This description is from ISTA document.

ISTA 3 Series tests are advanced tests and are designed to:
– Challenge the capability of the package and product to withstand transport hazards, but
– Utilize general simulation of actual transport hazards, and
– Do not necessarily comply with carrier packaging regulations.

When properly executed, ISTA procedures will provide tangible benefits of:
– Product to market time reduction
– Confidence in product launch
– Reduction in damages and product loss
– Balanced distribution costs
– Customer satisfaction contributing to increased market share

There are three sections to this Procedure: Overview, Testing and Reporting
– Overview provides general knowledge required before testing and
– Testing presents the specific instructions to do laboratory testing and
– Reporting indicates what data shall be recorded to submit a test report to |STA.

Two systems of weights and measures are presented in ISTA test procedures:  SI (Metric) or English system (Inch-Pound). Metric
units are shown first followed by the Inch-Pound units in parentheses; there are exceptions in some tables (when shown
separately).

– Either system may be used as the unit of measure (standard units) but
– The standard units chosen shall be used consistently throughout the procedure.
– Units are converted to two significant figures and
– Not exact equivalents.