Author Topic: Dust extraction L Class vs. M Class?  (Read 21288 times)

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Offline Locks14

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Dust extraction L Class vs. M Class?
« on: September 29, 2015, 06:27 AM »
Is there really any point to the different classifications?

I understand the filters/unit in a L class unit transmit <1% of what is extracted back into the air and class M 0.1%. However, when you consider the dust extraction on even the best powertools isn't anywhere near 99% in the first place, is it actually just a theoretical benefit as opposed to practical?

So is there really any point paying for a (for example) CTM26 over above the CTL26?
« Last Edit: September 29, 2015, 06:31 AM by Locks14 »

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Offline Kev

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Re: Dust extraction L Class vs. M Class?
« Reply #1 on: September 29, 2015, 07:02 AM »
You breath what is pumped out of the "bad" end of a DC ... make your choice [wink]

Offline Timtool

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Re: Dust extraction L Class vs. M Class?
« Reply #2 on: September 29, 2015, 07:10 AM »
From what i understood the sole difference between the Festool L and M class is the presence of a function on the M models that alerts you when the suction drops to far due to full bag or clogged filters. Besides that they should filter exactly the same in reality as they share the exact same filters, but to get the M class you need that additional function. For a home woodworker there is little benefit for an M model, but for some professionals it is required by legislation.
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Re: Dust extraction L Class vs. M Class?
« Reply #3 on: September 29, 2015, 08:42 AM »
I did also question this in the following thread: http://festoolownersgroup.com/festool-tools-accessories/festool-midi-dust-classification/

As for the MIDI, i did not find any conclusive information whether it was just the suction alarm that was missing or if it was the filter causing the extractor to be classified as a class L. However, on the CTL/M 26 it looks like it is only the suction alarm that are different.

Festool (and other brands) recommend the following uses for L/M class:
Dust class L:
Simple, harmless dust such as house dust and materials such as soil.
 
Dust class M:
All wood dust and dust originating from repair compound, filler and clear coats, plaster, cement, concrete, tile cement and paints such as latex and oil paints or quartziferous materials such as sand and pebbles.

I find this very strange, since this would make the MIDI (class L) useless for woodworking. Festool also states that the MIDI extractor is "Best suited to smaller sanding, routing, sawing and drilling tasks" on their international site. I tried asking Festool about this, but i never received any answers.

Offline Locks14

  • Posts: 291
Re: Dust extraction L Class vs. M Class?
« Reply #4 on: September 29, 2015, 08:53 AM »
I did also question this in the following thread: http://festoolownersgroup.com/festool-tools-accessories/festool-midi-dust-classification/

As for the MIDI, i did not find any conclusive information whether it was just the suction alarm that was missing or if it was the filter causing the extractor to be classified as a class L. However, on the CTL/M 26 it looks like it is only the suction alarm that are different.

Festool (and other brands) recommend the following uses for L/M class:
Dust class L:
Simple, harmless dust such as house dust and materials such as soil.
 
Dust class M:
All wood dust and dust originating from repair compound, filler and clear coats, plaster, cement, concrete, tile cement and paints such as latex and oil paints or quartziferous materials such as sand and pebbles.

I find this very strange, since this would make the MIDI (class L) useless for woodworking. Festool also states that the MIDI extractor is "Best suited to smaller sanding, routing, sawing and drilling tasks" on their international site. I tried asking Festool about this, but i never received any answers.

This appears to be the same with Bosch also. They even advertise the main filter is class M. It's just the alarm that's missing. In which case, as pointed out by Timtool, if you're a home wood worker or don't work in an environment where class M is mandated, it's an extra £/$75-100 for a beep when suction drops low.
« Last Edit: September 29, 2015, 09:04 AM by Locks14 »

Offline GarryMartin

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Re: Dust extraction L Class vs. M Class?
« Reply #5 on: September 29, 2015, 09:11 AM »
Is there really any point to the different classifications?

The different classifications exist so that you can be sure a particular extractor is appropriate/certified for the use you intend. As @Timtool notes, legislation in various countries may require a particular classification or may promote its use. In the UK, the Control of Substances Hazardous to Health Regulations (COSHH) set out a legal requirement to protect workers from health risks arising from hazardous substances at work, and stipulate that when cleaning up, you should use vacuum equipment that meets at least the dust class M (medium hazard) classification for example.

I understand the filters/unit in a L class unit transmit <1% of what is extracted back into the air and class M 0.1%.

They are maximum degrees of penetration; L Class is 1% (99% efficient), M Class is 0.1% (99.9% efficient) and H Class is 0.005% (99.995% efficient).

You can expect dust with a MAC (maximal concentration of dust allowed in the working place in milligram per m3 (mg/m3)) value greater than 1mg/m3 when using Class L, greater than 0.1mg/m3 when using Class M and less than or equal to 0.1mg/m3 when using Class H.

However, when you consider the dust extraction on even the best powertools isn't anywhere near 99% in the first place, is it actually just a theoretical benefit as opposed to practical?

It's hardly theoretical; an employer has a duty of care to their employees to minimise any risk. And surely if it's your own health, you'd want to do the same?

So is there really any point paying for a (for example) CTM26 over above the CTL26?

We've moved from maximum degrees of penetration at dust classes now to actual models, so there are some differences as the classes deal with maximums allowed and many manufacturers, Festool included, improve on those in individual models. Again, as @Timtool notes, the CTL and CTM are identicial in terms of extraction capability and do indeed use the same filters. The major difference is that the CTM has an additional feature that monitors the airflow through the house and sounds an alarm if it drops below a particular level to ensure filtration is always sufficient; a full bag on a CTL will reduce airflow and could reduce filtration efficiency whereas a full bag on the CTM will sound the alarm and alert the operator.

I find this very strange, since this would make the MIDI (class L) useless for woodworking.

As I believe an audible alarm is a requirement for M classification, even though the CTL and the Midi may meet the requirements for M classification from a filtration efficiency perspective, they cannot be sold or advertised as such without the alarm.

So if you are covered by legal requirements, you will almost certainly need the CTM. If you are a home woodworker, my advice would be to go for the CTL. If you value your health and want the best filtration, I'd also advise using the HEPA filters that come as standard in the US market. The HEPA Main Filters are 99.99% efficient at capturing particulate matter down to 0.3 microns.

The part number for the HEPA filter for the CTL26 is 498994 if anyone is interested.

Offline Locks14

  • Posts: 291
Re: Dust extraction L Class vs. M Class?
« Reply #6 on: September 29, 2015, 09:18 AM »
Is there really any point to the different classifications?

The different classifications exist so that you can be sure a particular extractor is appropriate/certified for the use you intend. As @Timtool notes, legislation in various countries may require a particular classification or may promote its use. In the UK, the Control of Substances Hazardous to Health Regulations (COSHH) set out a legal requirement to protect workers from health risks arising from hazardous substances at work, and stipulate that when cleaning up, you should use vacuum equipment that meets at least the dust class M (medium hazard) classification for example.

I understand the filters/unit in a L class unit transmit <1% of what is extracted back into the air and class M 0.1%.

They are maximum degrees of penetration; L Class is 1% (99% efficient), M Class is 0.1% (99.9% efficient) and H Class is 0.005% (99.995% efficient).

You can expect dust with a MAC (maximal concentration of dust allowed in the working place in milligram per m3 (mg/m3)) value greater than 1mg/m3 when using Class L, greater than 0.1mg/m3 when using Class M and less than or equal to 0.1mg/m3 when using Class H.

However, when you consider the dust extraction on even the best powertools isn't anywhere near 99% in the first place, is it actually just a theoretical benefit as opposed to practical?

It's hardly theoretical; an employer has a duty of care to their employees to minimise any risk. And surely if it's your own health, you'd want to do the same?

So is there really any point paying for a (for example) CTM26 over above the CTL26?

We've moved from maximum degrees of penetration at dust classes now to actual models, so there are some differences as the classes deal with maximums allowed and many manufacturers, Festool included, improve on those in individual models. Again, as @Timtool notes, the CTL and CTM are identicial in terms of extraction capability and do indeed use the same filters. The major difference is that the CTM has an additional feature that monitors the airflow through the house and sounds an alarm if it drops below a particular level to ensure filtration is always sufficient; a full bag on a CTL will reduce airflow and could reduce filtration efficiency whereas a full bag on the CTM will sound the alarm and alert the operator.

I find this very strange, since this would make the MIDI (class L) useless for woodworking.

As I believe an audible alarm is a requirement for M classification, even though the CTL and the Midi may meet the requirements for M classification from a filtration efficiency perspective, they cannot be sold or advertised as such without the alarm.

So if you are covered by legal requirements, you will almost certainly need the CTM. If you are a home woodworker, my advice would be to go for the CTL. If you value your health and want the best filtration, I'd also advise using the HEPA filters that come as standard in the US market. The HEPA Main Filters are 99.99% efficient at capturing particulate matter down to 0.3 microns.

The part number for the HEPA filter for the CTL26 is 498994 if anyone is interested.

Thanks for the detailed reply.

One thing however, and it's a bit of an odd one. But your suggestion of using the HEPA filters I believe is flawed, because after some research it appears to be class M/H approved the machine must be equipped with an automatic filter cleaning function that momentarily pulses a burst of reverse airflow into the filter every 15 seconds or a vigorous shake with an electromagnet (depending on manufacturer). Now apparently the HEPA filters being so fine as to be classified as HEPA are actually damaged by this reverse airflow/shaking action, so installing them would soon mean they would be damaged and no better than standard class M filters within a few days.

Offline GarryMartin

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Re: Dust extraction L Class vs. M Class?
« Reply #7 on: September 29, 2015, 09:57 AM »
Thanks for the detailed reply.

You're welcome.

One thing however, and it's a bit of an odd one. But your suggestion of using the HEPA filters I believe is flawed, because after some research it appears to be class M/H approved the machine must be equipped with an automatic filter cleaning function that momentarily pulses a burst of reverse airflow into the filter every 15 seconds or a vigorous shake with an electromagnet (depending on manufacturer). Now apparently the HEPA filters being so fine as to be classified as HEPA are actually damaged by this reverse airflow/shaking action, so installing them would soon mean they would be damaged and no better than standard class M filters within a few days.

Perhaps the wording wasn't clear, but the comment about the HEPA filter was a follow on from the "if you are a home woodworker, my advice would be to go for the CTL" and hence I was suggesting that you might choose to use a HEPA filter in the CTL for the best filtration.

The automatic filter cleaning you mention is what Festool refer to as AUTOCLEAN (AC) and for absolute clarity, I'm not referring to the AUTOCLEAN models when I suggest using HEPA filters; the HEPA filters are "not suitable for mobile dust extractors with AUTOCLEAN function" and are marked as such.

I wasn't aware that automatic filter cleaning is a requirement for M/H classification though, and I know devices without AUTOCLEAN are sold in those categories so I'm surprised. Do you have a reference I could take a look at?

Offline Alex

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Re: Dust extraction L Class vs. M Class?
« Reply #8 on: September 29, 2015, 10:46 AM »
I wasn't aware that automatic filter cleaning is a requirement for M/H classification though,

It's not.

Offline Locks14

  • Posts: 291
Re: Dust extraction L Class vs. M Class?
« Reply #9 on: September 29, 2015, 11:34 AM »
I wasn't aware that automatic filter cleaning is a requirement for M/H classification though,

It's not.

Sorry, I must have jumped to a conclusion. Bosch, Metabo, Dewalt all have auto filter cleaning on their class M models. So I wrongly assumed it was part of the directive along with the warning sound.

Offline GarryMartin

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Re: Dust extraction L Class vs. M Class?
« Reply #10 on: September 29, 2015, 11:41 AM »
Sorry, I must have jumped to a conclusion. Bosch, Metabo, Dewalt all have auto filter cleaning on their class M models. So I wrongly assumed it was part of the directive along with the warning sound.

No problem. Festool offer models with and without the auto filter cleaning. As mentioned, you're looking for AUTOCLEAN or the AC designator in the model name, e.g. Festool CLEANTEX CTM 48 E AC.


Offline sploo

  • Posts: 33
Re: Dust extraction L Class vs. M Class?
« Reply #11 on: October 02, 2015, 07:16 AM »
GarryMartin posted in my http://festoolownersgroup.com/festool-tools-accessories/ct-extractor-filter-question/ thread to let me know about this one, and it's more appropriate, so I'll jump over here.

Echoing some points already made here: I've had some amusing "off the record" conversations with Festool reps; where they're doing everything they can to answer the questions, without straying across a legal boundary.

In short - yes the L and M use the same main filter. Both appear identical apart from the low pressure warning. The M is mostly about approval/legislation, so Festool cannot be seen to condone the use of the L class machines for wood dust, even though they're practically the same (minus the low pressure warning).

To Locks14's original question about capture: I believe the legislation is about filtration rather than capture. However, the point of a low pressure warning (in the M class) is to ensure that capture is always good (because you're warned when the pressure drops).

What I've been trying to work out is whether the 498994 HEPA filter (I believe standard in the US market) is better than the standard L/M main filter (496170). When I asked about using one with the CTL, one Festool guy hinted that I should "consider the specs of the M filtration vs the HEPA". I think he was trying to hint that HEPA would be no better, but that doesn't quite seem right, given the 99.9% (M) vs "99.997% of all particulates down to 0.3 microns" (HEPA). He was also hinting that HEPA is more about allergens (so perhaps trying to tell me it's no better for wood dust), but I couldn't read between the lines on that one.

Offline GarryMartin

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Re: Dust extraction L Class vs. M Class?
« Reply #12 on: October 02, 2015, 07:36 AM »
What I've been trying to work out is whether the 498994 HEPA filter (I believe standard in the US market) is better than the standard L/M main filter (496170). When I asked about using one with the CTL, one Festool guy hinted that I should "consider the specs of the M filtration vs the HEPA". I think he was trying to hint that HEPA would be no better, but that doesn't quite seem right, given the 99.9% (M) vs "99.997% of all particulates down to 0.3 microns" (HEPA). He was also hinting that HEPA is more about allergens (so perhaps trying to tell me it's no better for wood dust), but I couldn't read between the lines on that one.

The HEPA filters are definitely better than the standard filters. Wood dust can cause asthma and other health issues, and some wood dusts are carcinogenic in nature, or have additives that can be, so the higher the filtration levels the better. It's all about reducing the risk associated with the exposure, and the HEPA filters can certainly do that.

Offline sploo

  • Posts: 33
Re: Dust extraction L Class vs. M Class?
« Reply #13 on: October 02, 2015, 08:54 AM »
The HEPA filters are definitely better than the standard filters. Wood dust can cause asthma and other health issues, and some wood dusts are carcinogenic in nature, or have additives that can be, so the higher the filtration levels the better. It's all about reducing the risk associated with the exposure, and the HEPA filters can certainly do that.

Thanks. I've taken the plunge and ordered one.

An Ultimate Dust Deputy has just turned up today, and the CTL 26 hasn't been used in anger yet, so hopefully I should be able to get the complete vac + cyclone + HEPA filter in place before it's first used. Cross fingers the cyclone will help keep the filter healthy for a decent period of time.

Offline Brice Burrell

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Re: Dust extraction L Class vs. M Class?
« Reply #14 on: October 02, 2015, 09:04 AM »
What I've been trying to work out is whether the 498994 HEPA filter (I believe standard in the US market) is better than the standard L/M main filter (496170). When I asked about using one with the CTL, one Festool guy hinted that I should "consider the specs of the M filtration vs the HEPA". I think he was trying to hint that HEPA would be no better, but that doesn't quite seem right, given the 99.9% (M) vs "99.997% of all particulates down to 0.3 microns" (HEPA). He was also hinting that HEPA is more about allergens (so perhaps trying to tell me it's no better for wood dust), but I couldn't read between the lines on that one.

The HEPA filters are definitely better than the standard filters. Wood dust can cause asthma and other health issues, and some wood dusts are carcinogenic in nature, or have additives that can be, so the higher the filtration levels the better. It's all about reducing the risk associated with the exposure, and the HEPA filters can certainly do that.

The question I have, is there really any appreciable difference in filtration between the standard L/M filter and a HEPA filter in normal use.  The bigger question is there really a meaningful difference for your health.  My gut says probably not.  The reason I say that is I believe the real issue would likely be the amount of uncaptured dust you're exposed to, not the exhaust from your high filtration vac.  Also keep in mind the limited amount of dust hobbyists are exposed to is far less likely to be dangerous to your health than professionals.  Still, if you are the health nut type a HEPA is pretty cheap piece of mind.     
   
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Offline Brice Burrell

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Re: Dust extraction L Class vs. M Class?
« Reply #15 on: October 02, 2015, 09:06 AM »
Thanks. I've taken the plunge and ordered one.

An Ultimate Dust Deputy has just turned up today, and the CTL 26 hasn't been used in anger yet, so hopefully I should be able to get the complete vac + cyclone + HEPA filter in place before it's first used. Cross fingers the cyclone will help keep the filter healthy for a decent period of time.

As long as you use filter bags in your CT26 you main filter should last many years.
Check out my new blog, The Green and Dark Blue Blog.

Offline GarryMartin

  • Posts: 1671
Re: Dust extraction L Class vs. M Class?
« Reply #16 on: October 02, 2015, 09:16 AM »
The question I have, is there really any appreciable difference in filtration between the standard L/M filter and a HEPA filter in normal use.  The bigger question is there really a meaningful difference for your health.  My gut says probably not.  The reason I say that is I believe the real issue would likely be the amount of uncaptured dust you're exposed to, not the exhaust from your high filtration vac.  Also keep in mind the limited amount of dust hobbyists are exposed to is far less likely to be dangerous to your health than professionals.  Still, if you are the health nut type a HEPA is pretty cheap piece of mind.     

It's a really good point Brice; I had similar thoughts when I originally looked at all of this. Although I don't in any way classify myself as a health nut type, considering how much money I've spent on everything else in the workshop, I thought the extra £55 was an easy justification if it reduced the risk further, even if the original risk was very, very low to begin with.

Offline leakyroof

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Re: Dust extraction L Class vs. M Class?
« Reply #17 on: October 02, 2015, 09:52 AM »
What I've been trying to work out is whether the 498994 HEPA filter (I believe standard in the US market) is better than the standard L/M main filter (496170). When I asked about using one with the CTL, one Festool guy hinted that I should "consider the specs of the M filtration vs the HEPA". I think he was trying to hint that HEPA would be no better, but that doesn't quite seem right, given the 99.9% (M) vs "99.997% of all particulates down to 0.3 microns" (HEPA). He was also hinting that HEPA is more about allergens (so perhaps trying to tell me it's no better for wood dust), but I couldn't read between the lines on that one.

The HEPA filters are definitely better than the standard filters. Wood dust can cause asthma and other health issues, and some wood dusts are carcinogenic in nature, or have additives that can be, so the higher the filtration levels the better. It's all about reducing the risk associated with the exposure, and the HEPA filters can certainly do that.

The question I have, is there really any appreciable difference in filtration between the standard L/M filter and a HEPA filter in normal use.  The bigger question is there really a meaningful difference for your health.  My gut says probably not.  The reason I say that is I believe the real issue would likely be the amount of uncaptured dust you're exposed to, not the exhaust from your high filtration vac.  Also keep in mind the limited amount of dust hobbyists are exposed to is far less likely to be dangerous to your health than professionals.  Still, if you are the health nut type a HEPA is pretty cheap piece of mind.     
   
  I would rethink your 'GUT' with those thoughts Brice.   [wink] [wink] [wink]
 I have family in health care work and friends in health care who would beg to differ on how much damage a weekend warrior or hobbyist can do to themselves.... [eek]
 I know where you're coming from, from the point of term of exposure or length of time in a dirty enviroment. But, many of the above tend to forgo the protective gear that daily professionals buy and use, and that also goes for expensive tools which are better at dust collection from both the source and extraction points.
 So, those 'hobbyists' can rack up health issues in a hurry since they aren't taking the same route to keep safe on a daily basis like we are, or are also not as well informed about these things like we are.  The ER stories I hear are amazing, and sad.
Now if we can just get Concrete workers to capture more of their saw cutting dust instead of using a leaf blower to blow it all away from their buddy while he's manning a saw during a long cut on a crowded mall parking lot[ I should have taken a short video of this while I was nimbly parking FAR away from those two the other day.... [eek] [eek] [eek]]
Not as many Sanders as PA Floor guy.....

Offline sploo

  • Posts: 33
Re: Dust extraction L Class vs. M Class?
« Reply #18 on: October 02, 2015, 11:19 AM »
Good points above; though I'd note that I believe the official guidance is to replace the HEPA filter every 6 months. Possibly every month for heavy use, as filters tend to lose effectiveness over time.

I agree that capture is likely to be a big issue with many tools, and of course the exhaust from a vac is likely to stir up any now settled dust, even if the exhaust air itself is clean.

There's no ideal solution, but trying to keep the workshop clean, get decent extraction at your stationary tools, and having a vac that's spitting out the least amount of nasties all helps.

Of course, nothing's ever safe. As a UK spoof news website pointed out today (in light of the UK ban on smoking in cars when kids are present); it's still safer to smoke inside a VW than stand behind one [wink]

Offline Dangermouse

  • Posts: 119
Re: Dust extraction L Class vs. M Class?
« Reply #19 on: October 02, 2015, 01:43 PM »
as has previously been said the only diffrences between an L class and M class dust extractor is the low suction alarm ona M class, On UK building sites, in theory you'd need at least an M class to work with timber/ man made boards, also if you'd considered an H class extractor it would need a test certificate every year, as its designed to be used to collect asbestos,

Offline ifit

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Re: Dust extraction L Class vs. M Class?
« Reply #20 on: October 03, 2015, 05:29 AM »
I need a new 'M class' sticker for my midi for use on site, where can i get one?
 

Offline sploo

  • Posts: 33
Re: Dust extraction L Class vs. M Class?
« Reply #21 on: October 03, 2015, 06:40 AM »
I need a new 'M class' sticker for my midi for use on site, where can i get one?
Festool, I'd presume? (as long as it is an M rated unit)

Offline tooluser41

  • Posts: 2
Re: Dust extraction L Class vs. M Class?
« Reply #22 on: October 17, 2017, 07:40 AM »
I found some useful info here which helped me decide https://mobiledustextractors.com/ There are also some reviews and other bits and pieces.  I went for the CTL 26 in the end and never looked back since!

Offline Midnight Man

  • Posts: 49
Re: Dust extraction L Class vs. M Class?
« Reply #23 on: October 17, 2017, 09:02 AM »
This is an interesting discussion, I'd like to throw a spanner out there in case someone can provide me with some guidance or a definitive answer.

I purchased some time ago a TS55 and CT36 - they came as a package deal here in Australia.  The TS55 included the ABSA dust guard, and was "promoted" as an MDF set: http://www.festool.com.au/epages/tooltechnic.sf/en_AU/?ObjectPath=/Shops/tooltechnic/Products/561555/SubProducts/574882

This kit, when I registered it at Festool, showed the CT model as "CT 36 E AUS 240V HEPA" in the service certificate.

I have always made the assumption that because the kit was sold as an "MDF" set, it would have to be the best filtration combination one can obtain on a Festool extractor.

As folks here have said, health is important, and as I'm going to soon be using this in an enclosed workshop (though only occasionally with MDF, more commonly with melamine and other sheet goods), I'd rather swap coin in my pocket for peace of mind, knowing I'm doing everything I can to protect my health.

My doubt on this stems from the fact that the extractor is listed as a CT 36 E... which doesn't seem to conform to an L or M standard of any sort :(

Are my assumptions that this is the best filtration possible correct?  Are we talking that it meets the HEPA standard noted earlier ("99.997% of all particulates down to 0.3 microns")?

Many thanks for anyone who may advise, and apologies to moderators if this should not be posted in this thread!

Offline Steven Owen

  • Posts: 409
Re: Dust extraction L Class vs. M Class?
« Reply #24 on: October 17, 2017, 01:44 PM »
Thanks for the detailed reply.

You're welcome.

One thing however, and it's a bit of an odd one. But your suggestion of using the HEPA filters I believe is flawed, because after some research it appears to be class M/H approved the machine must be equipped with an automatic filter cleaning function that momentarily pulses a burst of reverse airflow into the filter every 15 seconds or a vigorous shake with an electromagnet (depending on manufacturer). Now apparently the HEPA filters being so fine as to be classified as HEPA are actually damaged by this reverse airflow/shaking action, so installing them would soon mean they would be damaged and no better than standard class M filters within a few days.

Perhaps the wording wasn't clear, but the comment about the HEPA filter was a follow on from the "if you are a home woodworker, my advice would be to go for the CTL" and hence I was suggesting that you might choose to use a HEPA filter in the CTL for the best filtration.

The automatic filter cleaning you mention is what Festool refer to as AUTOCLEAN (AC) and for absolute clarity, I'm not referring to the AUTOCLEAN models when I suggest using HEPA filters; the HEPA filters are "not suitable for mobile dust extractors with AUTOCLEAN function" and are marked as such.

I wasn't aware that automatic filter cleaning is a requirement for M/H classification though, and I know devices without AUTOCLEAN are sold in those categories so I'm surprised. Do you have a reference I could take a look at?

I would think the HEPA filters are a little to fragile to use with AutoClean in many Vacs.
Festool CT Midi, Festool ETS 125, DF 700 Domino Coming Soon

Offline Alex

  • Posts: 5699
Re: Dust extraction L Class vs. M Class?
« Reply #25 on: October 17, 2017, 03:01 PM »

I purchased some time ago a TS55 and CT36 - they came as a package deal here in Australia.  The TS55 included the ABSA dust guard, and was "promoted" as an MDF set: http://www.festool.com.au/epages/tooltechnic.sf/en_AU/?ObjectPath=/Shops/tooltechnic/Products/561555/SubProducts/574882

This kit, when I registered it at Festool, showed the CT model as "CT 36 E AUS 240V HEPA" in the service certificate.

My doubt on this stems from the fact that the extractor is listed as a CT 36 E... which doesn't seem to conform to an L or M standard of any sort :(

Are my assumptions that this is the best filtration possible correct?  Are we talking that it meets the HEPA standard noted earlier ("99.997% of all particulates down to 0.3 microns")?

First off, L & M classification is a European standard, and does not apply to Australia, and HEPA is an American standard, and as such does not apply to Australia either.

Basically, every vac Festool makes is at least an L class vac, the lowest filtration standard in Europe. And then with some bells and whistles added they become an M or HEPA vac.

For the M class a suction alarm is added that monitors the suction that goes through the hose. If the suction drops below a certain threshold, an alarm sounds so you know it is time to change the bag. That's all, it still uses the same filter as an L class vac.

To make it a HEPA vac, a HEPA filter is placed instead of the standard L class filter. For the rest, it's still the same vac as an L class vac. But the HEPA filter offers an improvement over the L filter. Not sure how much though.

So all you need to know now, does your vac have a HEPA filter, or a standard L class filter. I don't know much exactly of how Festool Australia sells and promotes its packages, but since it has HEPA in the name of the package, you would assume it comes with a HEPA filter. But with Festool, you never know for sure.

So I would suggest you contact Festool Australia by phone (not email) to ask them if your package has a HEPA filter or not. They have no official presence here on this forum, so you must contact them directly.

You could also post a picture here of the filter you have, people might be able to tell which one it is.

And I think it would have been better to post this question as a new topic instead of adding it to an existing thread from way back in 2015.

Offline Midnight Man

  • Posts: 49
Re: Dust extraction L Class vs. M Class?
« Reply #26 on: October 18, 2017, 04:05 AM »
And I think it would have been better to post this question as a new topic instead of adding it to an existing thread from way back in 2015.

Wow, that shows I wasn't watching the detail - sorry, and thank you Alex!  I noticed the thread on the main page, and completely missed looking at the dates in it, I assumed it was current - my bad.

Also, many thanks for the clarification and information, now I understand why I didn't understand before :)  Will check these details by phone as suggested :)

Offline demographic

  • Posts: 377
Re: Dust extraction L Class vs. M Class?
« Reply #27 on: October 18, 2017, 02:42 PM »
I need a new 'M class' sticker for my midi for use on site, where can i get one?

I wasnt aware that they made an M class midi.
One of those situations where other people on site might well kick up a fuss if they find out they had to fork out another two hundred or so quid to be fully compliant and then someone ambles on site with the cheaper one with fresh stickers...

Offline Steven Owen

  • Posts: 409
Re: Dust extraction L Class vs. M Class?
« Reply #28 on: October 18, 2017, 09:32 PM »
What I've been trying to work out is whether the 498994 HEPA filter (I believe standard in the US market) is better than the standard L/M main filter (496170). When I asked about using one with the CTL, one Festool guy hinted that I should "consider the specs of the M filtration vs the HEPA". I think he was trying to hint that HEPA would be no better, but that doesn't quite seem right, given the 99.9% (M) vs "99.997% of all particulates down to 0.3 microns" (HEPA). He was also hinting that HEPA is more about allergens (so perhaps trying to tell me it's no better for wood dust), but I couldn't read between the lines on that one.

The HEPA filters are definitely better than the standard filters. Wood dust can cause asthma and other health issues, and some wood dusts are carcinogenic in nature, or have additives that can be, so the higher the filtration levels the better. It's all about reducing the risk associated with the exposure, and the HEPA filters can certainly do that.

The question I have, is there really any appreciable difference in filtration between the standard L/M filter and a HEPA filter in normal use.  The bigger question is there really a meaningful difference for your health.  My gut says probably not.  The reason I say that is I believe the real issue would likely be the amount of uncaptured dust you're exposed to, not the exhaust from your high filtration vac.  Also keep in mind the limited amount of dust hobbyists are exposed to is far less likely to be dangerous to your health than professionals.  Still, if you are the health nut type a HEPA is pretty cheap piece of mind.     
   

The bigger mistake I see is people who quit wearing dust masks and respirators because they’re using Hepa Vac’s and HEPA filters.  That’s just unwise.  The mask is another layer of defence. 

I see guys sanding varnish and fiberglass all the time with HEPA Vacs and no dust masks.  You just have to shake your head.   
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