Frequently Asked Questions About Leak Testing

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Leak testing detects and quantifies unintended leaks in components or systems to ensure quality, safety, and performance—especially in critical applications like fuel systems, batteries, or sealed enclosures. The basic function of the leak test system is sorting between good and bad parts.

• Bubble testing 
• Pressure decay / vacuum decay 
• Mass flow 
• Sniffer method  with helium or hydrogen tracer gas 
• Hard Vacuum with helium tracer gas 

Selection depends on:

• Required sensitivity (e.g., mbar·l/s or sccm) and test pressure
• Component volume and geometry 
• Production throughput (cycle time)
• Material compatibility 
• Cost and automation level

•  Gross leaks: Easily detectable, often visual (e.g., bubble testing)
•  Fine leaks: Smaller leaks requiring sensitive instruments (e.g., tracer gas)
•  Micro leaks: Extremely small, near molecular level, often in critical systems like medical implants or satellites

It varies by industry and function. For example:

• Medical devices may require < 10⁻⁶ mbar·l/s 
• Battery packs might target 10⁻⁴ to 10⁻⁵ mbar·l/s 
• HVAC or fuel systems tolerate higher limits depending on regulations

• Helium – inert, small molecule, non-flammable, highly sensitive
• Hydrogen (5% H₂ / 95% N₂ mix - commonly called forming gas) – cheaper, highly sensitive, but requires safety handling
  Choice depends on cost, sensitivity needs, and safety constraints

Yes. Modern leak testers integrate with automated assembly lines, using robotics, vision systems, and programmable logic controllers (PLCs) for real-time feedback and data logging. The cooperation between Nolek and ALPHR allows for the supply of a complete turnkey system.

• Porosity in castings or welds
• Improper sealing (gaskets, O-rings, adhesives)
• Material deformation during assembly
• Micro-cracks or damage during transport
• Incomplete joining or gluing processes.

• Use certified leak standards (calibrated leaks)
• Run regular reference tests
• Perform gauge R&R studies to verify system repeatability and reliability, this is often referred to as an Measuring System Analysis (MSA)
• Document traceability per ISO or FDA/QSR standards

• Non-destructive: Preserves the product (e.g., pressure decay, tracer gas)
• Destructive: Alters or destroys the part (e.g., burst tests, bubble tests on submerged sealed units