We're currently doing analysis work using NBC-2005 for Wind Loads on elevated piping systems. A comparison was made between using NBC-2005 and the Wind Pressure vs. Elevation by modeling 3 identical 1-meter pipe segments located at 5, 10 and 15-meter elevations. The base of each 1-m pipe segment was anchored and the top left free (like a stack).

The restraint summary showed that the NBC-2005 method had identical Fx=483N at anchor points for all 3 elevations (i.e. 5, 10, 15 meters). While on the Wind Pressure vs. Elevation method the results showed varying Fx results for the anchors points- 1133N for 5 meters elev., 1259N for 10 meters elev. and 2037N for 15 meters elev.

It appears the NBC-2005 method is not taking into account the elevations of the pipe segments. We were expecting results for effects of wind to vary with elevation. Is the NBC -2005 accurate or is our method not right?