Information on the most widely used ASTM standards within the materials testing industry
ASTM D1709: Standard Test Methods for Impact Resistance of Plastic Film by the Free-Falling Dart Method
ASTM D1709 test methods cover the determination of the energy that causes plastic film to fail under specified conditions of impact of a free-falling dart. This energy is expressed in terms of the weight (mass) of the missile falling from a specified height which would result in 50 % failure of specimens tested. It is widely used in the packaging industry to evaluate film durability during handling, transportation, and end-use.
Test Principle:
The test measures the impact failure weight (Wₚ), defined as the statistically estimated mass of a dart (falling from a fixed height) that causes 50% of specimens to fail. The core principle is to simulate sudden impact (e.g., during shipping/handling) and quantify the energy required to rupture the film. Failure is defined as any observable break (by touch or backlighting).
A weighted dart is dropped from a fixed height onto the center of a clamped film specimen;
Failure is defined as visible rupture through the film (not just puncture);
The Bruceton staircase method adjusts dart mass based on previous results (increase after pass, decrease after failure);
Results are expressed as the Impact Failure Weight (IFW): mass causing 50% failure probability of specimens;
Impact energy = mass × gravity × height (Joules).
Two test methods are described:
1. Test Method A employs a dart with a 38.10 ± 0.13-mm (1.500 ± 0.005-in.) diameter hemispherical head dropped from a height of 0.66 ± 0.01 m (26.0 ± 0.4 in.).
This test method can be used for films whose impact resistances require masses of about 50 g or less to about 6 kg to fracture them.
2. Test Method B employs a dart with a 50.80 ± 0.13-mm (2.000 ± 0.005-in.) diameter hemispherical head dropped from a height of 1.52 ± 0.03 m (60.0 + 0.25, −1.70 in.). Its range of applicability is from about 0.3 kg to about 6 kg.
| Parameter | Method A | Method B |
|---|---|---|
| Dart Head Diameter | 38.10 ± 0.13 mm (1.500 ± 0.005 in) | 50.80 ± 0.13 mm (2.000 ± 0.005 in) |
| Drop Height | 0.66 ± 0.01 m (26.0 ± 0.4 in) | 1.50 ± 0.05 m (60.0 ± 2.0 in) |
| Mass Range | 50 g to 2 kg | 0.3 kg to 6 kg |
| Film Type | Thin films, low impact resistance | Thicker films, higher impact resistance |
Test Device of ASTM D1709:
| Falling Dart Tester | A vertical guide tube, release mechanism (electromagnetic/pneumatic, with a centering device like a plumb bob), and a dart assembly.
|
| Darts | Hemispherical heads (Method A: 38.10 mm; Method B: 50.80 mm) with a 6.5 ± 1 mm diameter steel shaft (≥115 mm long) for incremental weights. Materials include stainless steel, phenolic, or composite. |
| Incremental Weights | Stainless steel/brass cylinder, with ±0.5% weight accuracy. Method A: 31.75 mm diameter; Method B: 44.5 mm diameter. |
| Specimen Clamp | A two-piece annular clamp (inside diameter: 125 ± 2.0 mm) with rubber gaskets (3.18 ± 1 mm thick, 50–60 Shore A hardness) to minimize thickness effects. Abrasive paper (crocus cloth) may be added to prevent slippage. |
| Positioning Device | Controls drop height (0.66 m for Method A, 1.52 m for Method B) and ensures vertical alignment with the specimen center |
Test Specimen Information
150 mm × 150 mm (6 in × 6 in) minimum, 254 mm × 254 mm (10 in × 10 in) typical;
A minimum of 30 specimens are required for the test;
Test Applications (Industry Fields)
Industry Application
Packaging: Flexible packaging films (food, pharmaceutical, industrial)
Agriculture: Greenhouse films, mulch films, silage bags
Medical: Medical device packaging, sterile barrier films
Consumer: Goods Shrink wrap, stretch film, laminates
Industrial: Protective films, geomembranes, construction films
Key Use Cases:
Material selection and comparison
Quality control during production
Performance validation for regulatory compliance
Failure analysis and product improvement
Transport simulation testing
Detailed Test Procedure of ASMT D1709 Free falling dart impact tester:
Pre-test Preparation
Select Method A or B based on expected impact resistance;
Condition specimens per standard requirements;
Calibrate equipment (dart mass, drop height, clamping force).
Testing Sequence
Mount specimen securely in clamp (no wrinkles or tension);
Set initial dart mass (estimated to cause ~50% failure);
Release dart and record pass/fail result;
Adjust mass by fixed increment (typically 5-10% of current mass);
Repeat until minimum 20 specimens tested with at least 5 reversals.
Data Analysis
Apply Bruceton staircase calculation to determine 50% failure mass;
Calculate standard deviation and confidence interval;
Report IFW, test method, conditioning, and equipment details.
Related Standards
| Standard | Relationship |
|---|---|
| ISO 7765-1:1988 | Technically equivalent with deviations |
| JIS K7124-1 | Similar free-falling dart method |
| ASTM D4272 | Standard Test Method for Total Energy Impact of Plastic Films by Dart Drop |
| ASTM D3420 | Standard Test Method for Pendulum Impact Resistance of Plastic Film |
Related products and device
Related Standard
ISO 7765-1:1988 Plastics film and sheeting — Determination of impact resistance by the free-falling dart method
Part 1: Staircase methods
ISO 7765-1 and ASTM D1709 specifies methods for the determination of the energy, that causes plastics films and sheet less than 1 mm in thickness to fail under specified conditions of impact of a free falling dart from a specified height, that would result in failure of 50 % of the specimens tested. Two methods are described. Method A employs a dart with 38 mm diameter hemispherical head, dropped from a height of 0,66 m, and method B employs a dart with a 50 mm diameter hemispherical head dropped from a height of 1,50 m. The measurement technique is the staircase method.
Drop Dart Impact Resistance of Plastic Film ASTM D1709, ISO 7765
FAQs about ASTM D1709 Free-Falling Dart Impact Test
Q1: What is the primary purpose of the ASTM D1709 test?
A: The ASTM D1709 test measures the impact resistance of thin plastic films (nominal thickness ≤ 0.25 mm) by determining the impact failure weight—the statistically estimated weight of a free-falling dart (from a fixed height) that causes 50% of specimens to fail. It is used for specification compliance, material selection, quality control, and correlating lab results with real-world performance (e.g., shipping/handling impacts).
Q2: Why is the ASTM D1709 test important for plastic film materials?
A: The test is critical because it:
Simulates sudden impacts to predict field durability (e.g., punctures during transport).
Ensures films meet performance standards for packaging, agriculture (greenhouse/mulch films), and consumer goods (disposable gloves).
Helps manufacturers optimize material formulations for impact resistance.
Prevents product damage or safety risks (e.g., packaging heavy items, protective barriers).
As noted in standard, it establishes a quantitative metric for comparing films and validating real-world performance.
Q3: What are the two main test methods in ASTM D1709, and how do they differ?
A: ASTM D1709 defines two test methods for different film strengths:
Method A: Uses a dart with a 38.10 ± 0.13 mm (1.500 ± 0.005 in.) diameter hemispherical head dropped from 0.66 ± 0.01 m (26.0 ± 0.4 in.). Applies to films requiring 50 g to 6 kg of mass to fracture.
Method B: Uses a dart with a 50.80 ± 0.13 mm (2.000 ± 0.005 in.) diameter hemispherical head dropped from 1.52 ± 0.03 m (60.0 +0.25/-1.70 in.). Covers films requiring 0.3 kg to 6 kg of mass.
Q4: How is "failure" defined in ASTM D1709?
A: Failure is any break through the film that can be observed readily by feeling or by viewing the specimen under backlighted conditions. Tests on materials that do not break are invalid.
Q5: Can ASTM D1709 results be compared with other impact tests?
A: No, results cannot be directly compared with other methods (e.g., ASTM D3420, D4272) due to differences in test variables (missile velocity, dart diameter, film thickness). ASTM D1709 measures initiation energy (failure start), while D4272 measures initiation + completion energy. Correlation requires sufficient data.
Q6: What does “50% failure weight” mean?
A: It is the dart mass at which 50% of the tested film samples rupture under the test conditions. It is the main result reported from ASTM D1709.
Q7: Can I use ASTM D1709 for plastic sheets thicker than 1 mm?
A: No. For thicker rigid/semi‑rigid sheets, use other standards such as ASTM D3420 or instrumented impact methods.
Q8: How does ASTM D1709 differ from ISO 7765‑1?
A:ASTM has much tighter dart diameter tolerances.
ASTM allows an optional group test method; ISO does not.
ASTM requires a vented dart well; ISO does not specify it.
Drop height tolerances also differ between the two standards.
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