Pfeiffer Vacuum says leak rates can quietly erode vacuum performance

Pfeiffer Vacuum+Fab Solutions is warning that leak rates in vacuum systems are not fixed and can shift with pressure, temperature, gas type and leak location. The company says understanding those changes is key to protecting process consistency, preserving design margin and preventing performance losses before they become failures.

Why it matters: - Leak rates can change the real-world performance of vacuum systems even when a leak looks acceptable on paper. - Variable leak rates can reduce process consistency, consume design margin and push maintenance problems from manageable to unavoidable. - The impact matters for operators in heat treatment, chemical processing and other vacuum-dependent applications where small changes can affect output quality.

What happened: - Pfeiffer Vacuum+Fab Solutions published an explainer on how leak rates affect vacuum process performance. - The company outlined how leak rate is defined, measured and influenced by operating conditions. - The article was issued from Asslar, Germany, on Sept. 22, 2026.

The details: - Leak rate is the quantity of a specific fluid passing through a leak under specific conditions, using standards terminology such as EN ISO 20484. - The most common unit is mbar·l/s, which expresses pressure, volume and time together as p·V/t. - A pressure rise test must be interpreted in relation to system volume, because the same pressure increase over the same time can represent very different gas quantities in small and large chambers. - Common equivalent units include Pa·m³/s, Torr·l/s and sccm, so unit comparisons require care. - Pressure difference drives flow through a leak, but the relationship changes once a system reaches choked flow. - In deep vacuum, a leak may not increase in mass flow, but the expanding gas still raises the volumetric load on the pump. - Temperature affects leak rate through gas behavior, seal expansion and contraction, and material permeability. - O-rings, gaskets, polymer hoses and elastomers can harden, soften, deform or become more permeable as temperatures change. - Leak position matters because pressure varies along a pumped system; a leak nearer the pump inlet can admit more gas than one closer to the process end. - Gas type also matters, with viscosity dominating at higher pressures and molecular weight becoming more important at lower pressures. - Air-based tests can misstate performance in systems using nitrogen, argon, refrigerants, hydrogen or other inert gases. - The company says systems should be tested under representative operating conditions, especially when they cycle across wide temperature ranges. - The article says there is no universal acceptable leak rate; the threshold must be tied to process requirements and available design margin.

Between the lines: - The core message is that leak rate is not a static spec. It is a moving target shaped by operating conditions. - That makes one-time leak checks less useful than trend monitoring, because a rising leak rate signals shrinking reserve capacity before failure appears. - The guidance also reframes small leaks as a design-margin problem, not just a pass-fail maintenance issue.

What's next: - Pfeiffer Vacuum is urging operators to build leak checks into regular maintenance programs. - The company recommends testing under operating conditions, accounting for system volume and tracking leak rates over time. - Operators are being told to act on deterioration early, before a leak consumes the spare capacity needed to keep the process stable.

The bottom line: - A leak that looks minor in one setting can become a process problem in another, and vacuum operators need to measure it in context rather than treat it as a fixed number.