1. Interior Cross-Contamination Prevention section requires exhaust from space where hazardous gases or chemicals may be present or used so does this exhaust need to be via dedicated exhaust fan or can it be combined with other exhaust? In our case we have an exhaust fan for toilet and lockers so we are planning to combine janitor space exhaust to this fan, please advise.                                                                                   2. Also the earlier version of LEED required pressure calculation to ensure the pressure difference is at least 5Pa and 1Pa at the minimum but I don't see this requirement in V4 version, so I assume keeping the space negative is sufficient for this credit, please advise.