What are the test parameter tolerances/variances in ISTA procedures?
ISTA test procedures generally do not include tolerances on test parameters such as drop height, compression force, vibration time and intensity, etc. In such cases the requirements given in ISTA test procedures and projects are considered minimums; i.e. no variation or tolerance below the stated values is allowed. Testing to exceeded levels is perfectly acceptable when using ISTA Procedures and Projects.
If any particular test in a test sequence is below the required minimum, that test does not count and must be repeated.
In the case of the low pressures in Procedure 3A and the temperatures in Procedure 7D, this requires some interpretation but basically means that the altitudes or temperatures, respectively, must be not less than what is shown as the minimum requirement. The equipment used for these test methods should always comply with the ASTM documents referenced in all ISTA Procedures and Projects under the Equipment Required sections. The ASTM reference will give applicable variances that are allowed with the specific equipment being used.