First, forget the HP rating on my small dust collection products, it's mostly marketing hype. Such as the Borgs 5hp dust collectors that run on a 120v 10amp circuit... defies all laws.... but regardless...
Total vacuum force is mostly a function of power. (of course you can tailor a design, but can never overcome the power issue which is the over-riding limitation) A large Cyclone Dust collector will draw 4 - 20x the power of a Festool Vac. Since most motor efficiency ratings are 90% range, the motor eff. is not much of an issue in a general discussion as this.
Next is the issue of restrictions.... smaller openings create greater restictions. Restrictions limit vacuum force / pressure. Smaller hoses create added friction, because the air moves at higher speeds....same as an automobile... when you travel at 80mph, fuel economy is greatly reduced due to MUCH greater air resitance vs. traveling at 20mph. Of course, there is always the restriction size vs. hose size. Once a restriction is put in place, you can not reverse its losses with a larger hose, although the larger hose will still reduce total resistance, so all is not wasted. If you ever want to see this play out, put a 50mm hose on the Festool, you will see what resistance is all about...
As mentiones previously, Festool vacs are unique mainly due to their specific features they designed in, for the market they serve, which are:
1) portability (in shop and bringing to job site)
2) Quiet... vs. other dust collectors, often important on job sites
3) HEPA filtration as the final filtering system. Very important on job sites and in shop.
The first two are self explanatory. We know Festool is limited in power by the available power in most 15 amp circuits, so they can not create the ultimate sucking machine. As matter of fact, you will notice Festool vacs suck much less than a cheap Borg unit. Which brings up the most overlooked issue, #3 above. A dust bag is a very crude filtration device, it traps relatively large dust particles. In most cases, large enough where you can see them with the naked eye. The more crude the collection, like a Borg unit, the less resistance, the greater suction.
However, the dangerous dust particles are invisible, under 10 micron in size. The most deadly are in the 1 - 5 micron size, as they seat perfectly in the lungs. Unfortunately, the lungs do not have a cleaning cycle, like the kidneys cleaning the blood 24/7. These foreign objects often stay in the lungs, creating all types of reactions. Some obvious, like allergic, some less obvious, some barely noticeable, all humans differ to foreign particles in their lungs, hence why some smokers die of lung cancer at 35 and others at 95.
Festool Hepa filters (last filter on system) captures dust particles down to 1 micron. The more aggressive a filter, the greater the restriction on air flow. Remember, a vac pulls air, and then must exhaust the air after filtration. The greater the filtration, the less suction. The system runs from point of suction, to point of exhaust. To maximize efficiency, (or to minimize suction loss) the fine filtration (HEPA filter) should be designed with the largest possible surface area. This is the key to minimizing the filters restriction on suction. This is where Festool Vacs shine.... they designed a Vac from the ground up, to maximize the amount of suction with the available power from standard 120V receptacles and at the same time, maximized filtration to prevent the deadly small particulate from re entering the work space where we can breathe them into our lungs, long after the cut is made. And yet, all this in a portable, lightweight and quiet unit. Festool knows their market very well...
A small caveat though.... the weak link in this chain is often at the point of collection... its not easy to collect all the dust where its generated. And while Festool does a better job than any maker in this regard (Fein being the other), with dust collection designed in every tool, there is some tools such as the saws which will allow some dust to bypass dust collection, hence why a dust mask is still required if you are concerned about lung health.
If portability is not an issue, and you have multiple areas where you need dust collection, the Festool vacs are clearly not the best choice. The BEST and healthiest solution is a large cyclone (large relative to the task) with the exhaust air blown outside the shop. The CFM at the tool will be much greater, capturing a higher % of dust at the point of generation, and the invisible < 10 - 20 micron fine particles the cyclone does not catch, "can" be exhausted to outside air, making the safest working environment.
Of course, exhausting vac air is not always feasible, since every cubic foot of air you exhaust, will introduce one cubic foot of fresh outside air. Not always good when its below freezing outside or dealing with summer heat. The main problem being varying inside tempertatures and high utility bills. When not possible to exhaust waste air, using the largest and finest filtration collection bags is the next best option. When I use my cyclone with Festool tools, the capture rate is much greater, as the suction is much greater.... but no surprise there, my cyclone pulls 40 amps at 240V, about 8x more potential than the Festool. If 60% of suction is lost in the duct runs and filtration bags, you are still way ahead of the game vs. using Festool. For some tools, like the routers, with the proper accessories, the dust is so well contained in the dust shrouds, there is little difference between the two dust collection system.
The max. efficiency and safety of a dust collection system resides in the exhaust air. By avoiding the very restrictive final "fine" filtration increases suction and avoids re circulating the very fine particles that can even escape the fine bags. IMO, this was one of Bill Pentz's excellent contribution to this field. By not utilizing this "100% exhaust" method in his woodworking years, has led to his health ills today. Bill is an incredibly kind, inteligent, articulate and gracious person who has taken a tremendous amount of his time and nrg helping fellow ww's avoid the health ills he must deal with on a daily basis. Thank you again Bill Pentz for your contribution and your tireless work towards helping yoru fellow ww's...
And remember, a dust mask should still be used when you are very close to the source of dust generation....mainly when there is a lot of dust generation, such as cutting sheet goods.
