The definition of vacuum pressure is the difference between atmospheric pressure and the absolute pressure. When the vacuum chambers are empty, the needles would point to zero. When the chambers are full a thus at atmospheric pressure, the needle would point to 29” .So this gauge represents the absolute pressure. In case, there are no molecules of air that cause pressure.
The central vacuum system is designed to create a central vacuum in the entire hospital complex, which is transmitted through the copper pipelines to the terminal unites in the hospital. Vacuum system is designed to suction for removing bodily fluids or gases in the hospital, laboratory, and Centers that need a suction system, and has duty for the suction system. Medical vacuum system is in accordance with the NFPA99 standard provides the requirement for the vacuum device and includes vacuum pumps (the quantity of inquired pumps is calculated and determined based on medical center needs) and the storage tanks.