Comments on: Metric howlers – Times hat-trick http://metricviews.org.uk/2006/12/metric-howlers-times-hat-trick/ Commentary on the measurement muddle in the UK Tue, 07 Feb 2012 12:03:27 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Martin Vlietstra http://metricviews.org.uk/2006/12/metric-howlers-times-hat-trick/comment-page-1/#comment-35 Martin Vlietstra Tue, 02 Jan 2007 10:44:06 +0000 http://www.metricviews.org.uk/2006/12/30/metric-howlers-times-hat-trick/#comment-35 I seem to recall that the fuel used PER PASSENGER by a jet airliner is comparable to the fuel used PER PASSENGER in a motor car (the Times journalist probably forgot the “per passengerâ€? part of the figures). The only difference is that I cannot drive from the United Kingdom to Germany for a business meeting, attend the meeting and drive back in the same day – if I did not have access to an aircraft seat, I would probably think twice about attending the meeting. How much CO2 is produced by an airliner (or a motor car)? If one uses metric units, the calculation is quite simple: Assume that: One litre of petrol, diesel or aviation fuel has a density of the order of 0.8 kg/L. All hydrocarbon fuels are made up of hydrogen and carbon in a ratio of 2:1 All the carbon is converted to CO2 and all the hydrogen to H2O Carbon has an atomic weight of 12, hydrogen an atomic weigh of 1 and oxygen an atomic weight of 16 Then 14 kg of fuel will produce 44 kg of CO2. This means that 1 kg of fuel will produce 3.1 kg of CO2 and that each litre of fuel will produce 3.9 kg of CO2. I seem to recall that the fuel used PER PASSENGER by a jet airliner is comparable to the fuel used PER PASSENGER in a motor car (the Times journalist probably forgot the “per passengerâ€? part of the figures). The only difference is that I cannot drive from the United Kingdom to Germany for a business meeting, attend the meeting and drive back in the same day – if I did not have access to an aircraft seat, I would probably think twice about attending the meeting.

How much CO2 is produced by an airliner (or a motor car)? If one uses metric units, the calculation is quite simple:

Assume that:
One litre of petrol, diesel or aviation fuel has a density of the order of 0.8 kg/L.
All hydrocarbon fuels are made up of hydrogen and carbon in a ratio of 2:1
All the carbon is converted to CO2 and all the hydrogen to H2O
Carbon has an atomic weight of 12, hydrogen an atomic weigh of 1 and oxygen an atomic weight of 16
Then 14 kg of fuel will produce 44 kg of CO2.

This means that 1 kg of fuel will produce 3.1 kg of CO2 and that each litre of fuel will produce 3.9 kg of CO2.

]]> By: Alex Bailey http://metricviews.org.uk/2006/12/metric-howlers-times-hat-trick/comment-page-1/#comment-32 Alex Bailey Sun, 31 Dec 2006 22:57:50 +0000 http://www.metricviews.org.uk/2006/12/30/metric-howlers-times-hat-trick/#comment-32 I'm interested in knowing how Harry Vanduyne got his figures and wether this is an example of a howler. If each engine burns 1.25 tons (Imperial Long Ton? US Short Ton?) then over what period? 1 hour? The lifetime of the engine? I did find one site which quoted "average 3 metric tonnes per hour". I read that the Long Ton is usually used for aviation fuel but none of these figures match. Is this a problem with our understanding of aviation fuel or part of the mess we get into when we mix units about? I remember asking the BBC a similar question when they quoted the fuel consumption of the space shuttle in gallons several years back. I asked "US or Imperial? Can you tell us in Litres please" and all they said was "We're just using a unit that people understand". They never did answer my question! I’m interested in knowing how Harry Vanduyne got his figures and wether this is an example of a howler.

If each engine burns 1.25 tons (Imperial Long Ton? US Short Ton?) then over what period? 1 hour? The lifetime of the engine? I did find one site which quoted “average 3 metric tonnes per hour”. I read that the Long Ton is usually used for aviation fuel but none of these figures match. Is this a problem with our understanding of aviation fuel or part of the mess we get into when we mix units about?

I remember asking the BBC a similar question when they quoted the fuel consumption of the space shuttle in gallons several years back. I asked “US or Imperial? Can you tell us in Litres please” and all they said was “We’re just using a unit that people understand”. They never did answer my question!

]]> By: Harry Vanduyne http://metricviews.org.uk/2006/12/metric-howlers-times-hat-trick/comment-page-1/#comment-30 Harry Vanduyne Sun, 31 Dec 2006 03:01:44 +0000 http://www.metricviews.org.uk/2006/12/30/metric-howlers-times-hat-trick/#comment-30 Hi, You mentioned the Howler on airline pollution. Would you happen to know how much CO2 a commercial airliner produces into the atmosphere? Each engine burns about 1.25 tons of aviation fuel. CO2? Thank you very much Regards Harry Hi,
You mentioned the Howler on airline pollution.
Would you happen to know how much CO2 a commercial airliner produces into the atmosphere?
Each engine burns about 1.25 tons of aviation fuel.
CO2?
Thank you very much
Regards
Harry

]]> By: Robin Paice http://metricviews.org.uk/2006/12/metric-howlers-times-hat-trick/comment-page-1/#comment-29 Robin Paice Sat, 30 Dec 2006 11:36:54 +0000 http://www.metricviews.org.uk/2006/12/30/metric-howlers-times-hat-trick/#comment-29 Arguably, howlers in the Times don't matter very much, but they are symptomatic of the British problem of innumeracy and incompetence resulting from the "very British mess" of trying to use two incompatible systems of measurement at the same time. UKMA contends that the only way to resolve this problem is for the Government to grasp the nettle and phase out imperial measures completely and standardise on metric units for all legal and official purposes. Arguably, howlers in the Times don’t matter very much, but they are symptomatic of the British problem of innumeracy and incompetence resulting from the “very British mess” of trying to use two incompatible systems of measurement at the same time. UKMA contends that the only way to resolve this problem is for the Government to grasp the nettle and phase out imperial measures completely and standardise on metric units for all legal and official purposes.

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