Medical gas networks are essential in hospitals to ensure the safe and efficient distribution of medical gases to all surgical and medical departments. These systems eliminate the need for individual gas cylinders and mobile devices, which pose several disadvantages.
About the Gases Used in Hospitals
Hospitals use several gases to treat patients and operate laboratory equipment. The most important ones include:
- Oxygen gas: Used in the treatment of patients with breathing difficulties.
- Nitrous oxide: Used for anesthesia during operations and for pain relief during childbirth.
- Compressed air: Mainly used in ventilators, surgical drills, and bone saws, as well as in equipment that requires a specific air-oxygen mixture.
- Evacuation system: Used for suction operations and the removal of secretions.
Pipe Identification and Colors
Network pipes are painted in international standard colors, and each pipe is labeled with the gas name and direction of flow.
- Oxygen: Green
- Nitrous oxide: Blue
- Medical Air: Yellow
- Clearance: Black
- Nitrogen: White
- Anesthetic gas system: Copper pipes (oxidized finish)
Components of the Hospital Gas Network
- Measurement Unit: Measures parameters such as oxygen, CO₂, nitrogen levels, and their temperature and pressure.
- Monitoring Unit: Controls and monitors gas parameters via a central control system.
- Alarm Unit: Alerts staff to gas shortages or surpluses in critical areas like operating rooms and incubator rooms.
- Treatment Unit: Works with control systems (PLCs) to calibrate gases in the network.
Working Principle of the Central Oxygen and Nitrogen Station
The central units supply oxygen and nitrogen continuously to hospital departments. Pressure reducers lower gas pressure from 200 bar to an operational level of 5–10 bar. Automatic valves switch between full and empty cylinder sections, and safety valves release excess pressure to prevent hazards.
In modern systems, oxygen is stored in two large tanks (about 5000 m³ each) containing liquid oxygen at -186°C. The tanks have evaporators that convert liquid oxygen into gas, pressure regulators, and safety valves that activate if pressure exceeds 8 bar.
Components of the Medical Air Pumping Room
- Air compressors
- Compressed air tanks (operating pressure: 5–12 bar)
- Moisture dryers
- Bacterial filters
- Two-stage pressure regulators
- Distribution units (5 bar for wards, 8 bar for operating rooms)
Working Principle of the Air Pumping Room
Air is drawn from the outside, filtered, and compressed into storage tanks. Moisture is condensed and drained, then air is dried and passed through bacterial filters for purification. Finally, it is distributed through pressure regulators to different hospital departments.
Procedures for Installing the Hospital Gas Network
Pre-installation Stage
Pipes are cleaned with special chemicals to remove grease and oil residues.
Post-installation Stage
- Blowing stage: The network is flushed with compressed air to remove welding residues.
- Nitrogen compression stage: The system is pressurized with nitrogen for 24 hours to sterilize and test weld integrity.
- Oxygen flushing stage: The system is finally purged with oxygen to remove nitrogen residues.