TME Leak Testing Orifice Size: Understanding Sensitivity and Calibration

Overview

This video explores how orifice size relates to leak test sensitivity and calibration when using the TME WORKER Integra Leak and Flow Tester. You’ll see how calibrated reference leak orifices are used to set the sensitivity of a leak testing process, why selecting the correct orifice size is critical to detecting the leaks that matter, and how this knowledge helps quality control and R&D teams establish reliable, validated leak testing procedures for packaging and product applications. 

Key Concepts Covered

• What a reference leak orifice is and how it is used to calibrate a leak test 
• How orifice size relates to the sensitivity of a pressure decay leak test 
• How to select the appropriate orifice size for a given product and leak specification 
• The role of the WORKER Integra in precision pressure decay, vacuum decay, and flow leak testing 
• How calibrated orifices integrate into a validated leak testing process for packaging and medical devices 

What You’ll Learn in This Video

• 0:15 – Introduction to leak orifice sizing and the 5 micron standard
• 0:21 – How orifice size relates to flow rate and pressure – the garden hose analogy
• 0:40 – How a leak orifice becomes your traceable leak standard during testing
• 1:09 – What 5 microns means in physical terms – microscopic scale explained
• 1:34 – The LAO4 leak orifice accessory: construction, quick connect and filter design
• 1:50 – Typical detection threshold for leak testing and why 5 microns is the benchmark
• 2:09 – Inline fault detection using a T-adapter for positive pressure testing
• 2:36 – How orifice specifications are set: pressure, flow rate (cc/min) and hole size
• 3:04 – Sending orifices to a certified lab for calibration and what that process involves
• 3:27 – How to identify a blocked or damaged orifice and when to send it for recertification
• 4:00 – Filter protection: 5-10 micron bronze inline filters on both sides of the orifice

Understanding Orifice Size in Leak Testing

Leak testing using the pressure decay method works by pressurising a sealed package or product, isolating the pressure source, and measuring how quickly pressure falls during a defined test period. The rate of pressure decay is directly related to the size of any leak present: a larger leak causes a faster decay; a smaller leak causes a slower, more gradual decay that the instrument’s sensors must be capable of detecting. 

To validate that a leak test process is capable of detecting a leak of a specific size, a calibrated reference orifice is used. A reference orifice is a precision-drilled hole of a known, verified diameter that produces a known, consistent airflow at a given pressure. By testing the instrument against a reference orifice – and confirming that it reliably detects the pressure decay that the orifice produces – the quality team can demonstrate that their test process is sensitive enough to detect any real leak that is equal to or larger than that orifice size. 

Selecting the right orifice size is therefore a critical decision in leak test method development. The orifice must be small enough to represent the smallest defect that is considered unacceptable for the product – but not so small that the instrument’s test cycle is too long or the test becomes impractical for production use. The TME WORKER Integra’s high resolution (pressure changes as low as 0.0001 psi are detectable) gives it the sensitivity needed for very fine orifice calibration, making it well-suited to the demanding leak specifications required in pharmaceutical, medical device, and electronics applications. 

Typical applications include: 

• Pharmaceutical and medical device packaging leak test validation 
• Flexible packaging seal integrity process development 
• Electronics and sealed component leak test calibration 
• Reference orifice selection for packaging quality control programmes 
• ASTM and ISO packaging integrity test method development 

Technical Summary

For full technical specifications on the WORKER Integra, visit the product page to download the product sheet. 

Speak With an Expert

If you’re looking for the right leak testing solution or need help developing a validated leak test method, our team is here to help. Contact our experts today.