# > Seal strength (ASTM F88) measures the force to peel a seal apart; seal integrity (ASTM F1929 / F2096 / F3039) detects leaks and channel defects. Compare the tests, see which ISO 11607 requires, and learn when you need each for medical device packaging. Source: https://lso-inc.com/seal-strength-vs-seal-integrity-testing/ --- # Seal Strength vs. Seal Integrity Testing: What’s the Difference? Two distinct ISO 11607 requirements for sterile barrier systems — one measures how strongly a seal holds, the other confirms it has no leaks. Here is what each test covers and when you need it. [Get a Packaging Validation Plan Reviewed](https://lso-inc.com/solutions/packaging-validation/#intake-form) [See Testing Standards](https://lso-inc.com/standards/) ![Seal Strength vs. Seal Integrity Testing: What’s the Difference?](https://lso-inc.com/api/media/file/Medical%20pouch%20testing%20methods%20comparison.webp) FDA-Registered Manufacturing Facility ISO 13485 Certified Quality System 12 Cleanrooms Class 5–8 125,000+ Sq Ft Regulated Manufacturing 3 Facilities CA | NH | Costa Rica ISO 17025 Accredited Packaging Lab **Seal strength** and **seal integrity** are two different things. Seal strength is the mechanical force required to peel a package seal apart, measured per [ASTM F88](https://www.astm.org/standards/f88). Seal integrity is the absence of leaks or channel defects in the sterile barrier, detected by methods such as [ASTM F1929](https://www.astm.org/standards/f1929), [F2096](https://www.astm.org/standards/f2096), or [F3039](https://www.astm.org/standards/f3039). ISO 11607 requires evidence of both. By the LSO Packaging & Validation team · Last reviewed June 2026 ## Seal Strength vs. Seal Integrity: Test Methods at a Glance The standards a medical device packaging validation typically draws on, and what each one proves. Comparison of ASTM seal strength and seal integrity test methods for medical device packaging, including the standard, what it measures, whether it is destructive, and when it is required. | Method | Standard | What it measures | Destructive? | When required | | --- | --- | --- | --- | --- | | Seal strength (peel) | ASTM F88 | Mechanical force required to peel a seal apart | Yes | Design & process validation; material or sealing changes | | Dye penetration, porous | ASTM F1929 | Leak channels in porous (e.g. Tyvek) seals | Yes | Integrity of porous sterile barrier seals | | Internal pressure (bubble) | ASTM F2096 | Gross leaks (to ~250 µm) via underwater pressurization | Yes | Whole-package gross-leak screening | | Dye penetration, nonporous | ASTM F3039 | Leak channels in nonporous foil/film barriers | Yes | Integrity of nonporous flexible packages | | Visual inspection | ASTM F1886 | Visible channels, voids, and seal defects | No | Routine in-process & 100% release inspection | ## Why ISO 11607 requires both ### Seal strength: how strong is the seal? [ASTM F88](https://www.astm.org/standards/f88) pulls a strip of the seal apart and records the peak force, reported in newtons per 15 mm (or lb/in). A seal that is too weak can burst during sterilization, distribution, or aseptic presentation; one that is too strong can tear the porous web on opening and shed fibers into the sterile field. Because the test destroys the sample, seal strength is used for design and process validation under [ISO 11607-2](https://www.iso.org/standard/70800.html) — not for 100% release. ### Seal integrity: does the seal leak? Even a strong seal can hide a microscopic channel that lets microbes in, so integrity is tested separately. [ASTM F1929](https://www.astm.org/standards/f1929) wicks a dye through channels in porous (Tyvek) seals; [F3039](https://www.astm.org/standards/f3039) does the same for nonporous foil and film; [F2096](https://www.astm.org/standards/f2096) pressurizes the package underwater to reveal gross leaks down to roughly 250 µm. Under [ISO 11607-1](https://www.iso.org/standard/70799.html), integrity of the sterile barrier system is a separate, mandatory requirement — passing a strength test does not satisfy it. For most Class II/III sterile devices, a complete packaging validation runs [seal strength and seal integrity testing together](https://lso-inc.com/solutions/packaging-validation/), often alongside accelerated aging and distribution simulation, in an ISO 17025 accredited packaging lab. ## Seal Strength vs. Seal Integrity: FAQ Is seal strength the same as seal integrity? No. Seal strength is the mechanical force needed to peel a seal apart (measured per ASTM F88), while seal integrity is the absence of leaks or channel defects in the sterile barrier (verified by methods such as ASTM F1929, F2096, or F3039). A package can have adequate seal strength yet still fail integrity if a microscopic channel lets contaminants through. What’s the difference between seal strength and seal integrity testing? Seal strength testing (ASTM F88) quantifies how strongly a seal resists peeling, reported as force per unit width. Seal integrity testing detects whether the package leaks at all — dye penetration (ASTM F1929 for porous, F3039 for nonporous) and internal-pressure bubble tests (ASTM F2096) reveal channels and breaches. Strength is a "how strong" measurement; integrity is a "pass/fail" for leaks. Which test does FDA or ISO 11607 require? ISO 11607-1 — the consensus standard the FDA recognizes for terminally sterilized medical device packaging — requires demonstrating both seal strength and seal integrity for the sterile barrier system. Most validation programs run ASTM F88 for strength alongside an integrity method (F1929, F2096, or F3039) chosen to match the package material. Is ASTM F88 destructive? Yes. ASTM F88 is a destructive test — the seal is peeled apart to measure the force at failure, so the package cannot be used afterward. It is used for design validation, process qualification, and verifying material or sealing changes, not for 100% release inspection. What does ASTM F1929 test? ASTM F1929 is a dye-penetration test for seal integrity. A low-surface-tension dye is applied to the seal of a porous package (such as a Tyvek pouch); if the dye wicks through a channel within the time limit, the seal fails. It detects leak paths that a visual inspection would miss. Do I need both tests for medical device packaging? Usually yes. ISO 11607 treats seal strength and seal integrity as separate requirements, so a typical validation includes ASTM F88 for strength and an integrity method (F1929, F2096, or F3039). Strong seals that still leak — or leak-free seals too weak to survive distribution — both fail in the field. ## Related reading [ ### Dye Penetration Testing — Recent ASTM Enhancements How ASTM F1929 / F3039 dye-penetration methods find seal-integrity defects. ](https://lso-inc.com/news/dye-penetration-testing-recent-astm-enhancements/) ### Gross Leak Test: Essential for Package Integrity Where the ASTM F2096 internal-pressure bubble test fits in integrity testing. ](https://lso-inc.com/news/how-gross-leak-testing-supports-medical-device-packaging-integrity/) ### 6 Methods for Medical Package Sterile Barrier Validation Testing The full method set — seal strength and seal integrity — at a glance. ](https://lso-inc.com/news/methods-for-medical-package-sterile-barrier-validation-testing-infographic/) ### Medical Device Packaging Validation and ISO 11607 How seal strength and integrity fit into a complete ISO 11607 validation. ](https://lso-inc.com/news/medical-device-packaging-validation-and-iso-11607/) ## Validate your seal strength and seal integrity with one lab LSO’s ISO 17025 accredited, ISTA-certified packaging lab runs ASTM F88, F1929, F2096, and F3039 — with data you can submit to FDA. Send us your package and we will review your validation plan. [Get a Packaging Validation Plan Reviewed](https://lso-inc.com/solutions/packaging-validation/#intake-form) [See Testing Standards](https://lso-inc.com/standards/) Or call us directly: [(714) 672-1090](tel:7146721090)