Letouttoplay

Life, photos but not the universe

I learn something new

On my way home from Oxford, I am often delayed.  Traffic crawls and sometimes stops and I wonder what it is that’s up ahead, somewhere – who knows how far away – which has brought the bunched-up traffic worm to a complete halt.  The traffic news is still, despite helicopters and instant communication, always an hour or so behind the event and anyway, during the half hour I spend on the 4 miles between Mrs Middle’s house and the A34, it’s rare that a traffic update happens.  One evening last Summer though, I found myself right up to date!  I was the very first person the fire brigade stopped when a caravan dropped it’s gas bottle which was then trapped under the caravan and leaking.  Everything had almost come to a halt and there was the obvious cause, listing slightly and half on the verge and I was just putting my foot down, gently to roll past it all when I realised that they were waving their hands at me!

Anyway, it was a nice hot evening and I sat there next to the two fire engines with my windows down and watched the blokes climbing into their fireproof armour and listened to their chief ♠ holding a little seminar while they waited for whatever would happen next.

Ah!  I thought.  A broken gas bottle.  Yes, good cause to stop everyone.  Actually, did they stop us soon enough – I’m really not very far away from the caravan and if it went up, surely so would all these fire engines – I wonder how much fuel they have in their tanks? Lots probably.

Are they trainees  I wondered?  Even I know that gas is heavier than air ♠♠ – mostly- unless it’s helium or one of those other gasses of which I can’t immediately remember the names.  And surely it’s obvious that the heavy gas will roll (such a suggestive word all of a sudden) down the hill.  Towards me!  So I spent a useful few moments assessing distances and imagining invisible, rolling gas and thinking maybe we shouldn’t all have our engines running but on the other hand I bet you get more … inflaming … sparks when you start an engine, so as long as it all keeps quietly ticking over it’s probably the best option out of what began to seem like some not very good ones – I really wasn’t so very far away from the caravan.

After a while, one of them came over to tell me that we were all waiting while the traffic was turned round and sent away down the wrong side of the dual carriageway and unfortunately I would be the last to escape leave.  I didn’t mind being last – there was obviously no alternative as the lanes were mostly blocked by fire engines.  And since the fireman seemed to have time in hand, I asked about all those engines running and he explained that the fire engines were diesel so had no sparks.  As it happens so is our car (but I didn’t know about all the cars behind me of course) so I learned something new. (Brought up on petrol, me ♠♠♠)

Then I wondered if I should have texted Barney to tell him I might not be back until very late if at all but decided not to worry about the risk of igniting gas fumes with the spark from a mobile phone since it seems the general consensus is that the explosions in petrol stations, which resulted in those little notices telling you not to use your phone while filling up, were actually caused by static from people’s clothes which sparked when they getting back into their cars.

The whole thing reminded me of the time my Stepfather, a well-respected scientist, decided to fix a leaking petrol tank.  Barney and I were somewhat shocked to encounter him blithely wielding a blowtorch in one hand and a naked, recently emptied petrol tank in the other.  Isn’t that a bit?  Um?  We said anxiously.  Oh no he said.  Petrol evaporates very quickly.  Most of it’s gone by now.  It’s only the vapour which is really volatile.   You can douse a match in a can of petrol quite safely.  (Very rational man, my Stepfather but I sort of feel that it’s not a good idea to try the match thing at home.  I might have missed an important detail. [Ed. I did.  He said cigarette not match – see Blue Witch’s comment below])

Well the fixing of the tank went ok.

All of which tells me that before you can assess the dangers of a situation, you really need a sound, basic grounding in science.  Or access to google, since you can look stuff up on google and find out that liquid petrol doesn’t burn as easily as it looks when you’re using it to light a bonfire and that diesel engines don’t spark and that mobile phones probably don’t really cause petrol station explosions. ♠♠♠♠  So it’s probably quite safe to sit in your car fifty yards away from a leaking gas bottle.  Unless you happen to be smoking of course which fortunately I wasn’t.  And as I was looking all these things up, out of interest and to find links I found this and enjoyed it quite a lot.  I particularly loved being told that “I spoke to a fire officer about that at work and he said that a mobile can set off a psark which could ignite the petrol causing a fire“.  Yes I know it’s just a typo but I like it.  I shall henceforward refer to the sparks that mobile phones don’t make as psarks.  They also serve who give me typos to play with.

I had intended to go into further boring details about the Yorkshire trip but I came across this forgotten draft which seemed like more fun.  Here’s a couple of photos though

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♠That’s what you call him isn’t it?  The chap who directs the others even when they all know exactly what to do.

♠♠Evidence of a misspent youth reading Dick Francis novels and other sources of useful information about explosions and fires and such like.

♠♠♠No not literally.

♠♠♠♠However, I may decide to stop filling the car with fuel in Spring as I always know when Spring has arrived because I start getting static shocks when I touch the car door.  

October 9, 2013 Posted by | Uncategorized | , | 20 Comments