Medical Gas Pipe Sizing Calculator

Size medical gas piping systems per NFPA 99 requirements

Outlet Information

System Configuration

Piping Requirements

Main Pipe Size --
Total Flow (SCFM) --
Design Flow Rate --
Diversity Factor --
Equivalent Length --
Branch Size (risers) --
Note: Medical gas piping must be Type K or L copper, ACR grade, cleaned for oxygen service.

Flow Rates by Outlet Type

Location O2/Air N2O Vacuum
Operating Room20 SCFM10 SCFM3 SCFM
ICU/CCU10 SCFM--1.5 SCFM
Patient Room1 SCFM--1 SCFM
Recovery10 SCFM5 SCFM2 SCFM
Per NFPA 99 Table 5.1.11

NFPA 99 Requirements

  • Type K or L copper pipe only
  • Brazed joints (AWS/BCuP series)
  • Cleaned for oxygen service
  • Nitrogen purge during brazing
  • Testing: 150 PSI for 24 hours
  • Certification by installer required

Pipe Sizing Table - Oxygen/Medical Air (50 PSI)

Pipe Size 100 ft 200 ft 300 ft 500 ft
3/8"7 SCFM5 SCFM4 SCFM3 SCFM
1/2"18 SCFM13 SCFM10 SCFM8 SCFM
3/4"50 SCFM35 SCFM29 SCFM22 SCFM
1"110 SCFM78 SCFM64 SCFM50 SCFM
1-1/4"210 SCFM150 SCFM120 SCFM95 SCFM
1-1/2"340 SCFM240 SCFM200 SCFM155 SCFM
2"700 SCFM500 SCFM410 SCFM315 SCFM
Based on 5 PSI pressure drop. Reduce flow 30% for 3 PSI drop.