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RE: Flag Drag

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Use ANSI/NAAMM FP 1001-97.  I don't think that there is a later edition.

Equation 4 will give you the wind load for nylon or cotton flags.
Equation 5 will give you the wind load for polyester flags.

You certainly need to know what the height of the building is and then use the appropriate formulas for that.   You also need to know what the governing wind speed is.  For unknown areas we usually use 130 mph with no flag.  (We consider the flag gone at that wind speed).  Then we check the flag and the pole combined at 90 mph.  The flag poles that we design are usually 400 feet and higher, free standing single poles.

The above mention code provides sample calculations in Appendix A.   If you are concerned about buckling, we then reference Section 4 of the Standard Specification for Structural Supports for Highway Signs....ect, published by AASHTO.

Neil Moore, SE, SECB
neil moore and associates
consulting structural engineers
shingle springs, california
530 677-4308

At 10:58 AM 9/11/2006, you wrote:
Wouldn?t it be waving in the plane of the wind? 
I think that the wind blowing on the surface area of the pole would govern the design.
Sharon Robertson, P.E.
Arcon Engineers
5625 Ruffin Rd, Ste 130
San Diego, CA  92123
858/503-7858 fax

Visit us on the web at

From: David Maynard [ mailto:DMaynard(--nospam--at)]
Sent: Monday, September 11, 2006 10:55 AM
To: seaint(--nospam--at)
Subject: Flag Drag
Here?s what I got.
A flag pole wants to be installed on top of a Structure.  I want to make sure that the flag pole on hand is capable of the loading.  Therefore, I need to know how to calculate the wind load on the waving banner.  Is there a spec out there, or can someone point me in the right direction, as to a design procedure for this.  I?d appreciate it.
David Maynard, PE
Gillette, Wyoming