I am writing regarding to fresh air requirements for Baseline Case. According to new ASHRAE 90.1-2010 requirement it should be modeled according to rating authority or building official. If we compare with ASHRAE 62.1-2010 requirement we were asked in few projects during Review project to include fresh air quantities to be consistent with values reported in Minimum IAQ calculator.
ASHRAE 62.1 - 2010 requires to design exhaust air volumes for toilets. In our project there is a special designed AHU which serves toilet spaces. AHU includes required exhaust airflow rate and the same quantity of fresh air which is supplied to vestibules to compensate exhaust rate.
ASHRAE does not require fresh air for toilet and in IAQ calculator we may eventually include fresh air for vestibules and assign them as corridor with 0.3 L/s/m2 requirement which is our method. This airflow is much more lower than required exhaust.
The question is if we can get savings by include the fresh air volume for vestibules as equal to exhaust rate required by ASHRAE 62.1 and if we can include that air somehow in IAQ calculator.