Smoke Management Systems

Smoke management systems keep escape routes clear of smoke and give fire-fighters usable access. Smoke, not flame, kills most people in building fires, so these systems are central to life safety in tall, large and complex buildings. They include stair and lift shaft pressurisation; smoke exhaust from atria, malls and large spaces; zone smoke control using the air conditioning in fire mode; car park smoke exhaust and jet fan systems; smoke curtains and smoke doors; natural smoke vents (automatic opening vents in residential corridors and stairs); and the fire fan control panel and fire-rated wiring that run them.

Smoke systems are designed together with the building: door positions, leakage paths, air make-up and the fire detection cause-and-effect. Changes to any of these (new doors, new seals, enclosed atria, altered AHUs) can stop a system working as designed even though every fan runs.

What shortens life:

• Disuse: fans and dampers that run only in tests seize.
• Building changes that alter leakage and air paths.
• Controls replacement that moves fire functions onto non-fire-rated systems.
• Incomplete testing that checks components but not the system.

Interface and control failures

Smoke systems start on a signal from the fire detection system. Changes to the fire panel, BMS or AHU controls break interfaces so fans do not start, start in the wrong mode, or AHUs keep supplying air to the fire floor. Fire functions moved onto a building management system that is not designed for fire duty may not work in a fire.

Pressure too high or too low

Pressurised stairs must hold smoke back without making doors too hard to open: Australian, British and US standards cap door opening forces, at about 110, 100 and 133 newtons respectively. New door seals, closers and lobbies raise pressures until doors cannot be opened by occupants; failed relief dampers, missing doors and new openings drop pressures so smoke enters.

Make-up air failures

Exhaust systems need replacement air to move smoke. Make-up air paths blocked by new shopfronts, closed doors or failed inlet vents reduce exhaust to a fraction of design.

Equipment seizure

Fans, dampers, curtains and vents operated only in tests seize, lose belts, or have motors that fail; smoke dampers corrode; curtains snag on new fittings.

Architectural changes

Atria enclosed with new floors, malls subdivided, car parks partitioned for storage, and stair doors held open all change smoke behaviour against the design.

Incomplete testing

Testing fans and dampers individually does not show the system works. Only an integrated test, with the fire alarm triggering the full sequence and pressures, airflows and door forces measured, does.

In the building

• Fire fan control panel showing faults or manual overrides.
• Stair doors hard to open, whistling or slamming during tests.
• Smoke curtains obstructed by fittings; smoke dampers inaccessible.
• Make-up air louvres blocked; car park storage blocking jet fans.
• Fans with belts missing or corroded casings.

In the records

• Fire engineering report and smoke control design.
• Integrated test reports, with pressures, airflows and door opening forces.
• Routine service records for fans, dampers, curtains and vents.
• Cause-and-effect matrix.
• Annual certification.

• Relief dampers in stairs stuck open or closed.
• Fire fan control panel without current labelling or zone plans.

Findings are graded by what they demand: safety (can hurt someone now), failure (failed and damaging the building), condition (distress present and progressing), lifecycle (renewal due on age and exposure), deadline (a regulator or ordinance sets the date), check (investigate before sizing works) and nil (cosmetic or stable).

A fire engineer leads, working from the fire engineering report or smoke control design, with a mechanical services engineer and the fire services contractor. Testing is done out of hours, with the fire brigade and monitoring centre notified.

• Design review: the smoke control design basis, performance criteria (pressures, airflows, smoke layer heights), cause-and-effect, and any performance solutions that rely on the system.
• Change review: every alteration since design that could change smoke behaviour or air paths, including new doors and seals, enclosed atria, subdivided malls, car park storage, and replaced AHUs or controls.
• Equipment inspection: fans (bearings, belts, motors, temperature rating), smoke dampers and actuators, relief dampers, curtains, vents, fire fan control panel, fire-rated cabling and power supplies.
• Integrated test initiated from the fire alarm in each smoke zone: confirm the full sequence starts, AHUs switch correctly, dampers move, curtains drop, vents open, and fire-fighters' overrides work.
• Measurement: stair pressure differentials with doors open and closed, door opening forces at every stair door, exhaust and make-up airflows, and car park jet fan coverage.
• Secondary power: confirm the system runs from the emergency supply where required.

The report should state whether the system meets its design performance today, list every failed function and measurement, identify changes that have compromised it, and set out rectification or redesign.

• Repair interfaces and update the cause-and-effect matrix; return fire functions from general building management controls to fire-rated controls where they were moved.
• Rebalance stair pressurisation: adjust fan speed, add or repair barometric relief dampers, or add variable speed control, so pressure holds smoke back and door opening forces stay within limits.
• Restore make-up air: reopen or add inlet paths, automate inlet doors and vents, remove obstructions.
• Replace equipment: fans with temperature-rated units, seized dampers and actuators, curtain motors and batteries, vent actuators.
• Car parks: clear storage and partitions from jet fan paths; reposition or add fans.
• Redesign after major alterations, with a fire engineer revising the design and performance solution.
• Testing regime: routine component tests plus a full integrated test annually and after any change.

Routine servicing and integrated testing are recurring costs; integrated tests need several trades present out of hours. Interface and controls repairs are itemised or lump sums. Equipment replacement is per item, with temperature-rated fans and dampers costing more than standard equipment. Rebalancing is a lump sum. Redesign after alterations is a lump-sum fire engineering and construction project, usually carried by the alteration that caused it.

Testing and safety rectification are code compliance; equipment replacement is lifecycle; repairs are repairs and maintenance.

• Australia. The National Construction Code sets smoke hazard management by building class and height (Part E2); AS 1668.1 sets the design of smoke control systems and the door opening force limit for pressurised stairs; AS 1851 sets routine service; smoke control systems are essential safety measures with annual certification; performance solutions often rely on them.
• United Kingdom. Approved Document B and BS 9999 and BS 9991 set requirements; the BS EN 12101 series covers smoke control components, including pressure differential systems in BS EN 12101-6; the Fire Safety (England) Regulations 2022 require higher-risk residential buildings to report defects in key fire safety equipment; responsible persons must keep systems maintained.
• United States. International Building Code Section 909 governs smoke control; NFPA 92 sets design and testing, with dedicated systems tested semi-annually and non-dedicated systems annually; NFPA 101 limits door opening forces; NFPA 4 covers integrated testing of fire protection and life safety systems.

• Fire engineering report and smoke control design, including performance solutions.
• Commissioning report and latest integrated test report, with measured pressures, airflows and door forces.
• Routine service records for fans, dampers, curtains, vents and the fire fan control panel.
• Cause-and-effect matrix.
• Annual certification.
• Records of alterations since the system was commissioned.