LEED IAQ Ventilation Compliance

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I don't think the IAQ calculator is significantly deficient.

Exhaust only spaces such as restroom and locker rooms are not found in the IAQ calculator because they are not listed in ASHRAE 62.1 TABLE 6-1 MINIMUM VENTILATION RATES IN BREATHING ZONE. They are unoccupied spaces. EQ Prerequisite Minimum indoor air Quality Performance and the IAQ calculator are for occupied spaces. OA flow rates in unoccupied spaces do not need to be added to the IAQ calculator and the Minimum Energy Performance Calculator (MEPC). If you want to add the OA flow rates in unoccupied spaces to the MEPC dut to the energy consumption of precooling/preheating the OA, please explain the difference in the total OA flow rate between the IAQ calculator and MEPC to GBCI.

I don't see the numbers 0.17CFM/SF for Science labs and 0.33CFM/SF for Kitchens in the IAQ calculator. The OA flow rates in the IAQ calculator are 0.43CFM/SF for Science labs and 0.27CFM/SF for Kitchens with default zone population. Rp and Ra in the IAQ calculator are consistent with those in ASHRAE 62.1 TABLE 6-1.

The minimum OA flow rates in TABLE 6-1 are for occupants. If you have local exhausts such as Fume hoods in Science labs to remove pollutants and Range hoods in Kitchens to remove odors, those local exhausts (and the makeup air supply fans, if any) are regarded process loads. In the Baseline case, the process loads should be modelled identically to the Proposed case. The makeup air (outdoor air or transfer air from the other zone) does not need to be added in the IAQ calculator.

1.00CFM/SF for Science labs and 0.70CFM/SF for Kitchens are the values in ASHRAE 62.1 TABLE 6-4 Minimum Exhaust Rates. TABLE 6-4 is irrelevant to EQ Prerequisite Minimum Indoor Air Quality Performance and EA Prerequisite Minimum Energy Performance.

Supplement to answer your comments

In LEED, Nonregularly Occpied Space is a more accurate description than Unoccupied Space for restrooms and lockers. I apologise. The definition 'an area that people pass through or an area used for focused activities an average of less than one hour per person per day' and the examples are in the LEED Reference Guide for BD+C: LEED V4. However, this classification misleads addressing your original questions, so please ignore it. Whether the Occupancy Category is listed in ASHRAE 62.1 TABLE 6-1 MINIMUM VENTILATION RATES IN BREATHING ZONE or not - that's all. If the Locker rooms in your project are used mainly for meetings for hours rather than just for changing clothes, you may need to select a different Occupancy Category such as Conference / meeting in the IAQ calculator in contrast to the space name shown on the floor plan.

Please do not confuse Ventilation with Exhaust. Ventilation requires outdoor air, but Exhaust does not necessarily require outdoor air (e.g. transfer air is allowed). ASHRAE 90.1-2010 G3.1.2.6 is ... (more)