Mission Statement - De-Spinning the Pro-Taser Propaganda

Yeah right, 'Excited Delirium' my ass...


The primary purpose of this blog is to provide an outlet for my observations and analysis about tasers, taser "associated" deaths, and the behaviour exhibited by the management, employees and minions of Taser International. In general, everything is linked back to external sources, often via previous posts on the same topic, so that readers can fact-check to their heart's content. This blog was started in late-2007 when Canadians were enraged by the taser death of Robert Dziekanski and four others in a short three month period. The cocky attitude exhibited by the Taser International spokespuppet, and his preposterous proposal that Mr. Dziekanski coincidentally died of "excited delirium" at the time of his taser-death, led me to choose the blog name I did and provides my motivation. I have zero financial ties to this issue.

Saturday, April 19, 2008

Q: Which is more dangerous: M26 or X26?

A: I don't know.

It seems that Taser can't even discuss this question because then they would be forced to admit that the risk with either product is non-zero. Once we have a non-zero number from Taser, then we could multiply it by the annual usage rate to determine the expected annual death rate. I've not seen any indication that Taser has ever provided any explicit numerical value for the estimated risk. If anyone has ever seen such a thing, please leave a comment with a pointer.

The M26 was introduced in 1999 and was touted as having an "Advanced" waveform. It was Taser's first really successful product.

The X26 was introduced in May 2003. It's waveform is completely different than the older M26. It is now Taser's biggest seller.

The two products are compared more-or-less side-by-side in Taser document LG-STND-TECDBEC-001 (except it does not include the RMS current values which were mentioned in some earlier documents). See previous post [LINK] for some extracts from this document.

The most significant difference in the two waveforms relates to the 19 Hz component of the X26 waveform. Whereas the M26 produces a short pulse, the X26 waveform produces a continuous 100% duty cycle frequency component at 19 Hz. Because Taser's Kroll constantly mentions the "chronaxie" (a time constant) he seems to have not understood that the 19 Hz component of the X26 waveform is continuous 100% duty cycle for the full 5-second duration of each cycle.

On this point the X26 waveform is much different than the M26 waveform.

So the question really comes down to the significance of the following specifications for the X26 taser. And note that these are cut-and-paste or derived directly from Taser specification sheets.

Average current = 2 mA
RMS Current = 151 mA
Frequency = 19 Hz
Duty Cycle = 100%
Duration = 5 seconds (or 5000 milliseconds), and often repeated

When I plot these two current values on the IEC 479 graph I get the following (below). Although this graph is for "50 Hz" (as opposed to 19 Hz), another chart in that same IEC standard shows that the frequency effect (high frequencies are safer) flattens out at low frequencies such as 50 or 60 (or 19) Hz.

I note that 2mA is so low as to be incapable of even locking up muscle ('b'-curve). But since we know that is what the taser does, it leaves only the question about the importance of the 151 mA RMS current spec (data which was expunged from later revisions of the specification sheet).

These complexities are why I would like to see CSA get involved with this question.

No comments: