Preform ISBT

Purpose

This procedure evaluates the performance of bottle bases when they are exposed to a 0.2% solution of NaOH (Sodium Hydroxide) to simulate the failure associated with Stress Cracking.

Description

Each bottle is filled to net target content with water equilibrated to 22°C +/- 1°C (72 +/- 2°F). Bottles are pressurized with compressed air to the equivalent internal pressure of 531 +/- 4 kilopasclals (77 +/-0.5 psi). After 5 minutes, the fill line on each of the bottles is marked and they are placed in individual pockets of 0.2% Sodium Hydroxide solution. The containers remain in the caustic solution until they fail by either catastrophic burst or leaking through cracks that develop in the base. The time to failure is recorded for each container. Failed containers are removed and the location of the failure is determined and recorded.