AOV and smoke ventilation systems,
tested and compliant.
An AOV has one job: open when smoke arrives, and keep escape routes clear while people get out. Gemini AMPM designs, installs and maintains smoke control systems to the BS EN 12101 series. And because we are fire specialists first, every vent is treated as life-safety equipment, not just ventilation.
Smoke control is
fire engineering.
When a fire starts, smoke kills first, and it moves faster than flame. An AOV smoke ventilation system exists to hold escape routes tenable: automatic opening vents that open on smoke detection, shafts that pull smoke off corridors, fans that keep stair cores, lobbies and staircases clear long enough for everyone to use them. The BS EN 12101 series governs the components, with BS EN 12101-2 covering natural smoke and heat exhaust ventilators and other parts covering powered extract.
This is fire engineering, and that is what we are. Gemini AMPM approaches smoke control from the fire side: BAFE SP203-1 registered for detection and alarm, so the interface between your smoke system and the fire alarm that triggers it is designed by people who understand both ends. Ventilation firms bolt smoke control on. For us it is the day job.
Scoped, delivered,
evidenced.
- AOV systems: roof and facade vents, hatches and louvres installed to the BS EN 12101 series.
- Residential smoke shafts: corridor and stairwell smoke ventilation for apartment blocks, natural or mechanical.
- Mechanical smoke extract: fans, dampers and controls engineered for buildings natural ventilation cannot serve.
- Controls & resilience: panels, actuators and battery backup, integrated with the fire detection system.
- Planned maintenance: function testing to BS 9999 and BS 7346-8, documented for the fire risk assessment.
- Emergency response: failed vents treated as fire safety defects, with a named engineer within 24 hours.
Opens in the test.
Opens in the fire.
We design and install natural and mechanical smoke ventilation systems in every common form: roof and facade AOVs, window actuators, hatches and louvres, residential smoke shafts serving common corridors and stairs, and mechanical extract (fans, dampers and controls) for buildings natural ventilation cannot serve. Control panels, actuators and battery backup keep vents working when the power does not, and every system is wired into the fire alarm cause-and-effect with manual override for the fire service. Equipment comes from the established smoke control names (Aumuller, Colt, WindowMaster and SE Controls).
Every AOV installation is commissioned and compliance tested before handover: vents proven open on detection, the alarm interface proven end to end, the paperwork completed while we are still on site. An AOV that opens for the demonstration but not for the fire is worse than no vent at all, which is why we test the chain, not just the actuator.
The duty is yours.
The evidence is ours.
If your building has AOVs, the law already has a name for you. The Regulatory Reform (Fire Safety) Order 2005 makes the Responsible Person accountable for keeping smoke control maintained and working, and the Building Safety Act has raised the documentation duties again for higher-risk residential buildings. Approved Document B, BS 9999 and BS 9991 for residential set out where smoke ventilation systems are required and what they must achieve. None of it accepts a vent that fails quietly on a roof nobody visits.
So everything we hand over is written for the people who carry that duty: facilities managers, managing agents, RTM companies and building owners who need test records, defect reports and remedial quotes that slot straight into the fire risk assessment and the building safety case. Evidence, not assurances.
Weekly checks.
Deeper servicing.
An AOV spends years doing nothing, then has one moment that matters. BS 9999 and BS 7346-8 expect smoke control systems to be maintained by competent people on a planned regime, with periodic servicing to BS 7346-8 and the manufacturer’s guidance, and weekly function checks by the building’s own staff are good practice between visits. Our AOV testing goes deeper than the test button: we function test vents, dampers, actuators and fans, check battery backup, prove the fire alarm interface and the manual override, and record all of it in a form your fire risk assessment can cite.
When something does fail, it is treated as what it is: a fire safety defect, not a ventilation snag, and callouts get a named engineer within 24 hours. Smoke control also sits inside our wider ventilation scope alongside pressure testing, so one contractor can hold the whole scope and the paperwork that goes with it.
Kept working for years,
not just handover day.
AOV maintenance is where smoke control quietly goes wrong. The installation was signed off years ago, the panel shows a healthy light, and nobody has proved a vent open since: the classic state of a system that fails on the one night it is needed. A proper AOV servicing regime works to BS 7346-8 and the manufacturer’s schedule: planned visits, function tests on every vent and actuator, battery and control checks, and the fire alarm interface proven end to end, with records written for the fire risk assessment rather than the filing cabinet.
The same discipline covers powered systems, because a mechanical smoke extract system stands or falls on its fans, dampers and controls, and those need servicing hands rather than a glance at the panel. For managing agents and facilities teams running more than one building, we run smoke vent maintenance as a portfolio: one contract, one standard, one set of paperwork across every block, with faults found at the service visit priced and repaired by the same team.
Smoke control plant, replaced
under a live building.
Smoke control work rarely happens in empty buildings, and ours is proof. Beneath Splashpoint Leisure Centre, the fire and smoke dampers had corroded badly enough to need replacing, their actuators outdated, in a basement where plant, ductwork and structure blocked the obvious ways in and the centre stayed open throughout. The team built a bespoke access strategy for each damper (modular scaffolding, adjustable platforms, carefully sequenced dismantling) and phased the works with centre staff so airflow to the public areas above was never interrupted.
The job finished on time and on budget with zero health and safety incidents: dampers replaced and upgraded, non-compliant fire stopping stripped out and reinstated, and larger access doors fitted so every future inspection is easier. The Splashpoint Leisure Centre case study has the full scope. It is the same discipline AOV work demands: life-safety ventilation kept working in a building that never gets to close.
London daily.
Nationwide from Sussex.
Gemini AMPM installs, services and repairs AOV systems across London and the South East, and nationwide from our Sussex base. Apartment blocks in the capital, stair cores and corridor shafts across the Home Counties, smoke ventilation systems in Berkshire and beyond: one-off installations or a planned maintenance portfolio across multiple sites, the team and the standards are the same. If you are looking for an AOV installer, London is where most of this work happens for us, and we install and service AOV systems London-wide, with the same engineers covering West Sussex daily from our Burgess Hill HQ.
Start with the building you are least sure about. Tell us what you have, or send the last test certificate if one exists, and we will survey it and tell you plainly what is compliant, what is not, and what it takes to put right.
The rest of the scope,
one accountable team.
Smoke ventilation rarely stands alone. Our ventilation service and repair team keeps the fans, controls and air handling around your smoke system working between fire tests, and fire damper testing covers the other half of smoke control: the dampers that must close as reliably as your vents must open. In residential buildings where the evacuation strategy is changing, evacuation alert systems to BS 8629 sit naturally alongside AOV work, designed by the same fire-side engineers. One contractor, one set of records, no gaps between trades.
Common questions on
aov & smoke extract.
What is an AOV smoke ventilation system?
An AOV (automatic opening vent) is a vent that opens automatically when smoke is detected, venting smoke from escape routes such as stair cores, corridors and lobbies so people can get out. A full AOV smoke ventilation system includes the vents themselves (roof vents, window or facade actuators, or a smoke shaft), a control panel with battery backup, and the link to the fire alarm that triggers it, with manual override for the fire service.
What triggers an AOV to open?
Smoke detection, through the fire alarm’s cause-and-effect programming: when a detector on the protected route activates, the panel signals the AOV controls and the vents open. There is also a manual override so the fire service can operate vents on arrival, and battery backup so the system still works in a power failure. The alarm interface is the part that fails most quietly, which is why we prove it end to end at every service.
How often should AOV systems be tested?
Weekly function checks by the building’s responsible person, with planned professional servicing on top: BS 7346-8 and manufacturers typically expect competent-person maintenance at least every six to twelve months, and your fire risk assessment may demand more. The professional visit goes deeper than pressing the test button: actuator condition, battery backup, damper operation, fire alarm interface. Records of both layers are what an enforcing officer will ask to see.
Who is responsible for maintaining AOV systems?
The Responsible Person under the Regulatory Reform (Fire Safety) Order 2005: usually the owner, employer, landlord or managing agent in control of the premises. Appointing a competent contractor does not move the duty, but it is how you discharge it, and the records prove you did. For higher-risk residential buildings the Building Safety Act has raised documentation expectations further: test and service records now form part of the building’s safety case.
What is the BS EN 12101 series?
It is the family of European product standards for smoke and heat control systems. Different parts cover different components: BS EN 12101-2 for natural smoke and heat exhaust ventilators, other parts for powered extract fans, smoke barriers and control equipment. Specifying equipment certified to the relevant part means the vent or fan has been fire tested as life-safety kit, not just weather-rated as a rooflight. We install to the series throughout.
Natural or mechanical smoke ventilation: which does my building need?
It depends on the building’s geometry and what the design standards ask of it. Natural systems (roof vents, window and facade actuators, natural smoke shafts) work on buoyancy: hot smoke rises and vents out. Mechanical systems add fans, dampers and controls, engineered for buildings natural ventilation cannot serve. Approved Document B, BS 9999 and BS 9991 for residential frame the requirement, but the honest answer comes from a survey of the actual building, which is where we always start.
Do apartment blocks need smoke ventilation maintenance?
Yes. If your block has AOVs or a smoke shaft serving common corridors and stairs (most modern blocks do), the Fire Safety Order makes maintaining them a legal duty on whoever controls the building, and post-Grenfell scrutiny of residential fire safety has made the paperwork matter as much as the plant. We run planned maintenance for managing agents and RTM companies, with records written for exactly that scrutiny.
Do you install AOV systems in London?
Yes. We install, service and repair AOV systems across London, from single roof vents to mechanical smoke shafts, working for managing agents, facilities managers and building owners. The same team covers the South East and the Home Counties, Berkshire included, and we take on work nationwide from our Sussex base. If you are looking for an AOV installer in London who treats smoke control as life-safety kit rather than ventilation, that is us.
What happens when an AOV fails?
Treat it as a fire safety defect, because that is what it is: an escape route that will not clear smoke. Report it, record it on the fire risk assessment, and get it repaired quickly; the Fire Safety Order does not pause while a part is on order. Our callouts get a named engineer within 24 hours, and because we are BAFE SP203-1 registered for fire detection, faults on the alarm side of the interface are fixed by the same firm rather than passed between contractors.
What does smoke vent replacement or repair involve?
Usually less than a full replacement. The most common failures are actuators that have seized or drifted out of adjustment, control panels with exhausted batteries, and faults on the fire alarm interface, all repairable without touching the vent itself. Where the vent unit has genuinely failed (corroded frames, obsolete parts no longer supported), replacement is scoped from a survey. Smoke vent replacement cost is driven by what has actually failed, how many vents are affected, how hard they are to reach, and whether the controls are current or obsolete, which is why we quote from a survey rather than a price list, and repair where repair is honest.
Talk to us about
aov & smoke extract.
A named engineer, not a call centre, comes back within 24 hours. Tell us the building and what you’re dealing with, and we’ll scope it properly.