Describe an engineered building's ventalation system, using a C.O. 2 sensors to get the required cfms ?

LOOKING FOR DIAGRAMS OR ENGINEERING SYSTEM GUIDE LINE TO PROVIDE FREASH AIR INTO A BUILDING

Describe an engineered building's ventalation system, using a C.O. 2 sensors to get the required cfms ?
A lot depends on the type of buidling and occupancy. The codes will govern the amount of fresh air needed. Usually it is based on a CFM per person. The codes differ from state to state.





On the air handling unit, there is duct work to take in outside air and then another duct for return air from the space. Those two duct will have dampers on them. The dampers will control the amount of air flow in each duct.





CO2 sensor I have used have been for a warehouse were gas fork lift trucks operate. CO2 sensor gets tripped, the air handling units go to 100% outside air and flush the space with fresh air until CO2 levels are reduced.
Reply:In the US:


Offices requires 20 cfm per person by ASHRAE standards, classrooms 15.





A hospital operating room has a requirement for 15 air changes per hour with a 20% outside air requirement.





Outside air requirements (usually as a percentage) vary by locality.





It will very much depend on where the building is located and what its classification (purpose) is.
Reply:You have to conform to building codes re: number of people to air changes depending on the space use.

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