Standard 25 mm
Pneumatic Vice Action Grip
Pneumatic vice action grips clamp the full specimen width at a constant, even pressure — which is what stops one side slipping or tearing before the other.
SpecificationsTesting standard
ISO 8871-5
Elastomeric parts for parenterals and for devices for pharmaceutical use — Part 5: Functional requirements and testing
Written and technically reviewed by Dak System Inc. engineeringLast reviewed
ISO 8871-5 gives the functional requirements and test methods for elastomeric closures used with vials and pierced by injection needles — penetration force, fragmentation, self-sealing and, where relevant, the equivalent tests with spikes. The forces involved are small, so the load cell dominates the measurement quality.
At a glance
- Test type
- Load–deflection & proof load
- Published by
- ISO
- Edition
- ISO 8871-5:2025
- Runs on
- Series 7200 and Series 9000
What the test does
A closure is mounted as it is used — crimped onto a vial or held in the equivalent service geometry — and a new needle of the specified gauge is driven through it at a constant controlled rate while the force is recorded. The maximum force during piercing is the penetration force. For fragmentation the piercing procedure is repeated a prescribed number of times, the container contents are then filtered, and the rubber fragments recovered are counted. Self-sealing is assessed by withdrawing the needle and checking, by the specified means, that the closure has closed behind it.
What it measures, and why it matters
Three separate things about the same component. Penetration force describes whether the closure can be pierced cleanly in clinical use — too high and it resists the needle, too low and it may not have the compression needed to seal. Fragmentation describes whether piercing chips rubber into the drug, which is a particulate contamination event in an injectable and therefore a regulatory finding rather than an engineering preference. Self-sealing describes whether the closure remains a barrier after the needle leaves. A closure can pass any one of the three and fail another, which is why all three are specified.
What is assessed
Three separate questions about the same closure: how hard it is to pierce, whether piercing chips it, and whether it closes again afterwards.
- Penetration force
- The force to drive a needle through the closureToo high and a nurse cannot pierce it cleanly; too low and the closure may not seal.
- Fragmentation
- Rubber particles released into the vial by piercingA fragment in an injectable is a particulate contamination event, which is why this is counted rather than judged.
- Self-sealing
- Whether the closure reseals after the needle is withdrawn
- Needle condition
- New and to the specified gauge for each piercingA blunted needle raises penetration force and increases coring, so reusing one changes both results.
- Closure support
- Mounted as it is used, in or on the container
- Condition the closures before testing
- As specifiedDakElastomer stiffness moves with temperature, and penetration force follows it directly.
Fragmentation is counted, not estimated. It is a particulate contamination test wearing the clothes of a mechanical one, and the count is what a regulator will read.
Test speed
- Rate
- Constant and controlledElastomers are rate-sensitive, so an uncontrolled rate makes penetration forces incomparable.
- Penetration force
- Recorded as the maximum during piercing
- Fragments
- Counted after filtration
- Use a fresh needle every piercing
- Without exceptionDak
Calculations
Penetration forceF
The maximum force recorded while the needle passes through the closure
A measured force compared against a requirement, not a derived quantity.
Fragmentationn
Number of visible rubber fragments recovered per number of piercings
Reported as a count against a limit. It is a particulate result, and it is why the piercing procedure is prescribed so tightly.
How the test runs
- 01Identify the closure type and the container or device it serves.
- 02Read the applicable requirements from ISO 8871-5 and the relevant container standard.
- 03Condition the closures as specified.
- 04Select a load cell whose range suits a few newtons, not the frame's capacity.
- 05Verify the load cell class at that working load.
- 06Mount the closure as it is used, in or on its container.
- 07Fit a new needle of the specified gauge for each piercing.
- 08Drive the needle through at the specified constant rate.
- 09Record the maximum penetration force.
- 10For fragmentation, filter the vial contents and count the rubber fragments recovered.
- 11For self-sealing, withdraw the needle and check the closure reseals by the specified means.
The fixture this method needs
What the report has to contain
- Reference to ISO 8871-5 and the edition
- Closure type, elastomer formulation and any coating
- Container or device the closure was tested with
- Conditioning applied
- Needle gauge and confirmation that a new needle was used for each piercing
- Load cell capacity and verified class at the working load
- Rate of penetration
- Penetration force results against the requirement
- Fragment count and the filtration method
- Self-sealing result
What the machine must be capable of
Very small forces measured well. Penetration forces sit at a few newtons, and an accuracy class applies only down to a stated fraction of load cell capacity — below that fraction the class no longer describes the instrument. A frame carrying a cell sized for materials testing will produce a precise-looking number with no traceability at this load, so the cell is chosen for the force. Beyond that the requirement is modest: a constant controlled crosshead rate, a holder that reproduces the service geometry, and a needle mount that keeps the needle axial.
What goes wrong in practice
Reusing needles is the most damaging error, because a needle blunts after a single pass through rubber and a blunt point both raises the penetration force and cores far more readily — inflating two results at once, progressively, through a test series. Oversized load cells are next. Mounting the closure in a convenient fixture rather than in its container changes how it deforms. And driving the needle at an uncontrolled rate makes penetration forces incomparable between operators, since elastomers respond to rate directly.
ISO 8871-5 within the ISO 8871 series
| Part 5 | Other parts | |
|---|---|---|
| Covers | Functional requirements and testing | Extractables, identification, and other properties |
| Questions asked | Penetration, fragmentation, self-sealing | Chemical and physicochemical behaviour |
| Equipment | A low-capacity testing machine | Analytical laboratory |
| Read with | The container standard for the vial or spike | The same |
Part 5 is the mechanical part of a series that is otherwise largely chemical, which is why it is the one that reaches a testing machine at all.
Questions we are asked about this test
What is ISO 8871-5?
It is Part 5 of the ISO 8871 series covering elastomeric parts for parenterals and pharmaceutical devices, and it holds the functional requirements — penetration force, fragmentation and self-sealing for closures pierced by an injection needle, together with the equivalent assessments where a spike is used instead.
Why is fragmentation counted rather than judged?
Because a rubber fragment released into a vial by the needle is particulate contamination in an injectable product, and that is a regulatory matter rather than an engineering opinion. Counting the fragments recovered after filtration turns it into a number that can be compared with a limit and audited, which a subjective assessment of the closure surface could never be.
Why must a new needle be used for every piercing?
Because a needle blunts measurably after even one pass through an elastomer. A blunted point needs more force to penetrate and is far more likely to core — to punch out a plug of rubber rather than part it. Reusing a needle therefore inflates the penetration force and the fragment count together, and does so progressively through a test series, which corrupts both results at once.
What makes the penetration force result difficult to get right?
The size of it. Penetration forces sit at a few newtons, and an accuracy class applies only down to a stated fraction of load cell capacity. A frame fitted with a kilonewton-scale cell is working far below the range its calibration certificate covers, so the reading may be precise-looking and untraceable. Choosing the cell for the force rather than for the frame is the whole of the problem.
Why does the closure have to be mounted in its container?
Because the support conditions determine how the rubber deforms under the needle. A closure crimped onto a vial is in compression and constrained at its flange; the same closure held loosely in a fixture is free to move and pierces differently. Since the requirement describes the closure in service, the test has to reproduce the service geometry to mean anything.
Why is the penetration rate specified?
Because elastomers are rate-sensitive: the force to drive a needle through rubber rises with the speed at which it is driven. An uncontrolled or hand-driven rate would produce results that cannot be compared between operators or laboratories, so a constant controlled rate is part of the method rather than a detail of it.
What else has to be read alongside it?
The standard for the container or device the closure serves — ISO 8362 for injection vials and their closures, ISO 8536 for infusion equipment where a spike rather than a needle is used. Part 5 supplies the functional test methods; those standards supply the context and often the specific requirement values the closure has to meet.
Running ISO 8871-5 on the Series 7200 and Series 9000
Dak verifies against whichever standard the method names, and where a class applies our frames sit a class tighter than it asks.
| The method asks for | Dak supplies | |
|---|---|---|
| Capacity | Very low — needle penetration forces are typically a few newtons | Load cells from 1 kg to 60 ton on the Series 7200, and 0.5 to 100 kN on the Series 9000 |
| Force accuracy | ISO 7500-1 Class 1 — verify the class at the actual working load, which is only a few newtons | ISO 7500-1 Class 0.5 — a class tighter than the method asks |
| Gripping | Needle penetration fixture holding the closure in a vial or a defined support, with a mounted needle | Our compression anvils, built to the specimen |
| Environment | 23 ± 2 °C standard laboratory atmosphere | 3009 series chambers, −150 °C to +400 °C — temperature only |
This page describes the method as practised. The governing text is the current edition from the issuing body. Tell us what you are testing and we will answer with the machine, the fixture and a quotation.