Scrutable

Dyson hand dryers and other makes are noisy, maybe dangerously so. Certainly the tiled echoey service station toilets on British motorways are desperately unpleasant places to be thanks to high speed air dryers.

Good paper here. https://www.ncbi.nlm.nih.gov/pmc/articl ... yf5ea0h8y0

I'm not sure that it is really a good paper though.

This kind of reads like a student essay, and on some points not a really good one. For example, the reference to the inverse square law is quite weird to me. The inverse square law applies if you can assume propagation in a free field (or something close enough). Restrooms are enclosed spaces (and the walls are usually not covered with absorbing material) so this doesn't apply at all here.

In the discussion, the author mention the possible effect of several hand dryers working at the same time, and an increase of 6 dBA per doubling of the number of machines. This is strange since we would usually assume a 3 dBA increase per doubling (the machines are uncorrelated sources).

There seems also to be some confusion with the manufacturers specs. For example for Dyson, the technical sheet provides a Sound Power Level (based on the acoustic power of the source) which is not a Sound Pressure Level (which is what you measure with a soundmeter). And yet, in table 1, the disctinction is not clear and it looks like the author is trying to compare the Sound Power Level to Sound Pressure measurements. This is a worrying mistake.

Also, I am not comfortable with the use of "sound intensity", since the acoustic intensity is a quantity in itself that is different from sound pressure levels.

And even if it is interesting to have measurements done in real situations, these are instantaneous measurements that provide peak values of noise.
Many regulations relie on a noise dose, corresponding to the noise level calculated from the average sound pressure over an 8 hours long shift. So it would have been interesting to have integrated levels over 8 hours to see what someone who is spending a whole shift in restrooms is exposed to. Here it seems that the author is somehow comparing instantaneous values to noise dose thresholds.

There may also be metrics and regulations (but I don't really have knowledge there) that account for short noisy events and some guidelines on peak values or number of occurences that may lead to hearing loss.

They certainly can seem uncomfortably noisy and with a high pitch to me.

it seems that the newer ones are better - we have two sets at work and the newer ones are comfortable on my ears

Basket of free ear-defenders at the entrance?

rockdoctor wrote: ↑

Wed Jan 01, 2020 11:21 am

Basket of free ear-defenders at the entrance?

Foam earplugs for anyone who has to work enough time in the room to get an 80dBA 8 hour dose or equivalent. Users may find the dryers obnoxiously loud but their exposed is only for seconds.

Martin Y wrote: ↑

Wed Jan 01, 2020 12:44 pm

rockdoctor wrote: ↑

Wed Jan 01, 2020 11:21 am

Basket of free ear-defenders at the entrance?

Foam earplugs for anyone who has to work enough time in the room to get an 80dBA 8 hour dose or equivalent. Users may find the dryers obnoxiously loud but their exposed is only for seconds.

That was what I was thinking, but noticed the newer airblades are quieter.

Not sure about janitors for example

Cleaners or someone popping in to fix the toilet seat are also presumably only in the room for a short-ish period of time a couple of times a day. They may well also be beyond 10 feet away from the dryer, which was the limit of the testing here.

Given that, unsure how many people would fit into the authors definition of a full day, see this quote from the discussion

At all the distances measured, a full-day exposure at work could damage overall hearing and speech perception in particular.

Author of that paper is a Professor, but has a pretty thin publication record.

mikeh wrote: ↑

Wed Jan 01, 2020 9:40 pm

Cleaners or someone popping in to fix the toilet seat are also presumably only in the room for a short-ish period of time a couple of times a day. They may well also be beyond 10 feet away from the dryer, which was the limit of the testing here.

Given that, unsure how many people would fit into the authors definition of a full day, see this quote from the discussion

At all the distances measured, a full-day exposure at work could damage overall hearing and speech perception in particular.

Author of that paper is a Professor, but has a pretty thin publication record.

Yes I find the argument that cleaners may spend a lot of time close to dryers so that the noise dose they are exposed to might be problematic a bit unconvincing without an a actual assessment of that.

Concerning the author, her area of work seems to be mainly with speech perception and communication disorders, so the present paper seems a bit out of this area.

Agreed. She is also the sole author of the paper. You'd have thought an actual expert would have been useful, or at the very least a second pair of eyes significantly contributing to construction of the manuscript. It just feels very naively written.

It seems like the reverberant space means there's a fairly high exposure to the noise no matter where you're working in the room. I think there might actually be a case for at least assessing the exposure, by asking the cleaners to wear noise dose recording badges.

I'm pretty sure the overall dose will be well under any action level as they won't spend their whole working day cleaning the loos and the dryers won't always be running anyway.

This one was quite noisy:



But I think I was warned.

Dries your cock quite effectively I suppose. So it's not all bad.

Martin Y wrote: ↑

Wed Jan 01, 2020 12:44 pm

rockdoctor wrote: ↑

Wed Jan 01, 2020 11:21 am

Basket of free ear-defenders at the entrance?

Foam earplugs for anyone who has to work enough time in the room to get an 80dBA 8 hour dose or equivalent. Users may find the dryers obnoxiously loud but their exposed is only for seconds.

In a large facility, service stations and the like, the facilities are used pretty much continuously, so you are exposed from the moment you walk in, to the moment you walk out.

But even an old sod like you won't spend more than a few minutes pissing.
Stop f.cking whining

tom p wrote: ↑

Sun Jan 12, 2020 12:23 am

But even an old sod like you won't spend more than a few minutes pissing.
Stop f.cking whining

You don't know me very well do you?

The difference in experience between an old style victorian gentleman's toilet equipped with roller towels and a modern "convenience" complete with the banshee howl of Dysons or equivalent, is huge. As I have said I have seen children point blank refuse to go in.

Is there any reason that you actually want modern life to be horrible?

Boustrophedon wrote: ↑

Mon Jan 13, 2020 12:09 pm

tom p wrote: ↑

Sun Jan 12, 2020 12:23 am

But even an old sod like you won't spend more than a few minutes pissing.
Stop f.cking whining

You don't know me very well do you?

The difference in experience between an old style victorian gentleman's toilet equipped with roller towels and a modern "convenience" complete with the banshee howl of Dysons or equivalent, is huge. As I have said I have seen children point blank refuse to go in.

Is there any reason that you actually want modern life to be horrible?

AH but, he is OK now - he can just pee into a canal

Gentleman Jim wrote: ↑

Mon Jan 13, 2020 12:27 pm

AH but, he is OK now - he can just pee into a canal

Or the cross the border and stand on a plinth to do it.

dyqik wrote: ↑

Mon Jan 13, 2020 1:39 pm

Gentleman Jim wrote: ↑

Mon Jan 13, 2020 12:27 pm

AH but, he is OK now - he can just pee into a canal

Or the cross the border and stand on a plinth to do it.

Charming.

Boustrophedon wrote: ↑

Mon Jan 13, 2020 12:09 pm

tom p wrote: ↑

Sun Jan 12, 2020 12:23 am

But even an old sod like you won't spend more than a few minutes pissing.
Stop f.cking whining

You don't know me very well do you?

The difference in experience between an old style victorian gentleman's toilet equipped with roller towels and a modern "convenience" complete with the banshee howl of Dysons or equivalent, is huge. As I have said I have seen children point blank refuse to go in.

Is there any reason that you actually want modern life to be horrible?

Won't somebody please think of the children?
How many Victorian motorway service stations are there?
Might there be some other reason why children refuse to go into a toilet with a grumpy old man lurking outside it?
Those old roller towels are horrible. Wet, dirty, costly. Ugh.

Sounds and noises are important, and need to be designed with care. One day this will be normal and people will look back on our present racket the same way we are horrified by the old practice of throwing human sh.t in the street.

plodder wrote: ↑

Tue Jan 14, 2020 9:30 am

Sounds and noises are important, and need to be designed with care. One day this will be normal and people will look back on our present racket the same way we are horrified by the old practice of throwing human sh.t in the street.

Yes, and I think Dyson are particularly at fault for this but others copying Dyson are equally loud if not louder.

tom p wrote: ↑

Tue Jan 14, 2020 8:35 am

Won't somebody please think of the children?
How many Victorian motorway service stations are there?
Might there be some other reason why children refuse to go into a toilet with a grumpy old man lurking outside it?

Tom, that was uncalled for. My kids hate going in service station or pub toilets with loud hand-dryers to the point it distressed them quite a bit when they were younger.

Grumble wrote: ↑

Tue Jan 14, 2020 11:26 am

Won't somebody please think of the children?
How many Victorian motorway service stations are there?
Might there be some other reason why children refuse to go into a toilet with a grumpy old man lurking outside it?

Tom, that was uncalled for. My kids hate going in service station or pub toilets with loud hand-dryers to the point it distressed them quite a bit when they were younger.
[/quote]

well, the last line was; but I was just teasing him because since retiring and moving to the middle of nowhere, Don is turning into a parody of a grumpy old man, grumbling about all manner of modern things.