What is the pipe capacity equation used to determine the maximum flow rate that a pipe can handle?

The pipe capacity equation, also known as the Manning formula, is used to calculate the maximum flow rate that a pipe can handle. It is expressed as Q (1.486/n)A(R2/3)(S1/2), where Q is the flow rate, n is the Manning roughness coefficient, A is the cross-sectional area of the pipe, R is the hydraulic radius, and S is the slope of the pipe.