AOV testing: the monthly check, the annual service and the record

01

What an AOV is, and the duty to keep it working

An AOV, an automatic opening vent, is a window, roof vent or vent into a smoke shaft that opens by itself when smoke detectors nearby sense smoke. Its job is to let out smoke that gets into the lobbies, corridors and stairways, so that the escape stairs stay usable for people getting out and for firefighters getting in. The government guide Fire safety in purpose-built blocks of flats (paragraph 58.12) describes three kinds of natural smoke vent, usually with a free area of at least 1.5 square metres:

• permanently open vents (PVs), recommended in some older design guides;
• manually openable vents (OVs), opened by hand or, in many buildings, by an electric switch;
• automatically opening vents (AOVs), "operated by smoke detectors provided specifically for this purpose".

The same guide (paragraphs 58.13 and 58.14) says current guidance expects the vents in lobbies or corridors next to a single stairway to be AOVs, and a vent of at least 1 square metre at the head of a protected stairway, which in a block with a single stairway is recommended to open automatically.

Once a smoke vent is installed, keeping it working is a legal duty. In England and Wales, article 17 of the Regulatory Reform (Fire Safety) Order 2005 requires the responsible person, where necessary to safeguard relevant persons, to ensure that the premises and any facilities, equipment and devices provided are "subject to a suitable system of maintenance and are maintained in an efficient state, in efficient working order and in good repair". Because a smoke vent also protects the stair firefighters use, article 38 of the Order applies the same duty to facilities, equipment and devices provided for the use or protection of firefighters. In a building with several occupiers, the responsible person may make arrangements with the others to meet the duty, and they must co-operate.

Scotland has the same maintenance duty in regulation 16 of the Fire Safety (Scotland) Regulations 2006, and Northern Ireland in regulation 16 of the Fire Safety Regulations (Northern Ireland) 2010. None of these names a test interval or a standard: the frequencies come from guidance, the British Standards and the manufacturer.

02

The parts of an AOV system, and what a test looks at

AOV systems are more than the vents. The code of practice BS 7346-8:2013, which covers the planning, design, installation, commissioning and maintenance of smoke control systems, lists natural and mechanical smoke ventilation, smoke barriers, ducts and dampers "and their controls, power supplies and interconnections". In a block of flats or an office core that typically means:

• the vents on each floor and at the head of the stair;
• the actuators, the motors or rams that push each vent open and pull it closed;
• the smoke detectors in the lobbies and corridors that trigger the system, often part of the building's fire alarm;
• the control panel, with its normal and fault indicators and its standby battery;
• the manual controls, switches that open and close the vents by hand.

The routine in-house test, sometimes called a functional test, uses those manual controls to prove that the vents still move. A sensible method is:

1. tell people first, so that nobody is alarmed by vents opening;
2. look at the control panel: it should show normal operation and no fault;
3. operate the vents from the manual control and watch each one open fully, floor by floor, including the vent at the head of the stair;
4. check nothing is in the way: no furniture, boxes or blinds against a vent, and no vent wedged, taped or blocked up;
5. close the vents again, see each one shut and seal properly, and check the panel returns to normal;
6. record what was found, vent by vent, and report anything that did not open, did not close or showed a fault.

The checklist for fire safety inspections in the flats guide adds one thing to watch for between tests: vents required for smoke control that have been "tampered with, forced open and damaged", for example by residents airing a stuffy corridor, or blocked up to stop draughts.

The annual test and service is different in kind. Paragraph 81.9 of the guide says testing the smoke detectors and controls associated with AOVs should take place at least once a year, in accordance with the manufacturer's instructions. That means setting the system off from its detectors, as it is designed to work in a fire, rather than from the switch, and following the manufacturer's instructions for the rest, which is normally a job for a specialist.

03

How often AOVs are tested

Every month, a functional test from the manual controls. Paragraph 81.8 of Fire safety in purpose-built blocks of flats says that systems of automatically opening vents, or vents electrically controlled but manually operated, should be subject to routine testing and periodic servicing, and that "AOVs and electrically operated OVs should be tested once a month for correct operation using the manual controls provided". It calls this "a simple test that can be undertaken readily by non-specialists".

At least once a year, the detectors and controls. Paragraph 81.9 sets that minimum, with the manufacturer's instructions deciding the detail. Paragraph 81.10 says other smoke control systems, such as smoke extract and pressurisation systems, should be tested and serviced periodically to the manufacturer's instructions, normally at least annually, though this may involve monthly or more frequent functional tests where they are intended to protect the means of escape. For further guidance, paragraph 81.11 points to BS 9999.

GOV.UK notes that the flats guide was written in 2011 and should be viewed as no longer comprehensive, and that the Home Office is working on a revised version. Its monthly and annual pattern is still the plainest published statement of a minimum. Agree the full schedule, including any service visits between the annual ones, in writing with the installer or the maintenance contractor, from the system's operation and maintenance information.

Every month, by law, in high-rise blocks of flats in England. Since 23 January 2023, regulation 7 of the Fire Safety (England) Regulations 2022 has required the responsible person for a high-rise residential building, one with at least two flats that is at least 18 metres high or has at least seven storeys, to carry out monthly routine checks of essential fire-fighting equipment. That equipment includes the key fire-fighting equipment listed in regulation 6(7), which names "smoke control systems", and fire detection and alarm systems in the common parts, "including any detectors linked to ancillary equipment such as smoke control systems".

A routine check, in regulation 7, is "a check that any lift or piece of equipment is in efficient working order and in good repair, carried out in accordance with the relevant industry standard or any recommendations made by the manufacturers of equipment within an operators' manual". The government's fact sheet on regulation 7 says it is not the intention to require specialists for these checks, and that the regulations "add to, they do not replace" the existing duties under the Fire Safety Order.

04

Who does what, what happens to a fault, and the record

The duty sits with the responsible person, usually the employer, the landlord or the managing agent acting for them. The work divides into three parts:

• The monthly functional test, from the manual controls, can be done by a site manager, caretaker, concierge or security officer who has been shown how. Paragraph 81.2 of the flats guide says in-house staff can do some of the testing provided they are suitably competent.
• The annual test of the detectors and controls, and any repair to vents, actuators, panels or batteries, is a job for a specialist smoke control contractor.
• The fire risk assessment should confirm that the smoke control system is maintained, and is the place to ask whether the arrangements are still adequate.

Know who to call before the test. Paragraph 81.3 says that where in-house staff do the testing, there should be access to a contractor who can attend at short notice for emergency repairs, giving as an example "a smoke vent will not close". Agree that call-out in advance, so that a vent left stuck open or shut after a test is put right quickly.

One organisation should own a shared system. In a mixed-use building, the detectors that operate the lobby AOVs may be part of a fire alarm covering the shops below. Paragraph 76.3 of the guide says a single organisation should take responsibility for its testing and maintenance.

In a high-rise block of flats in England, a fault has a clock. Regulation 7 requires the responsible person to take steps to rectify a fault found in a monthly check. If it cannot be put right within 24 hours of being found, they must report it to the local fire and rescue authority by electronic means as soon as reasonably practicable, and report again when it is fixed.

Records. Regulation 7 requires the monthly checks to be recorded and the records made accessible to residents; the fact sheet suggests a notice board or a residents' association. In any building, keep the AOV tests and the contractor's service reports with the other fire safety records, in the fire safety log book or wherever the building keeps them: they are how the responsible person can show that the maintenance duty is being met. A good record shows:

• the date, and who carried out the test;
• each vent by floor, including the head of the stair, rather than one tick for the system;
• the state of the control panel before and after;
• anything found, such as a vent that did not open fully, a blocked vent or a fault light;
• what was done about each fault, by whom and when, and any fire service reference;
• the date of the last annual service and the contractor's report, with each recommendation and when it was dealt with.

05

Where the record fails, and what SiteClara does about it

The annual service leaves a contractor's report; the monthly test often leaves very little. The vents are opened from the switch at the bottom of the stair, nobody walks up to see whether the sixth-floor vent moved, and the sheet says "AOVs tested OK" with no floors named. A vent that would not close is mentioned to whoever was passing rather than reported.

SiteClara puts a printed QR poster at each place a check is due, such as the AOV control point, each floor's lobby and the head of the stair, with an optional NFC tag behind it. Staff scan the code or tap the tag on their own phone, with no app to install, see the checks due there, and mark each one done or explain what stopped them. The time and the named person are recorded as it happens, with a photo when one is asked for. A problem, such as a vent stuck open, a fault light on the panel or a vent blocked by stored furniture, is reported there with a photo and goes onto the team's list of jobs until someone closes it.

The supervisor sees what is due, done and missed, and can record why a check was missed; a job that needs the building manager can be escalated to them to answer. Each day the supervisor reviews and approves a report that goes to nominated management or client contacts at 8am the next morning, showing what was reported, completed and still open, and how the scheduled checks went, for example 9 of 9 completed. That gives the responsible person a working record of every vent, floor by floor, kept as the tests happen.

06

Questions people ask

How often does an AOV need to be tested?

Paragraph 81.8 of the government guide Fire safety in purpose-built blocks of flats says AOVs "should be tested once a month for correct operation using the manual controls provided", which proves the vents open and close, and paragraph 81.9 says the smoke detectors and controls associated with them should be tested at least once a year, in accordance with the manufacturer's instructions. In a high-rise block of flats in England, regulation 7 of the Fire Safety (England) Regulations 2022 also requires monthly routine checks of essential fire-fighting equipment, which includes smoke control systems.

What is the British standard for AOV testing?

There is no single AOV testing standard: the flats guide points to BS 9999 (now BS 9999:2017) for testing and servicing smoke control systems, and BS 7346-8:2013 is the code of practice covering their maintenance. BS EN 12101-2:2017 is the product standard for natural smoke and heat exhaust ventilators, setting the requirements and test methods for the vents themselves rather than the routine test in a building.

What does AOV stand for in fire safety?

AOV stands for automatic opening vent, also written automatically opening vent. The glossary of Fire safety in purpose-built blocks of flats defines it as "a vent provided for smoke control in common parts, which opens automatically when smoke is detected by smoke detectors".

Are AOVs a legal requirement?

Whether a building needs AOVs is a design question for new building work under the Building Regulations, and for the fire risk assessment; once fitted, keeping them working is a legal requirement under article 17 of the Regulatory Reform (Fire Safety) Order 2005 in England and Wales. For existing blocks with unsatisfactory smoke control, the benchmarks in paragraph 62.11 of Fire safety in purpose-built blocks of flats say AOVs should be provided in single stairway blocks over six storeys where flats open directly onto the stairway.

Is a smoke vent an AOV?

An AOV is one kind of smoke vent, the kind that opens automatically. Paragraph 58.12 of Fire safety in purpose-built blocks of flats lists the other smoke vents as permanently open vents and manually openable vents.

07

Further reading, and a list to take away

Start with section 81 of Fire safety in purpose-built blocks of flats for the monthly and annual routine, and the government's fact sheet on lifts and essential fire-fighting equipment for high-rise blocks in England. BS 9999 and BS 7346-8 are published by BSI, and your local fire and rescue service can advise on your own building. If the AOVs are triggered by the fire alarm, the guide to the weekly fire alarm test covers the other half of the system.

Check that:

• you know where every AOV, its control panel and its manual controls are, floor by floor;
• the vents are operated from the manual controls every month, and someone sees each one open and close;
• in a high-rise block of flats in England, the monthly checks are recorded and the records are available to residents;
• each test names the person and covers every vent, not just the system as a whole;
• any fault not fixed within 24 hours in a high-rise block is reported to the fire and rescue service;
• nothing is stored against a vent, and no vent has been wedged, taped or blocked up;
• the last service report is filed and its recommendations have been dealt with.