Weight Loss Tests: To determine evaporation (water loss through the container wall or closure gaps) weight loss evaluation is one of the most important tests that must be conducted. This testing (performed in the actual package with the cap torqued to 100% of target torque) is done at room temperature and at 45oC (113F) for a period of three months. The weight loss should not exceed 1% per month for the package to be considered acceptable.