Ok, so this one might seem a bit random/weird. Sometimes I find that if there are a few things that I’m thinking about at the same time, they sort of collide inside my head, coming together in “I wonder if…” way.
The other day I burned my fingers – not badly, and I managed to get my hand under running cold water within seconds. I do some work with the water industry and as you may have already noticed am interested in trying to protect the environment. I was thinking about another blog post that I’m researching (and will hopefully put up here soon).
All of this came together and I started thinking about how much water goes down the drain as a result of treating burns. My first idea was to look up statistics on the number of burns treated each year. The Department of Trade and Industry (DTI) used to collect these statistics on an annual basis, collecting information on attendance at hospital as a result of an accident, with a lot of information included with this (age, occupation, cause of accident etc). Due to funding cuts they stopped this a number of years ago, but did a deal with the Royal Society for the Prevention of Accidents (RoSPA) for the information to remain available in perpetuity. From this I found out that information from 18 hospitals was collected and an algorithm applied to give a prediction about the national rate – in 2002, the last year that data were collected, 5081 burns were recorded, with the algorithm predicting 104,161 (lower limit = 103,529; upper limit = 104791) . It was at this point that I realised that this probably wasn’t the number I was interested in: these recorded data relate to attendance at hospital, and you’ve got to be going some if you need to go to hospital with a burn.
No, I was more interested in the little ones that you treat at home. Significant enough that you need to get it under water straight away but not so bad that you need specialist treatment. So, let’s assume that everyone in the UK burns themselves once a year. Some people are at higher risk, some at lower, but as a starting point this seems a sensible assumption. The current population of the UK is estimated to be 64.6 million.
The next step is to work out how much water is used in treating a burn. To some extent this is going to be dependent on your local water pressure, but you could make an estimate based on typical mains water pressure of four bar – but to some extent that defeats the object of a first order approximation. An easier way is to look at the Waterwise website (pausing to be horrified at the average of 150 litres that is used per person per day in the UK) and note that if you leave the tap running whilst you brush your teeth you are using 6 litres per minute (Pro-tip: Don’t leave the tap running). Further, any first aider will tell you that you should put a burn under running water for 10 minutes.
So, putting all of that together, we get 60 litres to treat a single burn and 3.9 billion litres to treat the UK’s burns for a year. What is slightly scary is that this is only 0.1% of the annual consumption of the UK. However, Sir David Brailsford’s doctrine of Aggregation of Marginal Changes, which is making a big splash all over the place, can be used here. To be clear, I am not advocating messing with your health, but you do not need to run the tap at full power. The whole point about treating a burn is to cool the sub-dermal layers quickly by removing the heat. What you have to be careful of is not going too far the other way and getting some kind of ‘cold-burn’. Water at high pressure/flowing extremely fast is not really doing anything for you – it will just pass over, wasting the thermal mass that you are trying to dump heat into. Even saving a half of this volume of water would be enough to cover a population increase of around 35,600 people. It might be a marginal change, but if we aggregate them, we can make a real difference.