0:00:03 > 0:00:05Take a look around your home.
0:00:07 > 0:00:10Can you be sure that every appliance is safe?
0:00:13 > 0:00:16Is everything a company tells you about a product true?
0:00:17 > 0:00:21And are you getting the best value for your money?
0:00:21 > 0:00:25With the help of the country's top experts, we're going to see
0:00:25 > 0:00:29what it takes to test the household products we use every day.
0:00:32 > 0:00:35We'll discover how they're pushed to their limits...
0:00:37 > 0:00:39..we'll put the makers' claims on trial...
0:00:41 > 0:00:44..and show you how to make your money go further.
0:00:44 > 0:00:47You'll find these products in any ordinary house,
0:00:47 > 0:00:50but this is no an ordinary house,
0:00:50 > 0:00:53and no ordinary street.
0:00:53 > 0:00:55This is the Watchdog Test House.
0:01:01 > 0:01:06Hello. We're deep inside one of Britain's leading science centres.
0:01:06 > 0:01:09Here at the Building Research Establishment, some of the products
0:01:09 > 0:01:14and materials that we use every day are put to the test
0:01:14 > 0:01:16to make sure that they're safe,
0:01:16 > 0:01:19environmentally friendly and that they don't fall apart.
0:01:20 > 0:01:22Coming up on today's programme,
0:01:22 > 0:01:26smoke alarms. A staggering one in four fail to go off in fires
0:01:26 > 0:01:28attended by the fire brigade.
0:01:28 > 0:01:31The smoke was coming out of the loft hatch quite severely,
0:01:31 > 0:01:34and the smoke alarms didn't go off at all.
0:01:34 > 0:01:38How do manufacturers try to ensure they're going to be fail-safe?
0:01:39 > 0:01:42Fitness trackers - they claim to count calories and steps.
0:01:42 > 0:01:45They're a fantastic motivation point. Track your calories
0:01:45 > 0:01:48every day and try and improve on it day after day, run after run.
0:01:48 > 0:01:53But how accurate are they? We put three products through their paces.
0:01:53 > 0:01:57And exploding oven doors - no stranger to Watchdog...
0:01:58 > 0:02:01..but aren't they supposed to be made of toughened glass?
0:02:07 > 0:02:10Smoke alarms - the best way you to protect you
0:02:10 > 0:02:13and your home against the threat of fire.
0:02:13 > 0:02:17The good news? About 85% of households have them installed.
0:02:17 > 0:02:20The bad news? They don't always go off.
0:02:22 > 0:02:25The upstairs of the house was full of smoke.
0:02:25 > 0:02:27I couldn't see where I was going.
0:02:28 > 0:02:31Darren King was spending a Sunday afternoon at home with his two
0:02:31 > 0:02:34children when his house caught fire.
0:02:34 > 0:02:37My two sons were out the front playing,
0:02:37 > 0:02:40and my eldest son came running in, just to say, "Daddy phone 999 -
0:02:40 > 0:02:42"there's smoke coming out the roof."
0:02:42 > 0:02:46When Darren went outside, he soon realised the fire was
0:02:46 > 0:02:49actually inside the walls of the house.
0:02:49 > 0:02:52The fire was actually started down in the bottom corner
0:02:52 > 0:02:53of the threshold.
0:02:53 > 0:02:58So I tried to put that out, and then when I came inside,
0:02:58 > 0:03:00I put my hand on here and noticed there was a lot of heat
0:03:00 > 0:03:01and I could hear crackling.
0:03:01 > 0:03:04I realised at that point then that the fire was going all
0:03:04 > 0:03:06the way up the cavity wall.
0:03:06 > 0:03:09Before long, the flames had reached the roof.
0:03:09 > 0:03:13That's how high the fire actually came up from the ground floor
0:03:13 > 0:03:14back door,
0:03:14 > 0:03:18and it's started burning through the wooden framework
0:03:18 > 0:03:19of the actual house.
0:03:19 > 0:03:23Darren called 999, and by the time the fire brigade had put
0:03:23 > 0:03:26the flames out, the house was full of smoke,
0:03:26 > 0:03:29but the smoke alarm was faulty and it never went off.
0:03:29 > 0:03:33Luckily the fire was in the afternoon and not in the evening,
0:03:33 > 0:03:36because if we'd been in bed, we wouldn't have noticed.
0:03:36 > 0:03:38The smoke alarms wouldn't have gone off,
0:03:38 > 0:03:40and we may not have got out of the house alive.
0:03:40 > 0:03:44Fire brigade statistics show that in more than one in four
0:03:44 > 0:03:48of the house fires they attend where a smoke alarm was present,
0:03:48 > 0:03:49it failed to go off.
0:03:49 > 0:03:52In Darren's case, the alarms were faulty,
0:03:52 > 0:03:55but there can be plenty of other reasons too.
0:03:55 > 0:03:58Smoke alarms have been going off, creating a false alarm,
0:03:58 > 0:04:00and people have actually taken the batteries out
0:04:00 > 0:04:03because of the nuisance factor, and forgot to put them back.
0:04:03 > 0:04:07There are also issues with inadequate siting within the homes.
0:04:07 > 0:04:10Smoke alarms must be sited where they can give adequate coverage
0:04:10 > 0:04:12and protection, so they can be heard.
0:04:12 > 0:04:15But of course that probably won't mean that it covers
0:04:15 > 0:04:16every room within a house.
0:04:16 > 0:04:20You also need to think about which type of alarm you buy.
0:04:20 > 0:04:24Broadly, there are two types - ionisation and optical,
0:04:24 > 0:04:27and fire and rescue services would recommend the fitting
0:04:27 > 0:04:31of optical-type detectors in all but specific circumstances.
0:04:31 > 0:04:35That's because optical detectors are safer in detecting
0:04:35 > 0:04:36a broader range of fires.
0:04:36 > 0:04:40Either way, you're better off with an alarm than without,
0:04:40 > 0:04:43as you're four times as likely to die in a house fire
0:04:43 > 0:04:45if you don't have a smoke alarm.
0:04:45 > 0:04:48And to make sure they operate effectively, every model
0:04:48 > 0:04:52on the market has to be thoroughly tested before going on sale.
0:04:52 > 0:04:55Later in the programme, we'll be at the British Standards Institution,
0:04:55 > 0:04:57to find out how.
0:05:01 > 0:05:02Now, fitness trackers.
0:05:02 > 0:05:05They monitor your activity throughout the day
0:05:05 > 0:05:07and tell how many calories you burn.
0:05:07 > 0:05:11They're marketed as the smartest way to stay active.
0:05:11 > 0:05:12But just how accurate are they?
0:05:16 > 0:05:19Well, Sophie, if you're anything like me and can't afford your own
0:05:19 > 0:05:22personal trainer to keep on top of your exercise regime, you may
0:05:22 > 0:05:25want turn to one of these nifty little gadgets for help.
0:05:25 > 0:05:27Just ask this lot.
0:05:29 > 0:05:30I just tell it I'm going running,
0:05:30 > 0:05:34and it'll basically keep track of how far I've gone,
0:05:34 > 0:05:36the speed that I'm going,
0:05:36 > 0:05:39and then it gives me a breakdown of my run at the end of the run.
0:05:39 > 0:05:41If you're the sort of person that likes to keep on top
0:05:41 > 0:05:44of things, see your progress and so on,
0:05:44 > 0:05:47I think these devices are excellent.
0:05:47 > 0:05:50They're a fantastic motivation point. Track your calories
0:05:50 > 0:05:53every day and try and improve on it day after day, run after run.
0:05:53 > 0:05:57But just how reliable are these devices?
0:05:57 > 0:05:59To find out, we've come to Brunel University, where,
0:05:59 > 0:06:02with the help of Richard Godfrey - a lecturer in sports psychology,
0:06:02 > 0:06:05Tom - a triathlete...
0:06:05 > 0:06:07Hi, Tom. Nice to see you. I'm Richard.
0:06:07 > 0:06:09..and Chris - the lab technician,
0:06:09 > 0:06:12we're going to put two of their many claims to the test -
0:06:12 > 0:06:15calories burnt and the number of steps taken.
0:06:15 > 0:06:18Tom will be wearing three products chosen from the UK's
0:06:18 > 0:06:21leading on-line retailers -
0:06:21 > 0:06:25the cheapest we could find, the V-fit WSG pedometer,
0:06:25 > 0:06:26costing just over £6,
0:06:26 > 0:06:31a mid-range product, the Fitbit Zip, costing £49.99,
0:06:31 > 0:06:34wand the top-of-the-range Nike+ FuelBand
0:06:34 > 0:06:36which costs £129 -
0:06:36 > 0:06:39all of which claim to monitor both calories and steps.
0:06:44 > 0:06:45First up, calories.
0:06:45 > 0:06:49Chris inputs Tom's vital statistics into all three devices
0:06:49 > 0:06:52according to the manufacturers' instructions.
0:06:52 > 0:06:54Then it's time for the work-out.
0:06:55 > 0:06:58Three, two, one, go.
0:07:00 > 0:07:02He's first of all going to do ten minutes of walking
0:07:02 > 0:07:05at an easy pace, wearing the devices and having
0:07:05 > 0:07:08oxygen consumption measured at the same time.
0:07:08 > 0:07:10He'll then have a bit of a break before we get him to do
0:07:10 > 0:07:14another ten minutes, this time at a higher intensity, just a jog,
0:07:14 > 0:07:17slow jog, and then he'll have another break,
0:07:17 > 0:07:21after which we'll do another ten minutes, this time at a faster jog.
0:07:22 > 0:07:28As Tom exercises, his muscles use oxygen to burn fuel - or calories.
0:07:28 > 0:07:32The more oxygen consumed, the more calories burned.
0:07:32 > 0:07:34Therefore, by tracking Tom's oxygen consumption
0:07:34 > 0:07:38throughout his work-out, Richard will have a scientifically accurate
0:07:38 > 0:07:40measure of calorie expenditure.
0:07:40 > 0:07:43He can then compare that to what our three devices say.
0:07:43 > 0:07:49Five, four, three, two, one, stop.
0:07:49 > 0:07:50With the work-out complete
0:07:50 > 0:07:53and the calorie data captured from all three devices,
0:07:53 > 0:07:55it's on to the second part of the test...
0:07:55 > 0:07:57There we go. That's got to be better.
0:07:57 > 0:07:59..steps taken.
0:07:59 > 0:08:02For this, Tom moves onto another crucial bit of scientific kit -
0:08:02 > 0:08:04the fire escape.
0:08:05 > 0:08:08According to Government guidelines, it's recommended that you take
0:08:08 > 0:08:10around 10,000 steps in a normal day.
0:08:10 > 0:08:13That's roughly the equivalent of a five-mile walk.
0:08:14 > 0:08:18So having an accurate idea of how many you've taken is important.
0:08:20 > 0:08:24We know that it takes exactly 152 steps to go to the bottom
0:08:24 > 0:08:26and back to the top.
0:08:26 > 0:08:30What we don't know is how many steps our devices will think he's taken.
0:08:32 > 0:08:35So just to make sure we're accurate, we do the test twice.
0:08:38 > 0:08:39With the tests now complete,
0:08:39 > 0:08:42it's time for Richard to crunch the numbers.
0:08:42 > 0:08:45And we'll be bringing you the results later in the programme.
0:08:49 > 0:08:52Next, exploding oven doors -
0:08:52 > 0:08:56a sudden bang, with glass spraying out across the kitchen floor.
0:08:56 > 0:08:58It's enough to give anyone a fright.
0:08:58 > 0:09:03But why does this happen when oven doors are made from toughened glass?
0:09:03 > 0:09:04A question for Lynn Faulds Wood.
0:09:07 > 0:09:11ARCHIVE: 'Welcome to Watchdog. In tonight's programme...
0:09:11 > 0:09:14'All these people have written to us.'
0:09:20 > 0:09:24In the 1980s, oven doors made of glass were still a bit of a novelty.
0:09:24 > 0:09:27Now, you might not have noticed, but over the past few years,
0:09:27 > 0:09:30there's been a revolution in the way our cookers are designed.
0:09:30 > 0:09:34But by 1988, hundreds of Watchdog viewers were complaining
0:09:34 > 0:09:37that so-called toughened glass in their oven doors
0:09:37 > 0:09:39had shattered without warning.
0:09:42 > 0:09:46There was a tremendous crashing noise. I turned round to find
0:09:46 > 0:09:50that the front glass of the cooker had exploded out, and he was
0:09:50 > 0:09:55actually standing in all these small pieces of very hot glass.
0:09:55 > 0:09:58Imagine that happening in your kitchen.
0:09:58 > 0:10:01And we discovered it was down to the way the glass had been
0:10:01 > 0:10:02fitted into the oven door.
0:10:03 > 0:10:07We go to the bottom oven, the glass is held in with these clips and
0:10:07 > 0:10:11there's no seal underneath, so it's pressing metal on the glass on both
0:10:11 > 0:10:15sides. Finally, if I shut the door, I think you'll see the problem.
0:10:15 > 0:10:16LOUD SMACK
0:10:16 > 0:10:18That's not good enough -
0:10:18 > 0:10:21it's stressing an already badly fixed door.
0:10:21 > 0:10:25With criticism like that, no wonder manufacturers were persuaded
0:10:25 > 0:10:28to spend millions improving door seals, hinges
0:10:28 > 0:10:32and fittings to reduce the stress on the surface of the glass.
0:10:32 > 0:10:35Philips even asked me to fly to their Italian factory
0:10:35 > 0:10:38to see the changes they'd introduced.
0:10:38 > 0:10:42The slot here that the glass fits into, before it was just two metal
0:10:42 > 0:10:46pieces. Now it's a continuous metal piece all the way along. Much better.
0:10:47 > 0:10:51But what is it about toughened glass that makes it prone to shattering
0:10:51 > 0:10:55so spectacularly if fitted badly to the oven door?
0:10:56 > 0:11:00Toughened glass is used in all sorts of modern inventions,
0:11:00 > 0:11:03from patio doors to windows in your car,
0:11:03 > 0:11:07but its origins date all the way back to the 17th century.
0:11:09 > 0:11:14Prince Rupert of Bavaria came across the phenomenon by accident.
0:11:14 > 0:11:18He found dropping hot molten glass into cold water formed
0:11:18 > 0:11:20tadpole-shaped droplets.
0:11:20 > 0:11:22These "Rupert drops", as they became known,
0:11:22 > 0:11:24have remarkable properties.
0:11:24 > 0:11:28CLINK The fat end is surprisingly strong.
0:11:28 > 0:11:30As you can see, it has survived the impact.
0:11:30 > 0:11:32The thin end, however, shatters
0:11:32 > 0:11:34at the slightest touch.
0:11:36 > 0:11:40The drop has disappeared. It has completely shattered.
0:11:40 > 0:11:44Why? When the hot glass is plunged into the cold water,
0:11:44 > 0:11:46the outside hardens really quickly.
0:11:46 > 0:11:50The glass on the inside, though, cools much more slowly, and like
0:11:50 > 0:11:55a coiled spring, it pushes against the already hardened outside layer.
0:11:55 > 0:11:58It's this tension between the inner glass pushing out against
0:11:58 > 0:12:03the already hardened outside surface that makes the droplet so strong.
0:12:03 > 0:12:06But if you damage that outside surface,
0:12:06 > 0:12:08the inner tension is released,
0:12:08 > 0:12:12and the droplet explodes into tiny, harmless fragments.
0:12:12 > 0:12:17And that's exactly the principles on which toughened glass is based.
0:12:17 > 0:12:20The glass is taken up to about 700 degrees
0:12:20 > 0:12:22and cooled very quickly with air jets.
0:12:22 > 0:12:25This has the same effect, where you get compressive layers
0:12:25 > 0:12:28under the surface and tension in the centre.
0:12:28 > 0:12:32At any point, if any scratch goes into that compressive layer,
0:12:32 > 0:12:34the glass will break.
0:12:37 > 0:12:41But it was its ability to be both strong and also break into harmless
0:12:41 > 0:12:45fragments that caught the attention of the car industry.
0:12:48 > 0:12:50This is what can happen with a windscreen
0:12:50 > 0:12:53made of toughened safety glass.
0:12:54 > 0:12:57As more cars came onto the roads in the '20s and '30s,
0:12:57 > 0:13:00the numbers of accidents increased,
0:13:00 > 0:13:03and with many injuries being caused by the windows breaking
0:13:03 > 0:13:07into razor sharp pieces, toughened glass seemed the perfect solution.
0:13:08 > 0:13:11The first British Standard for this glass in cars
0:13:11 > 0:13:13was introduced in 1939.
0:13:13 > 0:13:19Demand increased in the 1960s, as regulations were introduced actually requiring it
0:13:19 > 0:13:24to be used in cars and in certain windows in buildings.
0:13:29 > 0:13:33Today, wherever it's used, to meet current European standards,
0:13:33 > 0:13:35toughened glass needs to be strong enough
0:13:35 > 0:13:39to withstand the force of anything that might be thrown at it,
0:13:39 > 0:13:41and when I say anything...
0:13:41 > 0:13:42One, two...
0:13:49 > 0:13:52The weight of it, being 50kg,
0:13:52 > 0:13:55is very similar to a child running into a window, so it will
0:13:55 > 0:13:59demonstrate that that window or that patio door can survive that impact.
0:14:00 > 0:14:03But again, despite its vast strength,
0:14:03 > 0:14:07compromise that outer layer with a couple of scratches
0:14:07 > 0:14:11and it becomes extremely vulnerable
0:14:11 > 0:14:15and collapses into those harmless little cubes or dice.
0:14:15 > 0:14:19So looking back to those poorly designed oven doors,
0:14:19 > 0:14:22those exposed metal rims and clips that were
0:14:22 > 0:14:26pressing on the toughened glass were in fact compromising
0:14:26 > 0:14:30the surface in the same way as that scratch.
0:14:30 > 0:14:31And the result?
0:14:33 > 0:14:36Although the design of oven doors has much improved,
0:14:36 > 0:14:39toughened glass will always have the potential to become
0:14:39 > 0:14:43'compromised. But whether it's been scratched or chipped during
0:14:43 > 0:14:46'manufacture, or even as a result of aggressive cleaning...'
0:14:46 > 0:14:49At least you know with toughened glass
0:14:49 > 0:14:53that if it does shatter, it won't go into long, sharp shards
0:14:53 > 0:14:57but rather into something safer like this.
0:15:02 > 0:15:05If you're thinking about buying a car, there's certainly
0:15:05 > 0:15:07an awful lot to choose from,
0:15:07 > 0:15:12so where do you start, and is it ever good value to buy a new one?
0:15:12 > 0:15:15Well, Emma Butcher from What Car? is with us now. Is it?
0:15:15 > 0:15:18Well, surprisingly, sometimes it can, yes.
0:15:18 > 0:15:21Most people would think that buying new didn't represent good value
0:15:21 > 0:15:23at all over buying used, because, of course,
0:15:23 > 0:15:26when you drive away from the forecourts you get that massive
0:15:26 > 0:15:30hit of depreciation that can be up to 20% of the cost of the car.
0:15:30 > 0:15:34However, there are some amazing discounts out there at the moment,
0:15:34 > 0:15:36because manufacturers and car dealers,
0:15:36 > 0:15:38they really want you to buy a new car,
0:15:38 > 0:15:42and they're incentivising that, so that can be anything from a finance
0:15:42 > 0:15:47package with ultra-low interest rates, sometimes even 0% interest,
0:15:47 > 0:15:51to throwing in some free insurance or free servicing.
0:15:51 > 0:15:54So, potentially, you could be getting a better deal on a new car.
0:15:54 > 0:15:57What about the claims that car manufacturers make?
0:15:57 > 0:15:59Is it easy to compare them?
0:15:59 > 0:16:01Well, it's a bit of a lottery. You would think that you could
0:16:01 > 0:16:04benchmark them, but our research has found no,
0:16:04 > 0:16:05so those MPG figures that you see
0:16:05 > 0:16:09advertised basically come from Government-mandated laboratory tests
0:16:09 > 0:16:14which every car-maker must put its car through before they go on sale,
0:16:14 > 0:16:18but because they're conducted in a lab, that doesn't really reflect
0:16:18 > 0:16:20what happens when you're out in real traffic conditions.
0:16:20 > 0:16:24At What Car? we've tested about 400 different engines now,
0:16:24 > 0:16:27and we take cars out on the road, in real traffic,
0:16:27 > 0:16:31and work out their true MPG based on their tailpipe emissions,
0:16:31 > 0:16:33and we found that on average there can be
0:16:33 > 0:16:37a 17% shortfall from what is actually claimed that a car can do
0:16:37 > 0:16:39to what it actually achieves in real life.
0:16:39 > 0:16:42So when you're buying a new car, what should you look out for?
0:16:42 > 0:16:45First of all, make sure that you take the car out for a test drive.
0:16:45 > 0:16:46Don't ever buy without doing that.
0:16:46 > 0:16:49It's a really good idea to take someone with you who can
0:16:49 > 0:16:52distract the sales person so you can concentrate on the drive,
0:16:52 > 0:16:54and, similarly, you might want to leave the kids at home
0:16:54 > 0:16:57if you think they'll distract you as well, although do take
0:16:57 > 0:17:01along the buggies and the car seats to see what kind of a fit they make.
0:17:01 > 0:17:03- Emma, good advice. Thank you very much.- Thank you.
0:17:07 > 0:17:11Earlier, we put three fitness trackers through their paces.
0:17:11 > 0:17:15From the cheapest to the most expensive, they all claimed
0:17:15 > 0:17:19to count the number of calories burnt and the number of steps taken.
0:17:19 > 0:17:21So how did they perform? Let's find out.
0:17:25 > 0:17:27First up, counting steps.
0:17:27 > 0:17:30We asked triathlete Tom to climb up and down
0:17:30 > 0:17:32this 152-step fire escape twice.
0:17:34 > 0:17:37The actual number of steps is 304,
0:17:37 > 0:17:39but how many did our devices record?
0:17:41 > 0:17:46Starting with our most expensive product, the Nike+ FuelBand,
0:17:46 > 0:17:47costing £129.
0:17:47 > 0:17:51It didn't do quite so well, counting 281 steps -
0:17:51 > 0:17:5223 under the actual number.
0:17:52 > 0:17:55Quite surprising for a device as expensive as it is.
0:17:55 > 0:18:00The Fitbit Zip, our mid-range product, costing £49.99,
0:18:00 > 0:18:03did much better - it was only out by two steps.
0:18:05 > 0:18:10As for our cheapest product, at just over £6, the V-fit WSG pedometer...
0:18:10 > 0:18:13In terms of counting steps, the pedometer did really well indeed.
0:18:13 > 0:18:17304 steps were taken and it counted 305,
0:18:17 > 0:18:19so that's really good for a relatively cheap device.
0:18:19 > 0:18:23Yes, our cheapest device actually performed the best.
0:18:23 > 0:18:27It miscounted by just one step over the course of the two tests.
0:18:27 > 0:18:29The pedometer's quite a simple device
0:18:29 > 0:18:33and it's therefore best at measuring simple linear movement,
0:18:33 > 0:18:36so simply counting steps is what it does very well.
0:18:36 > 0:18:39So if it's just counting steps you're looking for,
0:18:39 > 0:18:42a cheaper product may well be perfectly adequate.
0:18:44 > 0:18:47But how good were the devices at measuring calorie-burn?
0:18:47 > 0:18:50Now, remember, during his work-out Richard asked Tom to walk,
0:18:50 > 0:18:53jog and run. He monitored Tom's oxygen consumption
0:18:53 > 0:18:56throughout as a measure of fuel consumption
0:18:56 > 0:18:58and therefore a more accurate record of calorie-burn.
0:18:59 > 0:19:02He then compared that to what the three devices said.
0:19:02 > 0:19:04Three, two, one, stop.
0:19:06 > 0:19:09In terms of estimated calorie expenditure,
0:19:09 > 0:19:12the Nike+ FuelBand, the most expensive device, did the best.
0:19:12 > 0:19:16With our laboratory-based kit, we measured 248 calories.
0:19:16 > 0:19:20The Nike FuelBand measured 310, so 62 more, which is actually very good
0:19:20 > 0:19:22for a device of that type.
0:19:22 > 0:19:27Our cheapest product, the V-fit WSG pedometer, struggled.
0:19:27 > 0:19:31Whilst our laboratory based kit measured 248 calories, the V-fit
0:19:31 > 0:19:35only measured 125 - a difference of 123 calories.
0:19:37 > 0:19:41But it was the mid-range product, the Fitbit Zip, that performed the worst.
0:19:43 > 0:19:48It measured 432 - an overestimation of 184 calories.
0:19:52 > 0:19:54None of the devices was completely accurate.
0:19:54 > 0:19:56However, the Fitbit Zip was the worst one,
0:19:56 > 0:19:58overestimating by almost half a chocolate bar.
0:19:58 > 0:20:01So if you used that device, you'd actually think you'd expended
0:20:01 > 0:20:03a lot more energy than you really had.
0:20:05 > 0:20:09But according to Richard, it might not be all bad news.
0:20:09 > 0:20:12Well, measuring calories is very useful, but being consistent
0:20:12 > 0:20:15is also important, and the device has to measure consistently.
0:20:15 > 0:20:18So you have to know that it's you that's improved in any change
0:20:18 > 0:20:20that you see, and not some quirk of the device.
0:20:22 > 0:20:25So, time for one final test - consistency.
0:20:25 > 0:20:28We had Tom repeat the work-out to see if the devices gave
0:20:28 > 0:20:31the same measurements for calorie-burn the second time around.
0:20:32 > 0:20:37First up, our cheapest product, the V-fit WSG pedometer.
0:20:37 > 0:20:39Although again it wasn't very accurate,
0:20:39 > 0:20:42it was at least consistent, as it gave an almost identical
0:20:42 > 0:20:44incorrect calorie reading on our second test.
0:20:45 > 0:20:48Next, our mid-range product, the Fitbit.
0:20:48 > 0:20:50Not only was it the least accurate
0:20:50 > 0:20:53when counting calories, it was also the least consistent.
0:20:53 > 0:20:55For both those work-outs, you'd expect to see
0:20:55 > 0:20:58the same results - you want to see reproducibility.
0:20:58 > 0:21:00That didn't happen. There was a big, big difference,
0:21:00 > 0:21:02which means it's not a particularly reliable device
0:21:02 > 0:21:05and it doesn't assess performance particularly well.
0:21:05 > 0:21:09As for the Nike+ FuelBand, our most expensive product, not only was it
0:21:09 > 0:21:13the most accurate, it was also the most consistent -
0:21:13 > 0:21:14at least in our test.
0:21:14 > 0:21:17The Nike FuelBand did much better. It showed greater consistency,
0:21:17 > 0:21:19and that's exactly what we want in devices of this type.
0:21:19 > 0:21:21That's the name of the game.
0:21:21 > 0:21:23Fitbit told us they are surprised
0:21:23 > 0:21:26and disappointed with the results of our test, which they say
0:21:26 > 0:21:29do not represent the normal experience of their customers.
0:21:29 > 0:21:33They say the tracker has undergone thousands of scientific tests,
0:21:33 > 0:21:36should be at least 95% accurate,
0:21:36 > 0:21:40and they do everything to ensure customer experience is positive.
0:21:40 > 0:21:42But whatever the device you choose to wear,
0:21:42 > 0:21:45according to Richard, there is at least one benefit they all share.
0:21:45 > 0:21:47With these devices, they're incredibly motivating.
0:21:47 > 0:21:51You can upload information, you can share it with family and friends,
0:21:51 > 0:21:52you can introduce elements of competition -
0:21:52 > 0:21:56all of this means these devices are motivating.
0:21:56 > 0:21:59So maybe these little devices CAN be your own personal trainer -
0:21:59 > 0:22:02just as long as you're not always expecting a precision calorie-count
0:22:02 > 0:22:03along the way.
0:22:08 > 0:22:10Back to smoke alarms now.
0:22:10 > 0:22:14You're four times more likely to die in a house fire
0:22:14 > 0:22:16if there is no working smoke alarm.
0:22:16 > 0:22:20So what do manufacturers do to try to ensure they're fail-safe?
0:22:20 > 0:22:22Test them, of course.
0:22:22 > 0:22:26The British Standards Institution in Hemel Hempstead.
0:22:26 > 0:22:30Here they don't just test products - they help write the rule book,
0:22:30 > 0:22:31known as the Standards.
0:22:31 > 0:22:34BSI was established in 1901.
0:22:34 > 0:22:37At the time, it was the world's first national standards body,
0:22:37 > 0:22:41and remains today the UK national standards body.
0:22:41 > 0:22:43For a smoke alarm to meet current safety standards,
0:22:43 > 0:22:46it has to pass more than 40 tests.
0:22:47 > 0:22:50It's critical that these products do actually
0:22:50 > 0:22:52perform the function that they're designed for.
0:22:52 > 0:22:55The last thing you want is to have a smoke alarm fitted
0:22:55 > 0:22:58in your house which doesn't go off in the event of a fire.
0:22:58 > 0:23:01Today we're going to be demonstrating some of those tests,
0:23:01 > 0:23:04using a mid-range smoke alarm currently on the market
0:23:04 > 0:23:06for about £20.
0:23:06 > 0:23:09We're starting with the most important piece of machinery -
0:23:09 > 0:23:10the smoke tunnel.
0:23:11 > 0:23:15We used to actually create real smoke for the tunnel,
0:23:15 > 0:23:17using this heated bar, here.
0:23:17 > 0:23:19Now we use atomised liquid paraffin.
0:23:19 > 0:23:24It's a much more controllable way of producing simulated smoke.
0:23:24 > 0:23:26So, in goes the alarm,
0:23:26 > 0:23:30then the smoke is blown gently around the tunnel,
0:23:30 > 0:23:32not that you'll be able to see it.
0:23:32 > 0:23:33It's very, very small quantities.
0:23:33 > 0:23:36So we're talking literally parts of a million, here.
0:23:36 > 0:23:39So when the smoke alarms are actually triggered, you wouldn't
0:23:39 > 0:23:43be able to see with the human eye the smoke in the atmosphere.
0:23:43 > 0:23:46The thickness of the smoke is gradually increased in order
0:23:46 > 0:23:50to measure exactly how much is needed to set the alarm off.
0:23:50 > 0:23:53ALARM BLEEPS
0:23:53 > 0:23:56What we're looking for here is to make sure it doesn't go off
0:23:56 > 0:23:58at too sensitive a level, otherwise, obviously, it would
0:23:58 > 0:24:02be going off at all hours of the night, and giving false readings.
0:24:02 > 0:24:07Effectively, it has to trigger at a higher point than 0.2dB per metres,
0:24:07 > 0:24:11and it triggered at 0.87, which is technically a pass.
0:24:11 > 0:24:14What we have to do now is take five more measurements,
0:24:14 > 0:24:16and then we'll assess the results to ensure
0:24:16 > 0:24:20the ratio between the highest and lowest trigger point isn't too wide.
0:24:20 > 0:24:24Effectively, what we're looking for here is to ensure that the product,
0:24:24 > 0:24:25once it's operated once,
0:24:25 > 0:24:29will operate again in the future at the same levels.
0:24:29 > 0:24:32Checking the consistency of the alarm in this way
0:24:32 > 0:24:34is called repeatability.
0:24:34 > 0:24:37Next, they need to find out whether it has any weak spots.
0:24:37 > 0:24:40This box is the ionisation chamber,
0:24:40 > 0:24:43so this is the actual detector of the smoke.
0:24:43 > 0:24:46We want to ensure that regardless of where the smoke's coming in,
0:24:46 > 0:24:49it will reach that chamber and the alarm will trigger.
0:24:49 > 0:24:52And you can see that if the smoke enters at this point, it has
0:24:52 > 0:24:55a lot of electronic components that it has to negotiate before it
0:24:55 > 0:24:58will actually reach that chamber and detect smoke.
0:24:58 > 0:25:01We'll put the product back into the smoke tunnel,
0:25:01 > 0:25:04and we'll turn it round at 45 degree angles.
0:25:04 > 0:25:08Once we've identified the worst point of access for the smoke,
0:25:08 > 0:25:12we'll carry out the rest of the tests in that particular orientation
0:25:12 > 0:25:14to ensure it's the worst-case scenario.
0:25:14 > 0:25:17Once you know that an individual alarm works,
0:25:17 > 0:25:21and in all positions, you need to be sure each one manufactured
0:25:21 > 0:25:23is roughly the same. The way to do that?
0:25:23 > 0:25:27Test another 20. And if they're sufficiently consistent,
0:25:27 > 0:25:30it's time for extreme conditions.
0:25:30 > 0:25:34What we're doing now is adjusting the temperature of the smoke tunnel.
0:25:34 > 0:25:36We're going to do two tests in here.
0:25:36 > 0:25:38We'll do a cold operational test at nought degrees C,
0:25:38 > 0:25:43and a dry heat test at 55 degrees C.
0:25:43 > 0:25:45If you have a product which is installed in a house and it's
0:25:45 > 0:25:49a particularly cold night, we want to make sure that it will activate
0:25:49 > 0:25:52when it's supposed to as well as it would do on a very hot, sunny day.
0:25:52 > 0:25:55So once you know the alarm can sniff out smoke in all manner
0:25:55 > 0:25:58of conditions, attention turns to sound.
0:25:58 > 0:26:02And for that you'll need some peace and quiet.
0:26:04 > 0:26:06This is one of our special test chambers.
0:26:06 > 0:26:08It's called an anechoic chamber.
0:26:08 > 0:26:12We're using it to measure the volume of the smoke alarm in this case,
0:26:12 > 0:26:14and what we don't want to do is to have the sound
0:26:14 > 0:26:17bouncing off the walls back to our measuring equipment.
0:26:17 > 0:26:21We only want to hear it once, as it comes out of the actual alarm itself.
0:26:21 > 0:26:23You can see the construction of the room here.
0:26:23 > 0:26:26It's covered with these special foam cones,
0:26:26 > 0:26:29which are designed to trap and absorb the sound.
0:26:29 > 0:26:31It's a very strange feeling with the door shut,
0:26:31 > 0:26:33because you literally can't hear anything.
0:26:33 > 0:26:35You can hear the pulse of your blood in your ears,
0:26:35 > 0:26:39and when you talk it sounds as though you're actually talking in your head,
0:26:39 > 0:26:41because there's literally no echo at all.
0:26:41 > 0:26:43HEARTBEAT
0:26:43 > 0:26:46The perfect environment for accurately measuring noise.
0:26:48 > 0:26:51ALARM BLEEPS
0:26:51 > 0:26:55What we're looking for is a sound level in excess of 85 decibels
0:26:55 > 0:26:58when measured at three metres from the alarm point.
0:26:58 > 0:27:00What we can't do is exceed 110 decibels.
0:27:00 > 0:27:04Basically, those parameters are set so that the alarm is loud enough
0:27:04 > 0:27:06to be heard when it needs to be, but not so loud
0:27:06 > 0:27:08that it becomes debilitating.
0:27:08 > 0:27:13So, your smoke alarm detects smoke and makes the right amount of noise.
0:27:13 > 0:27:15One last thing - is it robust?
0:27:15 > 0:27:19Yes, that's our alarm being hit with a hammer.
0:27:19 > 0:27:22What we're trying to do here is to replicate the kind of impact that
0:27:22 > 0:27:25it might realistically experience during the course of its lifetime -
0:27:25 > 0:27:29from the point of manufacture, transportation, installation.
0:27:29 > 0:27:32You might drop it on the floor... All these things we take into
0:27:32 > 0:27:35consideration, and we're trying to replicate the worst kind of impact
0:27:35 > 0:27:37that it's likely to experience.
0:27:37 > 0:27:42A single blow measuring 1.6 joules, to be precise.
0:27:42 > 0:27:46And if it survives, you can always try shaking it to bits.
0:27:46 > 0:27:49What we're doing is subjecting it to different
0:27:49 > 0:27:51cycles of vibration in three different axes.
0:27:51 > 0:27:54So forward and backwards, side to side, and up and down.
0:27:54 > 0:27:57At the end of the vibration test, we'll do a visual inspection.
0:27:57 > 0:27:59We need to make sure that the cover is still attached,
0:27:59 > 0:28:02that the electronic components are still firmly fixed to the board.
0:28:02 > 0:28:05And then what we'll do is put it back together,
0:28:05 > 0:28:08put it into the smoke tunnel, and subject it to the same smoke tests
0:28:08 > 0:28:10that we did previously, to make sure that it still activates
0:28:10 > 0:28:13in accordance with the manufacturer's specification.
0:28:17 > 0:28:20If you want more information on the safety of products in your home,
0:28:20 > 0:28:25you can go to our website:
0:28:28 > 0:28:30That's all for today. Thanks for watching.