Staircase Pressurisation Systems

Smoke spreads quickly through gaps around doors, shafts and service openings, and enclosed staircases act like chimneys. A staircase smoke control system holds the stair at a higher pressure than the floors, so smoke is pushed back rather than drawn in.

A clear, breathable, visible staircase lets residents, office staff, patients and visitors move down calmly. That matters most for older people, children and anyone who needs extra time on the stairs.

Firefighters use the same protected staircases and fire lift lobbies to reach the fire floor. Fire stair pressurisation gives them a smoke-free bridgehead from which to fight the fire and carry out rescues.

Pressurisation of enclosed staircases and lift lobbies is a standard requirement for high-rise and core-staircase buildings. A properly designed and tested system is essential to obtain a Fire NOC and, in turn, an occupancy certificate.

Axial or centrifugal staircase pressurisation fans deliver the required airflow at the calculated static pressure. Because they move clean outdoor air rather than hot smoke, they are selected first for reliability, correct duty point and fire-protected power, usually in a duty-standby pair.

Weatherproof louvres with bird screens admit outdoor air. The staircase pressurisation fresh air intake must be located well away from smoke exhaust outlets, basement vents and other possible sources of smoke.

A duct smoke detector at the intake detects smoke being drawn in. Depending on the approved design, it switches to an alternative intake or stops the fan, so the system never pressurises the staircase with smoky air.

A dedicated masonry shaft or a galvanised staircase pressurisation duct carries air to each injection point. Shafts must be sealed and smooth to limit leakage and stairwell friction loss.

Staircase pressurisation grilles with volume control dampers distribute air evenly along the stair height. Their size and spacing are chosen to avoid high local velocities that make doors hard to use.

A staircase pressure relief damper opens automatically when pressure exceeds its set point, venting excess air to outside. It is the simplest way to stop over-pressurisation in fixed-speed systems.

A differential pressure sensor for staircase pressurisation measures the pressure difference between the stair and the floor. The VFD panel adjusts fan speed to hold the set point as doors open and close.

A monitored interface links the fire alarm panel to the pressurisation controls, starting the fans automatically and reporting fan status back to the fire alarm system.

Fire-survival cables and a supply backed by the DG set keep the fans running during a fire, even if normal power fails. Staircase pressurisation emergency power is as important as the fan itself.

A fireman's override panel in the fire control room lets the fire brigade start, stop and monitor each staircase system manually, independent of the automatic controls.

Single injection staircase pressurisation supplies all air at one point, usually the top of the stair (top injection) or the bottom. It is simple and economical for low and mid-rise staircases, but in taller stairs pressure can become uneven, especially when a door near the injection point is open.

Multiple injection staircase pressurisation supplies air through grilles at several levels, often every two to three floors, from a vertical shaft or duct. It gives even pressure along the full height and is the usual choice for high-rise staircases.

The fan runs at constant speed, sized for the open-door condition. When doors close and pressure rises, barometric or motorised relief dampers vent excess air. This is a robust, low-complexity staircase pressurisation system with pressure relief damper control.

A closed loop staircase pressurisation system uses differential pressure sensors and a variable frequency drive to vary fan speed, holding the design pressure as doors open and close. This compensated stairwell pressurisation gives tighter control and reduces door-force complaints.

Staircase and lobby pressurisation protects both the stair and the lobby or vestibule leading to it, creating two layers of smoke protection. It is common in high-rise and hospital buildings and for smokeproof staircase pressurisation.

A lift lobby pressurisation system and lift well pressurisation keep smoke out of fire lift lobbies and shafts, so firefighters can use the fire lift safely and smoke does not spread vertically through lift shafts.

The National Building Code of India 2016, Part 4, defines pressurisation as creating a pressure difference across a barrier to protect an exit, stairway, lobby or room from smoke, and sets the fire and life safety framework that state rules and bye-laws build on. Indian model building bye-laws require a core staircase that cannot be ventilated at each landing to be held at a positive pressure of 5 mm water gauge (about 50 Pa) by electric blowers that start automatically on the fire alarm or sprinkler system, with manual operation also provided. Lift lobbies are typically held at 25–30 Pa and lift shafts at 50 Pa.

The Maharashtra Fire Prevention and Life Safety Measures Act, 2006 requires owners and occupiers to keep fire prevention and life safety measures in good repair and efficient condition at all times. It also requires a maintenance certificate from a Licensed Agency to be furnished to the fire authority twice a year, in January and July, which makes a reliable, well-documented pressurisation system essential.

The local fire authority reviews the design at the provisional Fire NOC stage and witnesses system performance before issuing the final Fire NOC; an occupancy certificate generally cannot be issued without it. In Maharashtra, building development control regulations add their own fire provisions, so we align the design with the specific authority approving your project.

EN 12101-13:2022 now covers the design, calculation, installation, acceptance testing and maintenance of pressure differential systems, while EN 12101-6 covers the system components. European practice limits door opening force to below 100 N. These standards are often specified for international or premium projects.

NFPA 92 sets minimum design pressure differences for smoke control, such as 0.05 in. w\.g. (12.4 Pa) in sprinklered buildings and higher values in non-sprinklered ones, with door opening force limited to 133 N (30 lbf) under NFPA 101. Many designs also draw on ASHRAE smoke control guidance for stairwell pressurization calculations.

With all doors closed, the staircase differential pressure must reach the design value on every floor. Indian bye-laws commonly specify about 50 Pa for staircases, which is why 50 Pa staircase pressurisation is the usual design target, subject to the approving authority.

When doors are open, pressure collapses across them, so protection depends on airflow velocity through the doorway. Designers typically target around 1 m/s for escape conditions and higher, up to about 2 m/s, where firefighters operate, depending on the standard followed.

Pressure acting on a door adds to the force needed to open it. Staircase door opening force is typically limited to about 100–133 N depending on the standard, so that children, older people and anyone carrying others can still open doors.

During evacuation, several doors may be open at once: the fire floor door, the final exit door and one or more floors in between. The design states how many doors are assumed open, and multiple doors open stairwell pressurization is checked against that assumption.

Staircase leakage calculation adds up the gaps around every door, the shaft walls and any other openings. Stairwell door leakage is often taken at around 0.01–0.02 m² per single-leaf door, and leakage flow is estimated as Q = 0.83 × A × √ΔP (Q in m³/s, A in m², ΔP in Pa).

Temperature differences between the stair and outside create pressure differences that grow with building height. In cold climates this can reach several pascals per floor. Staircase pressurisation stack effect is milder in Mumbai's warm climate but still needs checking on very tall towers.

Wind on exposed facades, especially on coastal high-rises, changes pressures at doors and at the fan intake. We check intake orientation and pressure margins for windward and leeward conditions.

Staircase pressurisation fan sizing takes the larger of two cases: leakage at design pressure with doors closed, and the airflow needed through the assumed open doors. Duct and shaft leakage and a safety margin are added on top. For example, 20 doors at 0.02 m² each, held at 50 Pa, leak about 2.35 m³/s (roughly 8,450 m³/h or 5,000 CFM) before any open-door allowance. This staircase pressurisation calculation sets the airflow; the static pressure comes from the duct design.

The intake is placed where smoke is least likely: away from smoke exhaust discharges, basement vents, kitchen exhausts and windows of the fire floor. Where risk remains, a second intake on a different face, with automatic changeover, is provided.

Shafts and ducts are sized for moderate velocities to control staircase pressurisation static pressure and noise. Masonry shafts are rendered and sealed, because unsealed blockwork can leak a large share of the fan's output before it reaches the stair.

In multi-injection systems, grilles are spaced along the stair, commonly every two to three floors, and positioned so jets do not blow directly onto doors. Each grille has a damper for balancing.

The relief damper is sized to discharge the difference between full fan airflow and doors-closed leakage at the maximum allowable pressure. Undersized dampers cause high door forces; oversized ones can flutter and cause pressure swings.

Duty standby staircase pressurisation fans with automatic changeover ensure that a single fan or motor failure does not leave the staircase unprotected.

Fans are fed from an emergency power source with fire-survival cables routed through protected paths, so the system keeps working while the building is on fire.

The staircase pressurisation fire alarm interlock starts the fans automatically on a confirmed alarm or sprinkler flow, typically on any floor of the building, so the stair is pressurised before smoke arrives.

Smoke detectors in lift lobbies and corridors near stair doors give early warning and, where the design requires it, trigger floor-specific actions such as lobby pressurisation.

In closed loop systems, a stairwell differential pressure sensor reads stair-to-floor pressure and the staircase pressurisation VFD adjusts fan speed to hold the set point, ramping up quickly when doors open.

If the intake detector senses smoke, the system switches to a clean intake or stops the fan, as agreed with the fire authority, so smoke is never blown into the stair.

Airflow switches or current sensors confirm each fan is running. Failures trigger standby changeover and an alarm at the fire panel and in the fire control room.

A fireman's override panel shows the status of every staircase and lobby system and lets fire officers start or stop them manually during operations.

On alarm, AHUs serving the fire zone shut down, smoke exhaust fans start where provided, and fire dampers close. Staircase pressurisation BMS integration records all events for review and audits.

Positive pressure keeps smoke out of the staircase from the first minutes of a fire, so the escape route stays clear when it matters most.

Clear visibility and breathable air let occupants move down steadily, without the panic and disorientation that smoke causes.

Firefighters gain a protected route and staging area close to the fire floor, which speeds up rescue and fire control.

A calculated, tested and documented system supports smooth Fire NOC approval, occupancy certification and the twice-yearly maintenance certificates required in Maharashtra.

A reliable pressurisation system adds to your building's safety credentials, supporting insurance, tenant confidence and long-term asset value.

Too much pressure can trap people behind doors they cannot push open. Correctly sized relief dampers or VFD control, verified by door-force testing, prevent this.

Unsealed shafts, gaps around services and poorly fitted doors waste airflow and starve upper floors. Early coordination with civil and door contractors avoids costly rework.

In very tall stairs, temperature-driven pressures vary from bottom to top. Multi-injection supply, VFD control and, where needed, staircase stack effect analysis address this.

Fans, dampers, sensors and interlocks must be tested regularly to remain dependable. Our AMC schedules and records this for you.

Multi-injection systems need a vertical shaft or duct the full height of the stair. Involving us at concept stage lets your architect reserve the right space before plans are frozen.

High rise residential staircase pressurisation protects families in towers where evacuation down many floors takes time, and where occupants include children and older people.

Commercial building staircase pressurisation supports the phased evacuation of large numbers of office occupants and protects business continuity.

Guests are unfamiliar with the building and may be asleep when an alarm sounds. Pressurised stairs and lobbies give them a clearly protected route out.

Hospital staircase pressurisation and lobby pressurisation support evacuation of patients who cannot move quickly, alongside horizontal refuge strategies.

Large crowds, mixed tenancies and atria call for well-coordinated staircase and smoke exhaust systems.

Multi-tower campuses with high occupancy and long operating hours need reliable escape route pressurisation across many staircases.

Basement staircase pressurisation stops smoke from car park fires rising into the building's escape stairs.

Airports, government buildings, schools and colleges with enclosed staircases rely on pressurisation to protect large and varied populations.

Widely specified in India for centrifugal and axial fans in HVAC and smoke-control applications, including staircase and lift lobby pressurisation.

A global ventilation manufacturer offering axial, centrifugal and smoke-control fans with a strong presence in Indian commercial projects.

Known for centrifugal fans and fan modules used in air handling, pressurisation and smoke-control systems.

Offers a broad range of axial, centrifugal and inline fans, along with dampers, specified on many international and premium projects.

An Indian manufacturer of industrial, ventilation and smoke-control fans, often selected for Indian high-rise and car park ventilation projects.

We also work with other reputed fan, damper, VFD and controls brands, selecting each for duty point, reliability, service support and budget. Where fans must be smoke-rated, for example in combined systems, we confirm the rating matches the design.

With all doors closed, we measure stair-to-floor pressure at every level with a calibrated digital micromanometer and record the results against the design value.

A staircase door opening force test uses a calibrated force gauge at the door handle on several floors to confirm the force stays within the design limit with the system running.

With the design number of doors open, we measure air velocity across each open doorway with an anemometer, confirming air flows out of the stair at the required rate.

We time how quickly fans reach duty after an alarm, and how fast the VFD restores pressure when doors open and close, tuning the controls to avoid overshoot and hunting.

Every cause-and-effect action is triggered from the fire alarm panel and observed: fan start, AHU shutdown, damper operation and status feedback.

We simulate duty fan failure to confirm the standby fan starts automatically and the alarm reports correctly.

We prepare the system and documentation for the fire officers' inspection, and our engineers attend to demonstrate performance and answer technical questions.

You receive a full report with design calculations, test readings by floor, door forces, velocities, interlock checklists, instrument calibration details and as-built drawings.

Short scheduled test runs confirm that fans start, rotate in the correct direction and prove airflow. This catches seized bearings, tripped starters and wiring faults early.

Relief dampers, motorised dampers and grille dampers are checked for free movement, correct setting and corrosion, which matters in Mumbai's humid, salty air.

Differential pressure sensors and their tubing are checked against a reference instrument and recalibrated, so the VFD controls to true values.

Intake louvres, bird screens and filters are cleared of debris, nests and monsoon blockages that would starve the fan.

Control panels, VFDs, interface modules and override switches are inspected, and the fire alarm interlocks are exercised to confirm the full sequence still works.

At least once a year we repeat floor-by-floor pressure, door force and velocity tests, and provide the data your licensed fire agency and fire auditors need.

Every visit, test result and corrective action is logged, giving you a complete history for fire audits, insurers and the twice-yearly maintenance certificates required in Maharashtra.

Over-pressurisation from undersized relief dampers, missing VFD control or excess fan capacity. We measure door forces, resize or reset dampers, or add pressure-controlled VFDs.

Usually caused by leaky shafts, unsealed penetrations, poorly fitted doors or undersized fans. A leakage survey identifies the losses; sealing and rebalancing often fix the problem without a new fan.

Low velocity through open doors, a single injection point in a tall stair, or doors wedged open. Adding injection points, raising open-door airflow and reviewing door management resolve it.

Faulty interface modules, incorrect cause-and-effect programming, tripped starters or isolated power. We trace the signal path end to end and retest the full sequence.

Corrosion, dirt, paint or seized hinges prevent dampers opening. Cleaning, adjustment or replacement with corrosion-resistant dampers restores operation.

High pressure across tight door gaps or grilles blowing at doors. Adjusting set points, relocating grilles and balancing airflow quiet the system.

Poorly located intakes near smoke exhaust or basement vents. Relocating the intake, adding a second intake with changeover, or adding intake smoke detection corrects it.

Aggressive control tuning, badly placed sensors or oversized fans cause pressure to swing. We retune the control loop, relocate sensors and add damping to stabilise pressure.

We survey the staircase, find a practical route for the fan, intake and supply, and design a system that fits existing structure, often using an external duct or a converted service shaft.

Adding a VFD panel and differential pressure sensors to existing fans gives tighter pressure control and solves recurring door-force complaints.

Rendering, sealing penetrations and repairing access doors recovers lost airflow, often restoring compliance without replacing the fan.

Where a staircase alone does not meet current expectations, lobby or vestibule pressurisation adds a second layer of protection on each floor.

Old panels and hard-wired relays are replaced with monitored interfaces, status feedback and a fireman's override panel.

Cost rises with height because taller stairs need more airflow, larger fans, longer shafts or ducts and usually multi-injection supply. Each additional staircase or pressurised lobby adds its own fans, dampers and controls, so a tower with two staircases and lobby pressurisation on every floor costs considerably more than a single-staircase mid-rise building.

Fans are usually the largest single item, especially in duty-standby pairs. Sheet-metal ducts cost more than builder's masonry shafts but leak far less. Relief dampers are a smaller line item; listed GI and SS units mostly fall between about ₹5,000 and ₹20,000 each.

Fixed-speed systems need only starters and relief dampers. VFD panels, differential pressure sensors, fire alarm interfaces, fireman's override panels and long fire-survival cable runs add cost but give better control and easier compliance in tall buildings.

• Building height and number of floors
• Number of staircases, lobbies and fire lifts to be pressurised
• Single-injection or multi-injection supply
• Fixed-speed with relief dampers or VFD closed-loop control
• Masonry shaft or sheet-metal duct, and shaft sealing works
• Fan brand, duty-standby arrangement and location (terrace or ground)
• Fire-survival cable lengths and emergency power arrangements
• Testing, Fire NOC witness support and AMC scope
• New construction or retrofit in an occupied building

Share your floor plans and staircase details for an itemised quotation.