0:00:06 > 0:00:09It's one of the most striking buildings in the world.
0:00:12 > 0:00:15In its short life, its distinctive shape
0:00:15 > 0:00:18has made it an icon for Dubai...
0:00:20 > 0:00:23..recognised the world over.
0:00:26 > 0:00:32It's the Burj Al Arab, or Arabian Tower.
0:00:33 > 0:00:39This is the tallest atrium in the world, 182 metres high.
0:00:39 > 0:00:43And that's just the beginning of the superlatives
0:00:43 > 0:00:47in one of THE most opulent hotels in the universe.
0:00:47 > 0:00:51There's enough gold and marble in here to make a rapper look dowdy.
0:00:51 > 0:00:55But behind the bling are some truly remarkable engineering achievements.
0:00:55 > 0:00:58They wouldn't have been possible without...
0:00:59 > 0:01:01..the children's game of jacks...
0:01:03 > 0:01:06..an engine cam...
0:01:07 > 0:01:10..the pages of a phone book...
0:01:10 > 0:01:12Ha-ha!
0:01:12 > 0:01:16..a revolution in fire hose design...
0:01:16 > 0:01:17Look at that!
0:01:17 > 0:01:19..and a camera flash.
0:01:21 > 0:01:23- I see your point. That is a potential problem.- Yeah.
0:01:23 > 0:01:25Cor blimey!
0:01:48 > 0:01:51Obviously, you don't usually see this bit
0:01:51 > 0:01:55but this is how I start every day's work, this is how we do things.
0:01:58 > 0:02:01Arriving by helicopter is par for the course here.
0:02:03 > 0:02:04Thank you.
0:02:07 > 0:02:10'I'm only doing it to blend in as I'm about to check in...'
0:02:10 > 0:02:12Thank you.
0:02:12 > 0:02:16'..to check out one of the most distinctive architectural achievements in the world.'
0:02:16 > 0:02:20- Thank you.- Would you like some Arabic coffee?- I'd love some, thank you.
0:02:20 > 0:02:21Cheers!
0:02:23 > 0:02:28Inside, the suites really are luxurious cocoons,
0:02:28 > 0:02:30sheltering you from the desert outside.
0:02:30 > 0:02:32There really is no sand in here.
0:02:32 > 0:02:37Unless you really want it, I'm sure room service could oblige.
0:02:37 > 0:02:39And then, while your bags are being unpacked for you,
0:02:39 > 0:02:41somewhere in your vast suite,
0:02:41 > 0:02:44you can stride around and look out over the whole of Dubai.
0:02:44 > 0:02:47But perhaps, as importantly, the whole of Dubai
0:02:47 > 0:02:49can look back at the hotel.
0:02:51 > 0:02:56Because this place was designed right from the start to be an icon.
0:03:00 > 0:03:04In the last 20 years, Dubai has shot upwards and outwards,
0:03:04 > 0:03:08looking to find its fortune through business and tourism.
0:03:10 > 0:03:12Oil was discovered in the early '60's
0:03:12 > 0:03:16but people here know it won't last forever.
0:03:17 > 0:03:21The iconic Burj Al Arab is part of Dubai's planned future...
0:03:21 > 0:03:24after oil.
0:03:24 > 0:03:27The architects on the project, however,
0:03:27 > 0:03:31were inspired by Dubai's past.
0:03:31 > 0:03:34Once upon a time, Dubai's wealth came from the sea,
0:03:34 > 0:03:36where they harvested pearls.
0:03:36 > 0:03:40And this building's distinctive shape recalls that history.
0:03:40 > 0:03:45That curve is inspired by dhows, the traditional sailing boats
0:03:45 > 0:03:48that have plied these waters since ancient times.
0:03:50 > 0:03:52Making an iconic building look like a ship
0:03:52 > 0:03:54was only part of the challenge.
0:03:54 > 0:03:57The architects wanted something more.
0:03:57 > 0:03:59They needed a statement.
0:04:00 > 0:04:04The solution, well, put your building 300 metres out to sea
0:04:04 > 0:04:07on its own tailor-made private island.
0:04:07 > 0:04:11Of course it's not going to be cheap or easy.
0:04:14 > 0:04:16Engineers had to make an island
0:04:16 > 0:04:21big and solid enough to hold a quarter of a million-ton tower.
0:04:23 > 0:04:26Most of all, they had to protect it from the sea
0:04:26 > 0:04:29and the power of the waves.
0:04:34 > 0:04:38Even this placid-looking gulf can have a dangerous temper
0:04:38 > 0:04:41which could easily wash away a man-made island.
0:04:42 > 0:04:45Back in the UK, I'm going to attempt
0:04:45 > 0:04:48to show how even a relatively small amount of water
0:04:48 > 0:04:51can do a surprising amount of damage.
0:04:51 > 0:04:54I'm going to create an artificial wave.
0:04:56 > 0:05:01'The man in charge of sea defences at the Burj Al Arab was Mike McNichols.'
0:05:01 > 0:05:04And these things can be pretty powerful?
0:05:04 > 0:05:06In the right circumstances, at the right speed,
0:05:06 > 0:05:10they can act like a solid, smashing into whatever's there.
0:05:13 > 0:05:16This plate glass will test the destructive power of our wave.
0:05:16 > 0:05:20And don't think that this glass is a pushover.
0:05:20 > 0:05:21It's ten mil thick.
0:05:21 > 0:05:26It's the safety stuff they use in tall buildings to stop people falling out.
0:05:26 > 0:05:29It's more than twice as thick as normal window glass.
0:05:34 > 0:05:37This is going to represent our wave - it's a ton of water.
0:05:37 > 0:05:41But it needs one more thing to be like a true wave.
0:05:41 > 0:05:44You need a bit of speed to get this thing going,
0:05:44 > 0:05:47just like a wave pushing through the air.
0:05:47 > 0:05:51Our wave will be set in motion by gravity and explosives.
0:05:53 > 0:05:56You'll like this, it's very subtle.
0:05:56 > 0:06:00At the bottom of the bag is a loop of det-cord, explosive,
0:06:00 > 0:06:02which will explode immediately
0:06:02 > 0:06:05and there will be no bottom on the bag so all this water,
0:06:05 > 0:06:09the whole lot, will fall out in a big solid lump.
0:06:09 > 0:06:11- And that's more like a wave? - Yes.
0:06:11 > 0:06:15Well, to complete this demonstration of the power of a lump of water,
0:06:15 > 0:06:20I've got this, it's a sort of industrial dining table,
0:06:20 > 0:06:23with a glass top, to give it its full title.
0:06:23 > 0:06:27We will position the bag above there on the crane, fire the explosives, bang, no bottom on the bag,
0:06:27 > 0:06:31all the water comes down in one go on to there.
0:06:31 > 0:06:32And we'll see what happens.
0:06:32 > 0:06:35Part of me thinks even in a solid lump,
0:06:35 > 0:06:39the water will pour round the sides and the biggest problem we'll have is a puddle.
0:06:39 > 0:06:42You'll see, it's going to puncture that glass.
0:06:42 > 0:06:46I'm going to make a suggestion. Whatever happens, let's watch it from over there.
0:06:50 > 0:06:53Now, I have always thought of water as kind of soft stuff,
0:06:53 > 0:06:55which flows around things.
0:06:57 > 0:07:01Sure, in a high-pressure jet, it's good for cleaning the car,
0:07:01 > 0:07:05but a cubic metre of it falling on to thick plate glass?
0:07:07 > 0:07:10Ah, the box.
0:07:10 > 0:07:14I really can't hear a thing now!
0:07:14 > 0:07:16- A nice loud countdown.- Sorry?
0:07:16 > 0:07:20- A nice loud countdown and press the button.- Right, this is it for real,
0:07:20 > 0:07:25here is comes, a wave - stand by in five, four,
0:07:25 > 0:07:28three, two, one...
0:07:31 > 0:07:33GLASS SHATTERS
0:07:36 > 0:07:41Well, that was quite a big bang. Thank you for the big bang.
0:07:52 > 0:07:55Yup, too much explosive.
0:07:55 > 0:07:56That's really...
0:07:57 > 0:08:03You can see the thickness of the glass now - ten mil thick, you could stand on that!
0:08:03 > 0:08:07Our ton of water only fell a couple of metres
0:08:07 > 0:08:10and it still had huge destructive power.
0:08:12 > 0:08:18Compared to the power of the waves in the gulf, however, it is a drop in the ocean.
0:08:18 > 0:08:24The biggest waves that batter the artificial island can deliver hundreds of tons of force.
0:08:24 > 0:08:29Each wave can be the equivalent of 130 small cars crashing into it.
0:08:31 > 0:08:35So how do you protect your island from the extreme forces of the waves?
0:08:35 > 0:08:38I think we will take our inspiration, Richard,
0:08:38 > 0:08:41from this little group of jacks here.
0:08:41 > 0:08:46So these are jacks... Forgive me, it seems like quite a leap
0:08:46 > 0:08:50because, how do they take the energy out of the wave?
0:08:50 > 0:08:52This is more a modern version of the jack -
0:08:52 > 0:08:54these things interlock together.
0:08:54 > 0:08:57So the principle is these shapes interlock.
0:08:57 > 0:09:01And the space between them, the water swirls within them,
0:09:01 > 0:09:03and loses its energy.
0:09:03 > 0:09:07- So it's these holes that are doing the work?- Yeah, the holes.
0:09:07 > 0:09:09It's nothing creates something.
0:09:12 > 0:09:15Holes are the answer, well, sort of.
0:09:16 > 0:09:21Holes were first used in revolutionary jack-shaped sea defences
0:09:21 > 0:09:24created by South African harbour engineers.
0:09:24 > 0:09:27They saw a local version of jacks being played
0:09:27 > 0:09:30and, fascinated by how the jacks interlocked,
0:09:30 > 0:09:35successfully redesigned the harbour defences for East London.
0:09:37 > 0:09:40Almost all coastal defences still rely on this idea of holes,
0:09:40 > 0:09:45including the Burj Al Arab.
0:09:49 > 0:09:53I'm creating a furniture protection system inspired by the sea defences
0:09:53 > 0:09:55used to protect the hotel...
0:09:56 > 0:10:00..in which spaces are the secret ingredient.
0:10:02 > 0:10:05Instead of trying to stop waves dead with a wall,
0:10:05 > 0:10:08the idea was to create a series of spaces -
0:10:08 > 0:10:11holes - that absorb the energy of the sea.
0:10:11 > 0:10:17And we are going to see if the same principle will protect my spare dining table.
0:10:20 > 0:10:23It will be the holes doing the work, I hope.
0:10:23 > 0:10:26We need to clear off out of the way, and let's do it again,
0:10:26 > 0:10:30only this time my table will survive. Probably. ..It's your theory.
0:10:30 > 0:10:32I know!
0:10:39 > 0:10:44Our homemade defences will use the holes in the tyres to redirect the water.
0:10:44 > 0:10:49It will swish around and SHOULD fall harmlessly out the bottom.
0:10:49 > 0:10:51- I have every faith. - Let's give it a go.
0:10:51 > 0:10:55If we have done our homework right this will save the glass...
0:10:55 > 0:10:58just as it saves the Burj Al Arab's man-made island.
0:11:00 > 0:11:03If we're ready? In five, four,
0:11:03 > 0:11:07three, two, one...
0:11:20 > 0:11:24This is one of those occasions where from seeing something,
0:11:24 > 0:11:25you suddenly really understand it.
0:11:25 > 0:11:28You can see the breakwater break that big lump of water up
0:11:28 > 0:11:30into eddies and swirls and bits.
0:11:35 > 0:11:39- It really was the holes doing the work?- The holes did all the work.
0:11:39 > 0:11:43Net effect, a protected table, a protected island, a protected hotel.
0:11:43 > 0:11:45Not that my table isn't important.
0:11:50 > 0:11:54In Dubai, the Burj Al Arab engineers used exactly the same principle
0:11:54 > 0:11:59for breaking up waves, except they used concrete, not old tyres.
0:12:02 > 0:12:06Their defences create a smooth, elegant and uniform shape -
0:12:06 > 0:12:10suitable for keeping a world-class hotel's head above water.
0:12:13 > 0:12:16The holes are so good at taking the energy out of waves
0:12:16 > 0:12:20that the island could be built at just seven and a half metres above sea level.
0:12:20 > 0:12:26Keeping the island relatively low allows the architects to continue the illusion
0:12:26 > 0:12:28of a boat on the water.
0:12:29 > 0:12:33But what I think is fascinating is how the architects completed
0:12:33 > 0:12:38the boat itself, inside the sea defences.
0:12:38 > 0:12:40Those are just the outer shell of the island.
0:12:40 > 0:12:45They needed to fill the middle in with something, and they chose... sand.
0:12:45 > 0:12:51I guess it is not in short supply around here, but call me old fashioned...
0:12:51 > 0:12:57I've never thought of sand as the ideal material to make firm foundations for a building...
0:12:57 > 0:12:59especially one that size.
0:13:00 > 0:13:04The Burj Al Arab is 321 metres high -
0:13:04 > 0:13:07slightly taller than the Eiffel Tower.
0:13:07 > 0:13:10How does it possibly stand on sand
0:13:10 > 0:13:14without keeling over in the first stiff breeze?
0:13:14 > 0:13:19Through a remarkably simple scientific principle, in fact.
0:13:19 > 0:13:21Skin friction is exactly what it sounds like -
0:13:21 > 0:13:24it's the friction between the skin, the surfaces of objects.
0:13:24 > 0:13:28If I rub my hands together, friction generates heat, I can feel it.
0:13:28 > 0:13:31Now ordinarily, skin friction is there
0:13:31 > 0:13:33but it's pretty easily overcome.
0:13:33 > 0:13:36So, two pages together, I can feel the friction between them
0:13:36 > 0:13:39but there's not a lot of it.
0:13:39 > 0:13:43However, if I multiply that effect by as many times
0:13:43 > 0:13:45as there are pages in these directories,
0:13:45 > 0:13:48well, let's see what happens.
0:13:48 > 0:13:54I'm going to interleave them page by page. One, two...
0:13:55 > 0:13:57Skin friction is one of the factors
0:13:57 > 0:14:00that keep the Burj Al Arab standing tall.
0:14:00 > 0:14:03'Mind you, I think they built the hotel in less time
0:14:03 > 0:14:06'than it's taking me to do this.'
0:14:08 > 0:14:111,407...1,408.
0:14:11 > 0:14:13There we go, all done.
0:14:13 > 0:14:16Now, according to the theory, the effects of skin friction
0:14:16 > 0:14:19should have been magnified by as many times
0:14:19 > 0:14:22as there are interfaces between the pages I have interleaved.
0:14:22 > 0:14:25It took a while, but I didn't have much else on this afternoon.
0:14:25 > 0:14:29Knowing how long it took, I'm reluctant to test it, but I'm going to.
0:14:29 > 0:14:30How tough is it?
0:14:30 > 0:14:32HE GRUNTS
0:14:32 > 0:14:38I'm pulling as hard as I possibly can. There is no glue, that is just skin friction.
0:14:38 > 0:14:39There's no way can I pull those apart,
0:14:39 > 0:14:42honestly, I'm trying as hard as I can.
0:14:42 > 0:14:43HE GRUNTS
0:14:43 > 0:14:48No, I need to try harder.
0:14:53 > 0:14:55OK. This should be more like it.
0:14:55 > 0:14:59Obviously skin friction already doing well just to hold this shackle on.
0:14:59 > 0:15:03Remember, nothing holding these together, just the friction between the pages.
0:15:03 > 0:15:04Right, lift it, please.
0:15:07 > 0:15:11How good is skin friction? I mean, really, how good?
0:15:11 > 0:15:12Up!
0:15:15 > 0:15:19OK. Time to demonstrate, if nothing else, my faith in science.
0:15:19 > 0:15:21HE CLEARS THROAT
0:15:21 > 0:15:23Um, yeah, skin friction...
0:15:23 > 0:15:26HE CHUCKLES
0:15:26 > 0:15:30That's all that's holding me up, and the weight of that shackle.
0:15:32 > 0:15:33Remember, no pins in there,
0:15:33 > 0:15:36no tape, no nails, nothing.
0:15:36 > 0:15:38Just friction.
0:15:43 > 0:15:49And friction is also one of the answers to building on unstable material, even sand.
0:15:51 > 0:15:55Otherwise the enormous tower would just topple over.
0:15:56 > 0:16:01The secret was to use reinforced concrete pile foundations,
0:16:01 > 0:16:03which are like long nails driven into the ground.
0:16:03 > 0:16:08They work using skin friction to keep the building in place,
0:16:08 > 0:16:09even in loose sand.
0:16:10 > 0:16:14To show how strong pile foundations can be, a simple demonstration.
0:16:14 > 0:16:18Jar of uncooked rice and a knife.
0:16:18 > 0:16:21Put knife into rice...
0:16:22 > 0:16:26..that's something called skin friction in action.
0:16:27 > 0:16:32Skin friction is strong enough to support a 320 metre tall tower...
0:16:32 > 0:16:34on sand.
0:16:36 > 0:16:41There are six miles of concrete piles bored 43 metres into the sand
0:16:41 > 0:16:44under the hotel to keep it upright and safe.
0:16:44 > 0:16:47Think of each pile as a page in the directory -
0:16:47 > 0:16:50every one makes the bond stronger.
0:16:50 > 0:16:53Combined, they make the sand as solid as a rock,
0:16:53 > 0:16:55and keep the building standing tall.
0:17:02 > 0:17:08In Dubai, temperatures can reach a blistering 49 degrees Celsius.
0:17:09 > 0:17:13And that heat posed a challenge for engineers and architects
0:17:13 > 0:17:15working with steel.
0:17:16 > 0:17:19Metal, like most materials, expands when you heat it up.
0:17:19 > 0:17:21Think about it, if you've got the lid stuck on a jar,
0:17:21 > 0:17:25warm it up and the metal lid will expand and you can free it, that's a good thing.
0:17:25 > 0:17:28But if you're working on giant metal trusses,
0:17:28 > 0:17:31and they're expanding and contracting according to the temperature
0:17:31 > 0:17:35at different times of day and you're trying to fit them together
0:17:35 > 0:17:39in a very precise way, it's going to be tricky.
0:17:40 > 0:17:45The Burj Al Arab was constructed using a steel exoskeleton,
0:17:45 > 0:17:46and external frame.
0:17:48 > 0:17:51The six steel trusses that support the building's weight
0:17:51 > 0:17:53are up to 85 metres long.
0:17:54 > 0:17:57That's longer than a Jumbo Jet.
0:17:59 > 0:18:04In the desert heat, the lengths of steel could expand by 5cm,
0:18:04 > 0:18:07which was critical during construction,
0:18:07 > 0:18:10when everything had to come together exactly.
0:18:14 > 0:18:17These two steel triangles will represent
0:18:17 > 0:18:20the huge steel trusses on the Burj -
0:18:20 > 0:18:22and they really are huge, 80 metres long,
0:18:22 > 0:18:25but the principles will be the same, even at this scale.
0:18:25 > 0:18:28So they've been machined very accurately
0:18:28 > 0:18:31so they can be fixed together using these fixings...
0:18:31 > 0:18:34That goes in there, that mounts in the hole...
0:18:36 > 0:18:38..and one here...
0:18:42 > 0:18:45So that's my steel structure firmly fixed together.
0:18:45 > 0:18:49Fine, but it hasn't yet had to cope with the problems of desert heat
0:18:49 > 0:18:52and the problems of heat expansion associated with it.
0:18:52 > 0:18:55Could be waiting a while here for some desert heat,
0:18:55 > 0:18:57but that's OK, we can bring our own.
0:18:57 > 0:18:59Gas axe, please. Thank you.
0:18:59 > 0:19:02While he's firing that up, I'm going to remove one of these fixings,
0:19:02 > 0:19:06because I want to see the effect of that thermal expansion.
0:19:23 > 0:19:25Right...
0:19:25 > 0:19:27Well, that was, I think we can agree, a hot day.
0:19:27 > 0:19:31But, if I try and put my original fixing back in...
0:19:32 > 0:19:35..and line it up - remember this is machined so the holes should align -
0:19:35 > 0:19:39and...oh, surprise, surprise, they don't,
0:19:39 > 0:19:42there's absolutely no way is that going to go through there.
0:19:42 > 0:19:45Because the metal's expanded, the hole's ended up in the wrong place.
0:19:46 > 0:19:50When the top metal bar undergoes thermal expansion,
0:19:50 > 0:19:51it becomes longer,
0:19:51 > 0:19:53but the bottom one stays the same.
0:19:55 > 0:19:58This means that the holes in each no longer align.
0:20:00 > 0:20:02If this were 80 times bigger,
0:20:02 > 0:20:04imagine the effect it would have then.
0:20:06 > 0:20:08But what can you do about it?
0:20:08 > 0:20:12The steel trusses ARE going to grow and shrink depending upon the time of day and temperature,
0:20:12 > 0:20:14that will happen.
0:20:14 > 0:20:17It could be disastrous, you could end up with a crooked tower.
0:20:17 > 0:20:20The engineers found an ingenious solution,
0:20:20 > 0:20:21thanks to the cam of an engine.
0:20:24 > 0:20:28Cams are used, of course, in car engines, you've probably heard of a camshaft.
0:20:28 > 0:20:29Well, here is one.
0:20:29 > 0:20:31This is the top of the engine,
0:20:31 > 0:20:33this assembly here is to operate the valves,
0:20:33 > 0:20:36which would be in the cylinder bores below.
0:20:36 > 0:20:39They have to open and close very quickly to let fuel and air in,
0:20:39 > 0:20:42and exhaust gases out, that's where the cams come in,
0:20:42 > 0:20:45so I'm going to be the engine turning here,
0:20:45 > 0:20:50and as I rotate the camshaft you can see the cams move eccentrically,
0:20:50 > 0:20:54these lobes where they bulge and stick out push down on this assembly here,
0:20:54 > 0:20:57open the valve and then shut it.
0:20:59 > 0:21:01It's a clever principle
0:21:01 > 0:21:05and one that's been used for a long, long time.
0:21:05 > 0:21:07The off-centre bulge of a cam allows it
0:21:07 > 0:21:13to open and close engine valves on each rotation of the camshaft.
0:21:13 > 0:21:16The builders of the Burj Al Arab borrowed from that idea
0:21:16 > 0:21:22to overcome the problems caused by extreme desert heat.
0:21:23 > 0:21:27This fixing is called an eccentric fixing.
0:21:27 > 0:21:30It's been designed using the same sort of principle -
0:21:30 > 0:21:33this is like a cam inside this hole here.
0:21:33 > 0:21:35And that gives us the flexibility we need
0:21:35 > 0:21:37to cope with this heat expansion.
0:21:37 > 0:21:43So let's put it in, line it up roughly, in the big hole there...
0:21:43 > 0:21:44and if I drop that in,
0:21:44 > 0:21:47we can manoeuvre it around, and there it is -
0:21:47 > 0:21:49that lines up perfectly.
0:21:51 > 0:21:54That's the connection between the engine's cam
0:21:54 > 0:21:56and our fixings for building in the desert.
0:21:58 > 0:22:02The eccentric fixing allows the top hole to be moved,
0:22:02 > 0:22:05so that no matter how much the steel expands,
0:22:05 > 0:22:08it can still be aligned to the bottom hole.
0:22:14 > 0:22:18Engineers at the hotel, taking their inspiration from engine cams,
0:22:18 > 0:22:21designed bespoke moveable fixings that allowed them
0:22:21 > 0:22:24to install the massive trusses accurately,
0:22:24 > 0:22:27despite the thermal expansion.
0:22:29 > 0:22:33Once installed, everything was welded firmly in place.
0:22:33 > 0:22:36Now the building expands and contracts as a whole,
0:22:36 > 0:22:37keeping it in shape.
0:22:47 > 0:22:50In the baking heat of the desert,
0:22:50 > 0:22:52one of the ultimate luxuries
0:22:52 > 0:22:56must be a cool, air-conditioned room.
0:22:57 > 0:23:01Even when temperatures approach 50 Celsius outside,
0:23:01 > 0:23:07the interior of the Burj Al Arab maintains a balmy 23 degrees.
0:23:07 > 0:23:12But keeping it this way isn't as simple as you might think.
0:23:14 > 0:23:18Creating and maintaining an oasis in the desert presented the engineers
0:23:18 > 0:23:21with a series of challenges, right from the very beginning.
0:23:23 > 0:23:26The real problem is managing the big difference
0:23:26 > 0:23:29between temperatures inside and outside the hotel.
0:23:31 > 0:23:36On a hot day, the difference between the two can be 20 degrees Celsius.
0:23:37 > 0:23:41Temperature differences create pressure differences.
0:23:41 > 0:23:44In nature, big pressure differences create violent winds,
0:23:44 > 0:23:46even hurricanes.
0:23:48 > 0:23:51Pressure differences affect all skyscrapers.
0:23:51 > 0:23:56They're especially bad in a structure the size of the Burj Al Arab, in the desert.
0:23:56 > 0:24:02It could literally stop people getting in and out of the building.
0:24:03 > 0:24:07'Back on home soil, Professor of Building Engineering Physics
0:24:07 > 0:24:10'Doug King explains why combining air conditioning,
0:24:10 > 0:24:15'a tall building and a scorching desert can stack up big trouble.'
0:24:17 > 0:24:21Big temperature differences, although they make life nicer inside,
0:24:21 > 0:24:25- they can bring big problems. - Absolutely. We're going to demonstrate that with this model,
0:24:25 > 0:24:28which is a scale model of the atrium at the Burj.
0:24:28 > 0:24:30I did wonder. It's not as big, is it?
0:24:30 > 0:24:34No, unfortunately, we couldn't get one that big in here,
0:24:34 > 0:24:37so we've had to scale things down. We've got a light bulb at the bottom,
0:24:37 > 0:24:41representing the heat gains from people and the sun shining in the windows.
0:24:41 > 0:24:45And we've got about a kilogram of dry ice on a tray at the top,
0:24:45 > 0:24:48representing the cooling effect of the air conditioning.
0:24:50 > 0:24:53'And the problem is all to do with airflow.
0:24:53 > 0:24:56'An air pellet will show how the air circulates.
0:24:56 > 0:25:03'Heat from people and the sun through the windows on the ground floor cause the air to rise.
0:25:03 > 0:25:08'The air conditioning cools it down, making it more dense, and the air falls...'
0:25:08 > 0:25:12So we've got up-flow on the one side and down-flow on the other side.
0:25:12 > 0:25:18'..leaving you with a tall column of cold, heavy air surrounded by the hot desert,
0:25:18 > 0:25:21'which doesn't sound like a problem.'
0:25:21 > 0:25:25- I still don't see - why the big problem?- If the building stays closed, it's not a problem.
0:25:25 > 0:25:29The problem happens when we've got this big stack of cold air inside.
0:25:29 > 0:25:33We've got warm air outside, and it's all being held back by the front door.
0:25:33 > 0:25:36- So why don't you open the door and see what happens? - This door down there?
0:25:36 > 0:25:38- That's the one. - So I'll open the door...
0:25:38 > 0:25:42- Wooh! Yes! - What's happening now... See how quickly it's clearing down?- Yes.
0:25:42 > 0:25:47You've got this big column of cold air inside, much heavier than the air outside,
0:25:47 > 0:25:51- and it's being forced out through that little opening. - You can see it's rushing out -
0:25:51 > 0:25:56that's not just tumbling out because I've opened the door, that's being pushed out...
0:25:56 > 0:26:00- Right.- ..by this pressure difference.- See how quickly all that air inside the model
0:26:00 > 0:26:04- has fallen down and pushed the air out.- So if that's how it works on this scale,
0:26:04 > 0:26:06how big a problem does it represent
0:26:06 > 0:26:08for something the size of Burj Al Arab?
0:26:08 > 0:26:11Well, for something as big as that atrium - it's 180 metres high -
0:26:11 > 0:26:15that's an enormous stack of cold air. Very, very dense at the bottom.
0:26:15 > 0:26:20Opening that door against that pressure is like trying to lift a sack of potatoes.
0:26:20 > 0:26:23To be more precise, the vast atrium at the Burj Al Arab,
0:26:23 > 0:26:27combined with the heat of the desert outside,
0:26:27 > 0:26:33could create the equivalent of 21 bags of sugar pressing against the door.
0:26:33 > 0:26:37So, a 21-kilo weight suspended from a pulley.
0:26:37 > 0:26:41This, then, is about as tough as it would be to open the door at the Burj Al Arab.
0:26:41 > 0:26:44I mean, it's not impossible, but it is a bit of a workout.
0:26:44 > 0:26:47I don't think you want a work out every time you open the door,
0:26:47 > 0:26:50especially if you've saved up to book a suite.
0:26:51 > 0:26:54With the largest atrium in the world,
0:26:54 > 0:26:57this problem is especially acute for the Burj Al Arab.
0:27:01 > 0:27:04The unwanted stack effect was first noticed
0:27:04 > 0:27:07with the rise of the skyscraper.
0:27:07 > 0:27:10Workers in New York and Chicago complained not only of draughts,
0:27:10 > 0:27:14but that they couldn't even open the doors of their buildings
0:27:14 > 0:27:17because of pressure differences inside and outside.
0:27:19 > 0:27:23One solution to the problem is to equalise the pressure inside the building
0:27:23 > 0:27:25with the pressure outside the building.
0:27:25 > 0:27:28But that would mean you'd need to equalise
0:27:28 > 0:27:31the temperature in here with the temperature out there...
0:27:31 > 0:27:32in the desert.
0:27:32 > 0:27:35You wouldn't be able to heat or cool the building.
0:27:35 > 0:27:39And I think having the temperature in here hover around the 40-degree mark
0:27:39 > 0:27:43does rather spoil the whole idea of an oasis in the desert.
0:27:43 > 0:27:46The hotel might lose a star or two for that.
0:27:46 > 0:27:51What you need is a means of getting between two areas of different pressure -
0:27:51 > 0:27:54outside on the street and inside the hotel -
0:27:54 > 0:27:57without allowing the pressures to equalise.
0:27:57 > 0:28:00There was a different solution
0:28:00 > 0:28:05and it came from something inspired by a 19th-century French coal mine.
0:28:06 > 0:28:11In 1839, French mining engineer Jacques Triger overcame the problem
0:28:11 > 0:28:14of moving between two areas of different pressure
0:28:14 > 0:28:16in waterlogged coal mines.
0:28:16 > 0:28:19He created the world's first airlock.
0:28:21 > 0:28:24This is how Triger's system worked. This is my waterlogged ground.
0:28:24 > 0:28:27Well, it's a glass, but you know what I mean.
0:28:27 > 0:28:29Here's my mine shaft.
0:28:29 > 0:28:32If I just sink a mine shaft into waterlogged ground like this,
0:28:32 > 0:28:34it's just full of water at the bottom,
0:28:34 > 0:28:36nobody can work down there.
0:28:36 > 0:28:37The answer to that is
0:28:37 > 0:28:39fairly simple - seal it at the top.
0:28:39 > 0:28:40That stops the air getting out,
0:28:40 > 0:28:43which means the water can't get in.
0:28:43 > 0:28:45That's all well and good until you need to open the top
0:28:45 > 0:28:47to let your workers go down the mine,
0:28:47 > 0:28:51then it flows with water again.
0:28:51 > 0:28:56That answer to that one - establish your dry mine shaft,
0:28:56 > 0:28:58fit an airlock at the top,
0:28:58 > 0:28:59let your workers in.
0:28:59 > 0:29:00Then once they're safely in,
0:29:00 > 0:29:05seal it behind them - everything stays dry, everybody's happy.
0:29:05 > 0:29:08What they needed at the Burj Al Arab was some sort of airlock
0:29:08 > 0:29:11so they could separate the pressure inside the hotel
0:29:11 > 0:29:13from the pressure outside.
0:29:13 > 0:29:16Sounds complicated, like something off a space station.
0:29:16 > 0:29:18But in fact, I've just been through it -
0:29:18 > 0:29:21it's a revolving door.
0:29:22 > 0:29:24Revolving doors are designed in such a way
0:29:24 > 0:29:28that there's never a direct opening to the street.
0:29:28 > 0:29:30The inside is sealed from the outside,
0:29:30 > 0:29:33even when the door is spinning.
0:29:34 > 0:29:39First used in Rector's Restaurant in Times Square in New York in 1899,
0:29:39 > 0:29:41its tagline was, "Always open, always closed",
0:29:41 > 0:29:46because the door keeps a seal, even when you go through it.
0:29:48 > 0:29:51This makes the sort of airlock that's needed
0:29:51 > 0:29:53to stop the big out-rush of air that would happen
0:29:53 > 0:29:55because of the stack effect.
0:29:55 > 0:30:01Now, everyone who can afford it can come and go in comfort.
0:30:01 > 0:30:04But comfort can bring its own difficulties.
0:30:05 > 0:30:07It's probably not surprising
0:30:07 > 0:30:10that pretty much every electronic gizmo conceivable
0:30:10 > 0:30:12has been incorporated into these rooms,
0:30:12 > 0:30:14all operated by remote control.
0:30:14 > 0:30:17At the touch of a button, televisions drop from the ceiling,
0:30:17 > 0:30:19or pop up out of pieces of furniture.
0:30:19 > 0:30:22You can change the temperature, open and close the doors,
0:30:22 > 0:30:26change the mood, adjust the lighting, dim it, make it romantic.
0:30:26 > 0:30:27Let's leave it bright.
0:30:27 > 0:30:30So, whilst all of this is great for the guests,
0:30:30 > 0:30:33it can be bit of a headache for an electrical engineer.
0:30:35 > 0:30:38Luxury calls for a lot of energy.
0:30:38 > 0:30:41Just the lights in one suite can draw more power
0:30:41 > 0:30:46than all the appliances in a British home burn in a whole day.
0:30:46 > 0:30:51And making the mood romantic could have shocking consequences.
0:30:51 > 0:30:54So, to dim the lights, simply press a button.
0:30:54 > 0:30:56Not complicated - we're all familiar with dimmers.
0:30:56 > 0:31:01But simply pressing that button could have had a catastrophic effect.
0:31:01 > 0:31:04The origin of the potential problem lies
0:31:04 > 0:31:08in what happens to an electrical current when you dim the bulb.
0:31:08 > 0:31:13It can heat the wires to abnormal levels and start a fire.
0:31:16 > 0:31:19To show what can go wrong when you're adjusting the ambience,
0:31:19 > 0:31:23we're going to check in to my own replica of a luxury hotel room.
0:31:30 > 0:31:35I've brought electrical expert Paul Mitcheson along
0:31:35 > 0:31:37to create a sophisticated lighting system.
0:31:41 > 0:31:42Oh, yeah, home from home.
0:31:42 > 0:31:46No, I'm not back in the Burj Al Arab, this is my replica.
0:31:46 > 0:31:49There's no en suite yet or Jacuzzi or under-floor heating,
0:31:49 > 0:31:52but it's got a bedside table and plastic roses.
0:31:52 > 0:31:56Everything the modern luxury bedroom needs, including lights.
0:31:56 > 0:31:59They don't really come on and off when you do that,
0:31:59 > 0:32:02that's just Paul out there operating them.
0:32:02 > 0:32:06Still, thank you! There it is, all working perfectly.
0:32:09 > 0:32:12My shed may not be a fully authentic replica,
0:32:12 > 0:32:14but it has two crucial similarities.
0:32:15 > 0:32:19It has a high voltage power supply for the electrical systems
0:32:19 > 0:32:22and it has a dimming system.
0:32:25 > 0:32:28Paul, in addition to providing adult supervision,
0:32:28 > 0:32:30has set up a high-tech monitoring station
0:32:30 > 0:32:35complete with a complicated array of gauges and test equipment.
0:32:35 > 0:32:39Paul, to me as a customer, staying in my luxury hotel room
0:32:39 > 0:32:43the lights are on, that's it. What is going on in there? What's happening?
0:32:43 > 0:32:47So, what we're doing is we have a wave form, which we can see on the oscilloscope,
0:32:47 > 0:32:50and this is electric current which is powering the lights.
0:32:50 > 0:32:54And at the moment, the key thing to note here is that this is a very smooth wave form.
0:32:54 > 0:32:59So, this is what a normal current looks like on an oscilloscope.
0:32:59 > 0:33:02It's regular and safe.
0:33:02 > 0:33:05So, a smooth wave form there. What if I change things a bit?
0:33:05 > 0:33:07This is what I want to change.
0:33:07 > 0:33:10It's a luxury bedroom, but that light is a bit harsh.
0:33:10 > 0:33:12You want something a bit more cosy?
0:33:12 > 0:33:14Yeah, I'd like to change the light setting.
0:33:14 > 0:33:19Instead of three on full, I'd like to put six lights on but dim.
0:33:19 > 0:33:23OK, in that case, what we could do is, we could dim those,
0:33:23 > 0:33:26bring up another three.
0:33:27 > 0:33:29It's a much better ambience in there.
0:33:29 > 0:33:33Am I right? That's the same amount of light.
0:33:33 > 0:33:35We've just got six lights on but lower.
0:33:35 > 0:33:38That's right. The same amount of power into the lights.
0:33:38 > 0:33:42We can see from the oscilloscope that something has changed drastically.
0:33:42 > 0:33:44So, what's different?
0:33:44 > 0:33:49The problem is now that we're delivering power to the lights in short bursts.
0:33:49 > 0:33:51So that's how the power's been halved then?
0:33:51 > 0:33:54That's exactly right, yes.
0:33:54 > 0:33:57Because I always thought a dimmer was like a tap,
0:33:57 > 0:33:59cos if you turn a tap on full and then that's too much
0:33:59 > 0:34:04you turn it down halfway and half the amount of water comes out. I thought a dimmer was the same.
0:34:04 > 0:34:08Turn it down and half the amount of electricity goes to the lights.
0:34:08 > 0:34:12So, it's more like turning the tap on and then off and then on and then off.
0:34:14 > 0:34:18Modern dimmer switches basically shut off the power to the light
0:34:18 > 0:34:20120 times a second.
0:34:20 > 0:34:25It has the effect of not letting the light ever achieve full brightness.
0:34:25 > 0:34:28It also has a side effect.
0:34:28 > 0:34:30So, it's the same amount of electricity
0:34:30 > 0:34:32but being switched on and off.
0:34:32 > 0:34:35- Right.- Why is that different? Why does that upset things?
0:34:35 > 0:34:38You're only delivering the power for a short period of time.
0:34:38 > 0:34:41And in order to that, you introduce extra heating effects in the wires.
0:34:41 > 0:34:44An electrical current in a wire always creates
0:34:44 > 0:34:46a certain amount of heat.
0:34:46 > 0:34:50But adding a dimmer switch can add extra heat to the wire,
0:34:50 > 0:34:53sometimes dangerously so.
0:34:53 > 0:34:58The on-off action of a dimmer switch creates so-called harmonic distortion,
0:34:58 > 0:35:01a sort of chaotic current in the wires,
0:35:01 > 0:35:05frequencies the system isn't designed to deal with.
0:35:07 > 0:35:10A wire heating up doesn't sound too ominous.
0:35:10 > 0:35:13It might smoulder away but, in the wrong circumstances,
0:35:13 > 0:35:17that wire can ignite flammable items close to it.
0:35:17 > 0:35:22If, for example, someone had carelessly left the exposed wire
0:35:22 > 0:35:25on a waste paper basket full of cotton wool,
0:35:25 > 0:35:29which might happen to be soaked in nail varnish remover.
0:35:29 > 0:35:31It could happen!
0:35:36 > 0:35:40With six lights on dim, let's see what does happen.
0:35:50 > 0:35:53My hotel's on fire, just so they know.
0:35:53 > 0:35:56That's a lot of heating!
0:35:56 > 0:35:59That took less than 20 seconds to catch.
0:35:59 > 0:36:02You really wouldn't want that in a top-class hotel.
0:36:03 > 0:36:07Our shed's on fire. You've ruined my hotel quite badly.
0:36:07 > 0:36:11I see your point. That is a potential problem!
0:36:13 > 0:36:15Cor blimey! Bloody hell.
0:36:22 > 0:36:23Man, that's hot!
0:36:26 > 0:36:31Obviously, this is a very exaggerated scenario.
0:36:31 > 0:36:37Electricians don't generally run exposed wires through flammable bins of cotton wool.
0:36:37 > 0:36:42But if it is a serious threat, how come dimmers are so common?
0:36:42 > 0:36:46Why isn't there a fire every time someone wants to change the ambience?
0:36:46 > 0:36:47That could ruin the mood.
0:36:48 > 0:36:54It's because of electrical defences that include part of a camera's flash.
0:36:58 > 0:37:01Yeah, I do see your point.
0:37:01 > 0:37:02It's not great, is it?
0:37:02 > 0:37:05My hotel's ruined. So clearly that needs to be avoided.
0:37:05 > 0:37:08It is. They have dimmers and that doesn't happen.
0:37:08 > 0:37:09So, what's the solution?
0:37:09 > 0:37:13So, the solution is the capacitor that's in the camera flash.
0:37:13 > 0:37:17We're all familiar with a regular camera.
0:37:19 > 0:37:24Early camera flashes used explosive powder to create the bright light
0:37:24 > 0:37:28but carrying that around was not for the faint-hearted.
0:37:32 > 0:37:35They needed a safe, portable alternative.
0:37:38 > 0:37:42And the solution came in the form of an electrical component,
0:37:42 > 0:37:44known as a capacitor.
0:37:44 > 0:37:48In cameras, the capacitor stores up energy
0:37:48 > 0:37:52and releases it all at once setting off the flash.
0:37:52 > 0:37:55But, in buildings, combined with inductors,
0:37:55 > 0:38:01they act like filters, removing the chaotic currents that can cause fires.
0:38:01 > 0:38:03This is a regular, relatively large capacitor.
0:38:03 > 0:38:08So, this is the thing that allows you to take energy more slowly
0:38:08 > 0:38:11and release it back to the lights.
0:38:11 > 0:38:15All that does is accumulates this energy and releases it at a controllable rate.
0:38:15 > 0:38:17And stops that happening.
0:38:17 > 0:38:19Burning your shed down.
0:38:19 > 0:38:24Wish I'd known that ten minutes ago, I'd still have a shed.
0:38:24 > 0:38:28The Burj al Arab's capacitors are buried deep in the building.
0:38:28 > 0:38:32With the inductors, they are the unsung electrical heroes
0:38:32 > 0:38:36that protect the hotel from itself and its pampered guests.
0:38:36 > 0:38:39I guess it is a relief to know that, when I dim the lights,
0:38:39 > 0:38:42I'm not going to set fire to the Burj al Arab.
0:38:42 > 0:38:46I imagine the bill would be quite big if I did.
0:38:46 > 0:38:48I'd never get that through on expenses.
0:38:50 > 0:38:54The designers of this amazing building
0:38:54 > 0:38:57didn't limit the spectacle just to the structure.
0:38:57 > 0:39:00It is, after all, a hotel.
0:39:00 > 0:39:03And the guests will spend most of their time inside looking around,
0:39:03 > 0:39:06not outside looking in.
0:39:09 > 0:39:11When it comes to earning its keep,
0:39:11 > 0:39:15this building is all about symbolising luxury and opulence
0:39:15 > 0:39:19so what could be the best possible luxury here,
0:39:19 > 0:39:23in a hotel perched in a scorching desert of sand and sea?
0:39:25 > 0:39:28Yep, fountains.
0:39:29 > 0:39:34Think about it, a fountain in the desert is the ultimate in opulence.
0:39:34 > 0:39:37And, not just any old fountains,
0:39:37 > 0:39:41a series of digitally-controlled million-pound masterpieces.
0:39:42 > 0:39:45And, whilst fountains are pretty and all that,
0:39:45 > 0:39:48it takes some surprising engineering to create the flair.
0:39:51 > 0:39:54You need to be seen to do something extravagant
0:39:54 > 0:39:56and opulent with the water.
0:39:56 > 0:39:59And the water features here are an engineering feat
0:39:59 > 0:40:02in their own right. Mesmerising.
0:40:03 > 0:40:07Sometimes the water doesn't even look like water.
0:40:11 > 0:40:14That's because it's not behaving like water,
0:40:14 > 0:40:16normal water that is.
0:40:16 > 0:40:19Normal water can't move like this does.
0:40:22 > 0:40:28To allow it to play these tricks, you need to eliminate turbulence.
0:40:28 > 0:40:31It has to achieve an almost unreal glassy smoothness,
0:40:31 > 0:40:35something called laminar flow.
0:40:36 > 0:40:38Here it comes, if you need it,
0:40:38 > 0:40:42a quick reminder of how water behaves in a flow normally.
0:40:44 > 0:40:47There it goes, that's...
0:40:47 > 0:40:50Well, it's a mess, that's because of turbulence,
0:40:50 > 0:40:52there's lots of eddies and flows and swirls in there,
0:40:52 > 0:40:56which is fine for use here on the farm.
0:40:57 > 0:41:01But if you want to make those beautiful polished glass-like tubes
0:41:01 > 0:41:06in the fountains at the Burj al Arab you need to smooth that flow out.
0:41:06 > 0:41:09You need to make it laminar.
0:41:09 > 0:41:12And to do that engineers turned to a type of hose
0:41:12 > 0:41:15used to help put out fires in sky scrapers.
0:41:17 > 0:41:22The 1930s. Buildings grew taller.
0:41:22 > 0:41:26Fire fighters needed to stream water higher to quench towering infernos.
0:41:26 > 0:41:30A helpful hydraulic engineer realised that turbulence
0:41:30 > 0:41:32reduced the range of fire hoses,
0:41:32 > 0:41:35because the water flow broke up in air.
0:41:35 > 0:41:38His invention to smooth out the flow in fire hoses,
0:41:38 > 0:41:40to make it more laminar,
0:41:40 > 0:41:43was the key to the Burj al Arab's glassy fountains.
0:41:43 > 0:41:46Right, quick quiet minute before we do the next bit
0:41:46 > 0:41:49and we'll be finding out about this laminar flow business.
0:41:49 > 0:41:54Which is far as I understand is doing, well what seems impossible?
0:41:54 > 0:41:56Here is an example, my coffee,
0:41:56 > 0:42:00don't worry, they'll get a coffee too, once they've earned it.
0:42:00 > 0:42:05If I stir in milk, there you go,
0:42:05 > 0:42:08stir it all in, there you go, it's all mixed up thoroughly.
0:42:08 > 0:42:12Wouldn't it be kinda cool if we could un-stir it,
0:42:12 > 0:42:16and we would be left with a blob of milk and black coffee?
0:42:16 > 0:42:19So maybe if I stir the other way?
0:42:19 > 0:42:23Obviously you can't, that would be turning back time.
0:42:25 > 0:42:30We haven't yet conquered time travel and you can't un-stir coffee
0:42:30 > 0:42:34unless you can make water behave in a fully laminar way.
0:42:34 > 0:42:39Amazingly, however you can un-stir some liquids.
0:42:40 > 0:42:43Professor Tom Mullen from Manchester University,
0:42:43 > 0:42:46an expert in fluid dynamics shows me how.
0:42:47 > 0:42:50So Tom, with this device are we about to spin a salad
0:42:50 > 0:42:54or do some painting and what's this got to do with laminar flow,
0:42:54 > 0:42:57whatever that is, and trying to unstir my coffee?
0:42:57 > 0:43:01That's your mission to explain all of that.
0:43:01 > 0:43:04Well, what you have to do is put this colour dye into the fluid
0:43:04 > 0:43:08and we will stir it around and see what happens.
0:43:10 > 0:43:13The liquid inside is thick viscous sugar syrup...
0:43:13 > 0:43:16- A bit further along here. This direction.- Right.
0:43:16 > 0:43:21..and the coloured blobs are the same stuff with food dye added.
0:43:23 > 0:43:26So three blobs, good, not much flowing,
0:43:26 > 0:43:28laminar or otherwise going on now.
0:43:28 > 0:43:31No, we have to create the flow, so to create the flow
0:43:31 > 0:43:36we have to turn that handle, say five times in that direction.
0:43:36 > 0:43:40- Right, it's quite thick stuff this. One...- Very sticky.
0:43:42 > 0:43:43Two...
0:43:43 > 0:43:45Keep going.
0:43:45 > 0:43:46Three...
0:43:48 > 0:43:49Four...
0:43:50 > 0:43:52Five. OK, I've done that.
0:43:52 > 0:43:56- Now, it looks like we've created a right mess.- It's a mess. It's all gone.
0:43:56 > 0:44:00What we need to do is go backwards, the same number of times.
0:44:00 > 0:44:03- So I'm literally un-stirring it? - Unstir.
0:44:03 > 0:44:07I feel like someone might be having a laugh at my expense.
0:44:07 > 0:44:08One...
0:44:10 > 0:44:12Two...
0:44:13 > 0:44:16Three...
0:44:18 > 0:44:25- Four. - Slow down a bit, slow, slow, slow.
0:44:25 > 0:44:28There you have your three blobs back again.
0:44:28 > 0:44:32Wow. Look at that! I have literally unstirred it.
0:44:32 > 0:44:33That's a great party trick.
0:44:37 > 0:44:40Thick, viscous liquids like sugar syrup are very smooth.
0:44:40 > 0:44:44It's easy to make them move in a laminar way.
0:44:44 > 0:44:46They don't behave turbulently like water.
0:44:46 > 0:44:50So you can un-stir them and make the blobs re-appear.
0:44:50 > 0:44:54If water behaved like that you could un-stir your coffee.
0:44:58 > 0:45:03To make water flow in a laminar fashion, you need to remove
0:45:03 > 0:45:06the turbulence, with a laminar flow nozzle.
0:45:06 > 0:45:09The good news immediately is, now correct me if I'm wrong,
0:45:09 > 0:45:12is that this appears to be laminar flow in water.
0:45:12 > 0:45:15This is laminar flow coming out of this nozzle here,
0:45:15 > 0:45:18whereas this is turbulent flow. The reason you can tell
0:45:18 > 0:45:22immediately that it's turbulent is that you can see it.
0:45:22 > 0:45:26It scatters the light and in this case it's glassy smooth and laminar.
0:45:26 > 0:45:30Quite a simple difference really, neat tidy and elegant, and scruffy and a mess.
0:45:30 > 0:45:33But to achieve this it needs this device here,
0:45:33 > 0:45:41- that looks like something from a '60s sci-fi movie, what is it? - You have turbulent flow coming in
0:45:41 > 0:45:46and you have the flow goes through these gauzes and these straws and so the turbulence decays as it comes
0:45:46 > 0:45:51through here and you end up with laminar flow coming out of the nozzle.
0:45:51 > 0:45:54The gauze and straws effectively smooth the water,
0:45:54 > 0:45:58removing the bubbles and swirls that cause turbulence.
0:45:58 > 0:46:03Non-turbulent water can flow quicker and more smoothly.
0:46:03 > 0:46:06So to solve the problem then of fast moving laminar flow in water
0:46:06 > 0:46:10for the Burj al Arab's fountains, what you need is a device like this.
0:46:10 > 0:46:13- To calm the water down.- Yes.
0:46:14 > 0:46:19And smoothly flowing water also helped fire fighters.
0:46:21 > 0:46:24In the '30s, American engineer Horace Barker had a brainwave.
0:46:24 > 0:46:29He realised that removing turbulence made the water travel further.
0:46:29 > 0:46:33His new fire hose design had metal feathers inside
0:46:33 > 0:46:36that aligned the water as it left, reducing this turbulence.
0:46:38 > 0:46:41Barker's flow-straightener extended the range of fire hoses.
0:46:43 > 0:46:45The smooth water flow travelled further.
0:46:45 > 0:46:48So fire-fighters could tackle blazes on the higher floors
0:46:48 > 0:46:50of sky scrapers more easily.
0:46:51 > 0:46:55Laminar flow nozzles go one step further than Barker's device,
0:46:55 > 0:46:56removing all turbulence
0:46:56 > 0:46:59and smoothing the water to a glassy finish.
0:47:04 > 0:47:08The fountains at the Burj al Arab incorporate 66 laminar flow nozzles,
0:47:08 > 0:47:13I'm pretty sure theirs aren't made from drinking straws though.
0:47:13 > 0:47:15Either way, they allow for breathtaking displays.
0:47:17 > 0:47:20You see, the crucial thing about the Burj al Arab is that
0:47:20 > 0:47:25it's all about the bling. It's engineering to impress...
0:47:25 > 0:47:28not just to survive.
0:47:28 > 0:47:31All these engineering achievements have made
0:47:31 > 0:47:35the Burj al Arab a spectacular feature on Dubai's skyline.
0:47:37 > 0:47:39The Burj al Arab instantly joined the world's list
0:47:39 > 0:47:42of iconic landmarks. Becoming the face of Dubai.
0:47:42 > 0:47:49Synonymous with it's re-invention as a luxury playground.
0:47:55 > 0:47:59Behind the glitz, the glamour and the spectacular show,
0:47:59 > 0:48:03there is some amazing, and solid engineering.
0:48:05 > 0:48:08And none of it would have been possible without...
0:48:08 > 0:48:09..a game of jacks...
0:48:11 > 0:48:14..an engine cam...
0:48:14 > 0:48:17..the pages of a phone book...
0:48:19 > 0:48:21..a revolution in fire-hose design...
0:48:21 > 0:48:25..and a camera flash.
0:48:25 > 0:48:29- You've ruined my hotel, man! - THEY LAUGH
0:48:36 > 0:48:39Subtitles by Red Bee Media Ltd
0:48:39 > 0:48:42Email subitling@bbc.co.uk