Test for Internal Pressure Strength of Glass Containers

What is the Internal Pressure Strength of Glass Containers?

Internal pressure strength testing determines the maximum internal pressure a glass container — bottle, jar, vial, ampoule, or vessel — can withstand before fracturing. It is a critical safety and quality parameter for containers used in carbonated beverage packaging, aerosol products, high-pressure laboratory glassware, and sealed sterile vials, where internal pressure from dissolved CO₂, propellant gases, or processing steam can cause catastrophic container failure.

Why Internal Pressure Strength Testing Is Essential

Glass containers holding carbonated beverages, aerosol products, or sealed sterile pharmaceutical preparations are subject to significant internal pressure that varies with:

• Temperature: Pressure increases with temperature as CO₂ or propellant gas expansion occurs
• Fill volume and headspace: Less headspace means higher equilibrium pressure at temperature
• Agitation and impact: Dynamic pressure surges during transport and handling

A container that fails the internal pressure test poses a safety risk — glass fragment injuries and product loss. Verifying that production containers meet defined minimum burst pressure requirements protects consumers and ensures regulatory compliance.

Test Methods for Internal Pressure Strength

Destructive Burst Pressure Test (ASTM C147)

ASTM C147 — Standard Test Methods for Internal Pressure Strength of Glass Containers — is the primary US standard for destructive burst pressure testing. Water or hydraulic fluid is pressurised inside the sealed container at a constant rate using a hydraulic pressure pump until the container bursts. The burst pressure at fracture is recorded.

The test provides the ultimate pressure capacity of individual containers and is used to characterise container design and production lot strength distribution.

Proof Pressure Test (Non-Destructive)

In a proof pressure test, all containers in a production lot are pressurised to a defined proof pressure below the expected burst pressure for a defined hold time. Containers that survive without fracture are deemed to meet the minimum pressure requirement. This non-destructive approach allows 100% production screening without destroying the product.

ASTM E9 — Compressive Testing

Some thick-walled glass vessels are also evaluated for compressive strength in combination with internal pressure, particularly for laboratory high-pressure reaction vessels and autoclave glass liners.

Factors Affecting Glass Container Internal Pressure Strength

Container wall thickness distribution (measured by X-ray or contact gauging), glass composition, annealing quality (residual stress level), surface condition (scratches, checks), and container geometry (shoulder radius, heel design) all influence burst pressure. Container defects introduced during forming (checks, blisters, stones) dramatically reduce pressure strength.

Standards for Carbonated Beverage Packaging

The beverage industry uses internal pressure testing to qualify new bottle designs and monitor production quality. Industry guidelines from ASTM, the Glass Packaging Institute (GPI), and ISO 7458 (carbonated beverage bottles) define minimum burst pressure requirements as a function of the maximum pressure the filled, pasteurised, and transported product can generate.

Industrial Applications

In the beverage industry, glass bottles for beer, sparkling wine, and carbonated soft drinks must withstand pasteurisation pressures and worst-case transport temperature conditions. In the laboratory glass industry, borosilicate pressure vessels and autoclaves must withstand sterilisation pressures and vacuum conditions. In the aerosol industry, glass aerosol containers must meet minimum burst pressure requirements before filling.

Conclusion

Internal pressure strength testing is a vital safety and quality assessment for glass containers used in pressurised applications. It verifies the ability of bottles, jars, vials, and specialised vessels to safely withstand internal gas or liquid pressure without fracture. By using destructive burst tests such as ASTM C147 or non-destructive proof pressure testing, manufacturers can ensure container integrity, regulatory compliance, and consumer safety. This testing is especially critical in industries such as beverages, pharmaceuticals, laboratory glassware, and aerosols, where pressure fluctuations during filling, storage, and transport can significantly affect performance.

Why Choose Infinita Lab for Glass Container Pressure Testing?

Infinita Lab provides ASTM C147 internal pressure strength testing and proof pressure testing for glass containers through our nationwide accredited glass testing laboratory network. Our specialists support container design qualification, production quality control, and regulatory submission testing.

Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you.

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