6 ms·

Except for one issue: it actually slows down the efficiency of the bathroom. See, by splitting up washing and drying into two steps, you allow two people to be

Except for one issue: it actually slows down the efficiency of the bathroom. See, by splitting up washing and drying into two steps, you allow two people to be in the process of cleaning their hands at a time. By bundling the two steps together, you reduce the amount of stuff in the bathroom, but you also reduce the efficiency of the bathroom. This AirBlade Faucet is a great idea for low-usage bathrooms: less paper towels, less equipment to maintain, etc. For high-volume bathrooms, (airports, etc) this would actually be a step backwards to put these faucets in, if a goal of the bathroom is to be able to quickly serve a large group of people.

dpcx 14y ago
This also allows you to remove towels and several trash cans, and add additional stations.
tocomment 14y ago
That's only if you assume unlimited paper towel stations. In reality hand drying is the bottle neck. So if every sink has its own dedicated dryer it will speed things up.
- lttlrck 14y ago
  "every sink has its own dedicated dryer" Exactly. Sinks seem to always outnumber dryers by a wide margin.
- epo 14y ago
  But you wouldn't get a queue for paper towels. People would grab 2 or 3 towels and move aside.
  - tocomment 14y ago
    Maybe but there's a bit of a shuffle getting around people who have grabbed towels. And there are always the people who stand by towels to dry because that's where the trash can is. Actually, I guess separating the towel dispensers and trash cans in existing bathrooms would be a smart efficiency move since it would encourage people to grab a towel and keep moving.
- r00fus 14y ago
  Don't ignore the folks who actually don't want to airdry their hands. I soap, wash, shake and wipe my hands in my pockets as I walk out the door if I'm in a hurry.
deleted 14y ago
[deleted]
rytis 14y ago
Not sure. Let's say a person spends 15 secs washing, and 15 secs drying. Combined it's still 30 secs. So if we have a long queue, does it really matter that two people are in the bathroom at any given time, or just one? The total processing time does not change. Or am I missing something here?
- cmsmith 14y ago
  I think your assumption of equal time for each task is incorrect. Either because people don't dry their hands, or it doesn't take as long as washing. Because typical bathrooms have 4 times as many sinks as they have hand driers, and I still see sink lines more often than drier lines.
  - rytis 14y ago
    OK, but still that doesn't change the equation. 22 secs washing and 8 secs drying is still 30 secs in total, whether it's done separately or not. And as you mentioned, the number of sinks and the number of dryers are balanced, so they combined have a similar throughput. I think you see sink lines more often just for that reason, if the sink line can handle 10 persons per minute, and the supply is 20ppm you will have a queue. But once we throttle people at the sinks, the supply to the driers is 10ppm, thus no lines (assuming the driers line is 10ppm)....
  - roc 14y ago
    Only because "air drying" is a more acceptable option than "not washing". So a combined station would only slow things down inasmuch as people no longer skip drying. In general (at least in the US) drying takes far longer than washing. Because most people wash quickly/poorly whereas driers are on timers and most are horrible. And when your hands are still wet even after negotiating the unresponsive sensor and waiting an entire drying duration, it's understandable that many people would just as soon skip it.
- beala 14y ago
  It actually does help, and the concept behind it is called pipelining [1]. Suppose there's a sink that washes and dries, and there are two people who want to use it. The second person will spend 30 seconds waiting, and 30 seconds washing/drying. So, 60 sec total. If there's a sink and a separate dryer, the second person will spend 15 sec waiting, 15 sec washing, and 15 sec drying. So, 45 sec total. The second person gets a 15 seconds savings, because he can start washing as soon as the first person finishes washing, rather than having to "block" until the first person is done washing and drying. [1] http://en.wikipedia.org/wiki/Pipeline_(computing)#Concept_and_motivation http://en.wikipedia.org/wiki/Pipeline_(computing)#Concept_an...
oh_sigh 14y ago
Have you done the math on this? I have a feeling you're relying on a gut instinct and didn't actually simulate it. From my simulation, this new gadget will simply shift lines from the paper towel dispenser/on the wall air dryer to the sink itself. It will not at all reduce the efficiency of the bathroom, infact it will increase it
- moe 14y ago
  I don't know about your simulation, but over here in the real world it doesn't work that way. Many people don't dry their hands at all in a public bath room (that's what god invented jazz hands[1] for). By combining faucet and dryer you force these people into the same bottleneck as the hand-dryer users. [1] http://www.youtube.com/watch?v=xuPSIbABYVU http://www.youtube.com/watch?v=xuPSIbABYVU
  - incongruity 14y ago
    It's actually worse because you take what were 2 parallel operations (washing your hands and drying them) and make them two serial operations, not able to be run in parallel.
    - oh_sigh 14y ago
      Yes, it does upset the balance slightly for people who want to wash their hands, but not dry them, and for people who want to dry their hands, but not get them wet. Those are the only scenarios where your argument holds, however.
      - incongruity 14y ago
        No, not at all. Simply put, you are moving from 2 independent operations to 2 mutually exclusive operations – meaning that 1 sink (in the Dyson case) can only service 1 user at a time vs 1 sink+1 dryer/towel dispenser which can, at a minimum, service 2 users at once (there's actually a much bigger set of time/path calculations that could go in to this, but the simple case is enough to make it clear that your thinking is confused on this.)
btgeekboy 14y ago
Does it though? While I agree with your premise, what I often see are available sinks while everyone hangs out around the 1 or 2 dryers or towel dispensers and trash cans, waiting for their hands to dry. That is, unless it's like another place I know of where there's a paper towel dispenser and trash slot between every sink, in which case this faucet wouldn't change anything - they'd just be using their sink instead of standing in front of it with a paper towel.
tikhonj 14y ago
Essentially, combining washing and drying reduces pipelining. It doesn't change the time for any individual person, but it does reduce throughput. Of course, most public restrooms have fewer drying stations than sinks, so this would probably be less of an issue.
incision 14y ago
>Except for one issue: it actually slows down the efficiency of the bathroom. With one exception, every bathroom within my memory had the drier as a bottleneck, typically at a ratio of 3:1 or worse. Having a drier per sink would actually improve the efficiency. The one exception was a older building which had towel dispensers over each of 5 sinks. They eventually replaced them with a single dispenser on the wall at the end of the row. Problem was, towels would inevitably fall in the sink and cause a clog.
ricardobeat 14y ago
It says fourteen seconds. Washing your hands in the sink then walking over to the dryer/paper dispenser, pressing levers or waving your hands, easily takes 30s. Plus you'll never find a bathroom that has a dryer for each sink, so there are massive gains in parallelism :)
GigabyteCoin 14y ago
It increases the space for more sink/dryer combinations, however. Side note: As a man, I think the last time I had to wait to dry my hands was half time at a sports stadium, and even then it was only a 20 second wait.
sliverstorm 14y ago
Forget about potential speed pitfalls, and consider the following: If your hands leave the sink dry, you no longer need a regularly cleaned tile room to keep things sanitary, because nobody will be dripping/flinging water everywhere. Where might you be able to put sinks now, or how might this change a washroom? That's what is really interesting to me right now.

dpcx 14y ago

This also allows you to remove towels and several trash cans, and add additional stations.

tocomment 14y ago

That's only if you assume unlimited paper towel stations. In reality hand drying is the bottle neck. So if every sink has its own dedicated dryer it will speed things up.

lttlrck 14y ago
"every sink has its own dedicated dryer" Exactly. Sinks seem to always outnumber dryers by a wide margin.
epo 14y ago
But you wouldn't get a queue for paper towels. People would grab 2 or 3 towels and move aside.
- tocomment 14y ago
  Maybe but there's a bit of a shuffle getting around people who have grabbed towels. And there are always the people who stand by towels to dry because that's where the trash can is. Actually, I guess separating the towel dispensers and trash cans in existing bathrooms would be a smart efficiency move since it would encourage people to grab a towel and keep moving.
r00fus 14y ago
Don't ignore the folks who actually don't want to airdry their hands. I soap, wash, shake and wipe my hands in my pockets as I walk out the door if I'm in a hurry.

deleted 14y ago

[deleted]

rytis 14y ago

Not sure. Let's say a person spends 15 secs washing, and 15 secs drying. Combined it's still 30 secs. So if we have a long queue, does it really matter that two people are in the bathroom at any given time, or just one? The total processing time does not change. Or am I missing something here?

cmsmith 14y ago
I think your assumption of equal time for each task is incorrect. Either because people don't dry their hands, or it doesn't take as long as washing. Because typical bathrooms have 4 times as many sinks as they have hand driers, and I still see sink lines more often than drier lines.
- rytis 14y ago
  OK, but still that doesn't change the equation. 22 secs washing and 8 secs drying is still 30 secs in total, whether it's done separately or not. And as you mentioned, the number of sinks and the number of dryers are balanced, so they combined have a similar throughput. I think you see sink lines more often just for that reason, if the sink line can handle 10 persons per minute, and the supply is 20ppm you will have a queue. But once we throttle people at the sinks, the supply to the driers is 10ppm, thus no lines (assuming the driers line is 10ppm)....
- roc 14y ago
  Only because "air drying" is a more acceptable option than "not washing". So a combined station would only slow things down inasmuch as people no longer skip drying. In general (at least in the US) drying takes far longer than washing. Because most people wash quickly/poorly whereas driers are on timers and most are horrible. And when your hands are still wet even after negotiating the unresponsive sensor and waiting an entire drying duration, it's understandable that many people would just as soon skip it.
beala 14y ago
It actually does help, and the concept behind it is called pipelining [1]. Suppose there's a sink that washes and dries, and there are two people who want to use it. The second person will spend 30 seconds waiting, and 30 seconds washing/drying. So, 60 sec total. If there's a sink and a separate dryer, the second person will spend 15 sec waiting, 15 sec washing, and 15 sec drying. So, 45 sec total. The second person gets a 15 seconds savings, because he can start washing as soon as the first person finishes washing, rather than having to "block" until the first person is done washing and drying. [1] http://en.wikipedia.org/wiki/Pipeline_(computing)#Concept_and_motivation http://en.wikipedia.org/wiki/Pipeline_(computing)#Concept_an...

oh_sigh 14y ago

Have you done the math on this? I have a feeling you're relying on a gut instinct and didn't actually simulate it. From my simulation, this new gadget will simply shift lines from the paper towel dispenser/on the wall air dryer to the sink itself. It will not at all reduce the efficiency of the bathroom, infact it will increase it

moe 14y ago
I don't know about your simulation, but over here in the real world it doesn't work that way. Many people don't dry their hands at all in a public bath room (that's what god invented jazz hands[1] for). By combining faucet and dryer you force these people into the same bottleneck as the hand-dryer users. [1] http://www.youtube.com/watch?v=xuPSIbABYVU http://www.youtube.com/watch?v=xuPSIbABYVU
- incongruity 14y ago
  It's actually worse because you take what were 2 parallel operations (washing your hands and drying them) and make them two serial operations, not able to be run in parallel.
  - oh_sigh 14y ago
    Yes, it does upset the balance slightly for people who want to wash their hands, but not dry them, and for people who want to dry their hands, but not get them wet. Those are the only scenarios where your argument holds, however.
    - incongruity 14y ago
      No, not at all. Simply put, you are moving from 2 independent operations to 2 mutually exclusive operations – meaning that 1 sink (in the Dyson case) can only service 1 user at a time vs 1 sink+1 dryer/towel dispenser which can, at a minimum, service 2 users at once (there's actually a much bigger set of time/path calculations that could go in to this, but the simple case is enough to make it clear that your thinking is confused on this.)

btgeekboy 14y ago

Does it though? While I agree with your premise, what I often see are available sinks while everyone hangs out around the 1 or 2 dryers or towel dispensers and trash cans, waiting for their hands to dry. That is, unless it's like another place I know of where there's a paper towel dispenser and trash slot between every sink, in which case this faucet wouldn't change anything - they'd just be using their sink instead of standing in front of it with a paper towel.

tikhonj 14y ago

Essentially, combining washing and drying reduces pipelining. It doesn't change the time for any individual person, but it does reduce throughput. Of course, most public restrooms have fewer drying stations than sinks, so this would probably be less of an issue.

incision 14y ago

>Except for one issue: it actually slows down the efficiency of the bathroom. With one exception, every bathroom within my memory had the drier as a bottleneck, typically at a ratio of 3:1 or worse. Having a drier per sink would actually improve the efficiency. The one exception was a older building which had towel dispensers over each of 5 sinks. They eventually replaced them with a single dispenser on the wall at the end of the row. Problem was, towels would inevitably fall in the sink and cause a clog.

ricardobeat 14y ago

It says fourteen seconds. Washing your hands in the sink then walking over to the dryer/paper dispenser, pressing levers or waving your hands, easily takes 30s. Plus you'll never find a bathroom that has a dryer for each sink, so there are massive gains in parallelism :)

GigabyteCoin 14y ago

It increases the space for more sink/dryer combinations, however. Side note: As a man, I think the last time I had to wait to dry my hands was half time at a sports stadium, and even then it was only a 20 second wait.

sliverstorm 14y ago

Forget about potential speed pitfalls, and consider the following: If your hands leave the sink dry, you no longer need a regularly cleaned tile room to keep things sanitary, because nobody will be dripping/flinging water everywhere. Where might you be able to put sinks now, or how might this change a washroom? That's what is really interesting to me right now.