The Owner wishes to take a source control approach to the control of chemicals and pollutants in a multi-family rental apartment building. We have addressed the first part of the Credit by providing floor grates at all high-traffic building entries, and have no common "housekeeping" areas (janitor\'s closets or laundry rooms) in the building. We do have attached garages beneath a portion of the dwelling units (78 dwelling units, but only 24 attached garages and of these only 8 are directly accessible (through a door) to their associated dwelling unit). These garages are considered unconditioned space and are physically isolated from the dwelling units by their thermal envelope. The Owner plans to implement a strict policy of no chemical / flammables storage in these garages, with signage in each garage to this effect. There is no air intake or return air grille from the garage into the attached dwelling unit, so no air recirculation into the unit is expected. When a vehicle is in use, the garage itself would be naturally ventilated by its door being open. Given that this is unconditioned space attached to the unit, rather than a space within the building envelope, please confirm whether the above measures will meet the intent of the Credit.
This intent of this credit is to avoid exposure of building occupants to potentially hazardous chemicals that adversely impact air quality. In order to meet this intent, any garage attached to a dwelling unit must have an independent ventilation system. Although the garage door may be typically open when vehicles are in use, an ASHRAE study ("Pollutant Entry From Attached Garages," by Don Fugler, P.E., Carmela Grande and Lisa Graham, 2002) has shown that there can be carbon monoxide transfer between homes and attached garages. The combination of the relatively small duration of time that the door is open with the fact that residential units are typically negatively or neutrally pressurized, leads to air transfer from the garage to the residential space. The inquiry also mentions that the building owner will prohibit the storage of chemical and flammables in the garages. This effort may be difficult to regulate and enforce, as these are products typically stored in a garage. In summary, without an active exhaust system in the attached garages, the intent of this credit cannot be met. Please note that the construction of the garage door may make it impossible to meet the pressure differential requirements for this credit under LEED Version 2.1. The project team may choose to comply with LEED v2.0 if preferred (mixed submittals are permissible).