F&B Kitchen Ventilation System

Fresh Air, Exhaust Air RPM & How to Avoid Negative Pressure

In any F&B kitchen, ventilation is not just about removing smoke. It directly affects working comfort, safety, hygiene and equipment life. Inadequate fresh air and exhaust balances are more often the cause of kitchen failures than cooking appliances.

Let’s understand this in a simple and practical way.

1. What is an F&B Kitchen Ventilation System?

A proper kitchen system mainly includes the following:

• Exhaust system— removes heat, smoke and oil fumes
• Fresh air system (Treated Fresh Air—TFA)— supplies clean air
• Make-up air balance – maintains pressure inside the kitchen

If these are not balanced properly, it leads to the following:

• Smoke leakage into dining area
• Difficulty in opening doors
• Poor working conditions for chefs
• AC failure in nearby areas

2. What is RPM in Fresh Air & Exhaust Systems?

"RPM" means "Revolutions Per Minute" of the fan motor.

• Higher RPM = higher air movement
• Lower RPM = lower airflow

But in kitchen design, we don’t only depend on RPM—we consider the following:

• CFM (Cubic Feet per Minute)
• Static pressure
• Duct size & length

Still, RPM plays a key role in selecting proper fan performance.

3. Exhaust Air System – How It Works

Kitchen exhaust is designed to pull out heat, smoke and oil particles.

Typical Exhaust Setup:

• Hood above cooking range
• Ducting system
• Exhaust blower (high RPM)
• Oil trap / filter

RPM Range (Practical Site Range):

• Small kitchen: 900–1200 RPM
• Medium kitchen: 1200–1800 RPM
• Heavy cooking (tandoor, Chinese): 1800–2500 RPM

Key Point:

Higher RPM ensures strong suction, but if not balanced, it creates negative pressure.

4. Treated Fresh Air (TFA)—Why It Is Important

Fresh air is not just normal air — it is filtered and treated air supplied inside the kitchen.

Methods of Fresh Air Supply:

5. What is negative pressure in a kitchen?

Negative pressure happens when:

Exhaust air > Fresh air supply

This creates a vacuum effect inside the kitchen.

Problems due to Negative Pressure:

• Smoke comes back from the hood
• Doors become hard to open
• AC air from the dining room gets sucked into the kitchen
• Staff feels suffocation.
• Gas burners may not perform properly

6. How to Avoid Negative Pressure (Most Important Part)

This is where many projects fail on site.

Ideal Rule:

Fresh Air = 80% to 90% of Exhaust Air

Example:

• Exhaust: 10,000 CFM
• Fresh Air: 8,000–9,000 CFM

Practical Solutions:

7. Site Experience Insight (Important)

In many projects, we see:

• Exhaust system installed perfectly
• But fresh air was ignored

Result:

• The kitchen becomes hot and suffocating
• Staff complains
• Client thinks equipment issue

But the actual issue is air balance failure.

8. Conclusion

A good F&B kitchen is not only about equipment or layout. It is about proper coordination of exhaust and fresh air systems.

Key takeaways:

• Always balance exhaust and fresh air
• Do not depend only on RPM; consider airflow
• Maintain 80–90% fresh air in exhaust
• Use a proper treated fresh air system for comfort

A well-designed ventilation system will:

• Improve staff efficiency
• Maintain hygiene
• Increase equipment life
• Enhance overall kitchen performance

We offer design / turnkey execution with lighting, MEP and visual merchandising integration for your space. Visit www.nextbc.in to learn more . . .