# Anyone know anything about Dust Categories?



## cumbrian (7 Dec 2006)

This has to do with the rating on a dust extractor - specifically Festool CTL Midi where the spec states it's suitable for "Dust Category L". (Interestingly most of their other machines don't quote anything.) I have no idea how that relates to the filtration levels quoted by other makers, and the desirable level of 0.5 micron for MDF. I emailed Festool with the question and got no reply (no use trying to phone them as I have hearing problems and struggle with phone calls), I've tried Googling and learnt something new about tea but that's all.

So - can anyone point me at something that translates Dust Categories such as L and M into equivalent filtration size, or am I mixing two totally different concepts here? :?


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## Adam (7 Dec 2006)

I thought it was to do with a German rating system. Could well be completely wrong though.

Adam


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## mudman (7 Dec 2006)

I love a challenge  

It seems there are three categories, L, M and H. These appear to stand for Low, Medium and High :roll: .
I found a few links, like these:

http://www.tiger-vac.com/Test Reports/filter chart.html
http://www.idealtools.com.au/category3787_1.htm
http://www.nilfisk-alto.co.uk/upload/uk/brochures/familysafeyvacjuly06.pdf

It seems to appear that the category relates more to the loading of the dust in the air rather than the particulate size.


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## cumbrian (7 Dec 2006)

Thanks for those links. It's starting to make some sense, just not enough.... It also led me off on another surf, and I found this article 

_A study on dust emission, particle size distribution and formaldehyde concentration during machining of medium density fibreboard _
here
which makes interesting reading but still doesn't tell me what I'm trying to find out! Back to surfing.....


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## Fred Page (7 Dec 2006)

I purchased the low cost SIP extractor and was supplied with two or three filter bags - one of which was for very fine particle filtration. Other suppliers wanted to charge for fine graded bags. Have a look at SIP's specification.
It is a serious subject since there's little point in adding to the general distribution of dangerous particles by not using a properly specified filter bag.
Fred.


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## jobsagooden (5 Apr 2007)

So cumbrian what did you find out? I'm also about to get one of these, and was ordering if it does filter down far enough. 

Also does it run on.


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## Loz_S (6 Apr 2007)

Staubklasse L and Staubklasse M are German standards relating to health in the workplace from an organization called BIA.

To achieve Class L an extractor must not allow more than 1% of extracted dust to pass out of the filter to a "maximum allowable concentration" (MAK value) greater than 1 mg/m^3.

To achieve Class M an extractor must not allow more than 0.1% of extracted dust to pass out of the filter to a "maximum allowable concentration" (MAK value) greater than 0.1 mg/m^3.

There are several higher categories but Class H is generally the highest for normal trade use.

To achieve Class H an extractor must not allow more than 0.1% (can be as low as 0.005%) of extracted dust to pass out of the filter to a "maximum allowable concentration" (MAK value) *less than* than 0.1 mg/m^3.


Class L is suitable for general work.

Class M is specifically for mineral dust, man-made wood-based dust, oak and beech woods.

Class H is used with anything that is a known carcinogen or has known health related effects. (Lead, cadmium, asbestos etc.)

So the Festool CTL extractors are OK for more general work. If you are routing/sanding MDF or certain wood sorts (oak, beech etc.) then you must use the CTM series.

As far as I know all Festool extractors run-on for 5 sec after turning the tool off, mine does anyway!

Protool also have a few extractors including one going up to H class.


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## jobsagooden (6 Apr 2007)

Thank you very much indeed. This means i can't get the midi as i do need the ctm. But at £500, is tooooo much. 

The Trend T30 with fine filter should do it.

thanks again.


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## jobsagooden (6 Apr 2007)

Or perhaps metabo ASR 2025 http://www.dm-tools.co.uk/product.php/s ... METASR2025


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## engineer one (6 Apr 2007)

interesting, thought which i have mentioned before,
the trend has a pto which allows you to attach it to a machine and start both together. the trend is rated toallow you to run a 2000 watt router type machine and the vacuum. the metabo has a much lower rating about 1200 watts i think. :? 

i would always advise going for the trend af model to get the finer filter.
decent machine, lots of suck, and decent length of wiring and extraction/vacuum hose, also good vac tools too.

very happy with mine which i have used when sanding newly plastered walls :roll: :twisted: 


paul :wink:


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## jobsagooden (17 Apr 2007)

I have been inform now from festool and my festool dealer that CTL are fine for use with MDF, even has same filters CTM!


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## cumbrian (18 Apr 2007)

jobsagooden":bujfmwar said:


> So cumbrian what did you find out?



I missed seeing that this thread had revived, so apologies for not answering sooner.



jobsagooden":bujfmwar said:


> I have been inform now from festool and my festool dealer that CTL are fine for use with MDF, even has same filters CTM!



My nearest Festool dealer gave me the same information as you've had - I believe he reckoned it even filtered to 0.3 micron - but I didn't get anything back from Festool when I emailed them, so interested to hear what they told you. Anything in print, or was it on the phone?
Anyway I bought the CTL and it certainly did a good job of sucking up 150 years' worth of muck from some old barn beams when hooked up to a Makita belt sander. Good piece of kit in my (very limited) experience and (probably worthless) opinion.


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## jobsagooden (18 Apr 2007)

She just said was fine for mdf, via email. Defiantly has the same filters so must be very good.


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## Loz_S (19 Apr 2007)

jobsagooden":k1a70s21 said:


> I have been inform now from festool and my festool dealer that CTL are fine for use with MDF, even has same filters CTM!


What the....? How weird is that! What, I wonder, is the point in selling the two different types of CT with German certificating if they use the same filter!? ...and why the price difference?!

I should add that, on the continent at least, Festool doesn't advertise the fact that it also sells HEPA filters for its CT extractors in the US and Australia (and UK?) I have discovered that it is available everywhere as a spare part though. This suggests to me that the standard filters aren't as good as they want us to believe.

Anyone who wants a HEPA filter needs part no. 493334.


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