Exhaust for Hazardous Material storage

Hi guys! I have a two part question on the Hazardous Materials Storage ventilation requirements according to ASHRAE 170. 1. Just to clarify, Hazardous Materials refer to any biological-infectious residue? 2. Does the storage refer to the main Hazardous Material Storage located outside of the Hospital? or does it also refer to the small closet-like spaces located throughout the hospital? I am asking because the client is a bit resistant on installing the exhaust. They say that it is because having an extraction would be a potential vehicle for contamination of other areas. On the other hand, having no pressurisation (either ventilation or exhaust) would forbid there to be any potential risks of spreading bacteria. According to what they have told us, it is in their operation protocols to have the hazardous materials wrapped in special containment sealed bags, inside sealed containers, and these spaces are emptied periodically every hour and taken to the mail Hazardous Materials Storage. I have sent the question to GBCI, and am waiting for answer. Any input from you guys will be greatly appreciated!