Clean room project, usually refers to the air purification project, refers to the air in the sealed space for recycling purification, the air in the space dust particles, plankton bacteria, bacteria and other things reduced, controlled within a fixed control value. Air purification works are usually carried out by using air conditioning systems for recycling purification, so it is also called air conditioning purification works. Clean room, dust-free room, purification workshop, dust-free workshop, GMP certification standard workshop, laminar flow operating room and other purification projects are clean engineering. This series will take “what contents are included in the design and calculation of the purification project” as the main line, guide the establishment of the basic ideas and framework of the purification project design, and give the basic content of the purification project design, the introduction of the specific design principle, the design steps, the calculation formula and so on.