USP 800 is a standard for pharmaceutical compounding that is done in local pharmacies. The requirements depend on if you are using hazardous or nonhazardous products. All USP800 is non-sterile compounding. If the user is working with non-hazardous compounding, then you are required to have a single HEPA system that recirculates back into the room. However, if you are working with hazardous compounding, it has to be done in its own room. The room has to be under negative pressure with 12 air changes per hour. The Length times Width times Height gives you the cubic feet of the room and you would multiply it by 12 and that will give you the cubic feet per hour that has to be recirculated. This may be accomplished by house exhaust or if the room is small enough it can be accomplished by our hood. You can have a single HEPA unit connected to house exhaust and exhausted out of the building or you can have a double HEPA unit that recirculates back into the room. All of your hazardous materials (raw drugs) have to be stored in the designated hazardous room separated from the non-hazardous drugs/room.