Flash Steam Generation in Imperial Units (psig)
When condensate leaves the steam traps - flash steam is generated. This table indicates the amount of flash steam generated at different pressures - psig
Sponsored Links
The amount of flash steam generated depend on the steam pressure - the pressure in the condensate before it leaves the condensate trap - and the condensate pressure after the trap - the pressure in the condensate return pipe lines.
The diagram and table below indicates the ratio of flash steam generated at different pressures before and after the condensate trap.

| Percent Flash Steam of Condensate (%) | |||||||||||
| Steam Pressure before the Steam Trap (psig) |
Condensate Pressure after the Trap (psig) | ||||||||||
| 01) | 2 | 5 | 10 | 15 | 20 | 30 | 40 | 60 | 80 | 100 | |
| 5 | 1.7 | 1 | |||||||||
| 10 | 2.9 | 2.2 | 1.4 | ||||||||
| 15 | 4 | 3.2 | 2.4 | 1.1 | |||||||
| 20 | 4.9 | 4.2 | 3.4 | 2.1 | 1.1 | ||||||
| 30 | 6.5 | 5.8 | 5 | 3.8 | 2.6 | 1.7 | |||||
| 40 | 7.8 | 7.1 | 6.4 | 5.1 | 4 | 3.1 | 1.3 | ||||
| 60 | 10 | 9.3 | 8.6 | 7.3 | 6.3 | 5.4 | 3.6 | 2.2 | |||
| 80 | 11.7 | 11.1 | 10.3 | 9 | 8.1 | 7.1 | 5.5 | 4 | 1.9 | ||
| 100 | 13.3 | 12.6 | 11.8 | 10.6 | 9.7 | 8.8 | 7 | 5.7 | 3.5 | 1.7 | |
| 125 | 14.8 | 14.2 | 13.4 | 12.2 | 11.3 | 10.3 | 8.6 | 7.7 | 5.2 | 3.4 | 1.8 |
| 160 | 16.8 | 16.2 | 15.4 | 14.1 | 13.2 | 12.4 | 10.6 | 9.5 | 7.4 | 5.6 | 4 |
| 200 | 18.6 | 18 | 17.3 | 16.1 | 15.2 | 14.3 | 12.8 | 11.5 | 9.3 | 7.5 | 5.9 |
| 250 | 20.6 | 20 | 19.3 | 18.1 | 17.2 | 16.3 | 17.7 | 13.6 | 11.2 | 9.8 | 8.2 |
| 300 | 22.7 | 21.8 | 21.1 | 19.9 | 19 | 18.2 | 16.7 | 15.4 | 13.4 | 11.8 | 10.1 |
| 350 | 24 | 23.3 | 22.6 | 21.6 | 20.5 | 19.8 | 18.3 | 17.2 | 15.1 | 13.5 | 11.9 |
| 400 | 25.3 | 24.7 | 24 | 22.9 | 22 | 21.1 | 19.7 | 18.5 | 16.5 | 15 | 13.4 |
1) It is common to vent the condensate system to the atmosphere - where the gauge pressure is 0 psig.
- 1 psi (lb/in2) = 6,894.8 Pa (N/m2) = 6.895x10-3 N/mm2 = 6.895x10-2 bar
Example - Generated Flash Steam
A condensate system is vented to the surroundings and the pressure in the condensate system after the condensate traps is 0 psig. The steam pressure before the condensate trap is 160 psig.
According the table above 16.8% of the condensate will evaporate as flash steam after the trap.
Note! Without any flash recovery system the energy in the flash steam will be lost to the surroundings.
If you prefer SI units - go here!
Sponsored Links
Related Topics
- Flash Steam - Flash steam generation - thermodynamic fundamentals, heat loss, energy recovery and more
- Steam and Condensate - Steam & condensate properties - capacities, pipe sizing, systems configuration and more
Sponsored Links
Related Documents
- Back Pressure and Steam Trap Capacity - Back pressure in a condensate systems will reduce the steam trap capacity
- Flash Steam Generation - Fundamental Physics - A short tutorial to the basic physics behind flash steam generation
- Flash Steam Generation - SI-units - When condensate leaves the steam traps - flash steam is generated. Amount of flash steam generated at different pressures - kN/m2
- Flash Steam Generation (bar) - When condensate leaves the steam traps - flash steam is generated. Table indicating amount of flash steam generated at different pressures - bar
- Flash Steam and Energy Loss - When flash steam is generated and vented to the surroundings, a considerable amount of energy is lost





