Vacuum System Sizing Calculator

Size vacuum piping and pump capacity for various applications

Application Type

Pipe Material

Inlet Configuration

Operating Room Inlets

ICU/CCU Inlets

Patient Room Inlets

Recovery/ER Inlets

System Parameters

Vacuum Level (in Hg)

Pipe Run Length (feet)

Number of Fittings Elbows, tees, valves - for equivalent length

System Requirements

Main Pipe Size --

Pump Capacity Required --

Total Connected Load --

Design Flow (w/ diversity) --

Diversity Factor --

Equivalent Length --

Branch Size --

Note: Medical vacuum per NFPA 99 requires duplex pumps with 100% standby.

Medical Vacuum Flow Rates (NFPA 99)

Location	SCFM/Inlet	Vacuum Level
Operating Room	3.0 SCFM	19" Hg min
ICU/CCU	1.5 SCFM	15" Hg min
Patient Room	1.0 SCFM	15" Hg min
Recovery/ER	2.0 SCFM	15" Hg min
Dental	1.5 SCFM	5" Hg

Pipe Sizing Guidelines

Pipe Size	Max SCFM @ 200 ft	Velocity (ft/s)
3/4"	3 SCFM	15-20
1"	7 SCFM	15-20
1-1/4"	15 SCFM	15-25
1-1/2"	25 SCFM	15-25
2"	55 SCFM	15-30
2-1/2"	90 SCFM	15-30
3"	150 SCFM	15-30

Based on 0.5" Hg loss per 100 ft equivalent length

Vacuum System Design Considerations

Medical (NFPA 99)

Duplex pumps (100% backup)
Receiver tank required
High vacuum alarm
Type L copper minimum
Brazed joints only

Laboratory

High vacuum level (22-25")
Chemical resistance
Multiple vacuum levels
Liquid traps required
Overflow protection

Industrial

Dust/debris collection
Larger pipe sizes
Cyclone separators
Filter systems
Higher velocities OK

Central Vacuum

2" minimum pipe
Low-voltage control
Single inlet operation
Exhaust to exterior
Filter/bag at unit