Content with J2

18 December 2015
J2 and JR refer to the material’s sub-grade - its fracture toughness - which is measured in joules [J] of a material’s toughness at a particular temperature. J2 is a material with a minimum of 27 joules at -20C while JR is a material with a minimum of 27 Joules at +20C (room temperature). A JR material is normally used in an internal environment whereas a J2 is for external use.
Read more about What is the difference between J2 and JR? Can they be used as substitutes for each other?