I am modeling Airport Traffic Control Tower project for LEED 2009 and I have question regarding economizer requirement. We have data center rooms which are served by CRAC units. We are not allowed to use air side economizer due to humidity concerns by client. Per Appendix G18.104.22.168A table, baseline system shall be included with air side economizer. Therefore, it is making baseline systems more efficient. I was wondering if anybody is aware of any exception which would allow us to not model air side economizer for spaces such as data center in baseline system when proposed system does not have air side economizer.