Co2 Monitoring

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Gentlemen I have a question regarding 90.1 when modeling a space.

The design we are using for a project is to provide minimum ventilation (as called for in ASHRAE 62.1-2007) to all the spaces based on max occupancy. The spaces are offices and conference rooms, one or two class rooms. The heating and cooling load is provide in each space by FCU. The make-up air is preconditioned to 55 Degree F. The relief air passes through a heat recover unit to collect the heat from the relief air.

If was are not varying the make-up air quantity do we need to have CO2 monitoring in each space.

Do you believe we would get any push back from USGBC on this.

Has anyone dealt with this issue before.

Robert O'Connell P.E.

Robert E. O'Connell's picture
Joined: 2011-09-30
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Hey Robert,

My understanding of the CO2 monitoring credit is that it ONLY requires
that you provide capabilities to monitor CO2 and not necessarily vary
the amount of outside air. So if your HVAC equipment cannot vary the
amount of OA you could still provide CO2 sensors that report the CO2

Everyone else: is this what your understanding as well?



Premnath Sundharam, AIA, LEED AP BD+C

Premnath Sundharam

DLRGroup_Phoenix's picture
Joined: 2011-09-30
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Bruce Easterbrook's picture
Joined: 2011-09-30
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Robert -

The two things I think to investigate:

1) Do you comply with section of 90.1-2007? This is the section that requires demand control ventilation for certain spaces on certain systems.

2) Is the project pursuing the LEED point for Outdoor Air delivery monitoring? If so, that has its own set of specifications, which include CO2 monitors (monitor only) for mechanically ventilated spaces that exceed a certain occupant density.


Aaron Dahlstrom , PE, LEED(r) AP

Dahlstrom, Aaron2's picture
Joined: 2011-09-30
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I have since discovered the monitoring is required. Thanks for the info.


Robert E. O'Connell's picture
Joined: 2011-09-30
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