ISO 9008:1991

Overview

ISO 9008:1991 - Glass bottles - Verticality - Test method specifies a standardized procedure to measure the verticality of glass bottles. The method determines not only the deviation of the bottle body from the vertical axis, but also the combined effect of related deformations (for example neck tilt, eccentric finishing ring or ring ovality). The standard is intended for quality control of glass packaging where accurate vertical alignment affects filling, sealing and handling.

Key topics and technical requirements

• Scope: Measurement of bottle verticality, capturing whole-body deviations and combined deformations.
• Definitions: Verticality is defined as the horizontal-plane deviation of the central axis of the bottle’s ring (finish) from the theoretical vertical.
• Apparatus:
  • For round bottles: base plate with V-support or a rotating table with a 3- or 4-jaw self-centering chuck, plus a vertical support carrying a horizontal tracer or a dial comparator.
  • For non‑round bottles: a device that holds the bottle centered on a turntable.
  • Alternative methods allowed: comparison with a horizontal scale, dial gauge comparator, or projection of an enlarged shadow onto a scale.
• Measurement accuracy: Apparatus must measure deviations with an accuracy of 0.1 mm.
• Procedure:
  • Rotate the bottle (or table) through 360° and record the maximum and minimum distances from a fixed reference point in the same horizontal plane, measured on the outside of the finish (ring).
  • Compute verticality as half the difference between the maximum and minimum measured distances.
• Sampling: Sample size is to be agreed between parties (buyer/supplier).
• Reporting: Test reports must include reference to ISO 9008:1991, sample size and bottle type, manufacturing details, apparatus used, results, and the inspector’s name, signature and date.

Applications and who should use it

• Glass bottle manufacturers: to verify production quality and conformity of bottle finishes and body alignment.
• Quality control laboratories: routine inspection and acceptance testing of glass containers.
• Filling and bottling plants / packaging engineers: to ensure bottles meet verticality tolerances required for automated filling, capping and labeling equipment.
• Suppliers and purchasers: to define acceptance criteria in procurement contracts and resolve production disputes.

Practical benefits include improved fill-line performance, reliable sealing, consistent downstream automation performance and reduced spoilage or machine stoppages due to misaligned bottles.

Related standards

• ISO 7348:1991 - Glass containers - Vocabulary (normative reference cited in ISO 9008:1991).
  Note: stakeholders are advised to check for later revisions and use the most recent editions of referenced standards where applicable.

Keywords: ISO 9008:1991, glass bottles verticality test, verticality measurement, glass packaging quality, bottle verticality test method, measurement accuracy 0.1 mm.