Knowledge Base
Burst Strength Testing – What It Is and Why It Matters
Burst strength testing in flexible packaging is the process of applying increasing internal pressure to a sealed package until it fails – measuring the maximum pressure the package can withstand before rupture. It is a fundamental method for evaluating seal strength, material performance, and overall package robustness.
Where leak detection identifies defects that already exist in a sealed package, burst testing evaluates the structural performance of the package itself. It answers a specific and essential question for quality, R&D, and operations experts: how strong is this package, and is the sealing process consistently producing to specification?
What does burst testing measure?
A burst test measures the maximum internal pressure – expressed in kPa, mbar, or PSI – at which a package seal or structure fails. It evaluates seal strength performance, the integrity of the heat seal bond, material resistance to internal pressure, and overall package robustness under simulated stress conditions.
Why does it matter?
Seals that pass visual inspection may still be structurally weak – vulnerable to failure during transit, stacking, or in the hands of the consumer. Burst testing reveals these weaknesses before they become market failures, giving quality teams the data they need to validate sealing process settings and protect brand reputation.
Applicable standards: ASTM F2054, ASTM F1140
The BT Integra from Industrial Physics is a burst strength tester designed for flexible packaging quality assurance – delivering accurate, repeatable results that support both production-line quality control and R&D seal validation.
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FAQs
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Sealing process validation is the process of confirming that a packaging machine’s sealing parameters – temperature, dwell time, and pressure – are consistently producing seals that meet the required strength specification. Burst testing is one of the primary tools used to achieve this.
During initial process setup, burst testing is used to establish the relationship between sealing parameters and seal strength – identifying the combination of temperature, dwell time, and pressure that reliably produces seals above the required threshold. This data forms the basis of the validated process window.
Once the process is in production, regular burst testing of samples from each run confirms that seal strength is being maintained within the validated range. A drop in burst strength is an early indicator of process drift – whether from seal jaw wear, temperature variation, or a change in film characteristics – allowing corrective action before the issue results in defective product reaching market.
The BT Integra captures and logs result data on every test, making it straightforward to track seal strength trends over time and build the documented evidence base that process validation and audit requirements demand. For quality and R&D teams, this turns routine burst testing from a simple pass/fail check into a continuous source of process intelligence.
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The BT Integra inflates a sealed package sample with air at a controlled, defined rate – continuously monitoring internal pressure as it rises. When the seal or package material reaches its structural limit and fails, the instrument detects the resulting pressure drop and records the peak pressure value reached at the point of failure.
This peak pressure value is the burst strength result for that sample. The BT Integra logs the result along with relevant test parameters, building a data record across samples and production runs that quality and R&D teams can use for trend analysis and process validation.
The test is conducted on a sample basis – it is a destructive method, meaning the package is pressurized to failure and cannot be returned to the line. This is why burst testing is used alongside, not instead of, inline integrity testing methods. To see the BT Integra in operation, watch the demonstration video.
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Burst strength testing is a quality assurance method in which a sealed flexible package is inflated with air or gas at a controlled rate until the seal or material fails. The maximum pressure reached at the point of failure – the burst strength – is a direct measure of how structurally robust the package and its seals are.
For quality managers and R&D specialists in flexible packaging production, this matters for several reasons. A package that passes visual inspection may still have seals that are insufficiently strong to survive the rigours of distribution, stacking, or consumer handling. Burst testing reveals these weaknesses before they become market failures – giving teams the data they need to validate sealing process settings, identify process drift, and protect the integrity of the product inside.
Burst testing is also an important tool for new packaging development. When evaluating new film structures, seal geometries, or heat seal parameters, burst strength data provides a quantitative basis for comparison that subjective assessment cannot match. The BT Integra from Industrial Physics supports both production QC and R&D applications, delivering the repeatability and precision that meaningful seal validation requires.
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Overview Burst strength testing is one of the most widely used methods for evaluating the performance of sealed flexible packaging. It applies controlled internal pressure to a package until failure, measuring the point at which the seal or material gives way. For quality managers, R&D specialists, and operations experts working across flexible packaging production, burst…
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