Double Pass ESP Filtration Systems: When a Single Pass Isn’t Enough

What Is a Double Pass ESP System?

A double pass ESP system uses two ESP units installed sequentially within the same ductwork system.

• The first ESP removes up to 98% of grease and smoke particulate from the extracted air.

• The second ESP then treats the remaining air stream, removing 98% of the residual 2% left behind after the first stage.

This staged approach results in extremely high overall particulate removal efficiency, dramatically reducing visible smoke, grease carryover, and downstream contamination. The outcome is a much cleaner exhaust air stream compared to a single-pass configuration, even under heavy cooking loads.

Why Double Pass Systems Are So Effective

ESP technology excels at capturing fine grease and smoke particles that mechanical filters struggle with. By applying this process twice:

• Particle loading on each ESP is reduced, improving long-term stability and performance

• Very fine smoke aerosols that escape the first pass are effectively captured in the second

• Cleaner ductwork is maintained downstream, reducing fire risk and maintenance intervals

• Odour control systems (such as carbon or UV-based solutions) operate more effectively due to reduced grease contamination

This makes double pass systems particularly suitable where air quality expectations are high and failure is not an option.

When Double Pass Systems Are Required

Double pass ESP filtration is typically specified in the most demanding commercial kitchen environments, including:

• Charcoal, solid fuel, and wood-fired cooking

• High-temperature grilling and heavy frying operations

• Sites with strict planning or environmental health conditions

• Urban or mixed-use developments with residential properties nearby

• Sensitive locations where visible emissions or odour complaints are unacceptable

In these cases, a standard single-pass ESP may not provide sufficient margin to consistently meet compliance or neighbour expectations.

Considerations and Trade-Offs

While double pass systems deliver outstanding performance, they do introduce additional considerations:

• Increased space requirements within the ductwork

• Higher capital cost compared to single-pass systems

• Additional maintenance planning, as two ESP units must be serviced

That said, these factors are often outweighed by the benefits in environments where emissions control is critical.

A Robust Solution for High-Demand Kitchens

Although more complex, double pass ESP filtration systems provide a proven, robust solution where standard filtration alone is insufficient. For kitchens producing extreme levels of smoke and grease, they offer peace of mind, regulatory confidence, and long-term operational reliability—ensuring clean exhaust air even under the most challenging cooking conditions.