Smoke control design in Singapore is the engineering of natural or mechanical systems that keep escape routes tenable and support firefighting, and it is governed mainly by Clause 7.4 of the SCDF Fire Code 2023. It is mandatory for certain building types and sizes, it must be shown in plans and calculations submitted by a Qualified Person (QP), and it must be tested and maintained for the life of the building. This article sets out what the system must achieve, when it is required, how it is designed, how it is approved and what owners must do afterwards.

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TL;DR

Engineered smoke control is required for specific cases, including atria where compartmentation is relaxed, compartments above 5,000 m² and large basements above 2,000 m², subject to the Fire Code’s conditions and exemptions.
Design follows Fire Code Clause 7.4 and accepted standards such as BR 186, BR 258 and BR 368, with performance-based alternatives requiring a Fire Safety Engineer (FSE) and a separate Peer Reviewer.
Submissions go through CORENET with QP-signed plans and calculations, and fire-safety works in renovations also need SCDF approval.
Systems need a secondary power supply, fire alarm integration, commissioning tests and documented maintenance.

What smoke control design is meant to achieve
Which buildings and spaces require it
System types used in Singapore buildings
Engineering factors the design must address
Submission and approval process
Testing, commissioning and maintenance
Planning for new builds, renovations and rebuilds
Our perspective
How Stellar Structures supports smoke control submissions
FAQ
Sources

What smoke control design is meant to achieve

SCDF’s performance-based guidance on mechanical ventilation and smoke control frames the objectives of Chapter 7 as maintaining tenable conditions for evacuation, protecting occupants from the effects of fire, and providing smoke management for firefighting. The sub-objectives address temperature, visibility, toxicity, smoke spread and compatibility with other life-safety systems.

In practical terms, the design controls where smoke goes and how deep the smoke layer becomes. For a compartment exceeding 5,000 m², SCDF states that the intent is to keep the smoke layer at least 1.8 m above floor level so that occupants can reach exits or exit staircases.

Smoke control is therefore a life-safety function first. It is not a comfort or air-quality system, and it cannot be treated as an item to be finalized after the architectural layout is fixed, because ceiling heights, void geometry and façade openings all determine what can be achieved.

Which buildings and spaces require it

The Fire Code’s Clause 7.4 requires an engineered smoke-control system in the following situations, subject to its conditions and exemptions:

Situation	Trigger
Atria	Where atrium compartmentation requirements are relaxed
Large compartments	A compartment exceeding 5,000 m²
Large basements	Basement occupancies exceeding 2,000 m²

Pressurisation is a related requirement for staircases. According to SCDF’s Fire Code amendments circular, internal exit staircases without natural ventilation must be pressurised in buildings with a habitable height exceeding 24 m, except in PG II buildings. In buildings with more than four basement storeys, the exit staircase connecting to the fire-lift lobby must be pressurised.

These thresholds are screening points, not a substitute for a code review. Exemptions, changes of use and building-specific conditions affect the outcome, and the QP should confirm the applicable clause with SCDF where the project is unusual. Further background on the wider regulatory drivers is available in our overview of what drives fire safety compliance in Singapore building projects.

System types used in Singapore buildings

The Fire Code provides for smoke ventilation by natural or mechanical extraction, designed to BR 186, BR 258, BR 368 or other acceptable standards. Where requirements differ from these documents, the clause advises QPs to consult SCDF.

Natural and mechanical smoke extraction

Natural extraction relies on vents and openings at high level, with replacement air entering low. It suits spaces with sufficient height and access to external walls or roofs. Mechanical extraction uses fans and ducts to remove smoke at a controlled rate, and it is common in deep-plan commercial floors, large basements and spaces where natural openings are not available. The choice depends on geometry, the permitted smoke reservoir size and the practicality of providing the required openings. Our article on smoke control systems for large commercial spaces with mechanical ventilation discusses the mechanical case in more depth.

Smoke purging

Smoke purging is a post-fire clearing function rather than a means of maintaining tenable conditions during evacuation. Under Clause 7.4, purging systems must be independent of other systems and provide at least 9 air changes per hour. They must start automatically from the fire alarm, with a remote manual start-stop switch and visual status indication at the fire command centre, or at the main fire-alarm panel where no fire command centre exists.

Ductless jet-fan systems in car parks

For conventional car parks, SCDF’s guidance on ductless jet fans requires sprinkler protection and smoke-control zones no larger than 2,000 m². It also requires a hot smoke test demonstrating containment, at least 12 air changes per hour in the fire condition unless modelling supports a lower rate, and resilience against fan failure.

Staircase pressurisation

Pressurisation keeps smoke out of exit staircases and fire-lift lobbies by maintaining a positive pressure differential. It is designed together with door-opening forces, leakage paths and the fire alarm logic, and its calculations form part of the submission where applicable.

Engineering factors the design must address

The Singapore Fire Safety Engineering Guidelines 2025 point to a set of factors that a smoke control design must work through:

fire size and growth, and the effect of sprinklers and detectors;
smoke reservoirs and compartmentation;
geometry and obstructions;
extraction and replacement-air paths;
wind effects and fan failure;
fire alarm cause-and-effect;
emergency or secondary power, and fire-resisting ducts and wiring;
discharge locations and interaction with other life-safety systems.

The 2025 Guidelines also specifically require smoke-management layouts and relevant architectural elements to be included in computational fluid dynamics (CFD) models.

Design fire

Design-fire size is generally based on the installed active protection. Sprinklered buildings may use second-ring sprinkler activation, while unprotected spaces use fuel load and burning area. The justification for the chosen fire size belongs in the fire-engineering report.

Reservoirs and replacement air

For smoke removed from the room of origin, the Fire Code’s prescriptive provisions limit a smoke reservoir to 2,000 m² for natural ventilation and 2,600 m² for mechanical ventilation. For circulation or atrium spaces, the limits are 1,000 m² and 1,300 m² respectively.

The same document requires natural replacement air for engineered smoke control. Replacement-air discharge velocity should not exceed 5 m/s, intake should be at least 5 m from the smoke exhaust discharge, and low-level discharge should be at least 1.5 m below the designed smoke layer.

Power, interfaces and failure

SCDF requires a secondary power supply for all smoke-control and smoke-purging systems, including associated equipment. A sound design also examines how each component can fail and what the consequences are. Methods such as effects analysis in FMEA are used in engineering practice to trace a single failure, such as a fan or damper fault, through to its effect on the whole system, and the results feed directly into the cause-and-effect matrix agreed with the fire alarm designer.

Submission and approval process

SCDF approval is required before fire-safety works begin, including relevant alterations and changes of use. Under SCDF’s plan approval process, ordinary submissions include QP-signed building and mechanical-ventilation plans, declarations and supporting documents. Pressurisation-staircase and smoke-control calculations are added where applicable, and everything is submitted through CORENET.

The Fire Code also requires a Fire Safety Report with building-plan submissions and a Fire Safety Instruction Manual for the Temporary Fire Permit or Fire Safety Certificate.

Performance-based route

Where a design departs from the prescriptive provisions, an alternative solution requires an FSE and a separate Peer Reviewer. SCDF identifies four core documents: the Fire Safety Engineering Design Brief (FEDB), the Fire Safety Engineering Report (FER), the Operations and Maintenance (O&M) Manual and the Peer Reviewer’s Report. The performance-based approval process runs as follows:

The FSE submits the FEDB to SCDF for in-principle agreement.
After agreement, the FSE prepares the FER and the O&M Manual.
A separate Peer Reviewer assesses the documents and how the plans integrate with them.
The Project QP collates and submits the endorsed plans and documents.

Agreeing the design brief early avoids rework in CFD modelling later. For the submission mechanics, see our guides on how to prepare an SCDF submission and how to obtain SCDF approval without delays.

Testing, commissioning and maintenance

SCDF’s jet-fan commissioning guidance calls for a 1 MW test fire for hot smoke tests. It requires CFD in specified cases, including fewer than 12 air changes per hour, larger vehicle fire sizes, mixed natural and mechanical replacement air, or excessive fan spacing.

After completion, the Fire Certificate process requires the owner or occupier to engage a Professional Engineer and a contractor for inspection. The annual building inspection includes pressurisation, atrium smoke control and basement mechanical ventilation. Site testing proceeds through a simulated alarm, secondary-generator operation and tests of the individual systems.

The Fire Code requires installed fire-protection systems to be maintained to the applicable referenced codes or standards. Maintenance details are documented in the Fire Safety Instruction Manual, which is handed to the building owner at project completion, and owners must keep it current after addition-and-alteration works.

Planning for new builds, renovations and rebuilds

Fire-safety works needing SCDF approval include the installation, addition, alteration, removal or relocation of fire-protection systems, changes affecting escape routes or fire compartments, air-conditioning or ventilation works, and changes of use affecting fire-safety requirements. Renovations are therefore within scope as well as new buildings.

Several planning points follow from this:

Involve the QP and fire engineer at concept stage, before ceiling heights, voids and façade openings are fixed.
Reserve space for extraction risers, replacement-air openings and discharge locations that satisfy the separation distances.
Agree the fire alarm cause-and-effect and the secondary power arrangement with the M&E designer early.
Check whether a change of use or an added mezzanine alters the smoke control requirement; see SCDF mezzanine requirements.
Keep the Fire Safety Instruction Manual updated after every alteration.

For the wider process, our SCDF submission guide for commercial and industrial properties and the overview of fire engineering design and SCDF compliance give additional context.

Our perspective

Smoke control fails most often at the interfaces, not at the fan. A well-sized extraction system can still underperform when the replacement-air path is blocked by a late architectural change, or when the alarm logic was agreed after the ductwork was fixed.

For this reason we treat smoke control as a coordinated engineering and authority-submission task. Architectural, structural, M&E and fire-safety inputs are reviewed together, so that the drawings and calculations that reach SCDF are consistent with each other and with what will be built.

Our team is led by a Professional Engineer with decades of experience in Singapore infrastructure, and we support clients across the statutory boards, including SCDF, BCA, URA and JTC. Our aim is a feasible, cost-effective design that is prepared to be approved without avoidable resubmission.

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How Stellar Structures supports smoke control submissions

Stellar Structures provides architectural, structural, M&E and authority submission services in Singapore, including SCDF/FSSD submissions, approvals and Fire Safety Certificate applications. Property owners, developers, contractors and architects can use our SCDF / FSSD submission and Fire Safety Certificate service to coordinate smoke control drawings with the wider building submission.

To discuss a project, see our full list of services or contact us through structures.com.sg.

FAQ

Is smoke control required in every commercial building in Singapore?

No. The Fire Code requires an engineered smoke-control system in defined cases, such as relaxed atrium compartmentation, compartments above 5,000 m² and large basements above 2,000 m². Other buildings may still need smoke purging or staircase pressurisation, so the QP should review each building against Clause 7.4 and its exemptions.

Which standards does Singapore use for smoke extraction design?

Clause 7.4 provides for natural or mechanical smoke extraction designed to BR 186, BR 258, BR 368 or other acceptable standards. Where the proposed design differs from these, the QP should consult SCDF, and an alternative solution follows the performance-based route with an FSE and a Peer Reviewer.

Do I need SCDF approval for a renovation that touches ventilation?

Yes, where the works involve air-conditioning or ventilation, fire-protection systems, escape routes, fire compartments or a change of use affecting fire-safety requirements. SCDF approval is required before such works begin, and the plans are submitted by a QP.

How are smoke control systems tested after installation?

Testing follows a simulated alarm, secondary-generator operation and tests of individual systems, as set out in the SCDF Fire Certificate process. For ductless jet-fan car park systems, SCDF’s guidance calls for a hot smoke test using a 1 MW test fire.

Does smoke control need a backup power supply?

Yes. SCDF requires a secondary power supply for all smoke-control and smoke-purging systems, including associated equipment. The power arrangement should be coordinated with the M&E design and the fire alarm cause-and-effect from the start.

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Smoke Control Design in Singapore: SCDF Requirements and Process