Technical Docs not on main website. Not for mass distribution. To aid specific higher level in person discussions.
Materials crack when the forces (internal and external) at any particular point exceed the strength of the material at that same point. This document explains why polyethylene tanks made from the wrong materials fail.
Innovations in polyethylene chemical storage tanks magazine article. Published June 2017 in Environmental Science & Engineering Magazine. 3rd party article overview of tank selection criteria and components