Applies To
	Product(s):	AutoPIPE
	Version(s):	All
	Environment:	N/A
	Area:	Report
	Original Author:	Bentley Technical Support Group
	Date Logged & Current Version	Mar. 2015 09.06.01.10

Problem:

All things being equal in the model except for wind speed. Found that pipe code stresses from W1 speed = 100 mph are higher than stresses from W2  speed = 110 mph. It appears that the wind pressure is correct from the model listing file.

Is  there a problem with AutoPIPE calculations? 

Solution:

AutoPIPE is working correctly.

Caution when reviewing the Model Input listing "Load Summary" sub report for Wind 1 and Wind 2, see the foot note highlighted below:

For more details, please see the following explanation:

This is a boundary value problem, in which AutoPIPE will jump from using an automatic Cf (force coefficient) value of 1.2 down to 0.7. AutoPIPE only takes in to consideration diameter D and qz value when calculating automatic Cf. When D*SQRT(qz) > 2.5, AutoPIPE uses a value of 0.7, otherwise AutoPIPE will use a value of 1.2. This may result in decrease in wind forces around that boundary condition.

Please see the following AutoPIPE help section for complete details on this subject:
Help > Contents> Search Tab> enter "Force coefficient Cf (ASCE 7-02)" (include the quotes), press List Topics button, double click on the selected topic from the list provided to see more information.

Workaround:

Only perform this step if you do not accept using the CF = Automatic explanation above. Instead of using Cf = Automatic, enter a user defined value (ex. 0.7) to be used for all piping regardless of height and pipe diameter.

See Also

"Code Compliance" sub-report using Results> Output Report

Bentley AutoPIPE

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

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the "Comments" area below. THANK YOU!

TFS-D187758.