29 Aug 2014

On Scottish Independence

In a few days time, Scotland will vote on whether to remain part of the United Kingdom. As an Englishman, albeit with a Scottish father, I don't feel very strongly about it but I do find myself unhappy about the prospect of the UK being dismembered bit by bit. A country consisting of England, Wales and N Ireland seems pretty illogical and somehow threadbare. I'd much rather we did it properly and all split up into separate nations, than have this hotch-potch of territories that would exist post-independence.

But there is another more troubling question posed and that is "What is a nation anyway?" I never asked to be English or British, I was just born here and I have to accept my fate whether I like it or not. Even if I emigrate someplace else, I will remain English because I have spent most of my life here. But it's not something I chose. I didn't get a vote about it: it's not something you could realistically vote on.

But when Scotland casts its vote on September 18th, its people will have an almost existential choice to make, the nearest they will ever get to voting on identity.  What sort of country do they want to live in? Do they want to be primarily Scottish? Or British? Or even European (though this isn't a question being asked)? And what are these seemingly abstract concepts of statehood anyway?

I've no doubt Scotland would make it as an independent country — there's no reason why it couldn't — but would it be better or worse off? No one has any idea. And is it, in any event, even about being better off, at least in an economic sense? These concepts are so nebulous that I find them quite unsettling.

At the heart of the matter is the fact that the United Kingdom is and always has been a mini-empire. Unlike the USA (or even Europe, bless it), it has never been a collection of equals. Rather it's been one big bully (England pop 60m) and three little Celtic statelets (combined pop just 10m). England and in particular London has been imposing its will on the UK ever since the UK existed and in some ways it's a wonder that is has survived so long in the format it has now. The Irish forced their way out nearly a hundred years ago. Why has it taken the Scots so long to do the same? And why are the Welsh so mealy-mouthed about independence as well? I bet if Scotland goes, Wales will follow them within ten years. Where that would leave N Ireland? In a mess. But then it's been in a mess for a long time. The Protestants would have to eat humble pie and troop off to Dublin, hopefully not literally, for political representation. Ouch.

What's interesting is to hear David Cameron speaking up for the current union using classic Tory mercantilist rhetoric. The arguments he makes could equally well be used to keep the UK in the EU: easier trading, access to bigger markets, common currency (well we could have had it if we had wished for it). But whilst England doesn't like the thought of losing some of its muscle by waving goodbye to little Scotland, it's much less keen on sharing what it has with states like France and Germany who have similar power and status. I sense playground politics at work here: there is something quite primeval about it all.

I'm beginning to sound like a rabid pro-independence campaigner here, but the reality is rather different. The problem is that in a perfect world we would probably all be both independent and conjoined at a national and international level. But we are not in a perfect world and having independence votes like these unleashes the dark powers of nationalism and resentment. Just by asking the question, we are letting that nasty little genie out of the bag. Whatever the outcome, the political landscape has already moved just a little further away from tolerance and interdependence, towards narrow parochialism and mistrust. Not things we need in the 21st century.

And if Scotland votes for independence, doesn't it call into question the legitimacy of many other so-called nations? Will it herald a century of territorial Balkanisation around the world? Do we need it? Aren't there enough global problems without everyone using up energy trying to determine which country they want to live in? I fear it's a small step from genteel Edinburgh to violent Donetsk.

28 Aug 2014

Six Questions on Heat You Never Thought To Ask

Q1 What is heat?

Heat is a by-product of ‘work’ going on or, if you like, energy being spent. Heat is most commonly found where one substance is in the process of breaking down into its constituent parts. Our bodies (like our houses) leak heat and this leaked heat must be replaced, which we do by eating. Calories are just another measurement of energy. The colder it is outside our bodies and our houses, the more heat we leak and the more energy we have to take on board.

Q2 What is ‘Feeling warm?’

The rate at which we lose heat determines how hot or cold we feel. ‘Feeling cold’ is a signal that we are losing high and potentially dangerous amounts of heat; ‘feeling warm’ signals that all is OK.

Q3 What determines how warm we feel?

The insulating capability (U value) of our clothes (or duvets, or houses)
The temperature of the surrounding air
Wind speed (wind chill factor)
 Level of water vapour around
Whether our skin is wet or dry
How much heat is being ‘given off’ (radiated) by surrounding objects (including the sun).

When assessing heating systems, we use air temperature as the man indicator of background comfort but it is important to be aware that air temperature is just one of several factors at play. Anyone who has ever had a thermostatic control dial in their home will be well aware that what’s warm on a dry day can be 2° or 3°C too cold on a wet or a windy day.

Q4 How does Heat Move?
Heat transfers via three different methods: conduction, convection and radiation. Conduction is the passage of heat through a solid – the classic example is the poker placed in the open fire that soon gets too hot to hold. Convection is what happens to heat when it transfers into a gas (typically air) – it rises. Radiant heat is the glow you feel on your face when you are standing near a bonfire; the air temperature may be minus 10°C but you feel as warm as toast. We don’t often feel conducted heat but most heating systems deliver a mixture of the other two, convection and radiation.

Convected heat (or warm air) is characterised by being very responsive – i.e. you feel warm very quickly – but it can also be rather unpleasant, drying the throat and watering the eyes – think of the fan heaters in cars. In contrast, radiant heat you hardly notice. We experience it from things like underfloor heating systems, night storage radiators and Agas. Despite their name, radiators deliver a mix of all three forms of heat. The air convects through them, they are hot to touch (conduction) and you are aware of their warmth if you sit nearby (radiation). All heating systems deliver heat by all three methods but the mix varies according to the delivery system.

Q5 So what’s the perfect heating system?
I haven’t really been much help here, have I? You just need to understand that you must make a series of compromises and your aim is to make the least bad compromise.

Q6 Watts it all about?
Finally a word about how we measure power output, because I know people find it confusing, not least because there are different systems of measurement in operation. Here I try to plump for one, the watt (W), and its big brother the kilowatt (kW) which is 1,000 watts. These are measurements of power, rather than energy used. If you want to a measurement of energy used, you need to express it as so much power per hour, which we routinely call kilowatt hour or kWh.

Why the capital W in the middle of kWh? It's a strange convention to do with the watt being a unit attributed to James Watt, inventor of the steam engine. We seem to routinely refer to watts or kilowatts with a lower case w, but when it's written shorthand it becomes kWh.

To make it even more complex, there are other units used for energy measurements and one you frequently come across is the British Thermal Unit or BTU which, as you might guess is an imperial unit. The Americans still use it. What many people (myself included until recently) don't realise is that the BTU is a measurement of energy rather than power so its the equivalent of a kWh. If you want to know the power output of a boiler, you need to divide by hours. Thus:

1W = 3.41 BTU/h            1kW = 3,410 BTU/h

Let's finish with a table

1 litre
1 litre
1 litre
1 litre
1 kg

14 Aug 2014

Be wary of using Registered Contractors

A reader has alerted me to a thorny problem that crops up when manufacturers insist on you using their own list of registered contractors to install their products. It's a practice that has crept into the up-market housebuiding sector over the past few years and, contractually, there are pitfalls awaiting us here.

Why would a manufacture care about who uses their products? It's clearly to do with maintaining a reputation for quality. However good a product may be, if the people installing it are useless, the product's reputation will go down the plughole. Hence it's quite logical for a business that sells itself on quality to insist that you use contractors familiar with their systems and products. So far so good.

But what happens when a job with a registered contractor goes wrong? This has happened to my reader who has had a disastrous experience with an external rendering job on her selfbuild. She (and her architect) think that the responsibility for repairing the defective job lies with the manufacturer who was the one that insisted that she use one of its registered contractors. But the company in question disagrees and thinks that the fault lies with the contractor who, unsurprisingly, has now walked off the job and refuses to have anything to do with either the manufacturer or the selfbuilder.

The manufacturer has a contract in place which expressly shifts liability for errors and omissions onto the contractor. They say they cannot be held responsible for what happens on site: they are materials suppliers, not contractors, and their responsibility ends with the supply of goods.

But, if this really is the case, why do they insist on their end-users, their clients, having to work with their registered contractors? Why not let every Tom, Dick or Harry have a go? If the products are as good as they are cracked up to be, then there must be very few jobs which cause problems and it must make sense for the manufacturer to pay for the repairs, if only to keep their reputation sweet.

I don't want to name names at the moment because there is every chance that there will be a positive resolution to this particular case and I have no wish to cause any reputational damage to a well-regarded external render company.  But it's a contractual trap that we should all be aware of. Just because you choose from a list of registered contractors doesn't mean that the liability for mistakes transfers from the contractor to the supplier and, if relationships break down, don't expect the materials supplier to ride in to the rescue.

5 Aug 2014

How good does a Damp Proof Membrane have to be?

A reader asks how to detail a damp proof membrane (DPM) on a solid floor where there is a service penetration. The clever-dick answer is that you should avoid service penetrations through ground floor slabs but, in reality, that's rarely possible. The question is then do you go for the full gas-barrier treatment with proprietary fixtures and fittings like Top Hats, as shown on the Visqueen website, or do you do something more rudimentary with sticky tape and plastic bags? Or maybe even just cut a hole?

Interestingly the building regs guidance (Part C in England) is silent on the matter. Neither do the NHBC's technical standards have anything to say about it. They both indicate that a DPM must be installed and that overlapping sheets should be taped together, but the fiddly issues like corner details and service penetrations are ignored.

What should we make of this? That DPM's don't really matter very much? Or that they matter but that you don't have to go overboard on the detailing? They are not gas barriers and therefore there is no danger should they not work perfectly? I'd be interested to hear how others treat their DPMs.