Author Topic: Bullshit units of measure  (Read 6706 times)

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Offline HalcyonTopic starter

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Bullshit units of measure
« on: October 12, 2022, 11:20:00 pm »
This is a new one... I'm shopping around for a new vacuum cleaner and Dyson boast on their website that their particular vacuums have x-number of "Air Watts" (even abbreviating it to AW). In the fine print it says "Suction tested to IEC62885-4 CL5.8 and CL5.9, tested at the flexible inlet, loaded to bin full, in Boost mode by independent third-party, SGS-IBR Laboratories US in 2022".

This smells of PMPO and other "made up" units of measure.

Edit: I stand corrected, it seems that there is some merit and standardisation to it. Looking at Wikipedia, the Air Watts article was created in 2008, so it seems it's not a new thing.
« Last Edit: October 13, 2022, 11:47:14 pm by Halcyon »
 

Offline jpanhalt

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Re: Bullshit units of measure
« Reply #1 on: October 12, 2022, 11:33:02 pm »
Output of air compressors can be related to watts (https://www.vmacair.com/blog/how-to-calculate-air-compressor-cfm-to-kw/ ). That's helpful in evaluating some wild claims of output from consumer units.  I wasn't aware of the same type of conversion for household vacuum cleaners. 

If done rationally and by third parties, I see no problem with it, particularly if other manufacturers follow suit.  It is, of course only one metric in a vacuum cleaner.  I have a Dyson bought 20 years ago.  It's OK, but there was a lot about my old Hoover that I liked better.
 

Offline james_s

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Re: Bullshit units of measure
« Reply #2 on: October 12, 2022, 11:52:28 pm »
It does annoy me, but the problem is there is no standardized unit accepted for measuring the performance of a vacuum cleaner. Power consumption is an easy one, but that obviously doesn't tell the whole story, it's easy to consume a lot of power producing mostly noise. I think actually air watts could make sense if it was made standardized. Connect a standardized air suction powered generator to the vacuum cleaner and record the power it is able to produce. Even that isn't necessarily a great measure of cleaning performance but it's a good start.
 

Offline bdunham7

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Re: Bullshit units of measure
« Reply #3 on: October 12, 2022, 11:58:02 pm »
If the airwattage is not some huge inflated number determined using some bogus method (like the ridiculous peak power rating) and it is applied uniformly, then I think it is great.  That does appear to be the case, airwatts are less than electrical watts by some margin.

https://en.wikipedia.org/wiki/Airwatt
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 
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Offline MikeK

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Re: Bullshit units of measure
« Reply #4 on: October 13, 2022, 01:58:46 am »
I think the bullshit unit of measure is the bucket, no?
 

Offline Bud

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Re: Bullshit units of measure
« Reply #5 on: October 13, 2022, 04:00:06 am »
To me it is Stone. Wikipedia seems to give all sort of figures what one Stone may equal to.
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Online ejeffrey

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Re: Bullshit units of measure
« Reply #6 on: October 13, 2022, 04:15:38 am »
This is a new one... I'm shopping around for a new vacuum cleaner and Dyson boast on their website that their particular vacuums have x-number of "Air Watts" (even abbreviating it to AW). In the fine print it says "Suction tested to IEC62885-4 CL5.8 and CL5.9, tested at the flexible inlet, loaded to bin full, in Boost mode by independent third-party, SGS-IBR Laboratories US in 2022".

This smells of PMPO and other "made up" units of measure.

Air watts is supposed to be closer to a real unit of useful work.  Here in the US, you often see wet dry vacuums rated for something absurd like "6.5 peak HP" -- on a 120 V / 15 amp power outlet...  Right... They get this by measuring the peak inrush surge current and multiplying by 120 V then dividing by 745 W/hp.  This obviously has nothing to do with anything important and actually encourages manufacturers to not limit inrush current to get a higher HP rating.

Take a look at this: https://www.homedepot.com/p/RIDGID-16-Gallon-6-5-Peak-HP-NXT-Wet-Dry-Shop-Vacuum-with-Detachable-Blower-Filter-Locking-Hose-and-Accessories-HD1600/304795082

Air watts should be something more like deltaP * deltaV at the flow rate where that is maximized.  In other words, mechanical work.  You would normally rate mechanical work in horsepower, but since that was already taken by scam artists we get air watts.  I'm sure there are ways to game the system but it is less bad than the BS horsepower ratings that it is trying to replace.
 

Offline jonpaul

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Re: Bullshit units of measure
« Reply #7 on: October 13, 2022, 04:56:48 am »
The D---n are ..overdesigned overpriced junk made in China
get a vintage hoover

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Online wraper

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Re: Bullshit units of measure
« Reply #8 on: October 13, 2022, 05:10:52 am »
The D---n are ..overdesigned overpriced junk made in China
get a vintage hoover

j
None of Dyson products are made in China AFAIK. Overpriced yes, but at least some of their products are very good. For example their hand driers are by far the best compared to anything else I've used. Hair driers are very good too, yes you can get something cheaper with similar performance, but it will be way bulkier and with way more annoying noise. There are a ton of crappy counterfeits on Amazon, ebay and other places though, so people often claim it's garbage. If you read something like magnetic attachments do not hold well, it's 100% counterfeit.
« Last Edit: October 13, 2022, 05:22:17 am by wraper »
 

Offline Berni

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Re: Bullshit units of measure
« Reply #9 on: October 13, 2022, 05:21:46 am »
According to the definition on Wikipedia it sounds like a pretty reasonable measure of performance. It is basically a dyno for moving air. But yes if i sen this written on a box i would think it is bullshit marketing numbers.

Tho units people are not familiar with are often manipulated by the no name brands. If you go looking for a flashlight online you will find plenty of handheld flashlights with claims like 5000 lumen 10 000 lumen sometimes even 100 000 lumen... yet the thing runs from 2xAA cells. Since people have no idea how bright a lumen is they beleve the numbers... even tho it would take multiple kW worth of LEDs to actually get such lumens.

 

Offline james_s

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Re: Bullshit units of measure
« Reply #10 on: October 13, 2022, 07:16:13 am »
The D---n are ..overdesigned overpriced junk made in China
get a vintage hoover

j

I've had a lot of different vacuums ranging from 1960s to modern and the Dyson I currently have is by far the best performing of any I've ever used. They're typically overpriced but I got mine on sale, I've had it for over a decade now and it's still going strong. I'd buy another one if I ever lost it.
 
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Offline james_s

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Re: Bullshit units of measure
« Reply #11 on: October 13, 2022, 07:20:30 am »
Tho units people are not familiar with are often manipulated by the no name brands. If you go looking for a flashlight online you will find plenty of handheld flashlights with claims like 5000 lumen 10 000 lumen sometimes even 100 000 lumen... yet the thing runs from 2xAA cells. Since people have no idea how bright a lumen is they beleve the numbers... even tho it would take multiple kW worth of LEDs to actually get such lumens.

Many of the flashlights are greatly exagerated, however it would not take multiple kW of LEDs to reach those numbers. A 1kW metal halide lamp of the sort used to illuminate parking lots and sports fields is about 125,000 lumens. Recently these are getting replaced by LED lights that consume about 1/3 that.
 
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Online thm_w

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Re: Bullshit units of measure
« Reply #12 on: October 13, 2022, 11:19:06 pm »
Yeah Dyson is not junk, not even close, its just expensive. Anyone who says that has never owned or taken apart a Dyson product.

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Offline TimFox

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Re: Bullshit units of measure
« Reply #13 on: October 13, 2022, 11:41:43 pm »
I think the bullshit unit of measure is the bucket, no?

The "barrel" is an multiply-defined unit, depending on what product is contained therein.
see  https://en.wikipedia.org/wiki/Barrel_(unit)
The "bushel" is similar, and legal usage in the US seems to define it by weight of material.
As a unit, "buckets" are rare, but seem to be defined as 4 gallons, and the "gallon" depends on which country defines it.
 

Offline aduinstat

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Re: Bullshit units of measure
« Reply #14 on: October 14, 2022, 12:20:30 am »
Miles are bullshit. The USA uses 3 different miles that are close to the same length, but slightly different.
 

Offline james_s

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Re: Bullshit units of measure
« Reply #15 on: October 14, 2022, 12:30:25 am »
Miles are bullshit. The USA uses 3 different miles that are close to the same length, but slightly different.

We do? The only mile I'm familiar with is 5,280 feet.
 

Offline Sal Ammoniac

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Re: Bullshit units of measure
« Reply #16 on: October 14, 2022, 01:13:14 am »
NASA uses nautical miles (at least in their launch commentaries) 1 nautical mile = 6076 feet.

"Knots" are nautical miles per hour.
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Offline aduinstat

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Re: Bullshit units of measure
« Reply #17 on: October 14, 2022, 01:13:56 am »
Miles are bullshit. The USA uses 3 different miles that are close to the same length, but slightly different.

We do? The only mile I'm familiar with is 5,280 feet.

We also nautical miles which are about 6,076 feet (after 1954), and survey miles which are about 1/8 inch longer than an international mile.
 

Offline IanB

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Re: Bullshit units of measure
« Reply #18 on: October 14, 2022, 02:41:36 am »
Even if air watts is a recognized measurement, neither it nor anything else is really useful unless everyone quotes it in the same way so you can make comparisons. If Dyson gives a value for air watts and no other manufacturer does the same, then it is completely useless.

Personally, I would be happy with something simple like air flow at the suction nozzle (cubic feet per minute in the USA or liters per second everywhere else). You are going to find that the vacuum with more air flow sucks better, because to get more air flow you need more suction.
 

Offline TimFox

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Re: Bullshit units of measure
« Reply #19 on: October 14, 2022, 02:47:24 am »
Miles are bullshit. The USA uses 3 different miles that are close to the same length, but slightly different.

We do? The only mile I'm familiar with is 5,280 feet.

We also nautical miles which are about 6,076 feet (after 1954), and survey miles which are about 1/8 inch longer than an international mile.

The US survey foot and survey mile (based on 1 meter = 39.37 inches exactly, the US definition before 1959) are being abandoned.
The US statute mile is 5,280 feet (based on 1 inch = 2.54 cm exactly, the current US definition of the customary unit, not "imperial" unit).
Nautical miles are an international standard, based on geodesy.
The term "mile" comes from the latin for one thousand paces.
 

Offline Someone

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Re: Bullshit units of measure
« Reply #20 on: October 14, 2022, 03:04:54 am »
Even if air watts is a recognized measurement, neither it nor anything else is really useful unless everyone quotes it in the same way so you can make comparisons. If Dyson gives a value for air watts and no other manufacturer does the same, then it is completely useless.

Personally, I would be happy with something simple like air flow at the suction nozzle (cubic feet per minute in the USA or liters per second everywhere else). You are going to find that the vacuum with more air flow sucks better, because to get more air flow you need more suction.
"professional" vacuum units already provide figures for the (peak) airflow and pressure, but that's at the hose/port and the cleaning capacity/effectiveness then depends on the chosen head.

How well a vacuum cleaner works? The EU has you covered: IEC/EN/BS/DIN 60312-1
 

Offline Ed.Kloonk

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Re: Bullshit units of measure
« Reply #21 on: October 14, 2022, 03:59:17 am »
Hey, pardon my ignorance since vacuuming is the woman's job and all but what's the difference between paper bags and synthetic ones for a non-dyson?

Other than being twice the price, why should I not just get the paper one?
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Offline Psi

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Re: Bullshit units of measure
« Reply #22 on: October 14, 2022, 04:13:29 am »
Dyson is one of those brands that just pisses me of. So much arrogance.

Apple being another.


I just won't buy their stuff on principle. 
Even if it was the best option. (Which it isn't.)
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Offline VK3DRB

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Re: Bullshit units of measure
« Reply #23 on: October 14, 2022, 05:21:57 am »
This is one of Dave's most entertaining videos about Dyson's :bullshit: marketing. My favourite. If you have not seen it, watch right to the end - including AFTER the credits! :-DD

 

Online wraper

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Re: Bullshit units of measure
« Reply #24 on: October 14, 2022, 05:30:14 am »
Personally, I would be happy with something simple like air flow at the suction nozzle (cubic feet per minute in the USA or liters per second everywhere else). You are going to find that the vacuum with more air flow sucks better, because to get more air flow you need more suction.
Then they could make a vacuum with wider and shorter hose, optimize fan for that and claim higher airflow. But it would be worse at sucking dirt from carpets because of lower static pressure difference fan can produce.
 


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