There are corresponding standards for the flow velocities of different media in pipelines.
In the process of designing fluid pipelines, the flow velocity determines the size of the pipeline diameter and the magnitude of the pipeline resistance.
Our team has summarized the flow rates of the fluid media involved for daily design use.
| Media | Types and conditions of pipelines | Flow velocity (m/s) |
| Saturated steam | Dg>200 | 30~40 |
| Dg=200~100 | 25~35 | |
| Dg<100 | 15~30 | |
| Low pressure steam | P<1Mpa(A) | 15~20 |
| Medium pressure steam | P=1~4Mpa(A) | 20~40 |
| High pressure steam | P=4~12Mpa(A) | 40~60 |
| Superheated steam | Dg>200 | 40~60 |
| Dg=200~100 | 30~50 | |
| Dg<100 | 20~40 | |
| Secondary steam: during utilization | 15~30 | |
| during idle time | 60 | |
| Off-gas | Exhaust pipe: for discharging from pressurized vessels. | 80 |
| Exhaust pipe: for discharging from unpressurized vessels. | 15~30 | |
| High pressure off-gas | 80~100 | |
| Compressed gas | Vacuum | 5~10 |
| P≤0.3Mpa（G） | 8~12 | |
| P=0.3~0.6Mpa（G） | 10~20 | |
| P=0.6-1Mpa（G） | 10~15 | |
| P=1~2 Mpa（G） | 8~12 | |
| P=1~3 Mpa（G） | 8~6 | |
| P=3~30 Mpa（G） | 0.5~3 | |
| Oxygen gas | P=0~0.05Mpa（G） | 5.0~10 |
| P=0.05~0.6Mpa（G） | 7~8 | |
| P=0.6~1Mpa（G） | 4~6 | |
| P=1~2 Mpa（G） | ||
| P=2~3 Mpa（G） | 3.0~4.0 | |
| Gas | Pipeline length of 50-100 meters | |
| P≤200 mm Hg | 0.75~3 | |
| P≤2000 mm Hg | 8~12 | |
| P≤6000 mm Hg | 3~12 | |
| Semi-water gas | P=0.1~0.15 Mpa(G) | 10~15 |
| Natural gas | 30 | |
| Flue gas | Inside of the flue | 3~6 |
| Inside of the pipeline | 3~4 | |
| Nitrogen gas | P=5~10Mpa（A） | 2~5 |
| Transform gas | P=0.1~2Mpa（A） | 10~15 |
| Hydrogen and nitrogen mixed gas | P=20~30Mpa（A） | 5~10 |
| Ammonia gas | P=vacuum | 15~25 |
| P<0.3 Mpa（G） | 8~15 | |
| P<0.6Mpa（G） | 10~20 | |
| P≤2Mpa（G） | 3~8 | |
| Water and similar liquids with viscosity. | P=0.1~0.3Mpa（G） | 0.5-2 |
| P≤1Mpa（G） | 0.5-3 | |
| P≤8Mpa（G） | 2-3 | |
| P≤20-30Mpa（G） | 2-3.5 | |
| Hot water circulating in the heating network and cooling water. | 0.5-1 | |
| Pressure return water. | 0.5-2 | |
| Gravity return water | 0.5-1.2 | |
| Tap water | Main pipeline pressure P=Mpa(G). | 1.5~3.5 |
| Branch pipeline pressure P=Mpa(G). | 1~1.5 | |
| Boiler feed water | P>0.8 Mpa(G) | >3.0 |
| Condensed steam | 0.5~1.5 | |
| Condensate | Free flow | 0.2~0.5 |
| Superheated water | 2 | |
| Oil and liquids with high viscosity | Oil and similar liquids | 0.5~2 |
| Viscosity of 50 cP at 25℃ | 0.5~0.9 | |
| Dg50 | 0.7~1.0 | |
| Dg100 | 1.0~1.6 | |
| Viscosity of 100 cP at 25℃. | 0.3~0.6 | |
| Dg50 | 0.5~0.7 | |
| Dg100 | 0.7~1.0 | |
| Dg200 | 1.2~1.6 | |
| Viscosity of 1000 cP at 25℃ | 0.1~0.2 | |
| Dg50 | 0.16-0.25 | |
| Dg100 | 0.25~0.35 | |
| Dg200 | 0.35~0.55 | |
| Liquid ammonia | P=vacuum | 0.05~0.3 |
| P≤0.6 Mpa(G) | 0.3~0.8 | |
| P≤2 Mpa(G) 0.8~1.5 | P≤2 Mpa(G) 0.8~1.5 | |
| Discharging of wastewater | 0.4~0.8 | |
| Slurry mixture | Concentration: 15% | 2.5~3 |
| 25% 3~4 | 25% 3~4 | |
| 65% 2.5~3 | 65% 2.5~3 | |
| Gas | Intake pipe of the blower | 10~15 |
| Exhaust pipe of the blower | 15~20 | |
| Intake pipe of the compressor | 10~20 | |
| Exhaust pipe of the compressor | ||
| P<1 Mpa | 8~10 | |
| P=1~10 Mpa | 10~20 | |
| P>10Mpa | 8~12 | |
| Intake pipe of the reciprocating vacuum pump | 13~16 | |
| Exhaust pipe of the reciprocating vacuum pump | 25~-30 | |
| Intake pipe of the oil-sealed vacuum pump | 10~13 | |
| Water and similar liquids with viscosity | Intake pipe of the reciprocating pump | 0.5～1.5 |
| Exhaust pipe of the reciprocating pump | 1～2 | |
| Intake pipe of the centrifugal pump (at normal temperature) | 1.5～2 | |
| Intake pipe of the centrifugal pump (70~110℃) | 0.5～1.5 | |
| Exhaust pipe of the centrifugal pump | 1.5～3 | |
| Exhaust pipe of the high pressure centrifugal pump | 3~3.5 | |
| Intake pipe of the gear pump | ≤1 | |
| Exhaust pipe of the gear pump | 1~2 | |
| Ammonia gas | <8 |
