In general, the raw material of crude drug production workshop production steps for the more, the process pipeline is relatively complex, the use of organic solvent type and usage is more, work time is longer, and refined area generally only one process step namely recrystallization reaction, a comparatively small amount of solvent used, working time is short, so you can design a special used for the coarse product synthesis class a workshop, And the recovery tower and vacuum pump for solvent recovery are arranged in the class A workshop. The refined area can be designed in the explosion-proof area of a class C workshop, and the power distribution, water, refrigeration, air pressure, air conditioning and other public engineering room layout, through the pipe gallery to introduce the pipeline into a class A workshop, can effectively solve the explosion-proof problem of public engineering equipment, save the cost of purchasing explosion-proof motor. At the same time, other areas of class C plant will be designed for pilot test or downstream production of API preparations, making full use of plant area and shortening the transportation route of raw materials and drugs. It should be noted that the spacing of two workshops should not be less than 12m(building grade is two or above), and the area of the explosion-proof area of the refined workshop should not exceed 5% of the fire prevention zone.