# > Understand ASTM F88 and its importance in testing seal strength for packaging. Learn about the Peel tests and their techniques. Source: https://lso-inc.com/medical-package-testing/standards/astm-f-standards/astm-f88/ --- # ASTM F88: The Importance of Seal Strength Tests [Get a Validation Plan Reviewed](https://lso-inc.com/solutions/packaging-validation/#intake-form) 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 / ASTM-F88 ## ASTM F88 Seal Strength Testing for Medical Device Packaging ASTM F88 / F88M is the industry-standard test method for measuring [**seal strength**](https://lso-inc.com/medical-package-testing/services/peel-strength-testing/) in flexible sterile barrier systems. It confirms the mechanical integrity of a package seal after manufacturing, sterilization, transit simulation, and shelf-life aging. Under [**ISO 11607**](https://lso-inc.com/medical-package-testing/standards/iso-11607/), seal strength testing is a **required component** of sterile barrier validation. At Life Science Outsourcing (LSO), we perform ASTM F88 seal strength testing as part of medical package validation and shelf-life programs, using calibrated tensile equipment and validated procedures. ### Video Overview: ASTM F88 Explained ## What ASTM F88 Measures ASTM F88 evaluates the **force required to peel open a sealed joint**, providing quantitative evidence of: - Seal uniformity - Adequate adhesive bonding or thermal seal strength - Package robustness after sterilization - Long-term performance following accelerated or real-time aging - Compliance with ISO 11607 packaging validation requirements **Q. What does ASTM F88 measure?** ASTM F88 measures the _strength of the seal itself_, not the material. It determines whether a sealed joint will maintain sterile integrity during the product’s expected shelf life. **Q. Is ASTM F88 required?** Yes. ASTM F88 is a recognized method for demonstrating sterile barrier performance under ISO 11607 and FDA expectations. ## Why Seal Strength Matters in Packaging Validation Seal strength is central to sterile barrier performance. A seal that is too weak may open prematurely, while one that is too strong may tear the material instead of peeling cleanly. F88 results support: - [Sterilization validation](https://lso-inc.com/validation/) (EtO, Steam, Gamma, eBeam) - [Accelerated](https://lso-inc.com/medical-package-testing/services/accelerated-aging/) and [real-time aging](https://lso-inc.com/medical-package-testing/services/real-time-aging/) shelf-life studies - Transit simulation testing ([ASTM D4169](https://lso-inc.com/medical-package-testing/standards/astm-d-standards/astm-d4169/), [ISTA](https://lso-inc.com/medical-package-testing/standards/ista/)) - Design verification and process validation **Q. What is an acceptable seal strength?** There is no universal minimum value. Acceptance criteria are set by the manufacturer based on material, seal process capability, and risk management. **Q. Does ASTM F88 replace burst testing?** No. F88 measures peel strength. Burst testing (ASTM [F1140](https://lso-inc.com/medical-package-testing/standards/astm-f-standards/astm-f1140/)/F2054) measures pressure resistance. ![peel\_test](https://lso-inc.com/api/media/file/peel_test-3.jpg) ## ASTM F88 Test Techniques A, B, and C ASTM F88 provides three test configurations. LSO documents all three  but performs **Technique A (Unsupported)**, the most commonly used method for flexible sterile barrier systems. **Technique A — Unsupported** The specimen is pulled apart without external support. - Most reflective of real-world opening - More sensitive to operator technique - LSO uses this method for customer studies **Technique B — Supported** The seal is supported by a plate to eliminate bending. **Technique C — Restrained** The specimen is clamped between rigid plates with an opening to expose only the seal. These three techniques measure the same property but may produce different numerical results. **Q. Which technique should I use?** For most pouches and Tyvek systems, Technique A is preferred. Technique B or C may be used when very thin films or stiff laminates require more controlled peel geometry. ## How ASTM F88 Testing Works (Step-by-Step Example) 1. **Condition Samples** Samples are conditioned to ambient laboratory conditions prior to testing. 2. **Prepare Test Strips** Cut uniform 1-inch (25 mm) wide strips perpendicular to the seal area and about 3 inches long.  The width of the strip can vary based on regulatory requirements or working area of the package. 3. **Load Specimen** Insert each end of the strip into the grips of a calibrated tensile tester. 4. **Set Crosshead Speed** LSO uses a speed of **250 mm/min** (placeholder).  Generally 200-300 mm/minute are used and can be customized. 5. **Pull to Seal Separation** The instrument measures force as the seal peels open. 6. **Record Data** Report: 7. - Maximum force (seal strength) - Average force (seal strength) - Force standard deviation 8. **Document Failure Mode** 9. - Adhesive Peel (which is the ideal peel) - Elongation - Delamination - Material tear - Cohesive failure - Incomplete seal (channels, seal creep, or narrow seals) **Q. What jaw speed should I use?** ASTM F88 recommends 200–300 mm/min. LSO uses 250 mm/min unless otherwise specified. **Q. How should F88 results be reported?** Maximum, average, the standard deviation, and sample failure mode. ## Sample Size & Seal Location Requirements 1. One of the most overlooked elements of F88 is sample planning. For compliance with ISO 11607, you must test: Recommended minimums: 2. - **Multiple seal locations** (3 manufacturer’s seal and 1 production seal locations are most typical) - **Multiple samples per location** (usually 30 or 60 depending on confidence and reliability calculations) - **Samples from each production lot** - **Samples from each aging time point** 3. - **30–60 replicates per seal location** - **Time-point testing** aligned with accelerated or real-time aging - **Representative sampling** for transit simulation **Q. How many samples do I need?** There is no fixed ASTM rule. Industry practice is 30–60 samples per location, per time point. **Q. Should I test across the entire seal?** Yes. It is best practice to test at least four locations to capture variability. ## Common Seal Failure Modes ASTM F88 requires documenting the type of seal failure. These modes provide insight into process capability: - **Adhesive Peel** – Clean, expected opening - **Elongation** – material stretches until seal peels or material breaks - **Material Tear** – Film tears before seal separates - **Delamination** – Laminates separate; indicates material issue - **Cohesive Failure** – Seal adhesive releases prematurely - **Incomplete Seal / Channels** – Process defect requiring immediate correction **Q. What failure modes are acceptable?** A clean peel is typically desired. Channels or incomplete seals, material breaks, elongation, and cohesive peels indicate failure. ![Peel Strength Testing for Medical Packaging – ASTM F88](https://lso-inc.com/api/media/file/peel-strength-testing-astm-f88-3.jpg) ## Equipment Requirements LSO uses calibrated tensile equipment designed specifically for medical package testing with: - Precision load cells - Pneumatic or mechanical grips - Jaw alignment controls - Verified speed accuracy (200-300 mm/min) - Routine calibration and preventive maintenance **Q. Can any tensile tester perform ASTM F88?** No. The instrument must meet speed accuracy and load accuracy defined by the standard. ## ASTM F88 and ISO 11607 Compliance Seal strength is explicitly required under **ISO 11607-1** as part of sterile barrier system performance testing. ASTM F88 supports: - **Design validation** - **Shelf-life validation** - **Package validation** - **Post-sterilization integrity verification** Regulators expect F88 data in: - 510(k) submissions - EU technical documentation - Change control justifications - Aging study reports **Q. Is F88 required for ISO 11607?** Yes — seal strength testing is mandatory. ## Frequently Asked Questions (FAQs) What does ASTM F88 measure? Peel strength of a sealed joint. Which technique does LSO use? Technique A (Unsupported). What jaw speed is recommended? 200–300 mm/min; LSO uses 250 mm/min. Does ASTM F88 detect defects in the seal? Yes — incomplete seals are considered failure modes. Is ASTM F88 required under ISO 11607? Yes — it is part of sterile barrier validation. How many samples do I need? Typically, 30–60 per location, per time point. ## Talk to a Packaging Specialist Get expert guidance on seal strength testing and packaging validation. ## Ready to get started? 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