The Markl-type fatigue test data presented in this report have been badly needed for a number of years to establish i-factors (SIFs) for forged tees with d/D rati's between 0.5 and 1.0 that conform to the ANSI B16.9 standard.These data clearly show that there is no peak in the i-factor for out-of-plane moment loading Mob on ANSI B16.9 tees.This is in sharp contrast with the i-factor for fabricated branch connections as established in WRC Bulletin 329 (Dec. 1987).These new data will provide ASME and ANSI with the experimental basis for establishing improved design rules for both nuclear and industrial piping systems.