Hi ,

When we select ASCE as the specified wind code and taken into CII calculation , how do we consider the parameter for structure damping coeff. ? CII marked the typical value could be 0.03 ; however, it can't be found that the specified valuces defined in ASCE code , is any reasonable reason to use 0.03 as default value ?

Thanks

Older documents (USNRC and ASME III) listed piping system damping values of 1% to 3% for seismic use. These sources now show 5% critical damping. In my opinion this change was implemented to better-match actual system performance regarding seismic events.
Usually lower damping will simply increase the applied model load so lower damping may be considered more conservative.

Hi Dave ,

Thanks for your reply and I will think it in deep.

Regards,