Overview
EN 29008:1994 (ISO 9008:1991) specifies a laboratory test method to determine the verticality of glass bottles. The method measures not only the overall deviation of the bottle body from vertical but also the combined effects of neck deviation, offset finishes and finish ovality. The procedure gives a repeatable way to quantify vertical axis deviation relevant to production quality and filling-line performance.
Key topics and requirements
- Scope: Measurement of verticality (vertical axis deviation) of glass bottles to assess how far the finish centre deviates from a theoretical vertical line through the base.
- Definitions: Verticality / vertical axis deviation equals half the diameter of the circle described by the finish centre when the bottle is rotated around the base centre.
- Measurement accuracy: Apparatus and method must permit measurement to an accuracy of 0.1 mm.
- Apparatus options:
- Simple verticality gauge with baseplate and V-block for round bottles.
- Rotatable plate with three- or four-jaw self-centring chuck.
- Vertical pillar carrying a horizontal scribe or dial gauge adjustable for height/length.
- Non-contact light-scanning or magnified shadow projection on a scale.
- Special centring device for non‑round bottles.
- Procedure:
- Position bottle on the device (V-block or rotatable chuck).
- Rotate the bottle or plate through 360° and record the minimum and maximum distances from a fixed horizontal reference to the outside of the finish, to 0.1 mm.
- Compute vertical deviation as half the difference between maximum and minimum distances.
- Sampling: Sample size and selection are to be agreed between parties.
- Test report must include: reference to the standard, sample size and container type, manufacturing details, apparatus used, test results, tester name/signature and test date.
Applications
- Quality control in glass container manufacturing to ensure bottles meet verticality tolerances.
- Incoming inspection by bottlers and fillers to prevent problems on fast-filling lines caused by neck/finish misalignment.
- Product development and tooling verification (mould adjustments, finish alignment).
- Independent testing laboratories and regulatory conformity checks.
Related standards
- ISO 9008:1991 - equivalent international text for this method.
- ISO 7348:1991 - referenced for glass container vocabulary and related definitions.
Keywords: EN 29008:1994, ISO 9008:1991, glass bottles, verticality test, vertical axis deviation, verticality tolerance, finish ovality, dial gauge, V-block.
