Rating System

LEED BD+C: New Construction, LEED BD+C: Schools, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell, LEED O+M: Existing Buildings

Rating System Version

v2 - LEED 2.2, v2 - Schools 2007, v2 - LEED 2.0, v2 - LEED 2.0, v3 - LEED 2008

Inquiry

Our project is an engineering educational facility with extensive laboratory and research spaces. Our building is mechanically ventilated, and for densely occupied spaces (occupant density above 25 persons/1000 SF), we are able to provide calculations demonstrating that the outside air rates never drop below those required by ASHRAE 62.1-2004. In addition, based on the outside air rates, the CO2 concentrations never exceed the limits as set by ASHRAE 62.1-2004, Appendix C. In this case, if calculations are included with our LEED submittal, can we be exempted from the requirement for CO2 monitors in densely occupied areas? Below is the calculation for the building. 4 Supply Units at 42,500 CFM each = 170,000 CFM 1 Return Unit at 40,000 CFM 1 Exhaust Unit at 126,000 CFM Max OA = 130,000 CFM = 76% Below are minimum values based on minimum exhaust requirements and 30% turndown on VAV spaces. These values are based on minimum everything for a conservative calculation, and the assumption is that in reality, not all spaces will be minimal at once. Supply = 72,000 CFM Return = 16,000 CFM Exhaust = 53,000 CFM OA = 56,000 CFM = 78% Below is then the calculation for one example 1,400 square foot laboratory space. Min Supply = 1,100 CFM Min OA = 856 CFM (78% of Supply) ASHRAE 62.1-2004 OA = 672 CFM