Barrels of oil

The media always report statistics of oil production, reserves etc in “barrels”. But how many people know how big a “barrel” is?* Indeed is it an appropriate unit of measurement to use in the context of world energy policy?

The oil industry used to be dominated by American companies, and as with aviation and computers, American units have largely been adopted as the industry standard.

This might not matter since the only people who trade in oil are industry insiders, and arguably the general public do not need to know how big a “barrel” is. They will understand that if OPEC reduces output by x million barrels per day, that’s a lot of oil, and price rises can therefore be expected. In any case, outside the USA, they will still buy the end product in litres.

Yet although it is not a consumer protection issue, there is a problem. Any departure from the International System of Units should be discouraged, as it results in dual labelling, conversion errors, the need to know two systems when one will suffice – and of course general incomprehension.
More particularly, the “barrel of oil equivalent” is used as a
measure of global energy production and consumption. For this, all energy sources (m3 of gas, tonnes of coal, etc.) are converted by energy content into the equivalent energy available in a barrel of crude oil.

BP produces an annual report of world energy consumption and has just produced this year’s. See
I notice that they are now using the tonne of oil equivalent alongside, or sometimes in place of the barrel. Whilst this is clearly an improvement, it doesn’t really give you what you’re looking for. If you’re talking about world energy consumption, rather than just oil, then surely joules (or gigajoules – GJ) are the unit they should be working with? I can see some logic in using a quantity of oil to measure reserves, and refinery throughput, but if you’re comparing nuclear and gas, for example, what has oil got to do with it? The joule only gets a mention in the conversion tables – 1 tonne oil equivalent ~= 42 GJ.

*A “barrel” is 42 US gallons (equivalent to approximately 159 litres)

A new definition of the kilogram?

A new method of defining the kilogram is being sought by various teams of scientists around the world. However, it may be some years before a decision emerges. (NB – this will obviously not alter the actual size of the kilogram). This article, contributed by Martin Vlietstra, will be of interest to the more technically minded.

The kilogram is an anomaly in the world of physical constants – its current definition relies on a particular artefact or object – the prototype kilogram that is held by the BIPM on behalf of its “shareholders”, its subscriber governments. Every other physical constant is defined in terms of one or other physical phenomena that can, in principle, be measured in any laboratory in the world. Ever since the retirement of the prototype metre in 1960, scientists have been looking for a means of defining the kilogram by means of a scientific experiment and yet maintaining the accuracy that can be obtained using the prototype kilogram

One of the projects to redefine the kilogram is to define it in terms of a sphere of silicon. Such spheres are currently being produced in the laboratories of the Australian Council for Scientific and Industrial Research (ACSIR) – See

Once the sphere has been manufactured, there are a number of problems associated with defining the kilogram. Firstly, the diameter of the sphere must known to an accuracy of better that one part in 10^8. If the sphere has a mass of exactly one kilogram, its radius will be approximately 93.58 mm, so its diameter needs to be known to better than 1 nm (which is approximately two wavelengths of light). Details of some of the scientific techniques used and the participating laboratories (Australian, Belgian, British and German [in alphabetic order]) can be found at

In addition to measuring the diameter, the scientists concerned will need to identify which is the more practical – to define the kilogram in terms a specific number of silicon atoms or to define it in terms of the mass of a sphere of specified radius. Part of the experiments currently under way is to decide which of the two techniques give the better results.

This is not the only experiment that is being developed to redefine the kilogram; another is the Watt Balance which is being carried out by the BIPM. (See ).

Who will decide which experiment is the better? This will ultimately be decided by the CGPM on the advice of the CIPM and is likely to be some years off.

CGPM = Conférence Générale des Poids et Mesures / General Conference on Weights and Measures, a body consisting of representative of the governments that have subscribed to the Convention of the Metre.

CIPM = Comité International des Poids et Mesures /International Committee of Weights and Measures, a body of 18 eminent scientists elected by the CGPM.

“Office rents per sq ft not legal” – says LACORS

Metric Views has received confirmation – from an impeccable authority – of what it has long suspected: that the widespread practice of pricing and advertising office rents “per square foot” is illegal under UK law.

The full story, which has only recently come to light, seems to be as follows. Upon receipt of a complaint from a member of the public about giving business grants “per square foot”, a northern local authority Trading Standards Department initially responded that “services” are not covered by the Price Marking Order (PMO), and as this grant was considered to be a “service”, pricing “per square foot” was legal. It appears that this interpretation was frequently given by other Councils, and it was even supported by Consumer Direct, a national online helpline.

However, this interpretation was challenged by the member of the public, and LACORS (the Local Authority Co-ordinating body for Regulation) was asked to look again at the issue. In August 2004 they issued new guidance which reversed their previous opinion. Specifically, they rejected the previously quoted view that the PMO only applies to the pricing of goods for sale, and that prices “per sq ft” for or a fixed area are legal because they are merely for ‘guidance’.

The opinion is reproduced in full below, but briefly it confirms that Section 8 of the Weights and Measures Act 1985 prohibits the use of imperial units “for trade” (as they are not included in the list of permitted units in the relevant Schedule to the Act). Moreover, “use for trade” includes any “transaction involving the rendering of money, where the transaction is by reference to quantity.” The opinion goes on to argue that, since office space, boat moorings, allotments etc must be priced per metre or square metre, it would be obviously sensible for them to be advertised inthe same way.

Trading Standards Departments which hitherto have relied on the earlier interpretation will now have to review their policy, and we can look forward to the gradual disappearance of imperial pricing of shop and office rents, storage space, allotments etc as Trading Standards Departments advise estate agents of the correct legal position.

The full text of the LACORS advice is given below. We have emboldened some of the more significant passages:



Advice on the use of imperial units

(Specifically, transactions (sale, rental, lease, grants) relating to floor
space, areas of land, length of boat moorings, length of archiving space,

LACORS has received a number of enquiries regarding the use of imperial
units relating to transactions such as:

Sales, rental or lease of floor space (commercial or domestic
property) by reference to floor area
Rental of boat moorings by reference to length
Lease of archiving space by reference to length
Award of development grants by reference to floor area
Rental of allotments by reference to length and/or area of land

LACORS previously issued advice that “it is unlikely that room space is ‘goods’ for the purposes of either the Weights & Measures Act 1985 or the Price Marking Order 1991″. There was, therefore, no recommendation to use only metric units.

The LACORS Metrology Focus Group has revisited the question, and now finds this advice to be out-of-date. The following advice replaces that given

The legislation

The relevant section of the Weights & Measures Act 1985 reads as follows:

Section 8. Units of measurement, weights and measures lawful for use for
(1) No person shall-
(a) use for trade any unit of measurement which is not included in Parts I
to V of Schedule 1 to this Act.

It can be clearly seen from Schedule 1 that imperial units including the
foot, square foot etc. may NOT be used for trade, since they do not appear
in Parts I to V of that Schedule.

The definition of ‘use for trade’ is found in Section 7:
7. Meaning of ‘use for trade’.
(1) In this Act ‘use for trade’ means, subject to subsection (3) below, use
in Great Britain in connection with, or with a view to, a transaction
falling within subsection (2) below where-
(a) the transaction is by reference to quantity or is a transaction
for the purposes of which there is made or implied a statement of the
quantity of goods to which the transaction relates, and
(b) the use is for the purpose of the determination or statement of
that quantity.
(2) A transaction falls within this subsection if it is a transaction for-
(a) the transferring or rendering of money or money’s worth in
consideration of money or money’s worth, or
(b) the making of a payment in respect of any toll or duty.

A unit of measurement may, therefore, be deemed to be in ‘use for trade’ if
it is used in connection with a transaction involving the rendering of
money, where the transaction is by reference to

Since 7(1)(a) can be split into two separate clauses (that is to say ‘the
transaction is by reference to quantity’ or ‘is a transaction for the
purposes of which there is made or implied a statement of the quantity of
goods to which the transaction relates’). In the former case, there is no
requirement for the transaction to involve a quantity of ‘goods’.

Therefore, any reference to quantity, whether voluntary or otherwise, must
be made in metric units.

For clarification, it is also necessary to establish what constitutes a
‘transaction by reference to quantity’. Consider the two examples below:
1. Offices for rent
First floor offices, fully serviced, available now, 3,500 sq ft
£35,000 per annum
2. Offices for rent
First floor offices, fully serviced, £10 per sq ft per annum
3,500 sq ft unit available now

Clearly, the same office space is being offered at the same annual rental
price in each case; however, in example 1, the reference to area may be
considered to be a description – the rental price is a total sum for the
offices as described – and therefore the use of imperial units is
acceptable. In example 2, there is a clear relation between the floor space
and the calculation of the total rental price (“£10 per sq ft”), which
renders it a transaction by reference to quantity and therefore subject to
the requirements of the Weights & Measures Act 1985 requiring the use of
metric units.

When a transaction is by reference to quantity, as described above, this is
a legal requirement; where the quantity forms part of a description only,
metric units should be indicated for the sake of clarity and consistency.

Units of alcohol – rational metric sizes would solve the problem

Today’s TV news carried a leading story that units of alcohol will be appearing on all bottles, cans cartons etc of alcoholic drinks. People were asked in the street what they thought of this move. Several people asked, what’s a unit?

Continue reading “Units of alcohol – rational metric sizes would solve the problem”

Improving Numeracy – Why joined-up government is needed

Yesterday, Gordon Brown stressed the importance of improving numeracy skills when talking to the news media and the CBI. A modern, competitive UK clearly requires a numerate workforce. Numeracy is a life skill that everybody needs whether for managing your bank account, understanding your body weight or retiling the bathroom.

However, focusing just on schools is not enough. A child in Finland, Singapore or New Zealand will learn decimal arithmetic, decimal currency and metric units – and immediately be able to apply them outside the classroom. In Britain, a child’s numeracy skills are hobbled because it is harder for them to use their skills practically. As soon as children leave the classroom they face a hodgepodge of incompatible units: metric units (with which they can calculate) and imperial units (for which they have not been taught calculation skills).  If Mr Brown is serious about numeracy he needs to give British children the same chance as those in most other countries.

Numeracy is vital for everyday life and work, yet British proficiency is quite woeful. The DfES Skills for Life Survey showed that 15 million adults in England failed to achieve the basic level 1 proficiency in numeracy. In the workplace it is mainly applied to measurement or money but a Department of Education study in 2002 showed that one in three adults could not calculate the floor area of a room in either metric or imperial!

When I went to junior school in the mid 1960s we learned arithmetic not just with numbers but with pounds, shillings & pence; yards, feet and inches; stones, pounds & ounces – not forgetting fractions thereof. Some of my worst memories of that period were of doing long division and multiplication using “old money” and “old” imperial units. Working with a hodgepodge of bases including 3, 8, 10, 12, 14 & 20 was complex and confusing. Much time was lost in teaching us unnecessarily complex calculation, delaying the teaching of more interesting topics such as algebra, geometry and data analysis.

The educational benefits of using the metric system have long been recognised. In 1862 the Report from the Select Committee on Weights and Measures stated “Economy of time in education is one of the beneficial results of the Metric system. While the study of English weights and measures is laborious and repulsive to both teacher and pupil, any one can easily master the Metric system. The time which the use of a decimal system would save in education has been stated to be at least a year“. The report went on to unanimously recommend that Britain adopt the metric system.

Roughly 40 years ago my junior school teacher announced that everything would soon “go decimal”. He outlined the basics of decimal currency and metric measurement for us. The decision to adopt the metric system in the UK was announced in Parliament on 24 May 1965 on the merits of its simplicity, modernity and international usage. This was nothing to do with EEC pressure; after all President de Gaulle had vetoed our entry earlier.

Around 1970 we were told that then Education Secretary, Margaret Thatcher, was requiring us to change our textbooks and the new ones were all decimal. After improving my maths skills in secondary school, thanks to using metric units and decimal currency, it was hard to use any of it in everyday life. In 1975, when buying food for the first time I was faced again with wretched pounds, ounces and ugly fractions. My metric education was betrayed and I faced the schizophrenic world of easy calculation in metric, but imperial in most practical situations.

Today – 42 years after starting with metric – we have a “very British mess” of metric and imperial. Fuel is sold by the litre (rather than the gallon) but road signs are still based on miles (rather than kilometres); making fuel consumption calculations very difficult. Do you use metric, imperial or simply give up because it is too messy?

As a parent I have now seen how my children fail to apply their calculating skills because it is not “cool” to talk in metric units and they do not really understand imperial. One day my youngest son asked “Dad, how many metres are there in a mile?”. When I told him “1,609” he was very baffled, but would have been equally confused if I had said “well 1,760 yards”. He is not alone, last year Times straw poll yielded answers of 52 to 10,000 for the number of yards in a mile. We have now taught a second generation to calculate in metric units but prevent them from applying it.

Numeracy is not just for abstract manipulation of numbers but is a practical life skill. In almost every case it is applied either using measurement units or money or both. However, most politicians want to do nothing to change. For example, a year ago Alistair Darling rejected a call to modernise our road signs to use metric units. The Government continues to ban the metric units taught for the last 30 years from distance signs and spends millions on new signage using imperial units that have not been taught since the early 1970s. So much for “joined-up” government!

The decimal number system is the foundation of modern numeracy. Most calculations today will be done with a calculator or a spreadsheet; but they both only work with decimal numbers. It is time to acknowledge the important link between decimal numeracy skills and applying them using metric measurement. Parents can help by measuring and weighing their offspring using metres and kilograms. Teachers can help their pupils understand their classroom exercises by giving real examples of metric quantities like a kilometre, a tonne, a hectare, etc without imperial conversion.

If Britain really wants good basic skills in the workplace and the home, urgent and decisive action is needed. Just as “old money” was taken out of circulation in 1971, “old units” must be withdrawn as soon as practicable. It cannot be that difficult – after all Australia and New Zealand managed it in the 1970s. Let’s stop undermining of our children’s numeracy and complete the metric conversion once and for all.

If Gordon Brown really wants better numeracy he needs to look beyond schools and fix our shops, adverts and road signs too. This requires a ‘joined-up’ government approach to measurement; something that has been missing in the UK for four decades.

[Roddy Urquhart]

“Metric martyrs” – what was the fuss about?

On Wednesday, 9 May, the air waves and the prints were full of fanciful stories about Brussels caving in and allowing Britain to carry on using lbs, oz and other imperial units. The so-called “metric martyrs” * (Oh no, not them again!) declared a victory for their campaign. So what has really happened?

It appears that at a recent Committee meeting of the European Parliament, one of the 27 Commissioners, Günter Verheugen, indicated that, in response to lobbying from European and American exporters, he intended to propose to fellow Commissioners that the current authorisation of “supplementary indications” alongside metric units should be extended beyond its current deadline of 2009. If the Commission approves this proposal it will then have to go through the decision-making machinery of the EU before the current Units of Measurement Directive can be revised.

This has been claimed by a spokesman for the “metric martyrs” as a victory for their campaign to be allowed to weigh and price in lbs and oz. The reality is quite different.

No difference

If Mr Verheugen’s proposal were eventually to be agreed as reported (big “if”), it would make absolutely no difference to the current situation. Traders will still have to price and weigh goods at the point of sale in metric units, with the option of an accompanying supplementary indication, which must be no more prominent than the legal metric unit. Most shops and supermarkets now comply with the law, and many have given up on showing lbs, oz, pints, sq yds, etc. Only a handful of recalcitrant market traders and small shopkeepers still hold out against the law, and their numbers are dwindling.

A special exemption for US imports and exports?

However, this is by no means the end of the story. The reason given for authorising supplementary indications is that the USA requires dual labelling (metric and “US customary” – not the same as imperial, by the way) on packaged goods. Thus, if the EU insists on metric-only labelling, exporters will require separate packaging for the two markets. It is difficult to see why putting an extra sticky label on a package is a significant business cost, but even if it is, there is a simple solution which need not affect the great majority of transactions within the EU. All that is required to solve the exporters’ alleged problem is a special exemption for imports of packaged goods from and exports to the USA. This is exactly what was proposed by the UK Metric Association (UKMA) in its submission to the EU consultation on revising the Directive, which can be seen at
It remains to be seen whether the Commission will accept the obvious logic and common sense of our proposal.

Pints and miles

Contrary to many media reports, Mr Verheugen’s proposal would not affect the status of the pint for draught beer and cider and for milk in returnable containers, nor would it affect the mile, yard, foot and inch for road signs, distance and speed measurement. The UK Government will still be required to name a date for phasing out these measures. As far as road signs are concerned, UKMA has proposed that a new deadline of 2014 should be set.

* Footnote:

The suggestion that the original so-called “metric martyrs” have been exonerated is absurd. They were properly prosecuted and convicted under the current law for using illegal scales and other offences, and all their appeals to various UK and European (!) courts were dismissed. Even if the Directive were to be amended as suggested, they would still be breaking the law. They were guilty as charged and remain so.

Imperialist ‘victory’ or checkout muddle?

Today’s (9/5/2007) news media have widely reported a story that imperial measures may continue to be displayed alongside metric ones in this country for an indefinite period. ( This is being trumpeted by some as a “monumental victory”. It is ironic that in the very year when we are celebrating the bicentenary of the abolition of slavery, clinging on to our imperial past is so widely embraced. However, this news just means ‘business as usual’ in the UK. Weighing machines will not be changed back to imperial. We shall continue to see some unnecessarily complex price labels and, for those who stick to using imperial, a muddle at the supermarket checkout.

What most reports fail to state is that at the greengrocer, butcher and supermarket still legally need to weigh and measure using metric. So if your trader uses imperial scales, they have not been tested recently. But what is the value of labelling in imperial? If you read a price in imperial you cannot check if you have been charged correctly without using a calculator.

Take this real example of a supermarket advert for bananas above. A customer reading “34p/lb” may have the impression that it is a lower price compared with the shop down the road offering bananas a price of say 69p/kg. The equivalent price is actually 74p/kg.

At the checkout, however, the customer cannot check whether he or she has been charged correctly. The weighing machine uses kilograms and the receipt shows the kilogram price 74p/kg.

Common sense would suggest that the most sensible thing would be to display the price using the units of the weighing machine and receipt. Adding the imperial supplementary price adds nothing and can be confusing. Seven years after changing to metric for loose goods, we have all had enough time to change over.

What a pity that some of our politicians and news media despise consumer protection and see a victory in perpetuating an obsolete unit. It is high time that the British Government – without any pressure from the EU – finishes off the metric conversion in the interests of the consumer.