How to calculate ventilation rates from 62.1? 6 Min Solutions HVAC - Q66, Q67, Q76.

Working through the 6M solutions right now and not following the seeming inconsistency between these three ventilation questions that reference ASHRAE 62.1.

Q66 calculates the ventilation requirement using Vbz = RpPz + RaAz while Q67 and Q76 use only the occupant density (RpPz) to calculate the required airflow rate.

Do you only add the area outdoor rate when you aren't given the # of people and need to calc it based on density? Thanks.

Nevermind - I didn't understand how the "default values" column worked. Bad first post!

Q66 uses 15 cfm/person. Q67 uses 20 cfm/person. Does anyone know where those numbers come from? I have a 62.1-2010 but couldn't find those numbers, at least not in the table 6-1

It depends on space type. Look under the default values column and directly under combined outdoor air rate.

Normally the range is 15-20 cfm for most spaces (office, classroom, etc).