Modular clean rooms solve the problem of adding a clean room environment to an existing facility. The air supply is filtered through HEPA filter or ULPA filter fan units. ISO Class 8 to ISO Class 3 cleanliness levels are possible with these rooms. Modular walls are assembled to isolate an area; the walls can be floor to existing ceiling or ceiling panels can be added. The walls can be soft vinyl or rigid panels and are also available in fire proof or ESD materials. Positive air pressure is maintained in the clean room area and airlocks must be added so air from the surrounding room can be purged before entering. The walls are designed to have no ledges and smooth seams to make cleaning easy. Many different sizes are available making design extremely flexible. The rooms include lighting, and can include electrical outlets.