ASTM C147 Test for Internal Pressure Strength of Glass Containers

Scope:

ASTM C147 is used to test glass containers expected to contain products that apply sustained pressure on the inside walls of the containers. This test is used in the selection process, design data generation, and quality control. 

Test Procedure:

Two test methods are used in ASTM C147 to determine the strength of the glass containers against internal pressure:

Test Method A: 

A uniform internal pressure is applied for a predetermined period.

Depending upon the purpose of the ASTM C147 test, one of the following test procedures are used: 

Pass Test: A fixed internal pressure is applied for a predetermined time. The pressure is usually 50% higher than the pressure the container will experience under actual conditions of use. It is used for routine testing of samples from the continuous production line in a manufacturer’s plant. 

Progressive Test: Pressure is increased by uniform increments (25 or 50 psi at each step) until a predetermined percent of containers break. 

Progressive Test (Total): The internal pressure is increased by uniform increments until all of the containers break.

Test Method B: 

Applied internal pressure increases at a predetermined constant rate. The containers are filled with a low density liquid such as water as the medium for applying pressure.

Depending upon the purpose of the ASTM C147 test, one of the following test procedures are used: 

Pass Test: Internal test pressure is increased at a constant rate until it reaches or exceeds a predetermined value. The pressure is usually 50% higher than the pressure the container will experience under actual conditions of use. Pass test is used for routine testing of samples from the continuous production line in a manufacturer’s plant. 

Test to Destruction: Internal pressure is increased at a predetermined constant rate until every container breaks. 

Specimen Size: 

The specimens sizes for ASTM C147 varies depending on the type of test:

• Pass Test: 50 containers, randomly selected, but representative of the mold cavities, are tested as the first sample in a double sampling method, followed, when necessary, by the second sample of 50 containers equally random and representative. 
• Progressive Test: A single sample of 50 containers is employed. 

Data: 

The following data is calculated for ASTM C147:

Test Method A:

The following information is reported: 

• The method of sampling. 
• The number of containers from each mold included in the sample. 
• Time of transfer used. 
• Results of test employed.

For the pass test, the following are reported:

1) The pressure applied (2) The number of containers that broke.

For the progressive test, the following are reported: 

(1) The pressure at which the first failure occurred and the number of containers that failed at that pressure (2) The pressure required to break the predetermined percent of the sample.

Test method B: 

The following information is reported for ASTM C147: 

• The method of sampling. 
• The number of containers from each mold included in the sample. 
• Time of transfer used. 
• Results of test employed.

For the pass test, the following are reported: 

(1) The pressure of the pass level, and (2) The number of containers that failed at or below the pass level.  

For the test to destruction, the following are reported: 

(1) The pressure level at which the first failure occurred, and (2) The average breaking pressure. 

Conclusion:

ASTM C147 determines the strength of glass containers against internal pressure.