The exhaust system is the infrastructure item that most frequently causes problems for food factory tenants, and the one that is hardest to fix after you have signed the lease. If the building does not support adequate exhaust routing, no amount of renovation can correct it. Confirming exhaust infrastructure during the first viewing is the single most important due diligence step for any food factory operator.
This guide covers what to look for when assessing existing exhaust systems, how to evaluate routing potential when no system exists, and the questions to ask building management before committing.
Existing Exhaust Infrastructure: What to Check
When viewing a unit that has been previously used for food production, or one in a building designated for food factory use, start with the existing exhaust infrastructure.
Duct condition and history. Ask whether the unit has an existing exhaust duct running from the cooking area to the roof. Inspect the visible sections for damage, corrosion, or accumulations of grease residue. Heavy grease buildup on the inside of ducting indicates inadequate extraction and is a fire risk. A duct in poor condition may need to be replaced entirely rather than simply reconnected.
Duct diameter. Duct diameter determines extraction capacity. An undersized duct cannot move enough air to clear smoke, heat, and grease from a busy cooking line. Ask for the duct dimensions and compare against what your cooking equipment requires. A standard exhaust hood over a single burner may work with a small duct; a full cooking line with charbroilers and deep fryers will not.
Shared vs dedicated duct. Some buildings have a common exhaust shaft shared across multiple floors. This creates backflow risk: exhaust from a tenant on the floor below can push back into your duct if the system is not properly balanced. It also means your extraction capacity is shared and potentially limited. A dedicated duct running directly from your unit to the roof is preferable.
Roof termination location. Where the exhaust duct terminates on the roof matters for both performance and neighbour relations. Discharge near windows, air intakes for other tenants’ ventilation systems, or neighbouring buildings can cause complaints and may violate NEA guidelines on air quality and neighbours. Confirm the termination point’s position relative to other buildings and openings.
When No Existing System Exists
If the unit has no existing exhaust infrastructure, assess the routing potential before committing to the space.
Designated exhaust shaft. Many purpose-built food factory buildings have a designated exhaust shaft running the height of the building, typically with connection points at each floor. This is the simplest installation path: you connect horizontally from your unit into the shaft, and the building’s common exhaust system handles roof termination. Check whether the shaft has available capacity for your connection.
External wall routing. If no shaft exists, routing ducting externally along the building facade to the roof may be technically feasible. However, this requires building management approval and may be restricted by URA planning rules or building facade guidelines. External routing also means the duct is exposed to weather, requires additional structural support, and may be aesthetically restricted in certain estates.
Multi-floor routing. If the unit is on an upper floor and no shaft exists, ducting must traverse multiple floors vertically. Each floor penetrated adds cost and structural complexity. The penetrations themselves may require fire-rated sealing at each floor level to maintain the building’s fire compartmentation. This is expensive and may be impractical in some building configurations.
Obstructions along the routing path. Before finalising any routing plan, walk the proposed path through the building and check for obstructions: structural beams, existing ducting, electrical cable trays, or fire-rated partitions that cannot be penetrated without professional involvement.
Make-Up Air: The Forgotten Half
Exhaust systems remove air from the kitchen. Replacement air, called make-up air, must come from somewhere. Without adequate make-up air provision, exhaust systems underperform. The most common symptom is negative pressure: doors become difficult to open against the suction, smoke backflows into the kitchen instead of being drawn up the duct, and the extraction rate drops even though the fan is running.
Check whether the building or unit provides for make-up air through any of these means: a dedicated fresh air intake linked to the exhaust system; operable windows or external doors that can supply replacement air; a mechanical make-up air unit. In a tight, well-sealed building, relying on air infiltration through gaps and doors is insufficient for a heavy cooking load.
What to Ask Building Management
Before leaving the viewing, get clear answers to these questions:
- Has this unit previously been used for food production? If so, what type and scale?
- Is there a designated exhaust shaft in the building with available connection capacity?
- Are there any building rules or restrictions on exhaust duct installation, diameter, or routing?
- What is the maximum duct size the shaft or building infrastructure can accommodate?
- Have there been any neighbour complaints or building management notices related to exhaust from this unit or adjacent units?
- Who is responsible for maintaining the common exhaust system, and what is the cost?
Summary and Closing
Exhaust infrastructure is not something you assess loosely and hope to resolve later. If the building cannot support the extraction your cooking setup requires, no amount of redesign inside the unit solves it. Confirm the duct, the shaft capacity, and the make-up air provision at the viewing stage, before you sign.
References
- NEA — Environmental Public Health — Ventilation requirements for food establishments
- BCA — Development Control: Industrial — Ventilation and exhaust routing for food production
- SFA — Food Factory Licensing — Ventilation requirements for food production
- SFA — Food Manufacturing — Exhaust system requirements for licensed food factories
- PUB — Drainage Connection Requirements — Grease trap and drainage infrastructure
- NEA — Ventilation Requirements for Food Establishments — NEA guidelines on kitchen exhaust and make-up air
- BCA Building Control — Structural requirements for duct penetrations
- JTC — Space for Rent — Purpose-built food factory listings and infrastructure standards