The Complete Guide to Designing a Commercial Kitchen Exhaust System

Designing a commercial kitchen exhaust system is one of the most critical aspects of building a successful restaurant or central kitchen in Singapore. A properly designed system does more than just remove smoke and odors—it ensures fire safety, staff comfort, energy efficiency, and regulatory compliance.

With Singapore’s dense urban environment and stringent SCDF (Singapore Civil Defence Force) and NEA (National Environment Agency) regulations, every detail in design and installation matters. Whether you’re setting up a new restaurant, retrofitting a hawker stall, or constructing a large-scale central kitchen, understanding how to plan and design your kitchen exhaust system correctly is essential.

This comprehensive guide explains the design process, key components, regulations, and practical considerations that every F&B operator should know.

1. Understanding the Role of a Commercial Kitchen Exhaust System

A commercial kitchen exhaust system’s main purpose is to extract heat, smoke, grease, steam, and odors from the cooking area and release them safely outside.

Without proper exhaust ventilation, cooking fumes accumulate, leading to:

• Uncomfortable and unsafe working conditions

• Grease buildup and fire hazards

• Equipment overheating

• Odor complaints from neighboring businesses or residents

A well-designed exhaust system ensures your kitchen is safe, compliant, and efficient, enabling chefs to work comfortably even during peak hours.

2. Components of a Kitchen Exhaust System

Before diving into the design, it’s important to understand the system’s key components and how they interact.

a. Exhaust Hood

The hood captures cooking fumes, grease, and smoke at their source. Hoods are usually installed above stoves, fryers, and grills.

Common hood types include:

• Wall-mounted canopy hoods (for line cooking stations)

• Island hoods (for open kitchens)

• Proximity hoods (for compact areas)

• Pass-over or low proximity hoods (for quick-service kitchens)

b. Filters or Baffles

Grease filters trap airborne oil particles before they enter the ducts. Stainless-steel baffle filters are the most common choice in Singapore for their fire-resistance and ease of cleaning.

c. Ductwork

Ducts transport the contaminated air from the hood to the external exhaust outlet. Ducts must be fire-rated, air-tight, and made from non-combustible materials such as galvanized or stainless steel.

d. Exhaust Fan

The fan creates suction to draw air through the hood and ducts. It’s typically mounted on the rooftop or external wall.

e. Make-Up Air System

As exhaust fans pull out large volumes of air, make-up air systems replace it with fresh, filtered air—maintaining pressure balance and preventing negative air pressure.

f. Fire Suppression System

Automatic systems, such as wet chemical fire suppression, detect high heat and extinguish flames before they spread through the exhaust ducts.

Together, these components form a complete ecosystem that maintains a safe and efficient kitchen environment.

3. Planning and Design Considerations

Designing a kitchen exhaust system involves much more than installing fans and ducts. It requires a holistic approach that considers layout, equipment load, fire safety, and energy use.

a. Determine the Cooking Load

Different cooking methods generate different levels of smoke and grease.
For example:

• Light-duty: Boiling, steaming (e.g., cafés, salad bars)

• Medium-duty: Grilling, baking, pan-frying (e.g., Western restaurants)

• Heavy-duty: Wok cooking, deep-frying (e.g., Asian or hawker kitchens)

Your design should match the required exhaust airflow rate (CFM) to the cooking intensity.

b. Calculate Airflow Requirements

The airflow capacity determines how effectively the system removes contaminants. Engineers calculate airflow based on:

• Hood size and capture area

• Type of cooking equipment

• Heat and grease output

• Local air quality and humidity

Oversized systems waste energy, while undersized ones lead to smoke and odor issues. Balance is key.

c. Layout and Space Planning

The hood placement should align directly with cooking stations to maximize capture efficiency. Avoid long or complex duct runs with multiple bends, as these restrict airflow and increase cleaning challenges.

In Singapore’s compact kitchens, strategic duct routing through ceiling voids or external shafts is often necessary—requiring careful coordination with architects and landlords.

4. Singapore Regulatory Requirements

Singapore’s SCDF Fire Code and NEA Environmental Public Health Regulations govern how commercial kitchen exhaust systems must be designed and maintained.

Key requirements include:

1. Fire-rated ducts (minimum thickness specified by SCDF).

2. Non-combustible materials for hoods and ducts.

3. Grease filters in hoods to trap flammable vapors.

4. Access panels every 3 meters for cleaning.

5. Proper discharge height and distance from air intakes and windows.

6. Fire suppression systems above cooking appliances.

7. Regular maintenance and cleaning documentation.

Compliance is mandatory before obtaining or renewing your Fire Safety Certificate (FSC).

Failing to follow these standards can lead to:

• Fines or suspension of your operating license

• Insurance claim rejection in case of fire

• Costly retrofitting later on

5. Choosing the Right Exhaust Hood

Selecting the right hood is crucial for performance and safety. Consider the following:

a. Size and Capture Area

The hood should extend beyond the cooking surface by at least 150–300mm on all sides to capture rising fumes efficiently.

b. Material

Use stainless steel (Grade 304 or higher) for durability, hygiene, and fire resistance.

c. Grease Filter Type

• Baffle filters: Easy to clean, efficient at trapping grease.

• Mesh filters: Suitable for light-duty cooking only.

• High-efficiency filters: Used in high-end or odor-sensitive locations.

d. Lighting and Controls

Built-in LED lighting enhances visibility, while digital control panels allow operators to adjust fan speeds based on cooking load—improving energy efficiency.

6. Duct Design and Routing

Proper duct design ensures smooth airflow and minimizes grease accumulation.

Key principles:

• Keep duct runs short and straight.

• Avoid 90° bends whenever possible; use gradual turns instead.

• Install ducts at a 3% slope toward grease collection points.

• Seal all joints with continuous welds (no screws or rivets).

• Provide inspection panels every 3 meters.

In multi-tenant buildings or malls, ducts must discharge above roof level to prevent smoke from affecting other units.

7. Selecting the Right Exhaust Fan

The fan must generate sufficient suction without being excessively noisy or energy-consuming.

Types of exhaust fans:

• Centrifugal upblast fans: Common for rooftop installations.

• In-line axial fans: Used in long duct runs or internal shafts.

• Mixed-flow fans: Combine high efficiency with quiet operation.

Always match fan capacity (CFM and static pressure) to hood size and duct configuration.

Additionally, include vibration isolators and sound dampers to minimize noise transmission.

8. Integrating Make-Up Air Systems

Exhausting large volumes of air without replacement can create negative pressure, making doors hard to open and reducing exhaust efficiency.

Make-up air systems:

• Supply fresh, filtered air to balance indoor pressure.

• Improve energy efficiency when combined with heat recovery systems.

• Help maintain consistent air temperature for staff comfort.

Balancing exhaust and make-up air flow is crucial for both performance and compliance.

9. Fire Safety Integration

Fire protection is a key design factor for any kitchen exhaust system in Singapore.

Fire-safety design considerations include:

• Installing automatic wet-chemical suppression systems in hoods.

• Ensuring fire-rated ducting if the system passes through walls or ceilings.

• Using fusible links that automatically activate suppression when temperatures rise.

• Coordinating exhaust shutdown with the building’s fire alarm panel.

Designers must also allow access for maintenance and inspection of fire suppression components.

10. Odor and Smoke Control Enhancements

In mixed-use buildings or residential areas, controlling cooking odor is a top priority.

Solutions include:

• Electrostatic precipitators (ESP): Remove fine grease and smoke particles.

• Activated carbon filters: Absorb odors and gases.

• UV-C systems: Break down grease molecules for cleaner emissions.

These filtration technologies, combined with regular cleaning, ensure that your exhaust meets NEA air emission standards and keeps neighbors happy.

11. Energy Efficiency and Sustainability

Energy-efficient ventilation is now a growing trend in Singapore’s green building movement.

Design strategies include:

• Variable speed drives (VSDs) to adjust fan speeds automatically.

• Demand-controlled ventilation (DCV) that detects cooking activity.

• Heat recovery ventilators (HRVs) to reclaim waste heat from exhaust air.

• LED lighting and automation systems for energy savings.

Though these systems cost more initially, they offer long-term savings and may qualify for government sustainability incentives.

12. Maintenance Access and Cleaning Design

A well-designed exhaust system simplifies maintenance and cleaning—critical for safety and compliance.

Include:

• Access doors or panels at all bends and intervals.

• Grease collection trays that are easy to empty.

• Removable filters and fans for cleaning convenience.

• Clear signage showing cleaning frequency and inspection dates.

Designing for maintainability reduces downtime and ensures compliance with NEA’s recommended cleaning schedule.

13. Collaboration Between Designers and Contractors

Successful exhaust system design requires coordination between:

• Architects and M&E engineers (for layout and duct routing)

• Fire-safety consultants (for code compliance)

• Exhaust system contractors (for fabrication and installation)

• Restaurant owners and chefs (for operational input)

Each stakeholder plays a part in ensuring the system performs optimally and passes inspection without delays.

14. Common Design Mistakes to Avoid

Avoid these costly errors during design:

• Using undersized ducts or fans that cause poor ventilation.

• Installing ducts with too many sharp bends.

• Combining multiple hoods into one undersized duct.

• Neglecting fire suppression system integration.

• Failing to plan for regular access panels and cleaning.

Correcting these mistakes after installation can be expensive and may require downtime or rework.

15. Working with Certified Exhaust System Specialists

A certified commercial kitchen exhaust contractor can provide:

• Customized system design based on your kitchen size and cooking volume.

• Compliance assurance with SCDF and NEA codes.

• Professional installation and testing.

• Maintenance contracts for cleaning and servicing.

When choosing a contractor, check for track record, certification, and after-sales support. Reliable specialists provide documentation, drawings, and performance testing reports that help you secure your Fire Safety Certificate faster.

Conclusion

Designing a commercial kitchen exhaust system is both an art and a science. It requires balancing airflow, fire safety, and energy efficiency while complying with Singapore’s strict building and environmental codes.

A properly designed exhaust system protects your investment, enhances kitchen productivity, and ensures the health and safety of everyone in your restaurant.

Whether you’re building from scratch or upgrading an existing system, always engage certified professionals who understand both the technical and regulatory aspects of commercial ventilation in Singapore.

Find out more at https://commercialkitchenexhaust.sg/