Dust extraction L Class vs. M Class?

[Locks14]

Is there really any point to the different classifications?

I understand the filters/unit in a L class unit transmit

 

[Kev]

You breath what is pumped out of the "bad" end of a DC ... make your choice [wink]

 

[Timtool]

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.

 

[Magpal]

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.

 

[Locks14]

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.

 

[GarryMartin]

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 [member=10829]Timtool[/member] 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

 

[Locks14]

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 [member=10829]Timtool[/member] 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

 

[GarryMartin]

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?

 

[AlexThePalex]

I wasn't aware that automatic filter cleaning is a requirement for M/H classification though,

It's not.

 

[Locks14]

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.

 

[GarryMartin]

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.

 

[sploo]

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.

 

[GarryMartin]

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.

 

[sploo]

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.

 

[Brice Burrell]

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.     
   

 

[Brice Burrell]

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.

 

[GarryMartin]

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.

 

[leakyroof]

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]]

 

[sploo]

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]

 

[Dangermouse]

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,