Leckrate

Leckrate is a measure of the rate at which a system loses fluid or gas through unintended openings. It quantifies the size or severity of a leak and is used to assess the integrity, safety, and performance of sealed or pressurized systems. Leckrate can be expressed as a volumetric flow rate (for example liters per second, L/s; cubic meters per second, m^3/s) or as a mass flow rate (kilograms per second, kg/s). In vacuum technology and gas containment, the common unit is the leak rate expressed as mbar·L/s or Pa·m^3/s, reflecting how much gas enters a system at a given pressure differential.

Leaks arise from manufacturing defects, wear, improper assembly, temperature changes, or material fatigue. The leak rate depends on the leak path area, the pressure difference across the leak, and the properties of the fluid; in many cases, flow through a small crack follows orifice flow principles and increases with pressure difference.

Measuring leak rate involves leak testing methods such as helium mass spectrometry, pressure decay, vacuum rise, or tracer gas methods. In practice, engineers specify acceptable maximum leak rates for components and assemblies to ensure product quality, safety, and performance. Higher leak rates can lead to contamination, loss of vacuum, safety hazards, or energy inefficiency.

Applications span aerospace, automotive, electronics, pharmaceuticals, and process industries, where maintaining containment of gases or liquids is essential. The term Leckrate is commonly used in German-language documents, but the concept is widely used in English as well.