ASHRAE 90.1-2007 Appendix G states for baseline system types: "For laboratory spaces with a minimum of 5000 cfm of exhaust, use system type 5 or 7 that reduce the exhaust and makeup air volume to 50% of design values during unoccupied periods."

Should this statement be interpreted as if the sum of all lab exhaust on a particular system is greater than 5000 cfm or if an individual lab space is greater than 5000 cfm?