Photo source

Passive Windoor using Sparklike Laser PortableTM to measure argon concentration in insulating glass units as part of quality control. Photo: Sparklike

Date: 27 May 2026

Ensuring the right argon fill rate is essential for high-performance insulating glass — and Passive Windoor is taking quality control to the next level with direct gas concentration verification.

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manufactures high-performance system windows and doors designed to meet building requirements. Their products are expected to deliver consistent thermal performance, airtightness, and long-term reliability. To meet these requirements, insulating glass unit quality must be controlled beyond visual inspection and predefined process settings.

Gas filling rate is one of the key parameters affecting insulating performance. For Passive Windoor, controlling and verifying this parameter is part of routine production quality management. Read.

Production Requirements and Company Objective

Passive Windoor’s production environment is characterized by:

High-performance targets for window and door systems
Multiple insulating glass configurations
Continuous process optimization
Defined internal quality criteria for insulating glass units

The company’s objective is to ensure that insulating glass units consistently meet thermal performance requirements while maintaining stable, repeatable production processes supported by measurable data.

The Problem: Gas Filling Was Not Directly Verified

Insulating gas concentration has a direct impact on the thermal performance of an insulating glass unit. During production, gas filling is typically controlled through predefined parameters, such as:

Gas filling time
Gas flow rate
Cavity size and spacer configuration
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These parameters support repeatability, but they do not confirm the actual gas concentration inside a sealed insulating glass unit.Read our article .

Passive Windoor identified the following limitations:

Gas concentration could vary between insulating glass units despite identical filling parameters
Filling losses caused by sealing issues or handling could remain undetected
Finished units could not be verified against internal gas concentration targets

Without direct measurement, gas filling quality was based on process assumptions rather than verified results.

The Solution: Measuring the Gas Filling Rate of Finished IGUs

In 2022, Passive Windoor introduced to measure argon concentration in insulating glass units as part of quality control.

The device allows them to:

Measure gas concentration non-invasively, without damaging the insulating glass unit
Perform measurements on finished, sealed units
Carry out checks during production, final inspection, or on-site
Collect measurement data to verify the effectiveness of gas filling parameters

Because the measurement is optical and non-destructive, it does not affect the insulating glass unit and can be repeat to use as needed.

Use in Daily IGU Production and Quality Control

Sparklike Laser Portable^TM is used to verify that defined gas filling parameters result in the intended gas concentration in finished units. Measurement results are applied to:

Confirm compliance with internal gas concentration targets
Detect deviations related to gas filling or sealing
Adjust filling parameters based on measured outcomes
Support communication between production and quality teams using shared data

Gas measurement complements process control rather than replacing it.

The Result: Improved Process Control and Consistent IGU Quality

By combining controlled gas filling parameters with direct measurement of finished insulating glass units, Passive Windoor improved visibility into actual gas content across production batches. This enabled:

More consistent thermal performance of windows and doors
Verification that filling parameters deliver the intended results
Faster identification of process deviations
Documented quality control based on measured data

How Quality-Focused IGU Manufacturers Measure and Verify Gas Filling Rate

Manufacturers with strict quality requirements typically apply several layers of control:

Process Control During Gas Filling

Gas filling parameters such as filling time, flow rate, cavity volume, and unit configuration are controlled during production. This supports repeatability but does not confirm final gas concentration.

Sample-Based or Laboratory Testing

Destructive testing and laboratory analysis can provide accurate results but are slow and not suitable for frequent checks. In addition, tested insulating glass units cannot be delivered to customers and are therefore considered production waste, which creates additional material and cost losses. As a result, this approach is typically limited to audits or occasional verification.

Non-Invasive Measurement of Finished IGUs

Measuring gas filling rate directly on sealed insulating glass units confirms actual gas concentration. This allows manufacturers to:

Verify finished units without damage
Detect gas losses related to sealing or handling
Measure double and triple glazed units
Maintain traceable quality documentation

This approach enables verification of gas filling parameters under real production conditions. Read

Summary

For insulating glass unit manufacturers, controlling gas filling parameters alone is not sufficient. Measuring the gas filling rate of finished units verifies whether those parameters produce the intended result. This supports stable production, consistent thermal performance, and documented quality compliance.