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Trial Judgment Dismissing Patent Infringement Action for Want of Evidence Upheld

February 8, 2021


In Tensar Technologies, Limited v Enviro-Pro Geosynthetics Ltd. (2021 FCA 3), the Federal Court of Appeal (the “Court”) dismissed an appeal challenging the Federal Court’s determination that Enviro-Pro Geosynthetics Ltd. (“Enviro-Pro”) did not infringe Tensar Technologies Limited’s (“Tensar”) patent for a geogrid.


Tensar and Enviro-Pro sell multiaxial geogrids. Tensar brought an action against Enviro-Pro alleging that it had infringed its patent (the “858 Patent”) for a particular geogrid (2019 FC 277). Specifically, Tensar claimed that Enviro-Pro infringed the 858 Patent by selling geogrid products that incorporated all of the elements of the 858 Patent, including the “continuous orientation” of molecules in the geogrid “from the edge of one strand, around the crotch and to the edge of the adjacent strand.”

Justice Manson of the Federal Court construed the term “continuous orientation” to mean, that: (1) a predominant amount or substantial percentage of the molecules around the crotch are oriented in a direction tangential to the curvature of the crotch; and (2) a predominant amount or substantial percentage of the molecules oriented around the crotch are in the crystalline phase”.

Justice Manson of the Federal Court held that Tensar had failed to establish infringement of the 858 Patent. In arriving at this determination, he emphasized that Tensar’s expert evidence did not establish the degree or direction of the orientation of the strands in the crotch of Enviro-Pro’s products. Tensar appealed.

The Federal Court of Appeal’s Decision

On appeal, the Federal Court of Appeal considered three issues.

First, the Court considered Tensar’s submission that the trial judge made a reviewable error by contradicting himself.

Specifically, Tensar argued that the trial judge rejected Enviro-Pro’s expert evidence but then later afforded it weight. The Court, however, was not satisfied that the trial judge acted in the manner claimed by Tensar. Rather, the Court recognized that the trial judge expressed concerns with both Tensar’s and Enviro-Pro’s expert evidence. It was therefore open to him to select those aspects of the evidence that he favoured from both experts and to use this evidence to arrive at a conclusion on the interpretation of the term “continuous orientation”.

Second, the Federal Court of Appeal determined that the trial judge did not err in his construction of the term “continuous” as it appears in the 858 Patent.

On appeal, Tensar argued that the trial judge erred in constructing this term by reading in the words “predominant amount or substantial percentage” as they do not appear in the claims of the patent, the patent specification or the common general knowledge of the skilled person. In rejecting this argument, Justice Locke explained that Tensar’s position “boils down to a desire to have its expert’s interpretation prevail over that of [Enviro-Pro’s expert]”. Ultimately, the Federal Court of Appeal held that, in the absence of any wording in the 858 Patent itself that defined the word “continuous” therein, the trial judge was entitled to rely on expert evidence before the court when construing the term “continuous”.

Finally, the Federal Court of Appeal considered Tensar’s argument that the trial judge erred in concluding that the evidence did not support a finding that the 858 Patent had been infringed as there was a want of evidence about the degree of orientation of molecules in the geogrid.

According to Tensar, such evidence was not necessary as “it goes without saying that direction or orientation goes hand-in-hand with degree of orientation.” Once again, the Federal Court of Appeal rejected Tensar’s argument, explaining that the trial judge was entitled to find that Tensar’s evidence on this issue was insufficient.


Authors: Rachel Oster, Nargis Fazli and Jaclyn Tilak


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