Applies To
	Product(s):	Bentley FlowMaster
	Version(s):	08.11.01.03
	Area:	Modeling
	Original Author:	Jesse Dringoli, Bentley Technical Support Group

Problem

In a grate inlet on grade worksheet, why do I see the following message in the messages tab, even though results are computed? What does this mean?

"Grate Length should be within the defined range of HEC-22's Chart 5 (approx. 0.5-4.5 ft / 0.15-1.35 m)."

Solution

The reason you get this message is because Flowmaster uses HEC-22 methodology for its inlet calculations, and a grate length greater than 4.5 feet is beyond the scope of the charts provided from HEC-22. Please open the HEC-22 manual (included with Flowmaster and located in its start menu folder) and turn to page A-10 and A-11, which show charts 5A and 5B. You will see that these charts do not go beyond 4.5 ft., so care must be taken when using grate lengths above this value, as extrapolation will be used.

Basically the results may not be accurate as they are outside the bounds of the normal values used with the HEC-22 methodology. Results should be carefully checked.