UK Building Regulations Ventilation: Approved Document F: Volume 2

John Donne once wrote, “No man is an island”.  The same could be said of a country during a pandemic, with lessons still being learned all over the world in reducing the risk and speed of viral spread that took every nation by surprise.  


In every realm of life we are seeing innovation, future strategies and new solutions to keep our populations safe should we be faced with a similar event.  With over 80% of our time typically spend indoors, a keen eye on the role of building ventilation has not been spared in this respect and we are seeing regulatory changes globally to how air is monitored and flows within both commercial and residential properties.


approved document F

Changes to UK Building Regulations to Improve Ventilation

Belgium last month announced a Spring “ventilation plan”, which will require all public places such as gyms, theatres, nightclubs and restaurants to install CO2 monitors, carry out air quality risk analyses, maintain inventories of air purification equipment and draw up necessary action plans based on results.   

The UK government has also considered the increasingly important role of building ventilation going forward, with the introduction of new legislation within the Building Regulations.  Wider spread awareness of the impact of ventilation on wellbeing, concentration and productivity means more is being asked of building construction companies and owners to consider air quality and flow within properties. 

From 15th June this year we will see changes to Building Regulations Parts L and F under the Building Regulations etc. (Amendment) (England) Regulations 2021, with standard improvements hoping to help with decarbonisation and ventilation.  Introduced by the Department for Levelling Up, housing and Communities (DLUHC), the new regulations are primarily being driven by the 2050 carbon net zero goal, but also incorporate better ventilation practice as a direct influence of pandemic learnings. 

Specifically related to ventilation, the following two approved documents will come into force*:

  • Approved Document F: Volume 1 applies to dwellings
  • Approved Document F: Volume 2 applies to buildings other than dwellings


*Importantly, if planning application, notice or initial notice of a building works has already been passed to a Local Authority before 15th June 2022 the changes in regulations will not apply, provided that the building work starts before 15 June 2023.

Digest of Approved Document F: Volume 2 (Buildings other than dwellings)

In this article we provide a quick digest of the Approved Document F.  (Please note this is not a comprehensive listing of all guidance within the document, simply our interpretation of the key points.)  The details in full and all associated reference material links can be found here:  Approved Document F

Requirement F1(1):  Means of Ventilation

Requirement F1(1) states,

“There shall be adequate means of ventilation provided for people in the building.”


In the Secretary of State’s view, requirement F1(1) is met in a new building other than a dwelling if it has a means of ventilation that achieves all of the following.

  • Extracts water vapour and indoor air pollutants from areas where they are produced in significant quantities before they spread through the building, following the guidance on extract ventilation in Section 1 for the relevant building type.
  • Supplies a minimum level of outdoor air for occupants’ health, following the guidance for whole building ventilation in Section 1 for the relevant building type.
  • Rapidly dilutes indoor air pollutants and disperses water vapour when necessary in occupiable rooms and sanitary accommodation, following the guidance for purge ventilation in Section 1 for the relevant building type.
  • Monitors air quality in specific types of occupiable rooms, following the guidance in paragraphs 1.21 to 1.23.
  • Minimises the entry of external pollutants, following the guidance in Section 2.
  • Achieves all of the following, as far as is reasonably practicable.
  1. Produces low levels of noise, following the guidance in paragraphs 1.5 and 1.6.
  2. Offers easy access for maintenance, following the guidance in paragraph 1.7.
  3. Provides protection from rain.
  4. Provides protection from cold draughts.
  5. Does not significantly risk occupants’ health.


In the Secretary of State’s view, requirement F1(1) is met for work on an existing building other than a dwelling by following the guidance in Section 3.

Ventilation Provision (Section 1) 

  • Mechanical ventilation systems should be designed and installed to minimise noise
  • Mechanical ventilation systems should be designed and installed for easily accessible maintenance
  • Any ventilation strategy should include provision for extract ventilation from rooms where water vapour or pollutants are likely to be released (e.g. bathrooms, sanitary accommodation and kitchens in buildings other than dwellings), to minimise their spread to the rest of the building
  • Any ventilation strategy should include whole building ventilation to provide fresh air to the building and to dilute, disperse and remove water vapour and pollutants not removed by extract ventilation
  • Any ventilation strategy should incorporate purge ventilation to remove high concentrations of pollutants and water vapour. Purge ventilation is used intermittently and required only for pollutants produced by occasional activities (e.g. fumes from painting)
  • Any ventilation strategy should include monitoring of indoor air quality.
  • Any ventilation strategy must meet performance criteria and ventilation rates contained within the guidance or associated documents
  • Ventilation equipment must be installed in line with the guidance and in a way that does not compromise its intended performance.
  • Ventilation equipment must be installed in line with equivalent area calculations
  • Ventilation provision must meet the specified ventilation rates for the different building spaces listed within the guidance
  • Ventilation equipment should be controllable and adjustable by each individual space
  • Ventilation systems incorporating recirculation of air must be able to operate in a mode that reduces the risk of transmission of airborne infection.  This could be through the use of 100% outdoor air at acceptable levels, UV-C germicidal irradiation system or HEPA filters for example.


Importantly, any ventilation strategy should also consider associated regulation and guidance where required, such as the CIBSE Guide B2 Ventilation and Ductwork, HSE Catering Information Sheet No. 10 Ventilation in catering kitchens, BESA TR 40 Guide to Good Practice for Local Exhaust Ventilation and HSG 258 Controlling Airborne Contaminants at Work.  Interaction with other Parts of the Building Regulations are required to be considered e.g. Part B, J, L, K, M and O. 

Minimising the Ingress of External Pollutants (Section 2)

  • Any ventilation system should be designed to minimise intake of external pollutants if they exceed acceptable levels within the guidance or if the building is located near to any significant sources of pollution.
  • Ventilation intakes should be located away from any direct sources of local pollution
  • Ventilation exhaust outlets should not be located where they will result in reintake of exhausted air or cause harm to the surrounding area

Work on Existing Buildings (Section 3) 

  • Any new work on ventilation systems following commencement of the new guidance should confirm to the new approved document. Where work is not directly on ventilation but impacts its activity then it should not be less satisfactory than before it was carried out.

Requirement F1(2) and regulations 39 and 44

The requirement for F1(2) is that,

Fixed systems for mechanical ventilation and any associated controls must be commissioned by testing and adjusting as necessary to secure that the objective referred to in sub-paragraph (1) is met.”


Regulation 39:

  • This regulation applies where paragraph F1(1) of Schedule 1 imposes a requirement in relation to building work.
  • The person carrying out the work shall not later than five days after the work has been completed give sufficient information to the owner about the building’s ventilation system and its maintenance requirements so that the ventilation system can be operated in such a manner as to provide adequate means of ventilation


44 (Commissioning):

  • This regulation applies to building work in relation to which paragraph F1(2) of Schedule 1 imposes a requirement, but does not apply to the provision or extension of any fixed system for mechanical ventilation or any associated controls where testing and adjustment is not possible.
  • This regulation also applies to building work in relation to which paragraph L1(b) of Schedule 1 imposes a requirement, but does not apply to the provision or extension of any fixed building service where testing and adjustment is not possible or would not affect the energy efficiency of that fixed building service.
  • Where this regulation applies the person carrying out the work shall, for the purpose of ensuring compliance with paragraph F1(2) or L1(b) of Schedule 1, give to the local authority a notice confirming that the fixed building services have been commissioned in accordance with a procedure approved by the Secretary of State.
  • The notice shall be given to the local authority:
  • not later than the date on which the notice required by regulation 16(4) is required to be given; or
  • where that regulation does not apply, not more than 30 days after completion of the work.


In the Secretary of State’s view, requirement F1(2) and regulation 44 are met if building work that involves installing a mechanical ventilation system, for a new or an existing building, follows the guidance in paragraphs 4.1 to 4.3 to achieve all of the following.

  1. All fixed mechanical ventilation systems for which testing and adjustment is possible are tested and commissioned.
  2. Commissioning results show that systems are operating as required to achieve adequate ventilation, including achieving the flow rates specified in this approved document.
  3. Commissioning results show that controls are operating as required to achieve adequate ventilation.
  4. The person carrying out the work gives notice to the building control body and building owner that commissioning has been carried out following the procedure given in this document.


In the Secretary of State’s view, when building work that affects ventilation is carried out, the requirements of regulation 39 are met if the installer provides clear and simple written guidance for the building owner on how to operate and maintain the ventilation system, as described in paragraphs 4.4 to 4.9.

Commissioning and providing information (Section 4) 

  • Mechanical ventilation systems must be commissioned in accordance with CIBSE’s Commissioning Code M and provide adequate ventilation. A commissioning notice must be given to the building control body
  • Sufficient information about the ventilation system and its maintenance requirements must be given to the building owner to allow the system to be operated effectively, as well as al completed documentation and how and when the ventilation system should be used.


Appendices covering Key Terms, Performance-based Ventilation, CO2 Monitoring and Standards & Documents referred to are also included within the Approved Document. 

Summary of Key Changes in Approved Document F: Volume 2 (Buildings other than dwellings)

Although many aspects included within the new Approved Document remain similar to previous guidance, there are some key areas of change that we think are important to highlight below.

There are new standards on reducing the ingress of external pollutants by ventilation systems and specific guidance on acceptable levels for specific pollutants.

Rather than using total Volatile Organic Compounds (VOCs) in air quality testing, individual VOCs may now be used where evidence can support their selection.

Common spaces such as offices or those spaces used mainly for circulation such as lobbies and lifts should benefit from a minimum air supply rate of 0.5l/s.m2 if mechanically ventilated or should have natural ventilation openings at at least 1/50th of the floor area within the space. This is different for those classing as occupiable rooms in offices, which must have a supply rate of 10l/ps pp or 1l/ps per m2 floor area (whichever is highest.)

New building must have indoor air quality monitoring in spaces classified as “occupiable rooms” such as offices, those with aerosol-generating activities, where members of the public may gather and those maintained at low temperature/low humidity levels e.g. cold stores.

New requirements for the installation of CO2 monitors in offices are included, specifically in “high risk” areas. These monitors should be mains-powered, non-dispersive, infra-red NDIR type, located at breathing height, away from room openings where possible and at least 0.5m away from where people may be located.

Replacement windows should now all be fitted with background trickle ventilators unless it is proven that this replacement would not reduce useful ventilation or that a mechanical system is present.

Ventilation systems using recirculatory air must have a mode that prevents cross-space recirculation – unless suitable air filtering/cleaning systems are available.

Providing access for maintenance of ventilation systems is now key, including for; replacement of filters, fans and coils; cleaning ductwork; and; general maintenance of the plant.


Within our new world of airborne risk reduction and clear air improvement it is clear that improvements to ventilation standards and systems will continue to gather pace. 

Large numbers of HVAC studies have explored their role in keeping us safe and two years later we know much more, but with further understanding and innovation sure to come. 

Any effort to improve wellbeing and health in the places we occupy is a positive outcome and here at FEG we are proud to be part of the circle of experts driving forward best practice in ventilation.  We offer a number of solutions in air pollution control, HVAC systems, LEV and ventilation and extraction

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