Taser tests find variation in weapon charge

A team of researchers led by a Carleton University professor has found the charges delivered by some Tasers and other conducted electricity weapons can vary from the manufacturer's specifications.

Researchers led by a Carleton University professor have found the charges delivered by some Tasers and other conducted-electricity weapons can vary from the manufacturer's specifications, delivering either too much or not enough of a jolt.

Andy Adler, the Canada Research Chair in biomedical engineering at Carleton in Ottawa, said three to 10 per cent of the 6,000 Tasers and other stun guns tested were found to be delivering charges that were outside specified thresholds, or tolerances.

Weapons that deliver a more powerful shock than they are rated for could put the target at greater risk, said Adler. And weapons that deliver too little charge can also pose dangers too, he said.

"The weapon that is below tolerance would have less effect on the subject," said Adler. "That would worry a police officer because they are looking for a particular effect. They are relying on their equipment to do something and if the equipment doesn't do it, it puts everyone involved in a dangerous scenario."

Electricity delivered with force

Tasers and other stun guns are high-voltage, low-current weapons, meaning that while they deliver only a small amount of electricity, they do so with a great amount of force.

Voltage, measured in volts, is the amount of force driving a flow of electrons, while current, measured in amperes or amps, is the rate of the flow of electrons.

Taser sets standards for the weapon's average charge, which is derived from multiplying the current by the time, in seconds, that the jolt lasts. Currently, Taser calls for an average charge of 125 microcoulombs.

As a result of the preliminary findings, Adler and four industry researchers are recommending a new testing procedure that goes beyond the guidelines specified by the manufacturer — one that tests the minimum and maximum charges reported, and not just the average. The recommendation also proposes a maximum charge limit for the weapons.

Welcomed by police

Adler said he hopes the report will help inform police in Canada on whether the age of the weapon has an impact on its performance over time. He said police welcome the research.

"Police are fascinated by the research we're doing. They very much want to know that they're functioning correctly, that they're within specifications, that they can be relied on," he said.

The recommendations are limited to testing the weapons and do not address questions of when and where the weapons should be used.

Last year, former B.C. Appeal Court justice Thomas Braidwood issued a report on the use of Tasers after the death of Robert Dziekanski at the Vancouver airport.

Braidwood found that stun guns can be deadly and said police should have stricter limits on when the weapons should be used.

With files from the CBC's Evan Dyer