Saint-Gobain PAM SA v Fusion Provida Ltd & Anor

An invention is not obvious merely because the relevant step could have been included in a research programme. An “obvious to try” case requires a sufficient expectation of success. The proposed solution must be more or less self-evidently likely to work.

Where obviousness involves evaluating evidence and matters of degree, an appellate court should exercise caution before reversing the trial judge. If an error of principle affects the overall conclusion, however, the appellate court may reconsider that conclusion as a whole.

The claimant owned a European patent for a buried iron pipe whose anti-corrosion coating used a porous zinc-aluminium alloy layer beneath a porous sealing layer. The defendants accepted infringement if the patent was valid, but alleged that claim 1 was obvious in light of a recently published paper, Johnsson, concerning soil tests on zinc, aluminium and alloy-coated steel plates.

Pumfrey J held the patent valid and infringed. The defendants appealed, arguing that he had wrongly relied on historical considerations even though Johnsson had appeared shortly before the patent’s priority date. The central question was whether Johnsson gave the skilled person a sufficient reason to replace zinc with zinc-aluminium alloy in a coating intended to protect buried pipes over a long service life.

1. Appeal dismissed unanimously. The judge had made no error of principle in holding claim 1 non-obvious. His conclusion was also correct on an independent evaluation of the evidence.

2. The structured approach in Windsurfing v Tabur Marine [1985] RPC 59 required the court to identify the inventive concept, the common general knowledge, the differences from the prior art and whether those differences would have been obvious. The inventive concept was the substitution of zinc-aluminium alloy for zinc in the established coating system for buried pipes.

3. Johnsson did not provide a sufficient pointer towards that substitution. Protection of buried pipes depended for much of their service life upon zinc corrosion products forming a durable barrier and migrating onto damaged areas. Johnsson did not address those mechanisms, the protection of damaged areas or the long service life required for buried pipes. Its findings concerning galvanic corrosion in other conditions added little to the skilled person’s existing knowledge.

4. The evidence showed that results in this field could not reliably be predicted. A possibility that zinc-aluminium alloy might be included somewhere in a programme of experiments did not make its use obvious. Applying the approach in Johns-Manville’s Patent [1967] RPC 479, an “obvious to try” case requires more than an experiment from which useful information might emerge. The proposed solution must be more or less self-evidently likely to work. No such likelihood existed here.

5. Biogen v Medeva [1997] RPC 1 required appellate caution where the application of a legal standard such as obviousness depended upon an evaluation of evidence and matters of degree. The judge had assessed the evidence in the round, and no true error of principle was demonstrated. The court added that, where an error of principle does affect an overall conclusion on obviousness, that conclusion becomes open to reconsideration as a whole; appellate caution cannot be applied separately to isolated parts of the reasoning.

• Court of Appeal (Civil Division): The defendants’ appeal was dismissed unanimously. They were ordered to pay the claimant’s costs of the appeal, including the respondent’s notice. Permission to appeal to the House of Lords was refused.

• High Court, Chancery Division (Patents Court): Pumfrey J held the patent valid and, on the parties’ agreed position, infringed. The judgment was given on 3 November 2004; no neutral or report citation is stated.