If you are maintaining old infrastructure, it is indispensable. If you are learning, the 2006 edition provides the foundational logic of hydrodynamic seismic design with less complexity than the newest iteration.
One of the most practical sections deals with —the vertical distance between the maximum water level and the top of the tank wall. Using the convective period, the standard calculates the maximum vertical displacement of the sloshing wave. If your tank lacks the required freeboard, the water will slosh out during an earthquake, potentially flooding sensitive equipment or causing erosion. ACI-350.3-06.pdf