Smoke detector bypass fails the validity test

Smoke detector bypass fails the validity test

Smoke detector bypass fails the validity test

Aspirating IP Limited v Vision Systems Limited [2010] FCA 1061

On 30 September 2010, the Federal Court gave judgment on the validity of a patent application filed by Aspirating IP Limited (AIP) and opposed by Vision Systems Limited (Vision) in 1998. The matter was on appeal from two decisions of the Commissioner holding that the patent application in two amended forms was invalid. Davies Collison Cave Law acted for Vision in the appeal.


The patent application claimed a smoke detection apparatus and method using a “simple bypass” arrangement whereby only part of the sample of air was passed through a filter (to remove dust and other non-smoke particles) to the smoke detector.

The claimed invention was said to ameliorate the problem of filter-clogging by reducing the airflow through the filter.

The decision

Justice held that the bypass arrangement was not novel and that none of the claims involved an inventive step (other than the omnibus claims in relation to which there were no substantive submissions by either party and consequently no findings). His Honour made his findings on validity after emphasising that Vision must discharge the Patent Office standard, namely that the Court is “practically certain” that the patent, if granted, would be invalid (Commissioner of Patents v Microcell Ltd (1958) 102 CLR 232; Genetics Institute Inc v Kirin-Amgen Inc (1999) 92 FCR 106). While Vision had to discharge this weighty onus in relation to the ultimate question of validity, his Honour noted that the primary facts (such as whether a document was published or not) were established on the balance of probabilities (Austal Ships v Stena Redari Aktiebolag (2005) 66 IPR 420).

Claim construction

An important issue in the case was the construction of the phrase “main duct means in the form of sampling duct means of a smoke detection system”. Vision submitted that the phrase embraced both air-conditioning ducts and dedicated sampling pipes, whereas AIP contended that the phrase was limited to dedicated sampling pipes because air-conditioning ducts would not be installed solely for the smoke detection system. If the phrase included air-conditioning ducts, AIP did not dispute that the claimed invention was anticipated by certain prior art smoke detection systems, including one system manufactured by an Australian company acquired by Vision (“IEI (Aust)”).

Applying well-established principles, Justice Besanko stated that claim construction was a matter of law for the Court but that to determine the meaning of the phrase, he needed to have regard to the common general knowledge of the skilled addressee at the priority date. Justice Besanko noted that before the priority date, smoke detection systems had used either air-conditioning ducts or dedicated sampling pipes to transport air to the detector. His Honour considered the ordinary English meaning of the words and emphasised that the word “means” in the claims had the broadest connotation and directed attention to the result or effect of something rather than the reason it was designed or built. His Honour concluded that the “main duct means” would include air-conditioning ducts.

Novelty and inventive step

Justice Besanko’s conclusion that the “main duct means” of the claims included an air-conditioning duct led to a finding that the claimed invention was not novel in light of certain prior art publications of smoke detection systems utilising air-conditioning ducts.

Vision also relied on prior art uses in the form of particular systems installed by IEI (Aust) using dedicated sampling pipes. In relation to three installations in Australia in the early 1980s and early 1990s, Justice Besanko declined to find them anticipatory because Vision had relied on the testimony of a single witness whose recollection of events that had transpired many years earlier was not considered sufficiently reliable. However, His Honour did accept Vision’s evidence (notwithstanding numerous challenges) and found that the claimed invention was also anticipated by presentations made in Australia of an IEI (Aust) system installed at CERN (the European Organisation for Nuclear Research) in Switzerland. Although the system was located outside Australia and therefore did not form part of the “prior art base” at the priority date, presentations had been made in Australia showcasing the system and disclosing the features of the claimed invention.

On inventive step, His Honour carefully considered the onus on Vision and held that he was “clearly satisfied” and it was “practically certain” that the bypass arrangement would have been obvious to a person skilled in the art when faced with the filter–clogging problem before the priority date. AIP had submitted that the evidence from Vision’s witnesses on obviousness should be disregarded because they had read the specification before giving their evidence and were therefore “tainted by hindsight” (relying on Minnesota Mining and Manufacturing Co v Tyco Electronics Pty Ltd (2002) 56 IPR 248). It was held that the evidence was admissible but the objection was relevant to the weight he gave that evidence. His Honour relied on the witness’ fact evidence as to how they might have solved the problem at the priority date but gave no weight to their opinion evidence as to whether the bypass arrangement was obvious.


Justice Besanko’s decision represents an important judicial pronouncement on several important patent law issues. His Honour gave close consideration to the onus of proof to be discharged by an opponent, and importantly recognised that the primary facts on which findings of validity will be based remain to be proven according to the lower standard of the balance of probabilities. On claim construction, His Honour provided useful guidance on the meaning of the commonly used word “means” in patent claims. The judgment is also significant in that lack of inventive step (generally regarded as a difficult ground of opposition in Australia, particularly compared to Europe) was upheld notwithstanding the burden of the onus. In relation to evidence of prior uses, the judgment demonstrates the importance of contemporaneous documents and corroborated witness testimony, particularly in opposition proceedings where the opposition will only be upheld where it is “practically certain” that the patent, if granted, would be invalid.