Medical Gas System Demand and Diversity (NFPA 99)

Connected flow = station (outlet/inlet) count x per-station design flow, and the system design flow = connected x a diversity (simultaneous-use) factor that falls as the station count rises. 20 oxygen outlets at 1.0 scfm with diversity 0.25 give a 5.0 scfm design flow; medical-surgical vacuum's higher simultaneous use (0.50) drives a larger design flow per inlet. The per-station flows and diversity factors are read from the adopted NFPA 99 edition and the facility's equipment list (user-supplied here); medical-gas piping is installed and certified by brazing-qualified plumbers and pipefitters (ASSE 6010), and a medical-gas verifier and the AHJ govern. This feeds pipe sizing, not the system design itself.

connected_scfm = stations x per_station_scfm; design_scfm = connected_scfm x diversity, the diversity (simultaneous-use) factor in (0, 1] falling as the station count rises.

NFPA 99 Health Care Facilities Code (medical gas and vacuum systems) demand and diversity, with ASSE 6010 for the installer qualification, by name.

The connected-times-diversity demand relation is the NFPA 99 sizing method; the per-station flows and diversity factors are read from the adopted edition and the facility equipment list.

Estimate. AHJ and licensed professional govern.

Field names used by the API: stations, per_station_scfm, diversity, connected_scfm, design_scfm

• Per-station flow the per-station design flow is read from NFPA 99 / the equipment list (user-supplied)NFPA 99
• Diversity the simultaneous-use factor falls as station count rises and is read from the adopted table (user-supplied)NFPA 99
• Installer medical-gas piping is brazed and certified by ASSE 6010-qualified plumbers/pipefitters; a verifier and the AHJ governASSE 6010 / NFPA 99