Hello everyone,
I am working in a underground metro station which is aiming for LEED certification. I am facing difficulties with placing CO2 sensors in breathing level in Public, Entrance, concourse and platform areas. this is a huge station and the client requirement is to consider 1 sqmt per person which is 10.76 sqft person considering it as a worst case scenario.
As per the credit requirement the density is lesser than 40 Sqft which leads to go for CO2 sensors in breathing level. as per the space matrix we need to consider all the transition areas if they have less than 40 Sqft per person (please confirm my understanding on this)
The problem here is how to place these sensors in these areas. these areas are huge and may require at least 60 to 70 sensors if i consider 200 Sq ft coverage per sensor and also we don't have many columns in these areas to fix these sensor to sense the CO2 concentration.
Our mechanical engineer says that we are considering 10.76 Sq ft per person as a worst case scenario and the chance for this situation is very meager and as per my understanding people will not stand or sit or do anything in these areas for an hour or more, they will move around continuously so there is no need to consider these space for the CO2 requirement. ( please clarify).
your inputs and suggestions are much appreciated.
Thanks
Kulandhaivel
Dylan Connelly
Mechanical EngineerIntegral Group
LEEDuser Expert
472 thumbs up
September 14, 2015 - 8:59 pm
How did you determine 200 sq ft/ sensor? You don't need "full coverage" for LEED. Just a sample size.
I'd say consider it a space that needs CO2 and find strategic locations but much less. Even just a few for a large space is fine.
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
September 15, 2015 - 10:37 am
In addition to Dylan's appropriate response; when you do your design, you are allowed to do an occupancy average over a period of time based on the total volume of space. All of the equations are in ASHRAE 62.1 - 2007 chapter 6.