ASTM D4226, D5420 Gardner Impact Test

Falling Dart Impact Test (Gardner Impact) by ASTM D4226 and ASTM D5420 testing impact resistance of flat, rigid plastic materials. The impact test is needed for products that are damaged by some extent of impact force and several types of organic coatings.

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Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation
Results and Deliverables

Overview

ASTM D4226 and ASTM D5420 define standardized falling-weight impact test methods for evaluating the resistance of rigid plastic sheets and laminates to fracture from a single concentrated impact. The Gardner impact test is one of the most widely used impact-resistance tests for flat plastic panel products, providing a practical pass/fail measure of toughness under conditions representative of dropped-object or localized-impact scenarios.

Both standards use a falling dart or striker of defined geometry dropped from a measured height onto a clamped flat plastic specimen. ASTM D4226 covers rigid plastic sheets directly, while ASTM D5420 is a more general instrumented or non-instrumented impact method applicable to both plastics and laminated systems. The stup method (mean failure energy) is used to statistically determine the 50% probability-of-failure energy from a series of specimens tested at incrementally varied drop heights.

Scope, Applications, and Benefits

Scope

ASTM D4226 / D5420 evaluates:

Impact resistance (failure energy) of rigid plastic sheets
Mean failure energy (F₅₀) using the stup statistical method
Effect of thickness on impact resistance
Low-temperature impact behavior of plastic panels
Comparative impact ranking of plastic sheet products
Pass/fail evaluation at the specified impact energy

Applications

Acrylic, polycarbonate, and PVC sheet quality control
Laminated safety glazing impact performance
Printed circuit board (PCB) laminate impact resistance
Automotive glazing and lighting panel qualification
Architectural plastic sheet specification
Protective panel and barrier material qualification
Consumer product plastic panel evaluation

Benefits

Provides practical impact resistance data for flat plastic panels
Uses a statistical approach for precise failure energy determination
Simple and rapid test for production quality control
Detects product brittleness and processing defects
Supports material selection for impact-critical applications
Enables compliance with panel product specifications

Test Process

Specimen Preparation

Flat plastic sheet specimens are cut to the standard size and thickness is measured.

Temperature Conditioning

Specimens are optionally conditioned at low or elevated temperature.

Impact Testing

Dart is dropped from incrementally varying heights onto clamped specimens; pass/fail is recorded for each drop.

Statistical Analysis

Stup method is used to calculate the mean failure energy (F₅₀) from the series of pass/fail results.

Technical Specifications

Parameter	Details
Test Principle	Falling dart impact on clamped flat specimen (stup method)
Dart Geometry	Specified hemispherical or flat-tipped striker
Applicable Materials	Rigid plastic sheets and laminates
Output Units	J (mean failure energy, F₅₀)
Measured Outputs	Mean impact failure energy (F₅₀), pass/fail at specified energy

Instrumentation Used for Testing

Gardner falling-weight impact tester
Calibrated drop weights and guide tube
Clamping fixture for flat specimens
Micrometer for specimen thickness
Temperature conditioning chamber
Statistical analysis software for the STUP method

Results and Deliverables

Mean failure energy (F₅₀) values
Pass/fail record for each specimen
Statistical analysis output (stup method)
Specimen thickness data
Temperature-dependent impact results (if applicable)
Compliance documentation and quality assurance reports

Why Choose Infinita Lab for ASTM D4226 and D5420?

Infinita Lab is a trusted USA-based testing laboratory offering ASTM D4226 and D5420 testing services across an extensive network of accredited facilities across the USA.

Infinita Lab is built to serve the full spectrum of modern testing needs—across industries, materials, and methodologies. Our advanced equipment and expert professionals deliver highly accurate and prompt test results, helping businesses achieve quality compliance and product reliability.

Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote

Frequently Asked Questions

ASTM D4226 and D5420 evaluate impact resistance of plastic films using the Gardner impact method. They measure energy required to cause failure, helping assess durability and toughness under sudden impact conditions.

Key parameters include drop height, weight, specimen thickness, and support conditions. Controlled impact conditions ensure accurate measurement of resistance to sudden force applied on plastic films.

The test measures impact energy required to cause failure, typically expressed in joules. Results indicate toughness and resistance of plastic films to impact damage.

ASTM D4226 and D5420 apply to plastic films such as polyethylene, polypropylene, and multilayer films used in packaging and industrial applications requiring impact resistance.

ASTM D4226 and D5420 results depend on test setup and sample condition. They may not fully represent real-world impact scenarios, requiring additional testing for comprehensive material performance evaluation.