The shower

it wouldn’t be an ergonomics and human factors conference without an animated discussion about the ergonomics of the venue. This year, the shower has vexed several delegates:

https://twitter.com/profnjmansfield/status/587885683869671424

So, why does this design cause us problems? 

Here is a photo.

  

So, what is our overall goal when we want to start a shower? We want water to come out of the right place, at the right pressure, and at the right temperature. 

And we don’t want to step under the shower until the temperature is correct.

There are some elements of the system that my photo doesn’t capture. The shower is over a bath, and there is a glass screen that prevents the water splashing onto the bathroom floor. In my room this screen doesn’t really move, so I had to step into the bath before switching it on. So to prevent myself from being drenched in cold water I removed the shower head from its holder on the wall before I started.

Task 1: adjust the temperature. I’ve got a hot and a cold tap, so my first approach was to adjust these so that the water coming out of the bath tap was a good temperature. This seemed to work.

Task 2: get the water to come out of the shower head, and check the pressure.. My past experience tells me that the control in the middle will control a valve, that changes the water flow from the bath taps to the shower. So I turned it (the control afforded the action of twisting to enable this). I twisted it completely round about 270 degrees. Water came out of the shower, the pressure seemed ok. Great.

Except, when I turned off the control in the middle, I realised that water was still coming out of the bath taps. And had been for the whole time. The bath taps are a complete irrelevance, and in fact the control on the middle is not a valve, but a completely separate control which adjusted the temperature of the shower at a constant pressure. I think. At least I achieved my goal of a warm, efficient and safe shower. 

Three of us (me, Colin Drury, Peter Hancock) discussed this at breakfast. Two things strike me.

 1. Why on earth can we still not get simple things like shower design correct? How have so many different standards emerged (this isn’t a new problem – last year I had cold showers at the conference for two days because a heat control was occluded by another part of the mechanism)? Should we be taking more responsibility for communicating and disseminating ‘best design’. This problem isn’t restricted to showers,where the consequence of an error is scalding or discomfort, but hopefully not death. Bryn Baxendale, an Anaesthetist from Trent Simulation and Skills Centre has highlighted the variety in syringe labelling and infusion pumps design; errors in this context can and have lead to patient death. It is shocking that it has taken nearly 10 years for the NHS to change the design of syringes to prevent errors such as occurred in the sad death of Wayne Jowlett. 

2. As ergonomists, we love a bad design to critique. We all spend our lives being distracted by toilets, door handles, information signs, maps and trip hazards. And one of the things that is brilliant about the conference is that rather than boring our family and friends with our rants and analysis as we encounter examples of bad design, we can enjoy an enthusiastic debate about why the design was so bad and why we or others might have made errors. But, this focus on ‘bad design’ makes us problem driven and maybe distracts us from developing principles to support future design (this was raised by Peter  Hancock in our workshop yesterday, more of that in another post). It can also make us the bad cops, who are perceived as being critical, slowing down design processes, whereas we should be the good cops, making design more efficient, less risky and more successful. 

The shower

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