ABSTRACT:- Corona Virus is deadly spread out to thousands of healthy people and so strong as to infect to the surrounding people after people. We must keep the deadly virus indoor as much as we can. How? We must not allow the indoor air already contaminated to leak out to the atmosphere, which will transmit to other people. The new virus is so strong and so fast to transmit, it will spread within a few seconds to thousands of people and became patients immediately. To solve the problem, we must build a pressure vessel to keep the virus inside the vessel and not to leak outside. It should be a negative pressure compare to the atmospheric pressure. Another words, is to keep the indoor pressure lower than atmospheric pressure, so the contaminated indoor pressure is lower than outdoor pressure. It is a part of a traditional HVAC operation. This article shows step by step procedures of HVAC system design procedures, with emphasis of the air duct system design. Care must be taken to keep close attention to the maintenance of the system. Together, whether we want it or not, the corona may be forced to go into the 4th industrial revolution.