Results 16 to 22 of 22
-
12th April 2024, 09:51 AM #16.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
A couple of cuts with a saw or most short term activity in a shed containing only low amounts of suspended dust won't show up much on a particle counter.
What little fine dust is generated is rapidly diluted into the relatively larger volume of shed air.
Cutting with a sharp toothed blade also generates relatively little fine dust compared to the total volume of sawdust produced.
Try something like sanding for 20 minutes. Then it becomes a competition between how quickly the dust settles and what hands in the air.
If you want to tackle dust collection improvements it's often more instructive to use a particle counter that shows the particle size distributions that way you can see what is being collected and what is escaping.
-
12th April 2024 09:51 AM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
12th April 2024, 10:19 AM #17Novice
- Join Date
- Sep 2008
- Location
- Melbourne
- Posts
- 22
Thanks BobL! I have been meaning to try sanding and see what that does. I did some measurements again last night and I was getting readings from about 20 - 30 μg/m3 for most of the evening while working in the shop using both hand and power tools. Unfortunately this particular sensor measures only PM2.5 but I think I will buy a different model which takes PM1.0 and PM10 readings as well.
-
12th April 2024, 12:14 PM #18.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,803
PM2.5 readings are a catch all used for general air quality (smoke, ICE pollution, house and office dust, industrial pollution) but most wood working dust is above PM2.5 so they wont catch the bigger stuff
Here is a graph showing particle sizes for sanding pine with 80 grit sandpaper. Interestingly the distribution does not change much going to 120 or even 240 paper.
What this shows is that there's not much PM2.5 (that's particles of <2.5 microns) so to measure sanding dust you show uses PM5 or 10 counter.
Thsi graph comes from this post which you may find useful.
Dust Concentration Measurements
What constitutes a safe level and what particles sizes are dangerous is a "how long is a piece of string question".
Wood dust particles >20 microns generally fall out of the air quickly and within the vicinity of the tool/machine so unless you have your constantly head under a sawdust stream (eg lathe) you generally wont pick these up. If they do get inside your knows these are the ones you blow out when you blow your nose.
Dust particles around the 10 micron range are the ones you can start to breath in but they don't go much beyond the upper respiratory tract - these are the ones implicated in nose and upper respiratory cancers. If you breathe enough in of coloured timbers you can see stains of these when you blow your nose.
Dust particles <2.5 microns will go far deeper into the respiratory tract and because they are so tiny they act more like air molecules than saw dust chip so fortunately most will be breathed out. Of course the higher the exposure level (amount and time) the more will stay inside you. Also they hand around in the air for longer so will produce a greater exposure. In other words not much are needed to have an effect.
Fortunately wood work doesn't not produce much dust <0.5 microns BUT again exposure (time acts even more air like BUT as these are tiny they have significant penetrating power and can pass through skin, eyes and easily get into blood and lymph streams. Their exact effects are largely unknown but what is known is that this dust triggers and/or exacerbates many medical conditions from Cardio Vascular to pulmonary to auto immune diseases. Even mental health problems.
With regards aussie wood working the existing OHS standards are still those "borrowed" from the brits in 1972, 5000 µg/m^3 for softwoods (like pine) and 1000 µg/m^3 for hardwoods (like oak). A few timbers like WRC and MDF have 500 µg/m^3. These standards all are for an 8 hour working period. BUT This is for all sawdust particle sizes including the bigger ones that have little impact on humans health, and there is no allowance made for the added toxicity of Aussie timbers.
The particle sizes <PM2.5 are the ones to really worry about and there are no OHS standards set for wood working however there are general population standards that range from 20 - 50 µg/m^3 for a 24 hour period Some health organisations still consider these too high especially for seniors and children, and far too high for people with pre-existing medical problems and are proposing not more than 20 µg/m^3 for seniors and children and around half that for people with medical conditions.
-
12th April 2024, 12:31 PM #19Novice
- Join Date
- Sep 2008
- Location
- Melbourne
- Posts
- 22
Great, thank you!
-
13th April 2024, 12:04 PM #20
When putting the case for better dust extraction at our local men's shed I gave them the following...
A 2002 study found that "Each 10 μg/m3 elevation in fine particulate air pollution (PM2.5) was associated with approximately a 4%, 6% and 8% increased risk of all-cause cardiopulmonary, lung cancer and mortality, respectively." Pope, C. Arden; Burnett, Richard T.; Thun, Michael J. (March 6, 2002). "Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air Pollution". PMID11879110. Retrieved 4 May 2017
In my own woodturning workshop I'm stringent about keeping my exposure to PM2.5 levels very low because of my existing lung condition and now also a senior. I'm also in my workshop for more hours of exposure than at the men's shed.
I only keep an eye on the PM10 readings if I'm turning toxic woods. I grew up where they were still logging Aust Red Cedar when I was a child and there was talk of the high number of workers in the sawmills who died prematurely from upper respiratory cancers. Anecdotal evidence only, but enough for me to be very cautious.Stay sharp and stay safe!
Neil
-
13th April 2024, 01:17 PM #21
OK, I run the IKEA alongside one of my other particle counters.
What I found was that up to readings of about 20 PM2.5m3 they were closely calibrated...
Then the IKEA started to read lower...
But when the readings got higher the IKEA gave much higher numbers...
Make what you will of that. My other particle counters have always given much closer readings when run side-by-side.
As I normally never let the dust levels in my workshop get above about 10 PM2.5 the IKEA unit will still be a useful spare for me.
However, the economy particle counters offered on eBay, etc., that provide the readings for the other particle sizes, while selling for just a bit more, look to me to be a better buy than the IKEA.Stay sharp and stay safe!
Neil
-
15th April 2024, 09:52 AM #22Novice
- Join Date
- Sep 2008
- Location
- Melbourne
- Posts
- 22
Thanks for the comparison Neil! Similar to what you said, my plan will be to keep the levels down to around 10 so I think it will be a useful tool for me.
Similar Threads
-
Ikea VINDRIKTNING Air quality sensor $15
By jimbo16 in forum SAFETYReplies: 1Last Post: 14th December 2021, 08:20 PM -
Dust sensor?
By riverbuilder in forum DUST EXTRACTIONReplies: 3Last Post: 5th October 2020, 10:13 AM -
CO gas sensor monitor
By BobL in forum ELECTRONICSReplies: 9Last Post: 7th July 2017, 10:00 PM -
Is there a stud sensor that works?
By AlexS in forum HAND TOOLS - POWEREDReplies: 15Last Post: 28th February 2015, 03:23 PM