Pacific Coast Building v CertainTeed Gypsum, Appeal 2019-1524, Decided June 30, 2020.
Pacific Coast Building Products Inc. sued CertainTeed Gypsum, Inc and Saint-Gobain Performance Plastics Corp. (collectively CertainTeed) for patent infringement of claim 21 of US Patent No. 9,388,568 (the “‘568 patent”) in the Northern District of California. The ‘568 patent is directed to a laminated gypsum board that does not include an intermediate paper layer, thereby rendering the board more readily broken into the desired size. Asserted claim 21 recited a laminated structure of a first and second gypsum boards, bonded together with a layer of glue. The ability to easily break the laminated board was recited in the claim as:
a scored flexural strength of the laminated structure is about 22 pounds per 1/2 inch thickness of the structure;
the scored flexural strength being the flexural strength of the laminated structure after the outer, paper-clad surface of one of the first and second gypsum boards has been scored.
The phrase “scored flexural strength” is not a term of art. Rather, it had been coined by Pacific Coast, and was described in the specification as being determinable using ASTM C 473-06a, “Standard Test Methods for the Physical Testing of Gypsum Panel Products.” ASTM 473-06a sets forth the test for flexural strength as measuring the flexural strength in four different orientations. As described by the Federal Circuit:
In other words, the standard does not report a single flexural strength value; it instead reports and calculates four, with each of the four values representing an average of multiple measurements for a given test condition. Moreover, it does not suggest further averaging those four strength values.
Among other things, CertainTeed argued that the ‘568 specification was unclear as to how to derive a single value for the scored flexural strength, as required by the claim. CertainTeed further argued that the method for application of the ASTM method to varying board thicknesses was unclear. Pacific Coast argued that a skilled artisan would have chosen a particular configuration of the ASTM method, or, that the skilled artisan would have averaged the four described measurements. Pacific Coast’s argument during prosecution that “the prior art is silent with respect to a “scored flexural strength”” was not helpful to their cause, as the District Court found this further support for the idea that a skilled artisan would not know how to measure the the “newly coined scored flexural strength.”
The District Court found the claim term “scored flexural strength” indefinite and Pacific Coast appealed.
Appeal to the Federal Circuit
After balancing the case law holding claims indefinite when the claim requires a specific measurement or calculation for which more than one method may be used with no specific guidance as to which method to use with that wherein disclosure of every possible variable that may effect the calculation of a measured value was not required, the Federal Circuit ultimately affirmed the District Court and held claim 21 indefinite:
While the claims recite a particular value for “scored flexural strength,” i.e., “about 22 pounds per 1/2 inch thickness,” the claims and specification fail to explain what the value represents or how to consistently and reproducibly measure this new characteristic…The specification’s reference to ASTM 473-06a does not adequately fill the void…Contrary to Pacific Coast’s contention, the ASTM does not suggest that flexural strength can be represented by any one of the measurements alone or that all four can be averaged together…The evidence taken together clearly indicates that the various choices that could be made for determining the scored flexural strength of a board are material, contrary to Pacific Coast’s arguments…Accordingly, we agree with the district court that…a skilled artisan would have had no reasonable certainty in trying to figure out how to calculate a single value for the scored flexural strength of a drywall board.