The large scale application of Zircaloy-2 pressure tubes for structural use either in or out of reactor service, is without precedent. For more common materials, there normally are adequate data and long operating histories on which to base design and service limits. In the absence of such information for Zr-2, several investigative programs have been devised to provide much of the information from which design and service limits may be defined for Zr-2 pressure tubes. These investigations encompass in-and-out-of-reactor creep and stress-rupture testing, pre-and-post irradiation testing, and bust strength, as well as the effect of flaws or defects (from both fabrication and service origins) on burst strength and fracture characteristics. Already creep and stress rupture testing of unirradiated Zircaloy-2 is well advanced, and some experimental pre-irradiation burst testing has been carried out and will be extended rapidly as improved equipment becomes available. One irradiated KER tube sample has been burst tested and the requirement for post irradiation burst testing equipment have been defined.