Panhandle-A Gas Flow Formula

This formula is considered to be slightly better than the 10 percent accuracy of the Weymouth formula. 

If a line is made up of several different sizes, these may be resolved to one, and then the equation solved once for this total equivalent length. If these are handled on a per size basis, and totaled on the basis of the longest length of one size of line, then the equivalent length, Le, for any size d, referenced to a basic diameter, de. 

is the equivalent length of pipe size d, length Lm after conversion to basis of reference diameter, de. 

The calculations can be based on diameter de and a length of all the various Lc values in the line plus the length of line of size de, giving a total equivalent length for the line system. 

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