room ventilator so that might keep things a bit better - if it's on

Somewhat surprisingly, not that high - remember they had only been making dust for maybe two minutes before I took the reading.

Ventilator was not on, but after asking the supervisor if I could take a photo (I had already taken the dust level reading) he turned the ventilator on.
I wish I could have hung around to see if it had an effect. Unfortunately I had to leave but I may be going back.

Originally Posted by BobL

Ventilator was not on, but after asking the supervisor if I could take a photo (I had already taken the dust level reading) he turned the ventilator on.
I wish I could have hung around to see if it had an effect. Unfortunately I had to leave but I may be going back.

Oh so it actually was just like a set on a movie blockbuster - lights, camera, action, which included then turning the ventilator on

Originally Posted by poundy

Oh so it actually was just like a set on a movie blockbuster - lights, camera, action, which included then turning the ventilator on

I'm not pretending this was any sort of proper testing sequence. The shed had just opened (it had been closed all weekend so I knew the dust level would be low to very low) when the shed supervisor and I walked into the main machine section of the shed. I noticed DCs and machines and a layer of dust over everything - not that different to many mens sheds. The supervisor and I started about dust extraction and these two blokes walked holding pieces of wood. The noise was a bit much so we walked as far from the noise we could and kept talking. As I had a dust meter on me after a couple of minutes I decided to turn it on. The Supervisor saw the level and then turned on one of the 2 room air filters.

I'm having a stab in the dark, but would have said between 100-150.

Would be very interesting to see a full days worth of data.

If there's no prize for guessing the number of jelly beans in the jar what is the point of this thread.

The amount was 48 µg/m^3 at the sampling point and was still going up when I stopped measuring.

It's not as bad as I thought it was going to be
BUT
It would have been off a very low base - shed had not been used for two whole days so dust settles out
It involved just couple of minutes of dust making activity.
It would have been interesting to see how it changed in time especially with etc RAF on.

While the dust levels in the room at waist high read on the verge of unhealthy the boys are sucking in a lot worse with their noses right over the machines even if only for a short time. Seeing what the levels were like over the course of the day, or even better the week would be more telling. It is interesting to see that the reading came from a presumed near zero to 48 in a just a few minutes. Bob did it look like the dust was escaping from the machines or from passing through the dust pumps? The puff from the DC's being turned on.

Pete

Originally Posted by QC Inspector

While the dust levels in the room at waist high read on the verge of unhealthy the boys are sucking in a lot worse with their noses right over the machines even if only for a short time.

Yep. The reason for detector location was its a bit of a gamble putting basic dust detectors too close to dust sources.

Seeing what the levels were like over the course of the day, or even better the week would be more telling.

Agree - especially given that this is large mens shed (200+ members) so machine use would be more intense than for a small shed.

It is interesting to see that the reading came from a presumed near zero to 48 in a just a few minutes. Bob did it look like the dust was escaping from the machines or from passing through the dust pumps? The puff from the DC's being turned on.

I couldn definitely see some from the DC when it was turned on, but lighting was poor and I could not see any from machines, but it might have been just too fine.

With, at least 2?, DE's in the shed things are never going to be good and the dust levels at the end of a solid day of work would likely be right up there. I couldn't count the number of times you've said that the most important first move is to get the DE out of the shed, Bob. No doubt you'll be setting them on the right track, hopefully they have the readies to quickly incorporate the most immediate requirements.

Originally Posted by aldav

With, at least 2?, DE's in the shed things are never going to be good and the dust levels at the end of a solid day of work would likely be right up there. I couldn't count the number of times you've said that the most important first move is to get the DE out of the shed, Bob. No doubt you'll be setting them on the right track, hopefully they have the readies to quickly incorporate the most immediate requirements.

Yep, but its a bit of a toss up as to what they can/should do in the short term. They're located on the grounds of high school so just moving their DCs outside is not going to happen plus they're moving to a new shed by years end and will be getting a new large Felder? DC. What they really wanted me to do was help them with their new ducting layout etc. The bloke with the plans was not there so I;'m getting them sent out by email.

Went to a coastal Mens shed this afternoon for a consult. Nice big shed - nice atmosphere.

Shed's on a bit of a rise about 3 km from the beach.
Two very large roller doors at each end of the main shed.
A fairly stiff Fremantle doc was "in".
They have Felder 200 plus several other 2 and 3HP DCS (only the 3HP is outside their shed) but all with only 100 mm ducting so a pall of fine dust settled on everything.
Given the number of machine and potential simultaneous users this was not really enough suck for their requirements.
About half their Machines are on Auto blast gates (DCs are not auto)

They have 100's of members but only about 30 members were present today.
One guy was using a disc sander, one guy was using a radial arm saw and one a TS. Two guys using routers, the rest were either in the metal work area or painting assembling.
Chips all over the place.

Outside the PM2.5 was 1 µg/m^3 inside it was was 3 µg/m^3!
Shows the power of ventilation.
Of course they are smart enough to recognise that the "Doctor" is not going to help them on still days or when winter storms come in and the have to close the rollers.

Recommendation
All DCs outside
Get 9" trunks and 6" ducting to machines happening.
Get another Felder 200 to replace all the smaller DCs
Get some BMHs going

Overall appear very receptive

Another mens shed visit today.
Inner suburban small shed, with 3 large roller doors - two open today.
About 20 members present, not much dust making activities happening when I turned up.
Mainly blokes using hand tools, one pen turner.

One bloke fired up the table saw between the two open roller doors and sawdust went everywhere - turned out 4" Flex connected to TS cabinet was choked.
Whoopee I though get the particle counter out but . . . . .

Stiff breeze blowing - highest dust level observed was 8 µg/m^ 3 ie stuff all.
Of course what happens when there's no breeze?

Usual probs.
2500 CFM Micronair VibraClean extractor located outside (no enclosure but very quiet ~80dB) - should be adequate for their size of shed.
Inside shed, all "Not very professionally" installed all Galv ducting - for which they paid an arm and a leg.
Lots of 4" flex in use.
Takeoff at DC is 300mm but quickly drops to 200mm and then dropping to 100mm at machines.

Recommendations
Rip out all bar short 300mm galv trunkline ducting (Ouch!)
Install 9" PVC trunkline to all parts of shed and then 6" ducting as close to machines.
Shorten lengths of 6" flex
Modify machine to accept 6" ducting.
Get some BMHs going.
Get some exhaust fans to aid with general ventilation when breeze not present

Would you let us know what they decide to do? I'm curious to know if the follow all or some of your recommendations or just leave their sheds as is.

Pete