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

DSC_1881-CS5

DSC_2074-CS5

♠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.  

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October 9, 2013 - Posted by | Uncategorized | ,

20 Comments »

  1. It’s a long way to Oxford. I wonder if I’m closer or you, ’bout the same I should imagine. It doesn’t look far on a map but it’s long in time and you can’t do anything else when you’re driving really, it’s sort of frowned upon to catch up on your emails or such I imagine. I don’t recall a text but all my eLectric or is it eLectronic iphoney ipady imaccy stuff has taken on a life of its own and it’s hit and miss as to when it obeys me or chooses to delivers texts emails etc. such is life. I will shout at BT – it never achieves a totally working broadband but it reminds me I have other means of communication like a land telephone. Oops just realised I was commenting and not writing you a letter!

    Comment by Linda | October 9, 2013 | Reply

  2. Breaking news! Mig has a new asterisk-y thing!
    Well, that was a jolly good read! And psark is a Good Word.It has a nice Carollian ring to it. Of course, I’m going to be terrified now of all those fat, nylon-encased thighs squeezing into cars at the petrol station…

    Comment by dinahmow | October 9, 2013 | Reply

    • Di, my (less than slim) thighs are not encased in nylon but I give myself shocks against the car constantly. I’m never going to fill up with petrol again. Now, how will I manage that…

      Comment by Carol | October 10, 2013 | Reply

    • Get out of the car without touching the metal door with your hand.Instead, just touch the tip of your key to the door and that (apparently) will ground the charge.

      Comment by dinahmow | October 12, 2013 | Reply

  3. Mig, excellent story. I learned so much that I’d forgotten, so thank you! I’m so pleased you survived that bit of danger… Damn caravans!

    Comment by Carol | October 10, 2013 | Reply

  4. Well I always thought diesels had spark plugs with extra heating to ignite the less volatile diesel vapour. Live and learn,

    Comment by Rog | October 10, 2013 | Reply

  5. Home to Oxford takes about 35 minutes at midday Linda and the return journey at five-thirty takes about an hour. All the difference happens in the first four miles at the Oxford end. Letters welcome but I got your text – shall reply in a minute : )

    The trouble with *s is they’re so unobtrusive they might as well not be there Di so I thought I’d find something more obvious. And I do hope I can forget writing this post before Spring returns because if not I may simply be unable to get into the car at all.

    I spent quite a lot of time discovering things when I was writing the post Carol. It was fun so I’m glad you enjoyed it too.

    I had to look it up Rog and found that the diesel is warmed by a glow thingie (I want to call it a glow globe but I’m sure that’s something else) and then compressed until it heats up and spontaneously ignites. It’s nice to imagine that this ignition happens inside a safely sealed cylinder and is therefore not a fire hazard.

    Comment by Mig | October 10, 2013 | Reply

  6. Mmmm; psarks and glow thingies – every day is a school day.

    Comment by Liz | October 10, 2013 | Reply

  7. Yes that’s about the most I ever learned in a school day Liz. Oh, I mean two things is the most I learned.

    Comment by Mig | October 10, 2013 | Reply

  8. On diesels – glow thingies = glowplugs.

    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).

    You haven’t. There will always be vapour coming off petrol, at normal environmental pressure and temperature. That’s why so many people get horribly burned when starting fires with petrol. Putting a match into petrol would ignite the vapour on the match’s way in.

    Comment by Blue Witch | October 10, 2013 | Reply

  9. Aha thank you Blue Witch! Glowplugs. And also Aha – I did miss something important – it wasn’t a match he mentioned but a cigarette.

    Comment by Mig | October 10, 2013 | Reply

    • Don’t think diesle cars have glowplugs any more. They work on compressing the air in the cylinder until it heats sufficiently to ignite the diesle. A man told me this so I’m assuming it must therefore be correct.

      Comment by Linda | October 10, 2013 | Reply

      • Depends on the make and type of vehicle Linda (and somtimes the size of engine within a make) – there are lots of different types of diesel engine, with different starting methods.

        Been driving diesel cars for far too long…

        Comment by Blue Witch | October 11, 2013

    • Well, that would make rather a difference Mig!!!

      Comment by Blue Witch | October 11, 2013 | Reply

  10. The week before last, I went past an accident that had just happened, couldn’t see what was lying in the road behind a Transit van, but was very concerned it was a cyclist (it was 6.30 am, quite dark). On my way back, I heard the traffic news and it was two donkeys. I was very sad and yet relieved.

    Comment by Z | October 19, 2013 | Reply

  11. I’m always glad when the traffic news tells us that something has broken down and is causing the blockage Z.

    Comment by Mig | October 27, 2013 | Reply

  12. Having been stuck on A34 more than once it is easy to understand how your mind begins to work out things you wouldn’t normally think about.

    Comment by ladyinredagain | November 3, 2013 | Reply

  13. Yes Ladyinred, the A34 is designed to stimulate unusual thoughts.

    Comment by Mig | November 3, 2013 | Reply

  14. I have nominated you for an award 🙂

    Comment by ladyinredagain | November 19, 2013 | Reply

  15. Wow! Thank you Ladyinred : )

    Comment by Mig | November 23, 2013 | Reply


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