Why is airflow always measured?

Hatsuwr said:

I think your overall list of factors could use a bit of expansion, but environmental impact is a bit silly to talk about in the context of using battery powered appliances in a residential setting. Batteries are used for portability, not for performance or environmental friendliness lol. Battery powered appliances almost universally will have more of a negative impact than their equal performance/class mains-powered counterparts.

It would be funny to see a cleaning time comparison of a 12" cleaning path powerhead vs 9" or so you get with portables, especially once you factor in overlap and how how fast the head can be moved.

Your description of using a corded/bagged vacuum is funny though. Reminds me of this:

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Vacuum Facts said:

You missed the point I made. It's not about battery use; it's about the low power consumption to achieve excellent cleaning results. The battery is neither here nor there. If recycled, it's unlikely the battery will have as great an impact as the materials in a larger machine, not least the big heavy motors which are polluting to make. This scales up substantially over a population and isn't trivial. Ignoring this is a copout.


Yes, but the performance achieved must be the same and the cost to achieve it factored in so sloppy copouts can't just jam a jet engine on the back. I'm aware of no reputable test.


Well, people might attempt to trivialise it, but the data, which can't be argued with, shows clearly that people are moving away from the hassle of corded machines. Soon parity will be achieved and thereafter cordless stick vacs (DC35 clones) will dominate the market. So, those trivialisations fall flat in contrast to the data.

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Hatsuwr said:

The additional impact from the battery comes from raw materials and manufacturing, charging losses, lifespan, and disposal.
Higher efficiency is of course a good thing, but you can't just look at something as simplistic as average wattage by itself and expect to get any meaningful insight.

I hope this isn't just devolving into another attempt at the mental gymnastics required to pretend that Dyson's current chosen form factor is the best solution for applications where it clearly isn't. That routine is getting very tired.

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Vacuum Facts said:

There's no evidence that when recycled, they have any more impact than large machines with big heavy motors and all the materials needed, including transport and disposal.

I don't. I look at the data showing performance per Watt under real-world conditions.

It's not; It's a review of the data and evidence to support factual claims. Likewise, I hope your response isn't just devolving into another attempt to try to discredit and ignore when the data shows something that isn't what someone wants.

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And the data shows it all. It and the physics have proved that the Dyson form factor is the way to go, whether it's be DC35-hand (right angle version) or the gun of V10-and-beyond (in line version), or even outright power-broom like PencilVac. You can fit a small yet efficient AND powerful motor and superior whole-machine (and currently cyclonic) sealed filtration all into a lightweight and long-lasting machine, especially provided genuinely sufficient R&D.

@Vacuum Facts but Dyson has already patented nearly it all, with only the oldest and most common of said patents involved having expired. There's no way around currently, though at the very least Dyson is a case of progressive capitalism... recently the mistake in the V16 and the generic-ness of the Spot+Scrub (Picea) appear to suggest the company's change for the worse...

>_> and then you took it to a whole other level that killed this conversation.

Vacuum Facts said:

>_> and then you took it to a whole other level that killed this conversation.

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At least it's not my fault though... >_>

Japanese household vacuums offer a good basis of comparison because the Japanese have a uniform method of measuring the cleaning power of vacuums sold in Japan. They call this "Suction Work Rate". The lab measures sealed suction at the attachment end of the vacuum, then they measure the volume of air flowing over a defined period of time. Suction and airflow are multiplied together and then multiplied by a factor. The factor is used because unlike the ISO technique for measuring air watts, which is the simultaneous reading of suction and airflow at a given moment in time with a given orifice size. The Japanese measure the volume of air over a period of time, which normalizes for the differences in airspeed across the orifice and for the effects of turbulence. The resulting value for Suction Work Rate is expressed in Watts.

Most corded power nozzle canister vacuums manufactured for the Japanese market by Japanese companies are rated somewhere between 300 and 680 Watts of Suction Work Rate with Hitachi being the company producing vacuums rated to 680 watts. The most powerful European canister vacuum sold in Japan, the Hungarian made run of Lux D820s were rated at 280 watts. The Hungarian models had a more powerful motor from Domel than the Swedish made versions which were rated at 240 watts. Japan market Tristars only manage 190 watts. Mieles sold in Japan are rated from 190 - 240 watts depending on the model. An Electrolux Ergo 3 is rated at 240 watts.

But when you look at their battery powered stick vacs the suction work rate is 250 watts or less. Dyson interestingly does not rate their products sold in Japan using the Japanese standard but rather posts ISO Air Watt number.

That Japanese air Watts standard is also poor, since air Watts can technically be measured anywhere in the system, e.g. raw motor air Watts, or air Watts through a particular component/tool factoring in local air resistance, and it varies hugely. The international standard measures as a function of orifice size and thus indicates the maximum air power achievable. Air Watts are only relevant for above floor cleaning and indicate nothing about carpet cleaning potential for well understood reasons I cover in my lecture video. Carpet cleaning potential is driven by a) the cleaner head's pressure difference with atmosphere (suction) to drive high air speed through pile in whatever total air flow magnitude that results, and b) the cleaner head's propensity to maximise its utilisation by exposing trapped particles to the flow. How well this is achieved needs to be directly empirically measured. The cleaning performance can be compared against the total electrical power consumption that was required.

What I'm getting at above is the electrical power consumed to achieve very high levels of nominal carpet cleaning—so minimising energy consumption without affecting the very highest level of cleaning performance. I know you can get mains cleaner performance using just ~240 W of total electrical power (including brush bar and system losses), nominally. (This will transiently increase with increasing local dirt concentrations.) The machines you mention above I suspect there's no relative performance data for, and old machines that consume little power are usually terrible performers.

Here is a typical Japanese stick vac rated by the JASO standard for Suction Work Rate. 150 watts.
https://www.japantrendshop.com/pana...AJeAFU0o0Li1_YMhE4bG_FFT1ODMHzBGbntyC2tuBlu8Y

Vacuum Facts said:

That Japanese air Watts standard is also poor, since air Watts can technically be measured anywhere in the system, e.g. raw motor air Watts, or air Watts through a particular component/tool factoring in local air resistance, and it varies hugely. The international standard measures as a function of orifice size and thus indicates the maximum air power achievable. Air Watts are only relevant for above floor cleaning and indicate nothing about carpet cleaning potential for well understood reasons I cover in my lecture video. Carpet cleaning potential is driven by a) the cleaner head's pressure difference with atmosphere (suction) to drive high air speed through pile in whatever total air flow magnitude that results, and b) the cleaner head's propensity to maximise its utilisation by exposing trapped particles to the flow. How well this is achieved needs to be directly empirically measured. The cleaning performance can be compared against the total electrical power consumption that was required.

What I'm getting at above is the electrical power consumed to achieve very high levels of nominal carpet cleaning—so minimising energy consumption without affecting the very highest level of cleaning performance. I know you can get mains cleaner performance using just ~240 W of total electrical power (including brush bar and system losses), nominally. (This will transiently increase with increasing local dirt concentrations.) The machines you mention above I suspect there's no relative performance data for, and old machines that consume little power are usually terrible performers.

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Again, as usual you know nothing and didn't even bother to read what I wrote. The standard measures suction and airflow at the attachment end of the hose, wand or what have you. It is measuring air power at the cleaning surface.

(This will transiently increase with increasing local dirt concentrations.) The machines you mention above I suspect there's no relative performance data for, and old machines that consume little power are usually terrible performers.

Kenmore actually posted those values for their old vacuums on a big sticker inside the lid. It lists suction in inches of water lift, airflow in CFM and air watts at the attachment end of the hose. Here is such a tag for a 1978 vintage Kenny. The sealed suction and airflow numbers are pretty close to what I measure using my own suction gauge and anemometer. 227 air watts at the hose end. That was what vacuums were doing 47 years ago.

https://i.ebayimg.com/images/g/nqQAAeSwVGRoofg1/s-l1600.webp

For the sake of comparison my Kenmore 600 is producing 90 cfm airflow at the hose end and mid 80s inches of water lift sealed suction, the hose end makes it hard to get a good steady reading. Now you are going to try to tell me a stick vac has more cleaning power, lol.

cheesewonton said:

Again, as usual you know nothing and didn't even bother to read what I wrote. The standard measures suction and airflow at the attachment end of the hose, wand or what have you. It is measuring air power at the cleaning surface.

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I could retort in the same way. I know that. But that's only one use case. What about crevices, which are very different from the surface (resistance is lower)? This is what I meant by "air Watts can technically be measured anywhere in the system". And you claimed I "know nothing and didn't even bother to read what I wrote"...

Anyway, I'm also aware of the panasonic dupe of technology Dyson patented years before the release of this product and that was available publicly for all to copy from. There's no cleaning data to show such a machine can achieve mains equivalent performance. Again, this is what I meant by "The machines you mention above I suspect there's no relative performance data for, and old machines that consume little power are usually terrible performers."...and again, you claimed I "know nothing and didn't even bother to read what I wrote"

cheesewonton said:

Kenmore actually posted those values for their old vacuums on a big sticker inside the lid. It lists suction in inches of water lift, airflow in CFM and air watts at the attachment end of the hose. Here is such a tag for a 1978 vintage Kenny. The sealed suction and airflow numbers are pretty close to what I measure using my own suction gauge and anemometer. 227 air watts at the hose end. That was what vacuums were doing 47 years ago.

https://i.ebayimg.com/images/g/nqQAAeSwVGRoofg1/s-l1600.webp

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This is nice to see, but it's not relative cleaning performance data. Again, you claimed earlier I "know nothing and didn't even bother to read what I wrote".

cheesewonton said:

Here is a typical Japanese stick vac rated by the JASO standard for Suction Work Rate. 150 watts.
https://www.japantrendshop.com/pana...AJeAFU0o0Li1_YMhE4bG_FFT1ODMHzBGbntyC2tuBlu8Y

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Incidentally, It's not clear what that "150 Watts of suction power" actually refers to either. Is it air Watts or Watts of electrical power? 150 W of electrical power consumption is extremely weak and will unlikely achieve effective cleaning. Typical vague advertising from sloppy manufacturers.

Incidentally, It's not clear what that "150 Watts of suction power"

It refers to the Suction Work Rate according to the Japanese standard.

This is nice to see, but it's not relative cleaning performance data.

That is the most uninformed statement imaginable. Without suction and airflow you don't have cleaning power. Pretty basic stuff.

Watts can technically be measured anywhere in the system"

But again the Japanese standard measures Suction Work Rate at the attachment end. The Japanese standard is very detailed and specific that way and why comparisons of vacuums rated by the Japanese standard are objective.

cheesewonton said:

It refers to the Suction Work Rate according to the Japanese standard.

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I'm not convinced from their advertising, but it is believable. Also doesn't translate into cleaning performance on carpets.

cheesewonton said:

This is nice to see, but it's not relative cleaning performance data.

That is the most uninformed statement imaginable. Without suction and airflow you don't have cleaning power. Pretty basic stuff.

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What you said is true, but cleaning performance needs to be measured directly since, as discussed in the previous response, there are other factors associated with the cleaner head. Direct measurements are needed, not values from indirect variables. The science of this is well known and discussed in the lecture you write off as complicated. Well the real world is and if you want to understand it, an investment in education is needed. I've kindly made it available for those who want to learn, and it's accessible to the age of about 16.

cheesewonton said:

Watts can technically be measured anywhere in the system"

But again the Japanese standard measures Suction Work Rate at the attachment end. The Japanese standard is very detailed and specific that way and why comparisons of vacuums rated by the Japanese standard are objective.

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Again true. No argument from me. However, their standard measures for effectively one particular use case that isn't universally applicable to all situations (unlike the ISO). And it's only relevant for above floor cleaning. You claim it's for a tool sealed to a surface (which makes sense), but this is different to tool extracting from a deep crevice. Air watts are fixated on too much and not many seem to understand their value. Their real value for floor cleaning is outlined in the lecture associated with various low resistance flooring that allow high air currents, and more air watts sustains suction and air speed. All well understood and has been for a few hundred years.

@cheesewonton @Vacuum Facts please tell us all the differences between the Japanese Suction Work Rate and simple airwatts, so people would know, notice and be able to distinguish the two.

Also, here's a video for dummies, made by none other than @Vacuum Facts:

Absolute Rainbow said:

@cheesewonton @Vacuum Facts please tell us all the differences between the Japanese Suction Work Rate and simple airwatts, so people would know, notice and be able to distinguish the two.

Also, here's a video for dummies, made by none other than @Vacuum Facts:

Click to expand...

The primary difference is that the ISO Air Watt measurement is an instantaneous measurement of both airflow and suction at a given diameter orifice. It is a snapshot in time. Vacuum motor manufacturers will take this measurement at different orifice sizes starting at a closed orifice. At that point you get maximum suction and no airflow. Since Air Watts are Suction in Pascals multiplied by airflow in Cubic Meters per Second the Air Watts at a closed orifice is zero. The manufacturer will take airflow and suction measurements at progressively larger orifices and calculate the air watt value for that orifice until they reach a maximum orifice size, typically 50-52m at which point suction is nearly zero and airflow is maximum. They will also plot Airflow and Suction vs Orifice size. Where those graphs intersect, typically around 20-25 mm orifice size maximum air watts is achieved.

By comparison the Japanese standard measures maximum sealed suction at the hose end or the orifice in the nozzle of an upright, and they also measure the quantity of air that flows through the hose or suction nozzle over a period of time. This compensates for the difference in the speed of air flowing through a hose or tube from the center where it is highest to the walls where it is nearly zero. Instead of measuring air speed at the center and applying a rule of thumb correction factor the Japanese simply measure the total volume of air that flowed over a period of time. The measured suction and air volume are multiplied together and this value is multiplied by a factor to arrive at their Suction Work Rate.

cheesewonton said:

The primary difference is that the ISO Air Watt measurement is an instantaneous measurement of both airflow and suction at a given diameter orifice. It is a snapshot in time. Vacuum motor manufacturers will take this measurement at different orifice sizes starting at a closed orifice. At that point you get maximum suction and no airflow. Since Air Watts are Suction in Pascals multiplied by airflow in Cubic Meters per Second the Air Watts at a closed orifice is zero. The manufacturer will take airflow and suction measurements at progressively larger orifices and calculate the air watt value for that orifice until they reach a maximum orifice size, typically 50-52m at which point suction is nearly zero and airflow is maximum. They will also plot Airflow and Suction vs Orifice size. Where those graphs intersect, typically around 20-25 mm orifice size maximum air watts is achieved.

By comparison the Japanese standard measures maximum sealed suction at the hose end or the orifice in the nozzle of an upright, and they also measure the quantity of air that flows through the hose or suction nozzle over a period of time. This compensates for the difference in the speed of air flowing through a hose or tube from the center where it is highest to the walls where it is nearly zero. Instead of measuring air speed at the center and applying a rule of thumb correction factor the Japanese simply measure the total volume of air that flowed over a period of time. The measured suction and air volume are multiplied together and this value is multiplied by a factor to arrive at their Suction Work Rate.

Click to expand...

Since @Vacuum Facts thinks airwatts are better... How about people measure airwatts for above-floor-plus-crevice performance (like he suggested in his videos), and use the Japanese standard for base floor cleaning, at least in Japanese market? Also, it's not like you necessarily needs so many airwatts, because all of it would be wasted away by a sufficiently sloppy cleaner head, just like Vacuum Facts himself noted.

Measuring the airflow:

Absolute Rainbow said:

Since @Vacuum Facts thinks airwatts are better... How about people measure airwatts for above-floor-plus-crevice performance (like he suggested in his videos), and use the Japanese standard for base floor cleaning, at least in Japanese market? Also, it's not like you necessarily needs so many airwatts, because all of it would be wasted away by a sufficiently sloppy cleaner head, just like Vacuum Facts himself noted.

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The air watts of the motor can be in some cases irrelevant to what is happening at the hose end. Example. I am weird for Tristars and their several imitations from Miracle Mate, Schoettler ( Airstorm and Patriot among others ) and Vortech. I have Tristars going back to the very first Compact Model 1 circa 1944-45 up to the most recent models. All of them have hoses with a 28 mm inside diameter at the spout. And every single one of them regardless of the year made or the motor installed produce 27 to 28 cfm at the hose end. The OEM motor in a Tristar DXL is rated at 356 peak air watts. I have an EX-30, which is basically a DXL with a different upper body shape for the Japanese market I converted to a 120 volt machine. I have used different Ametek motors in it with peak air watt ratings of 356, 447 and 489 air watts ( 116884-49 the original DXL motor, 115923 and 119347-01 respectively ) as well as an Electromotor Inc. 6500-298 two stage motor rated at 438 air watts. All of these produced the same 27-28 cfm. I also have a couple of the current Tristar bodies used with the EXL, MG and CS series into which I have finagled other motors. They came with a VM3 motor that I have no data for but even this newer Tristar only produces 27-28 cfm. Wimpy by modern standards. I put an Electromotor 6500-298 in one and it still makes only 27-28 cfm. I put a 600 air watt Panasonic 3D Inducer Motor in one that came from a Kenmore Elite. That gave me a rip roaring 29 cfm at the hose end. The exact same motor in a Kenmore Elite with its 40 mm hose end gives me 43 cfm.

I put that Electromotor 6500-298 in an old Electrolux Epic 8000. These have a hose with a female hose end that is 38 mm diameter. The same motor that only produced 27-28 cfm airflow in the Tristar produces a healthy 61 cfm in the Epic. The Epic has a larger diameter hose and a really huge exhaust opening so there is very little airflow restriction, where the Tristar has a smaller 28 mm hose opening and because the exhaust is also designed to accept the hose and be used as a blower the exhaust opening is very small too.

I have a Sanitaire SP6952 in which I literally doubled the airflow at the hose end by doing detailed clean up of the hose ends. There were sharp edged corners, molding flash both of which are terrible for airflow and the inside surfaces of the hose ends were shiny and smooth which creates a boundary layer of dead air along the walls, effectively reducing the inside diameter of the opening. I sanded down the molding flash, rounded the sharp edges and sanded the inside in the direction of airflow to break up the boundary layer, all stuff I learned to increase airflow in cylinder heads and intake manifolds on gasoline engines. Doubled the airflow, no other changes.

Absolute Rainbow said:

Since @Vacuum Facts thinks airwatts are better...

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This is inaccurate. I've repeatedly said airwatts are misunderstood and fixating on them has limited value.

The thing I like about the Japanese rating system is that it is based on suction and airflow at the hose end or nozzle end depending on the configuration of the vacuum and the standard is applied consistently across all vacuums.

Yes, as above, It's fine, but it represents a specific use case and doesn't inform the potential for other use cases. Knowing the air power only has limited value. Most people don't appear to understand. It's all in my lecture video. Marketing love it because they can one up with it. It's of little value to the ordinary user. It's also not as valuable as industry standard determined cleaning performance.

cheesewonton said:

ISO Air Watt measurement is an instantaneous measurement of both airflow and suction at a given diameter orifice. It is a snapshot in time. Vacuum motor manufacturers will take this measurement at different orifice sizes starting at a closed orifice. At that point you get maximum suction and no airflow. Since Air Watts are Suction in Pascals multiplied by airflow in Cubic Meters per Second the Air Watts at a closed orifice is zero. The manufacturer will take airflow and suction measurements at progressively larger orifices and calculate the air watt value for that orifice until they reach a maximum orifice size, typically 50-52m at which point suction is nearly zero and airflow is maximum. They will also plot Airflow and Suction vs Orifice size. Where those graphs intersect, typically around 20-25 mm orifice size maximum air watts is achieved.

Click to expand...

Absolute Rainbow said:

Measuring the airflow:

Click to expand...

Since @Vacuum Facts dislikes the cubic-feet per minute, and there's the excessive overestimation if done wrong, I'm going to technically add to the formula, based on existing stuffs. This will apply to the ISO airwatts only, which has currently been used internationally.

ASTM F558-13 have us the common formula, which is the simplest one out of some other formulas out there, and graciously gave us the exact formula: 0.117354×F×S, F is for CFM airflow, S is suction level. An easy yet surprisingly accurate approximation would be 2/17×F×S. However, there's two direct problems with the formula in question:
- @Vacuum Facts thinks that CFM, the imperial, is outdated (measuring airflow video, timestamp is 6:20), so I am going for liter per second. 1 l/s = 2.11888 CFM, 1 CFM = 0.47194745 l/s.
- It's mistaken the water lift (in.H2O) with suction. You should be using the kilopascal (kPa) instead, and 1kPa = 4.01865 in.H2O and 1 in.H2O = 0.249089 kPa.
So the actual formula (in bold) should be: [AW] = 0.117354×[CFM]×[kPa] = 0.117354×2.11888[l/s]×[kPa] = 0.248659×[l/s]×[kPa] = 0.248659×[l/s]×0.249089[kPa] = 0.0619×[l/s]×[in.H2O] = 0.117354×[CFM]×0.249089[kPa] = 0.0292×[CFM]×[in.H2O]

You can only get away with rational approximation with the CFM-kPa version of the formula because it's incredibly accurate, especially for such simple fraction. It's best that you guys all use the more accurate full numbers like I did.

Absolute Rainbow said:

Since @Vacuum Facts dislikes the cubic-feet per minute, and there's the excessive overestimation if done wrong, I'm going to technically add to the formula, based on existing stuffs. This will apply to the ISO airwatts only, which has currently been used internationally.

ASTM F558-13 have us the common formula, which is the simplest one out of some other formulas out there, and graciously gave us the exact formula: 0.117354×F×S, F is for CFM airflow, S is suction level. An easy yet surprisingly accurate approximation would be 2/17×F×S. However, there's two direct problems with the formula in question:
- @Vacuum Facts thinks that CFM, the imperial, is outdated (measuring airflow video, timestamp is 6:20), so I am going for liter per second. 1 l/s = 2.11888 CFM, 1 CFM = 0.47194745 l/s.
- It's mistaken the water lift (in.H2O) with suction. You should be using the kilopascal (kPa) instead, and 1kPa = 4.01865 in.H2O and 1 in.H2O = 0.249089 kPa.
So the actual formula (in bold) should be: [AW] = 0.117354×[CFM]×[kPa] = 0.117354×2.11888[l/s]×[kPa] = 0.248659×[l/s]×[kPa] = 0.248659×[l/s]×0.249089[kPa] = 0.0619×[l/s]×[in.H2O] = 0.117354×[CFM]×0.249089[kPa] = 0.0292×[CFM]×[in.H2O]

You can only get away with rational approximation with the CFM-kPa version of the formula because it's incredibly accurate, especially for such simple fraction. It's best that you guys all use the more accurate full numbers like I did.

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What a bunch of hooey. First of all I don't use one of those fan style anemometers. Kludge! I measure the velocity of the airstream with a digital hot wire anemometer. I measure the inside diameter of the hose opening with an inside caliper and calculate the surface area of that opening in square feet. I have a spreadsheet with the surface area and diameter in inches for hose openings ranging from 28mm through 55 mm. After that the calculation is air velocity times surface area. That is true regardless of the units used, but you have to pay attention to the fact that the units used for the surface area and air velocity are the same, ft per minute and square feet, or meters per minute and square meters, etc.

Since the speed of the airflow is highest in the center of the column of moving air where my anemometer measures and lowest at the outside of the column of air due to the effects of boundary layer I apply a factor of 0.8, which is an HVAC industry standard rule of thumb adjustment factor used for calculating the airspeed of a column of turbulent air in a tube or pipe.

( air velocity in feet per minute ) x ( surface area of orifice in square feet ) x ( 0.8 ) = airflow in cubic feet per minute

I could do this in metric units but nobody in the US uses them and none of the companies selling vacuums in the US post their data in metric units. If you look at the data for Miracle Mate, Sebo or even that Vapamore MR500 Vento thing their US literature shows airflow in CFM. That is how it is done here. And obtw my way of determining airflow in CFM is within 1-2 CFM of the number in the Vapamore literature.

This stuff is not hard. And saying using English measurement is somehow less accurate is just not true.

Absolute Rainbow said:

Since @Vacuum Facts thinks airwatts are better...

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Not sure where you are getting this from. It's not true. You often regurgitate what I write, but on technical matters, you get it wrong. Replication isn't the same as understanding. An example of this kind of error, and similar to the stochastic generative AI failures, is below.

Absolute Rainbow said:

Also, it's not like you necessarily needs so many airwatts, because all of it would be wasted away by a sufficiently sloppy cleaner head, just like Vacuum Facts himself noted.

Click to expand...

Airwatts are not relevant in this way at the cleaner head and you've misunderstood. Loss of suction at the cleaner head is relevant there. Airwatts simply indicate the magnitude of airflow into the head that can be achieved whilst sustaining sufficient suction to maintain the speed of that airflow, which is what counts. This is relevant for low resistance flooring. This was discused in detail in the lecture.