Hello All,

I am working on a project which is a single story indoor firing range that about 125,000 sf. The indoor range spaces require a constant supply of air when in use in order to meet OSHA standards for lead contamination.  Based on ASHRAE 90.1 appendix G the baseline system is would need to be system #6 Package rooftop VAV with parallel fan power boxes and reheat. This seems like an unfair comparison to the proposed system since the baseline system will vary the airflow in the space which is something that is not feasible in reality.

I'm wondering if anyone has come across a similar condition like and if there exists any exception or an alternative which would allow us to model a constant volume system (system #4 PSZ-HP) in the baseline model due to this space requirement? 

Thank you,

Joel