[en] Fatigue crack growth rates of A 106 Gr. C and A 516 Gr. 70 carbon steels, and A 351-CF8A stainless steel in PWR environments have been determined over a load ratio range (R) of 0.2 to 0.85, a temperature range of 93⁰ to 338⁰C, and a test frequency range of 17 mHz to 1 Hz using sinusoidal waveforms. In addition, growth rates have been determined for various orientations of the crack plane with respect to the product form. Crack growth rates in 288⁰C air environments have been measured in order to provide a reference baseline. These results define the magnitude of and major influences on the environmentally-assisted fatigue crack growth rates for these piping steels, and are supported by fractographic observations of the fatigue fracture surface