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Measurements Under the Criminal Code of Canada Use SI Units

Updated: Oct 10, 2022


To connect the Criminal Code and its wording about concentration of alcohol in units of blood with the International system of SI units.

To establish the importance of SI units and their definitions according to the CGPM when construing and applying the Criminal Code of Canada, with respect to offences defined in terms of a concentration of alcohol in units of blood.

Concise summary of the International system of Units
Excerpt from A more recent version can be found online using the new definition of the metre.

Q. I just want to show you section 253(1)(b) of the Criminal Code and I just want to ask you a question from a scientist perspective, not a legal perspective. From a scientist perspective. A. Okay. Q. There’s a reference there in section 253(1)(b) that suggests a number 80, and something that I’m asking – I’m going to ask you if that’s a unit – milligrams of alcohol in 100 millilitres of blood.

Criminal Code of Canada section 253(1)(b)

A. Well, the units are milligrams, yes. Q. Yes. And..


A. Of alcohol. Q. ...there’s a – but then there’s a concentration, I take it? A. Yes. Q. Milligrams of alcohol in 100 millilitres of blood. There’s a unit of concentration... A. Yes. Q. ...that combines those two concepts of milligram and millilitres. A. Correct. So, you have a weight and you have a volume. Q. Yes. A. That’s – you get a concentration. Q. But the 80 is a quantity. A. Correct. Q. Now in Canada you mentioned the reference to inches. A. Yes. Q. Is inches a – a – a – a unit that is commonly in use? A. I still use it. I still use yards, right? I still use miles per gallon instead of hundred – hundred kilometres per whatever number of litres ‘cause it’s just simpler for me to understand because of the time I was born into. I still play golf in yards. Q. Yeah. A. I still use a 12-inch ruler but I’m familiar with the metric units, ‘cause I learned that in 1974. Q. So, in Canada it’s safe to use either metric units or non-metric units in anything that we measure? A. That would depend on the application and its purpose, yes.

Q. As a scientist, do you use both units? Both system – or multiple systems of units? Or do you stick to a metric system? A. Metric system. Q. Now in Canada we have a law called the Weights and Measures Act. A. I have no idea.

Front page of Canada's Weights and Measures Act

Q. All right. Let me see if I can show you a copy of it. Section 4(1) of the Weights and Measures Act, that’s at page three, of this document says – what does section 4(1) read? A. “Multiples and sub-multiples of units”? Q. Or – I’m sorry, in section 4(1)? A. Oh, section 4(1). Q. Yes. A. “All units of measurement used in Canada shall be determined on the basis of the international system of units established by the General Conference of Weights and Measures.” Q. Oh. So, if we’re trying to sort out a measurement and what it is, and we want to look at it scientifically, if it’s going to be used outside of a laboratory, I’m going to suggest to you, the Weights and Measures Act requires that we use units of measurement that are determined on the basis of the international system of units established by the General Conference of Weights and Measures. A. Yes. Q. And that would be the metric system? A. Correct. Q. And the reason why I ask you that, is that in the 8000C training there is a specific reference to the

international system of weights and measures. Sir, the document that I’m showing you, I would expect you recognise. The Intoxilyzer 8000C Training Aid, December 2013. A. Yes. Q. The document that I’m giving you, it’s the front cover and various excerpts. A. Okay, not the entire document. Q. Not the entire document. A. Okay. Q. All right. A. Excerpts. Q. So, if I can just – and I’m going to just give you the copy. A. Okay. Q. Just asking you to look please, for a moment, at page 16 of 238 of that document. A. Yes.

Excerpt from CFS Intoxilyzer 8000C Training Aid 2013

Q. And it suggests there, that in 1960 the General Conference on Weights and Measures adopted the international system of units with the international abbreviation SI. A. Correct, yes. Q. Système International d'Unités, in French, and that’s SI. That’s the modern form of the metric system. And it indicates there, that the units of all measurements needed in science, technology and everyday life, are derived from SI base units, derived units, and from units outside of the SI. A. Yes. Q. Right? A. Yeah. Q. And metric system of measurement is used in

science as the basis of measurement for most country and was adopted in Canada in 1971. A. My apologies. I think I said 1974. Q. Right? A. Yeah. Q. And based upon the decimal system and specifically with respect to metric units of the base metric units one of them is mass, which is kilogram. A. Yes. Q. And one of them is length, which is the metre. A. Yes. Q. Now when it comes to volume, it indicates that volume is a unit outside of the SI but I understand that volumes like litre are defined in terms of length? In other words, if you take a 10th of a metre, which is a decimetre, and you create a cube containing those dimensions, you have a litre? A. Yes. That’s correct. Q. So, if you were – as a scientist, to look at that section of the Criminal Code that I showed you, section 258 – or, 253 I should say, that had the 80 and the milligrams of alcohol in 100 millilitres of blood, then as a scientist, you would apply this measurement terminology that we’re speaking of right here? A. Yes. Q. It’s a concentration. It’s a concentration of mass in volume. A. Yes. Q. And a milligram is 1000th of – I’m sorry, is 1000th of gram, and a gram is 1000th of a kilogram. A. Correct.

Q. And in terms of volume, a millilitre is 1/1000th of a litre, and a litre is a cubic – is cubic decilitre. A. That sounds right, yes. Q. All right. So, our measurement terminology that we use in Canada, for all the things that we are talking about, and the work that you do at the Centre of Forensic Sciences, you use the same system of measurement that we’ve just talked about. A. Correct. For drugs as well.

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