From the BBC:
A massive fire at a recycling plant in the West Midlands is thought to have been started by Chinese lanterns. As well as fire risk they're associated with other problems. Fire chiefs called for an "urgent review" into the use of Chinese lanterns after more than 200 firefighters were called to the fire in the town of Smethwick.
From Wiki:
When lit, the flame heats the air inside the lantern, thus lowering its density and causing the lantern to rise into the air. The sky lantern is only airborne for as long as the flame stays alight, after which the lantern sinks back to the ground.
So who do we believe here: the fire chiefs who say that burning Chinese lanterns can fall to the ground or basic physics which says they only fall to the ground after the flame (i.e. glorified candle) has gone out?
I suppose if the paper lantern catches fire up there, that would cause it to crash, we can safely assume that the paper would turn to ash long before it lands, but wouldn't the glorified candle be snuffed out as if plummets to earth?
Tuesday, 2 July 2013
So who do we believe here..?
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20 comments:
I must admit I was a bit skeptical of the fire chief's conclusion.
Somewhere near to us releases quite a few of these, mostly during the summer weekends.
If the wind is in the right direction (normal prevailing SW'ly) they drift over quite a built up area.
I have yet to hear of one causing a fire.
A discount shop in my town is selling lanterns which appear to have a substantial wire frame which could well cause them to sink to the ground before the flame went out.
I wonder whether the surge in demand for the things has led to the manufacture and import of cheap, mass-produced models which deviate from the tried-and-tested design pattern of previous centuries.
With a solid frame and British weather, there is also the problem of getting properly airborne in the first place; I still savour the Schadenfreude of a work 'do' when a colleague masterminded the symbolic release of 15 sky lanterns from a roof, only to watch several of them sink majestically into the trees below, where they burned merrily for some time.
The cause, I am told, is releasing them too soon, before they have generated sufficient heat - a nice lesson in what happens when you adopt someone else's traditions without their background knowledge and quite possibly a factor in starting fires.
These things are a menace. The only reason we haven't seen many fires caused by them in the last few years is that the summers have been predominantly wet ones, since 2007 in fact. And this example (http://www.bbc.co.uk/news/uk-england-oxfordshire-10826445) happened in the only dry summer since 2007, which was 2010. If we get a blazing July this year, as predicted by the Met Office, then I predict there'll be more of these fires caused by lanterns.
This is all before the danger to cattle caused by the wire in them - if it ends up in forage for cattle they can eat it and the wire perforates their gut and they die in agony. Typical example here: http://www.dailymail.co.uk/news/article-2035992/Plea-ban-flying-Chinese-lanterns-cows-killed-them.html
Loads more if you google 'cow killed lantern wire'
They are litter. Anyone who throws a paper bag out of their car window is guilty of littering. I can't see how lighting a fire under a paper bag and letting that go from your garden makes it any less so.
Surely if they are hot when they fall to ground they can still start a fire?
I don't like banning things per se, but surely it is litter and therefore illegal?
(Of course you could make biodegradable ones)
BB, thanks for back up.
McH, I suppose the correct launch procedure must be from the ground up. Light them and don't let go until they take off by themselves.
S, yes, you have pointed the "cows are so stupid they will eat wire" thing before, it's probably quite true but it's a separate topic to fire risk/laws of physics.
LF, oh come off it, have you ever tried setting fire to something using "fairly hot metal wire"?
By definition the wire is very thin (or else the balloon would be too heavy and cows wouldn't be able to eat it) and therefore it must cool down very quickly.
And yes they are litter, of course they are, separate topic.
"LF, oh come off it, have you ever tried setting fire to something using "fairly hot metal wire"? "
No I haven't, I think to be honest it is unlikely but fires are not predictable even now.
Isn't possible that a gust of window could have blown one?
The 'sink to the ground' thing will only work safely if a) the paper bag bit remains in good shape and b) the air is still. I think that, once thousands of these things are being let off, the odds of one of them hitting something flammable whilst still lit (or very hot) will be very short. Since (as I understand it) they have CCTV of the start of the fire in Smethwick, I think we can take it that these lanterns are not always safe.
I have actually made these, years ago, in Switzerland, to celebrate their national day. The frame does need to be light, but a thin piano wire frame looks to weigh less than a stick frame of the same stiffness.
Mind you, living as I now do in Suffolk, I would be very chary of releasing any of these over the cereal crops in the fields around us. If they are anywhere near harvest the fields are tinder dry. I do not have bonfires late in the summer for this very reason as hot airborne ashes could easily set a field alight.
However, if you make a good lantern and release it properly and it gains a good altitude I have my doubts as to whether it would be hot enough to cause a fire on landing after the flame has gone out.
And lastly I am very much anti banning anything.
LF, H, if you ask "Is it possible that one in a thousand of these things is still hot enough to start a fire when it lands and is it possible that one in a thousand of those will land on something easily flammable?" then the answer must be "yes".
So that's one fire per million balloons. Seeing as there are half a dozen gas explosions in the UK, perhaps we ought to ban gas as well? How many people are electrocuted by accident? Band electricity. Etc.
L, ta for back up.
I was suggesting banning them because of litter not fire (unless of course people guarantee to pick them up later).
I thought that this
"I don't like banning things per se, but surely it is litter and therefore illegal?"
Was clear, obviously I am mistaken
LF, you might be quite right on the whole litter point and hence they should be banned, I'm not arguing with you on that.
I'm just saying, by and large, Chinese lanterns don't land until the fire has gone out.
I'm happy to leave the banning business to others. But presumably with gas and electricity, we think that the multiple benefits of warm houses, light etc. etc. are worth the risks of having the odd explosion, fire etc. With the lanterns, there is the unbridled joy of seeing a small candle ascend into the night sky... and.... ???
H, it's not just the person who launches the lantern who watches it though, thousands of people will see it travel along, and they can all share the unbridled joy.
Or in this country, they will all think "Oooh, fire risk, litter, threat to jet engines, bloody foreign customs, my prize cow Daisy might eat that, these things should have been banned yesterday."
And people like me then get unbridled joy at all the bansturbators and Homeys seething with impotent rage.
L Fairfax. If you replace the piano wire frame with one made of staws (the sort you can suck through) the whole thing bio-degrades anyway. That's how I would make a lantern as straws are light and being tubular are probably stiff enough if the thing is thoughtfully designed to make it work well.
Mrs L is away this weekend - I might see if I can make one... or not.
The joy of the bansturbators will exceed the sorrow of the libertarians. Possibly.
MW,
The bansturbators have been after Chinese lanterns for a while now for various reasons.
The main thing is always about whether something is frivolous or not. It's a fascinating thing that we defend things that are "useful" (but ultimately about allowing us to do the frivolous things) but not the frivolous things.
"The joy of the bansturbators will exceed the sorrow of the libertarians."
Show me how that those responsible for causing fires with their little random arson creators can be held accountable for the losses they cause others, and I'm happy for there to be no ban. I doubt many people would risk letting them off if they thought that they stood the risk of losing their house over losses caused by a fire started by one of their lanterns.
As that is not possible what other alternative is there? Just allow people to create random losses for other with no comeback whatsoever?
L, the best pyrotechnic fun you can have for little effort or expense is setting fire to a poppadom.
I think with Chinese lanterns, making the lantern is not too tricky. The tricky bit is getting a fierce burning candle that doesn't immediately get blown out.
H, probably.
TS, good points. But why not ban fireworks as well?
They are clearly frivolous, a ghastly foreign invention/tradition, a fire risk, litter when they land, a danger to cows if they eat the launch sticks etc.
S, yes, these lanterns do impose a small burden on others. Fair enough. If you can work out the cost of that burden, you divide it by the number of lanterns and that is the appropriate tax per lantern. Just like fuel duty etc.
You all seem to be ignoring Macheath's account of a fair proportion of incompetently managed lanterns sinking groundwards while still burning merrily. This scenario is unlikely to be unusual. Another point not addressed is that the air becomes colder as you go up, quite quickly in a built up area once the lantern leaves the vicinity of the ground that has been warmed by the sun all day, which could cause a lantern to rise, then fall once the heat source can no longer cope with the increased heat loss.
The cow problem can simply be addressed by banning the use of wire, and using bamboo or whatever those paper lampshades use.
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