192 - Fire Fundamentals pt. 14 - Jet fan systems for car parks

Fire Science Show

Jet-fan systems effectively control smoke in car parks by creating directed airflows that transport smoke from one point to another, similar to how longitudinal ventilation works in tunnels. These systems offer cost-effectiveness and simplicity by eliminating ductwork while providing powerful smoke management capabilities when properly designed and understood.
• Jet Fans create momentum transfer through air entrainment rather than directly moving smoke
• Two distinct operational modes exist: smoke clearance (reducing thermal stress) and smoke control (maintaining clear firefighter access)
• Systems require careful balancing of extraction capacity with Jet Fan thrust force
• Optimal design typically requires CFD modeling followed by hot smoke testing for verification
• Jet Fan activation timing presents challenges for evacuation - usually delayed until occupants exit
• Systems excel in tunnel-like geometries but struggle with complex layouts (the "Tetris rule")
• Particularly effective against heavier-than-air gases like LPG or EV battery fire emissions
• European standards now available through EN 12101 family for design guidance
If you need design assistance with Jet Fan systems for your projects, email me directly at [email protected].

Further reading:

- Jet-Fan Systems in Car Parks Design Methods: an Overview and Assessment of Performance

- Our in-depth multiparametric study on car park ventilation

- A. Król and M. Król, Study on numerical modeling of jet fans

- Thunderhead's guide to modelling jet-fans in FDS

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The Fire Science Show is produced by the Fire Science Media in collaboration with OFR Consultants. Thank you to the podcast sponsor for their continuous support towards our mission.

Chapters

1. 192 - Fire Fundamentals pt. 14 - Jet fan systems for car parks (00:00:00)

2. Introduction to JetFan Systems (00:00:54)

3. What is a JetFan System? (00:03:12)

4. Clearance vs. Smoke Control (00:08:31)

5. System Components and Operation (00:12:19)

6. Velocity Requirements and Space Impact (00:19:32)

7. Design Challenges and Evacuation Considerations (00:26:26)

8. CFD Modeling and Testing (00:33:30)

9. Design Factors and Final Remarks (00:36:57)