Overview
EN ISO 7458:2004 - Glass containers - Internal pressure resistance - Test methods - defines standardized laboratory tests to determine how glass bottles, jars and similar containers resist internal pressure. Prepared by CEN in alignment with ISO/TC 63, the standard specifies two complementary test methods (Method A and Method B), sampling rules, reporting requirements and safety guidance. The test medium is tap water.
Key topics and technical requirements
- Scope and sampling
- Applies to glass containers (bottles, pots, jars). Tests must use a predetermined sample size and untested containers (no prior mechanical/thermal tests).
- Test medium
- Tap water is specified as the pressurizing medium.
- General apparatus requirements
- Container held suspended by the finish.
- Resilient seal between sealing surface and pressure head to retain fluid.
- Accurate means for applying and measuring internal pressure; reproducibility requirements provided.
- Method A - Uniform pressure
- Apply a target internal pressure and hold it constant.
- Initial pressurization rate: (10 ± 2) bar·s⁻¹ (≈ 1.0 ± 0.2 MPa·s⁻¹).
- Pass test: hold for (60 ± 2) s (or corrected equivalent).
- Progressive test: after the pass stage, increase pressure in 1 or 2 bar increments until 50% and/or 100% of containers fail.
- Method B - Constant ramp (rate-controlled)
- Increase internal pressure at (5.8 ± 1) bar·s⁻¹ (≈ 0.58 ± 0.1 MPa·s⁻¹) until failure or a set limit.
- Apparatus must indicate failure pressure and relate ramp results to the 60 s (Method A) equivalent (example relationship provided).
- Test options: pass test to a predetermined level or test to destruction.
- Test report requirements
- Must reference EN ISO 7458:2004 and record sample size, mould sources, test type, detailed results (first-failure pressure, pressures to break specific percentages, mean breaking pressure, standard deviation), date, location and responsible signature.
- Safety
- Tests can be hazardous; appropriate safety measures and equipment are required.
Applications and users
- Quality control and R&D in glass container manufacturing
- Packaging engineers validating container performance for carbonated beverages, pressurized contents, or thermal processes
- Independent testing laboratories and conformity assessment bodies
- Regulatory or procurement teams specifying minimum internal pressure resistance for bottles, jars, and wide-mouth containers
Related standards
Part of a glass-container test methods series (as cited by the standard):
Keywords: EN ISO 7458:2004, internal pressure resistance, glass containers, test methods, Method A, Method B, pass test, test to destruction, packaging quality control.
