Dear All, I have a further question about the ventilation rate. I am currently in a LEED project in Europe, which has a garage in the building. The garage is ventilated by exhaust gas system with CO and CO2 monitors, the compensation of the air is supplied by the exahust air from the office floors. The problem I am having now is the ventilation rate in the garage in based on the local standard and calculated based on the formulars for CO concentratoin with considering of number of cars, occupancy rate and average driving distance in the garage. The calulated ventilaite rate is however much lower than what stated in the table 6-4 in ASHRAE 62.1-2007. To be able to accomply the LEED standard we have chose to use ACP, which states that we can either use local standard ( if we can show that it is more stringent than ASHRAE.) or CEN standard. My confusions here are 1. how ASHRAE calculate the ventilation rate needed for garage? 2. what emission it considers? 3. if we state that we use local standard or CEN, would it be ok to show that we calcuate based on this CO concentration level and it is OK for people health with the level we calculated based on local standard? is there any other emission we need to show as well? SOrry for so many questions. many thanks!