Vial stopper sizes, materials and puncture limits
ISO 8362-2:2015 specifies Type A (without) and Type B (with no-pop/blow-back feature) closures in nominal sizes 13 and 20 matched to ISO vial designations. ISO 8871-5:2016 sets penetrability ≤10 N, fragmentation ≤5 fragments per 48 piercings, and self-sealing for multi-dose containers. FDA 21 CFR 211.94 requires non-reactive, protective, clean closures with written specifications.
| Type | Nominal size | ISO 8362-1 vials | ISO 8362-4 vials | No-pop/blow-back feature |
|---|---|---|---|---|
| A | 13 | 2 R and 4 R | — | No |
| A | 20 | 6 R to 30 R | 5 H to 100 H | No |
| B | 13 | — | 2 I to 10 I | Yes |
| B | 20 | — | 6 H to 100 H | Yes |
Vial stopper sizes and specifications
ISO 8362-2:2015 (third edition) defines two closure types. They differ only by the no-pop/blow-back feature: Type A lacks it, Type B has it. The standard does not say what the feature does. Each type comes in nominal sizes 13 and 20, but the document never states what those numbers measure — not neck diameter, not flange diameter, not anything else. ISO 8871-5:2016 (second edition, superseded by a 2025 edition not retrieved) notes separately that a vial's neck finish size matches the closure size (e.g. 13 mm, 20 mm). That is a matching statement, not a definition.
The table above carries the type, size and vial-compatibility columns of ISO 8362-2 Table 1. Type A size 13 fits ISO 8362-1 vials 2 R and 4 R — two discrete sizes, not a range, so 3 R and 5 R are not listed. Type A size 20 fits ISO 8362-1 vials 6 R through 30 R and ISO 8362-4 vials 5 H through 100 H. Type B size 13 fits ISO 8362-4 vials 2 I through 10 I only. Type B size 20 fits ISO 8362-4 vials 6 H through 100 H only. Table 1's remaining columns are millimetre figures under the symbols d1 to d4 and h1 to h4, which the standard labels only on its drawing; they are not reproduced here because the document's text does not say what any of them measures.
Functional limits come from ISO 8871-5:2016. Penetrability must not exceed 10 N per closure, tested with a 0.8 mm external-diameter lubricated long-bevel needle per ISO 7864. Fragmentation must not exceed 5 particles visible to the naked eye per 48 piercings. That 48-piercing figure is a laboratory test condition on sample closures, not a usable puncture count for any individual stopper. Self-sealing is required for multi-dose containers only, verified by the absence of coloured solution traces. The published preview of ISO 8871-5:2016 ends at Annex A, so the fragmentation limit is readable but Annex B, which sets out how the 48 piercings are performed, is not in it.
ISO 8362-2 Clause 6 covers materials. The elastomeric formulation must withstand two autoclave cycles at (121 ± 2) °C for 30 minutes without exceeding specified limits or impairing performance. Closures shall be made from the formulation originally tested and approved by the end user. Dimensional tolerances follow ISO 3302-1 and ISO 3302-2 unless otherwise specified. Spacer height must not exceed 0.3 mm. Flange conicity, if present, is limited to 0.3 mm; edges may be rounded. Designations follow the pattern "Injection closure ISO 8362-2 - 13 – A".
Where to buy injection vial closures
We do not link a retail listing here. Closures of the kind specified above are packaging components supplied to fillers in bulk against an agreed formulation, and no catalogue number appears on this page for a listing to match.
Sources
- ISO 8362-2:2015 — Injection containers and accessories, Part 2: Closures for injection vials (third edition)
- ISO 8871-5:2016 — Elastomeric parts for parenterals, Part 5: Functional requirements and testing (second edition, superseded by ISO 8871-5:2025)
- 21 CFR 211.94 — Drug product containers and closures (eCFR, current as of 2026-08-07)
Specifications last verified: