Approved Document F: volume 2

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The Building Regulations 2010

F 7

Approved Document

Volume 2

Buildings other than dwellings

Ventilation

For use in Wales*

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This approved document supports Part F of Schedule 1 to the Building Regulations 2010.

This approved document takes effect on 29 March 2023 for use in Wales. It does not apply to work on a particular building where a building notice, full plans application or initial notice have been submitted before that date, provided the work for each building is started before 29 March 2024 and it does not apply to sites where a building notice, initial notice or full plans application were submitted before 31 July 2014 and building work commenced before 31 July 2015. Full detail of the transitional arrangements can be found in Circular Letter 005/2022 published on Building regulations | Sub-topic | GOV.WALES

This approved document gives guidance for compliance with the Building Regulations for building work carried out in Wales.

© Crown copyright Digital ISBN 978-1-80364-838-5 WG44620

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The approved documents

The approved documents

What is an approved document?

This Approved Document, which takes effect on 29 March 2023, has been approved and issued by the Welsh Ministers to provide practical guidance on ways of complying with the ventilation requirements of the Building Regulations 2010 for Wales, as amended, which are referred to throughout the remainder of this document as ‘the Building Regulations’.

These approved documents give guidance on each of the technical parts of the regulations and on regulation 7 (see the back of this document). The approved documents provide guidance for common building situations.

It is the responsibility of those carrying out building work to meet the requirements of the Building Regulations 2010. Although it is ultimately for the courts to determine whether those requirements have been met, the approved documents provide practical guidance on potential ways to achieve compliance with the requirements of the regulations in Wales.

Although approved documents cover common building situations, compliance with the guidance set out in the approved documents does not provide a guarantee of compliance with the requirements of the regulations because the approved documents cannot cater for all circumstances, variations and innovations. Those with responsibility for meeting the requirements of the regulations will need to consider for themselves whether following the guidance in the approved documents is likely to meet those requirements in the particular circumstances of their case.

Note that there may be other ways to comply with the requirements than the method described in an approved document. If you prefer to meet a relevant requirement in some other way than described in an approved document, you should seek to agree this with the relevant building control body at an early stage.

Where the guidance in the approved document has been followed, a court or inspector will tend to find that there is no breach of the regulations. However, where the guidance in the approved document has not been followed, this may be relied upon as tending to establish breach of the regulations and, in such circumstances, the person carrying out building works should demonstrate that the requirements of the regulations have been complied with by some other acceptable means or method.

In addition to guidance, some approved documents include provisions that must be followed exactly, as required by regulations or where methods of test or calculation have been prescribed by the Welsh Ministers.

Each approved document relates only to the particular requirements of the Building Regulations 2010 that the document addresses. However, building work must also comply with all other applicable requirements of the Building Regulations 2010 and all other applicable legislation.

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The approved documents

How to use this approved document

This document uses the following conventions.

a. Text against a grey background is an extract from the Building Regulations 2010 or the Building (Approved Inspectors etc.) Regulations 2010 (both as amended). These extracts set out the legal requirements of the regulations.

b. Key terms, printed in blue, are defined in Appendix A.

c. References are made to appropriate standards or other documents, which can provide further useful guidance. When this approved document refers to a named standard or other reference document, the standard or reference has been clearly identified in this document. Standards are highlighted in bold throughout. The full name and version of the document referred to is listed in Appendix D (standards) or Appendix E (other documents). However, if the issuing body has revised or updated the listed version of the standard or document, you may use the new version as guidance if it continues to address the relevant requirements of the Building Regulations.

d. Standards and technical approvals also address aspects of performance or matters that are not covered by the Building Regulations and may recommend higher standards than required by the Building Regulations. Nothing in this approved document precludes you from adopting higher standards.

User requirements

The approved documents provide technical guidance. Users of the approved documents should have adequate knowledge and skills to understand and apply the guidance correctly to the building work being undertaken.

Where you can get further help

If you are not confident that you possess adequate knowledge and skills to apply the guidance correctly or if you do not understand the technical guidance or other information in this approved document or the additional detailed technical references to which it directs you, you should seek further help. Help can be obtained through a number of routes, some of which are listed below.

a. If you are the person undertaking the building work: either from your local authority building control service or from an approved inspector b. If you are registered with a competent person scheme: from the scheme operator c. If your query is highly technical: from a specialist or an industry technical body for the relevant subject.

The Building Regulations

The following is a high level summary of the Building Regulations relevant to most types of building work. Where there is any doubt you should consult the full text of the regulations, available at www.legislation.gov.uk.

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The approved documents

Building work

Regulation 3 of the Building Regulations defines ‘building work’. Building work includes:

a. the erection or extension of a building b. the provision or extension of a controlled service or fitting c. the material alteration of a building or a controlled service or fitting.

Regulation 4 states that building work should be carried out in such a way that, when work is complete:

a. For new buildings or work on a building that complied with the applicable requirements of the Building Regulations: the building complies with the applicable requirements of the Building Regulations.

b. For work on an existing building that did not comply with the applicable requirements of the Building Regulations:

(i) the work itself must comply with the applicable requirements of the Building Regulations and

(ii) the building must be no more unsatisfactory in relation to the requirements than before the work was carried out.

Material change of use

Regulation 5 defines a ‘material change of use’ in which a building or part of a building that was previously used for one purpose will be used for another.

The Building Regulations set out requirements that must be met before a building can be used for a new purpose. To meet the requirements, the building may need to be upgraded in some way.

Materials and workmanship

In accordance with regulation 7, building work must be carried out in a workmanlike manner using adequate and proper materials. Guidance on regulation 7(1) is given in Approved Document 7, and guidance on regulation 7(2) is provided in Approved Document B.

Independent third party certification and accreditation

Independent schemes of certification and accreditation of installers can provide confidence that the required level of performance for a system, product, component or structure can be achieved.

Building control bodies may accept certification under such schemes as evidence of compliance with a relevant standard. However, a building control body should establish before the start of the building work that a scheme is adequate for the purposes of the Building Regulations.

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The approved documents

Energy efficiency requirements

Part 6 of the Building Regulations imposes additional specific requirements for energy efficiency.

If a building is extended or renovated, the energy efficiency of the existing building or part of it may need to be upgraded.

Notification of work

Most building work and material changes of use must be notified to a building control body unless one of the following applies.

a. It is work that will be self-certified by a registered competent person or certified by a registered third party.

b. It is work exempted from the need to notify by regulation 12(6A) of, or Schedule 4 to, the Building Regulations.

Responsibility for compliance

People who are responsible for building work (e.g. agent, designer, builder or installer) must ensure that the work complies with all applicable requirements of the Building Regulations. The building owner may also be responsible for ensuring that work complies with the Building Regulations. If building work does not comply with the Building Regulations, the building owner may be served with an enforcement notice.

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0.1This approved document is Approved Document F, volume 2: Buildings other than dwellings. It gives guidance on how to comply with Part F of Schedule 1 of the Building Regulations. For guidance on dwellings, use Approved Document F, volume 1: Dwellings.

0.3The guidance in this volume of Approved Document F, Volume 2 applies only to building other than dwellings. For blocks of flats with shared communal rooms, this approved document should be consulted for those rooms.

0.2This approved document contains the following sections:

Section 0

Section 0

Introduction

Summary

Application

Note: Rooms for residential purposes and buildings that contain rooms for residential purposes are not dwellings, and are covered by the guidance in this approved document.

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0.4The following classes of buildings are exempt from the Part F requirements.

a.Special buildings – any of the following:

b.Unoccupied buildings – provided that the buildings are a specified distance from buildings into which people normally go, as defined in the Building Regulations 2010 Schedule II, either of the following:

Section 0

Exemptions

i.buildings controlled under the Explosives Regulations 2014.

ii.buildings controlled under the Nuclear Installations Act 1965.

iii.buildings included in the schedule of monuments maintained under section 1 of the Ancient Monuments and Archaeological Areas Act 1979.

i.detached buildings into which people do not normally go

ii.detached buildings into which people go only occasionally to inspect or maintain a fixed plant,

c.Greenhouses - provided that the main purpose of the building is not retailing, packing or exhibiting.

d.Agricultural buildings (as defined in the Building Regulations 2010 Schedule II). Agricultural buildings used mainly for retailing, packing or exhibiting are not exempt.

e.Temporary buildings – buildings that are not intended to remain for more than 28 days

f.Ancillary buildings – any of the following:

i.buildings used for the disposal of buildings or building plots on site

ii.buildings on the site of construction or civil engineering works that both:

a.are for use only during the course of those works

b.contain no sleeping accommodation

iii.buildings on the site of mines and quarries that both:

a.do not contain dwellings

b.are not used as offices or showrooms.

g.Small buildings – detached single-storey buildings with a maximum floor area of 30 m2 that contain no sleeping accommodation, and that are either:

i.constructed substantially of non-combustible material

ii.at least 1 metre from the boundary of their curtilage

h.Very small buildings – detached buildings with a maximum floor area of 15 m2 floor area that contain no sleeping accommodation

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Section 0

i.Bomb shelters – detached buildings with a maximum floor area of 30 m2 that are designed and intended to be used as shelters from nuclear, chemical or conventional weapons, and for no other purpose, provided the site of the excavation for the building is a minimum of 1 metre plus the depth of excavation from any other exposed structure.

j.Conservatories and porches – extensions of buildings at ground level, with a maximum floor area of 30 m2, for a:

i.conservatory

ii.porch

iii.covered yard

iv.covered way

v.carport open on at least two sides

0.5The following types of buildings may not need to comply fully with the ventilation standards in this approved document.

0.6Work to a building in paragraph 0.5 should comply with the ventilation standards in this approved document to the extent that it is reasonably practicable. The work being done should not:

0.7New extensions to historic or traditional buildings should comply fully with the standards of ventilation in this approved document unless there is a need to match the external appearance or character of the extension to that of the host building.

0.8The local authority’s conservation officer should be consulted when doing work to a building in paragraph 0.5a or b.

Reasonable provision for historic and traditional buildings

a.Those listed in accordance with section 1 of the Planning (Listed Buildings and Conservation Areas) Act 1990.

b.Those in a conservation area designated in accordance with section 69 of the Planning (Listed Buildings and Conservation Areas) Act 1990.

c.Other historic buildings that have a vapour permeable construction that both absorb and readily allows moisture to evaporate. These include: wattle and daub, cob, stone and constructions using lime render or mortar.

a.unacceptably affect the significance of the listed building, conservation area or scheduled monument;

b.increase the risk of long-term deterioration of the building fabric or fittings.

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0.9For emergency repairs, if it is not practicable to notify the building control body in advance, the building control body should be notified at the earliest opportunity. If the installer is registered in a competent person scheme, see ‘Notification of Work’ (page 4) in this document.

0.10Minor works must comply with the relevant requirements of the Building Regulations, but do not need to be notified to the building control body.

Section 0

Emergency repairs

Minor works

For mechanical ventilation and air-conditioning systems, minor works include:

a.replacing parts

b.adding an output or control device where testing and adjusting the system would not affect its energy efficiency or would not be possible

c.providing a self-contained mechanical ventilation or air-conditioning appliance given all of the following apply.

i.Any electrical work is exempt from a requirement to give advance notice to a building control body.

ii.Testing and adjusting the system would not affect its energy efficiency or would not be possible.

iii.The appliance is not installed in a room that contains an open-flued combustion appliance.

0.11A unit that contains both living accommodation and space to be used for commercial purposes (e.g. as a workshop or office) should be treated as a dwelling, as long as the commercial part can revert to domestic use.

0.12The commercial part of the building can revert to domestic use if all of the following apply.

Live-work units

a.There is direct access between the commercial space and the living accommodation.

b.The commercial space and living accommodation are within the same thermal envelope.

c.The living accommodation occupies a substantial proportion of the total area of the unit. What constitutes a ‘substantial proportion’ should be assessed on a case-by-case basis by the Building Control Body.

Note: A large non-domestic building that contains a small flat for a manager is not treated as a dwelling. A dwelling that contains a room used as an office or utility space is still treated as a dwelling.

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0.13When constructing a dwelling as part of a larger building that contains other types of accommodation, often called a mixed-use development, refer to the two volumes of Approved Document F as follows.

0.14The approved documents set out what, in ordinary circumstances, may be accepted as one way to comply with the Building Regulations. Those designing or undertaking building work remain responsible for assessing, on a case-by-case basis, whether specific circumstances require additional or alternative measures to achieve compliance with the regulatory requirements. There are interactions between many of the requirements of the Building Regulations, below is guidance on examples of some key interactions.

0.15The requirements of Part B apply if, for example, ducts pass through any of the following:

0.16This document gives guidance on window openings for ventilation. In addition, Approved Document B gives guidance on the size of escape windows. The larger of the window openings in Approved Document B or F should be applied in all cases.

0.17Ventilation fans might cause combustion gases to spill from open-flued appliances. These combustion gases might fill the room instead of going up the flue or chimney. This can occur even if the combustion appliance and fan are in different rooms.

0.18The guidance in Approved Document J should be followed when installing and testing ventilation appliances. Combustion appliances must operate safely whether or not fans are running.

Section 0

Mixed use developments

a.For guidance on each individual dwelling, follow Approved Document F, volume 1: Dwellings.

b.For guidance on the non-dwelling parts of the building, such as shared communal rooms and commercial or retail space, follow this Approved Document F, Volume 2: Buildings other than dwellings.

Selected key interactions with other parts of the Building Regulations

Interaction with Part B

a.a fire-resisting wall or floor

b.a fire compartment

c.a protected stairway.

Interaction with Part J

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0.19Energy efficiency should be considered when specifying ventilation systems. Energy efficiency, including the control of infiltration, is dealt with under Part L of the Building Regulations.

0.20Where manual controls are provided for a ventilation device, they should be within reasonable reach of the occupants. Follow the guidance in Approved Documents K and M.

0.21This document sets guidance for purge ventilation for the purposes of rapidly diluting indoor air pollutants and water vapour where necessary in habitable rooms in buildings other than dwellings. For residential-type buildings, Part O may require a higher standard than given in this document for purge ventilation to remove excess heat. In this case, the higher of the two standards should be followed.

Section 0

Interaction with Part L

Interaction with Parts K and M

Interaction with Part O

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0.22This section deals with the Requirements of Part F1(1) of Schedule 1 of the Building Regulations 2010.

0.23In the Welsh Minister’s view, requirement F1(1) is met if the building other than a dwelling is provided with a means of ventilation which achieves all of the following.

0.24In the Welsh Minister’s view, requirement F1(1) is met for work on an existing building other than a dwelling by following guidance in Section 3.

Section 0

Requirement F1(1): Means of ventilation

Intention

a.extracts water vapour and indoor air pollutants from areas where they are produced in significant quantities before they spread through the building – by following guidance for extract ventilation in Section 1 for the relevant building type.

b.supplies a minimum level of outdoor air for occupants’ health – by following guidance for whole building ventilation in Section 1 for the relevant building type.

c.rapidly dilutes indoor air pollutants and disperses water vapour when necessary in occupiable rooms and sanitary accommodation – by following guidance for purge ventilation in Section 1 for the relevant building type.

d.Monitors air quality in specific types of occupiable rooms– following paragraphs 1.21 – 1.23.

e.Minimises the ingress of external pollutants – by following guidance in Section 2.

f.achieves all of the following as far as reasonably practicable:

i.produces low levels of noise, by following guidance in paragraphs 1.5 to 1.6;

ii.offers easy access for maintenance, by following guidance in paragraph 1.7;

iii.provides protection from rain;

iv.provides protection from cold draughts;

v.does not significantly risk occupants’ health.

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1.1The aim of Requirement F1(1) is to protect the health of occupants of the building by providing adequate ventilation. Without adequate ventilation, mould and internal air pollution may become hazardous to health and the risk of transmission of airbourne infection is incresed.

1.2This approved document sets out guidance for ventilation provision in the following types and uses of buildings and occupiable rooms:

a.Specific types of occupiable rooms – follow paragraphs 1.21 to 1.23.

b.Offices – follow paragraphs 1.24 to 1.37.

c.Car parks – follow paragraphs 1.38-1.40.

d.Building types other than offices or car parks– follow paragraph 1.41.

1.3Other ventilation solutions may be used, provided it can be demonstrated to the building control body that they meet Requirement F1(1).

1.4The guidance set out in this approved document has been designed to meet the pollutant levels in Appendix B where the outside air is of reasonable quality. In areas where the outside air is not of reasonable quality, Section 2 provides guidance on limiting the ingress of external air pollutants.

1.5Mechanical ventilation systems, including both continuous and intermittent mechanical ventilation should be designed and installed to minimise noise. This includes all of the following:

Section 1

Section 1

Ventilation provision

General

Note: The guidance in this approved document is not designed to deal with the products of tobacco smoking or vaping.

Noise

a.Correctly sizing and jointing ducts.

b.Ensuring that equipment is appropriately and securely fixed, such as with resilient mountings, where noise carried by the structure of the building could be a problem.

c.Selecting appropriate equipment, including following paragraph 1.6.

For mechanical ventilation systems, fan units should be appropriately sized so that fans operating in normal background ventilation mode are not overly noisy, taking into consideration the use and likely background level of noise from other sources. This might require fans to be sized so that they do not operate near the

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1.6maximum capacity of the fan when operating in normal background ventilation mode.

1.7Reasonable access should be provided for maintaining ventilation systems, including all the following:

a.Providing access to replace filters, fans and coils.

b.Providing access points for cleaning ductwork.

c.Providing access for the general maintenance of plant.

1.8The ventilation strategy in this approved document relies on a combination of all of the following:

1.9Ventilation may be delivered through natural ventilation, mechanical ventilation or a combination of both.

1.10Naturally ventilated buildings should follow additional guidance on ventilation in CIBSE’s AM10. Mixed mode buildings should follow additional guidance on ventilation in CIBSE’s AM13.

1.11The ventilation systems in this approved document are examples of systems that comply with Part F of the Building Regulations. Other ventilation systems may be acceptable if they can be shown to meet an equal level of performance.

1.12Performance criteria for acceptable levels of moisture and pollutants are given in Appendix B. Ventilation rates necessary to meet the performance criteria are given in this guidance or in the documents referred to.

Section 1

Access for maintenance

The ventilation strategy in this approved document

a.Extract ventilation from rooms where water vapour or pollutants are likely to be released (e.g. bathrooms, sanitary accommodation and kitchens), to minimise their spread to the rest of the building. Ventilation fans may be either intermittent operation or continuous operation.

b.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.

c.Purge ventilation to remove high concentrations of pollutants and water vapour. Purge ventilation is used intermittentently and required only for pollutants produced by occasional activities (e.g. fumes from painting).

d.Monitoring of indoor air quality.

Performance-based guidance

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1.13Some ventilation system designs can, in some circumstances, result in lower ventilation rates than stated in this guidance or in the documents referred to (e.g. systems with automatic controls). Where lower ventilation rates are proposed, expert advice should be obtained to demonstrate that the solution meets the performance standards in Appendix B.

1.14The size of background ventilators (including trickle ventilators) is given in this Approved Document as an equivalent area in mm2, not a free area. BS EN 13141-1 includes a method of measuring the equivalent area of background ventilator openings.

1.15Background ventilators should have the equivalent area marked where it will be easily visible from inside the dwelling when installed, to aid verification by building control bodies.

1.16Ventilation systems should be installed to meet both of the following:

1.17Rigid ducts should be used wherever possible. Where necessary, flexible ducts may be used for final connections, but their lengths should be kept to a minimum. All flexible ductwork should meet the standards of BSRIA’s BG 43/2013.

1.18Ductwork installations should be designed and installed to minimise the overall pressure losses within the system by taking all of the following steps.

1.19Duct connections should be both mechanically secured and adequately sealed to prevent leaks. Rigid connectors and jubilee clips should be used to ensure a good seal.

1.20Mechanical ventilation systems must be commissioned in accordance with an approved procedure. See Section 4 of this approved document.

1.21In new buildings, the following types of occupiable room, unless they are rooms of the size described in paragraph 1.22, should have a means of monitoring the

Section 1

Equivalent area of ventilators

Installation of ventilation systems

a.to comply with the guidance in paragraphs 1.17 to 1.20;

b.not compromise the performance of the system in-use.

a. Minimising the overall length of duct.

b. Minimising the number of bends required.

c. Installing appropriately sized ducts for the air flow rate.

Indoor air quality monitoring

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1.22The guidance in paragraph 1.21 does not apply to the following sizes of room.

1.23Where CO2 monitors are used, they should meet all of the following.

Section 1 indoor air quality. This may be achieved using CO2 monitors or other means of measuring indoor air quality.

a. Occupiable rooms in offices.

b. Occupiable rooms where singing, loud speech or aerobic exercise or other aerosol generating activities are likely to take place. These may include rooms, for example, in gymnasiums, other indoor sports venues, dance studios, theatres, concert halls, public houses, nightclubs, places of assembly, as well as in other types of building.

c. Occupiable rooms where members of the public are likely to gather. These may include rooms, for example, in public buildings, hotels, gymnasiums, indoor sports venues, exhibition centres, dance studios, theatres, cinemas, concert halls, retail premises, public houses, nightclubs, places of assembly, as well as in other types of building.

d. Occupiable rooms which are maintained at both low temperatures and low levels of humidity. These may include rooms used for chilled food processing and occupied cold stores.

a. Small spaces up to 125m3 volume, or 50m2 floor area.

b. Large spaces over 800m3 in volume, or 320m2 floor area a. Be non-dispersive infrared (NDIR) type CO2 monitors.

b. Be mains powered.

c. Be placed at breathing height and away from windows, doors or ventilation openings where practicable.

d. Be placed at least 500mm from people where practicable.

Note: Additional details on CO2 monitoring for indoor air quality can be found in Appendix C.

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1.24Extract ventilation should be provided in offices in all the following areas.

1.25For rooms designed to contain printers and photocopiers in substantial use (greater than 30 minutes per hour), both of the following should apply.

1.26Sanitary accommodation and bathrooms should have an intermittent air extract rate of both of the following.

1.27Extract ventilators in sanitary accommodation should be capable of continuous operation if required.

1.28Food and drink preparation areas should have an intermittent extract air rate of either of the following.

i.if the extract ventilator is adjacent to the hob/cooker: 30 litres per second

ii.if the extract ventilator is remote from the hob/cooker: 60 litres per second.

1.29Specialist buildings and spaces should follow the guidance in Table 1.1.

1.30For naturally ventilated offices which do not use mechanical supply and extract ventilation, both of the following should apply.

Section 1

Ventilation for Offices

Extract ventilation for offices

a.Sanitary accommodation.

b.Bathrooms.

c.Washrooms.

d.Food and beverage preparation areas.

e.Rooms that are designed to contain printers and photocopiers in substantial use (greater than 30 minutes per hour).

Note: Rooms that are designed to contain printers and photocopiers in substantial use (greater than 30 minutes per hour), should not be designed to be occupied.

a.The air extract rate should be 20 litres per second per machine during use.

b.The whole building ventilation rate should also be met.

a.15 litres per second per shower or bath.

b.6 litres per second per WC pan or urinal.

a.If the area is only for using a microwave and preparing drinks: 15 litres per second.

b.If the area is for using a domestic-type hob or cooker, either:

Note: This guidance does not apply to commercial kitchens, which should follow the specific guidance in Table 1.1.

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Section 1

a.Extract ventilators should be located both:

i.as high as practicable;

ii.a maximum of 400 mm below the ceiling.

b.Where used, passive stack ventilation terminals should be located in the ceiling.

1.31For a room with no openable window, the extract ventilation should operate both:

1.32Outdoor air should be supplied for occupiable rooms in offices at whichever of the following will provide the higher total rate.

1.33Common spaces, including rooms or spaces used solely or mainly for circulation such as corridors and lift lobbies, should be provided with either:

1.34If there are significant levels of pollutants other than body effluents/ odour, additional ventilation may be required. The calculation method provided in CIBSE’s Guide A Environmental Design should be followed to determine the whole building ventilation rate.

1.35Each office should have the means to provide purge ventilation, to reduce pollutants before the office space is occupied, or after activities such as painting.

a. while the room is occupied b. for a minimum of 15 minutes after occupants have left the room.

Whole building ventilation rates for offices

a. 10 litres per second per person b. 1 litre per second per m2 floor area.

a.natural ventilation by appropriately located ventilation opening(s) with a total opening area of at least 1/50th of the floor area of the common space;

b.mechanical ventilation installed to provide a supply of outdoor air of 0.5 litres per second per m2 of floor area of the common space.

Purge ventilation for offices

The purged air should both:

a.be taken directly to outside

b.not be re-circulated to any other part of the building.

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1.36Controls should be provided for ventilators so that the ventilation in each room can be adjusted. For mechanical supply and extract ventilation either manual controls or automatic controls are acceptable.

1.37Ventilation systems that, under normal operation, recirculate air between more than one space, room or zone should also be able to operate in a mode that reduces the risk of the transmission of airborne infection. This can be achieved by one or more of the following.

1.38For car parks below ground level, enclosed car parks and multi-storey car parks, the ventilation rate should be designed, and equipment installed, to limit the carbon monoxide to both of the following.

a.Average concentration: a maximum of 30 parts per million over an eight-hour period.

b.Peak concentration, such as by ramps and exits: a maximum of 90 parts per million over a 15-minute period.

1.39As an alternative to paragraph 1.38 either of the following may be considered to provide adequate ventilation.

Section 1

Controls for offices

Recirculation of air within ventilation systems in offices

a. Systems capable of providing 100% outdoor air to the levels specified in paragraphs 1.32 to 1.34 to all occupiable rooms and common spaces, without recirculating air.

b. Systems incorporating a UV-C germicidal irradiation system that is able to disinfect the air that is being recirculated. This type of system is commonly located within the heating, ventilation and air conditioning (HVAC) system or ductwork.

c. Systems designed so that they can incorporate HEPA filters, if required, which are able to provide filtration of the recirculated air.

Note: For some system types some recirculation is necessary or desirable in normal operation. Use of any full outdoor air mode, UV-C germicidal irradiation or HEPA filtration may not be necessary under normal conditions of operation.

Ventilation of car parks

Note: Guidance on the ventilation of car parks to manage the risk of fire is given in Approved Document B.

a.If the car park has natural ventilation, openings at each car parking level should comply with both of the following:

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i.Have a minimum aggregate equivalent area of 1/20th of the floor area at that level.

ii.Have a minimum of 25% of the aggregate equivalent area on each of two opposing walls.

i.All of the following:

a.permanent natural ventilation openings with a minimum equivalent area of 1/40th of the floor area.

b.a mechanical ventilation system capable of at least three air changes per hour.

c.For exits and ramps, where cars queue inside the building, provision to ensure a local ventilation rate of at least ten air changes per hour.

a.For a car park in a basement, the provision of a mechanical ventilation system should be capable of at least six air changes per hour.

b.For exits and ramps, where cars queue inside the building, provision to ensure a local ventilation rate of at least ten air changes per hour.

1.40Further guidance can be found in all of the following documents.

1.41Adequate means of ventilation in buildings other than offices and car parks may be demonstrated by meeting the relevant standards set out in CIBSE’s Guide A. Sources of further guidance, and relevant regulations, are listed in Table 1.1.

Section 1

b.If a car park has mechanical ventilatilation, either of the following should apply.

ii.Both of the following:

a.The Association of Petroleum and Explosives Administrations’ Code of practice for ground floor, multi-storey and underground car parks.

b.CIBSE’s Guide B2 Ventilation and Ductwork.

c.The Health and Safety Publication’s EH40/2005 Workplace exposure limits.

d.ASHRAE’s ASHRAE Handbook—HVAC Applications, chapter 16 ‘Enclosed Vehicular Facilities’.

Ventilation for buildings other than offices and car parks

Note: For residential non-domestic buildings within the scope of Part O (overheating) of the Building Regulations, higher purge ventilation rates may be required.

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Section 1

Table 1.1 Ventilation for buildings other than offices

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2.1Ventilation systems should be designed to minimise the intake of external air pollutants following paragraphs 2.2 to 2.6 if either of the following applies:

i.Road traffic, including traffic junctions and underground car parks.

ii.Combustion plant (such as heating appliances) running on conventional fuels, most commonly natural gas.

iii.Other combustion processes (for example, waste incineration, thermal oxidation abatement systems).

iv.Discharges from industrial processes.

v.Fugitive (i.e. not effectively controlled) discharges from industrial processes and other sources.

vi.Exhaust discharges from building ventilation systems.

vii.Construction and demolition sites, which are a source of particles and vaporous discharges.

viii.Other significant sources of local air pollution which may be detrimental to health.

Section 2

Section 2

Minimising the ingress of external pollutants

a.The pollutant values in the location of the building exceed any of the limits in Table 2.1. This may have been determined through an air quality assessment. Where modelling or monitoring data is required, expert advice should be sought.

b.The building is located near to any of the following sources of significant local pollution:

Source page 27

2.2Ventilation intakes should be located away from the direct impact of the sources of local pollution.

2.3Where urban traffic is a source of pollution, the air intakes for buildings next to busy urban roads should be both:

Section 2

Table 2.1 Limit Values from Schedule 2 of the Air Quality Standards Regulations 2010

Control of ventilation intakes

Note: CIBSE’s TM 64 and TM 40 give further guidance.

a.as high as possible

b.located on the less polluted side of the building.

Mechanical ventilation may be the most practical means of achieving this requirement.

2.4If practicable, ventilation intakes should not be located in courtyards and enclosed urban spaces where air pollutants are discharged. If this is unavoidable, intakes should be both:

Source page 28

Section 2

a.as far as possible from the source of pollutants

b.in an open or well-ventilated area.

2.5In areas where wind often comes from opposing directions (e.g. a valley), the air intakes should point in the opposite direction to the exhaust outlets.

2.6Where sources of pollution vary with the time of day, such as urban road traffic, it may be acceptable, for time limited periods to either:

a.reduce the flow of external air into ventilation intakes

b.close ventilation intakes when the concentrations of external pollutants are highest.

Note: In these circumstances, expert advice should be sought.

Location of exhaust outlets

2.7Exhaust outlets should be located so that both:

a.Re-entry of exhaust into a building, or entry into other nearby buildings, is minimised;

b.There is no adverse effect on the surrounding area.

2.8Where there is a prevailing wind direction, exhaust outlets should be downwind of intakes.

2.9Exhaust outlets should not discharge into any of the following:

a.courtyards

b.enclosures

c.architectural screens.

Note: Chapter 13 of McGraw Hill’s Indoor Air Quality Handbook provides further guidance.

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3.1When building work in an existing building includes work on ventilation (e.g. building an extension, adding a wet room, replacing part of the ventilation system) the work should meet the relevant standards in this approved document.

3.2When other building work is carried out that will affect the ventilation of the existing building (e.g. replacing windows or doors, doing energy efficiency work) the ventilation of the building should either:

3.3When a building undergoes a material change of use, Part F of Schedule 1 to the Buildings Regulations applies to the building or part of the building that has changed use. Guidance in Section 1 should be followed.

3.4If work is carried out which increases the energy efficiency of a building, airtightness may be increased. In these circumstances, any useful ventilation which was lost should be replaced in order to maintain a healthy indoor environment. When carrying out work which is likely to increase the airtightness of the building, it should be demonstrated to the building control body that the work meets the requirements of Requirement F1(1), where it is an applicable requirement. Refer to paragraphs 3.1 and 3.2 for the relevant standards that should be met. For domestic-type installation of common energy efficiency measures in existing buildings, Approved Document F, Volume 1: Dwellings contains guidance on meeting the requirements of Part F of Schedule 1 of the Building Regulations.

Section 3

Section 3

Work on existing buildings

General

a. meet the standards in the relevant approved document b. not be less satisfactory than before the work was carried out.

Note: Ventilation through infiltration should be considered to be part of the ventilation provision of a building. Reducing infiltration might reduce the indoor air quality of the building below the standards given in Appendix B.

Note: Ventilation equipment is considered to be a ‘controlled service or fitting’ and the provision or extension of such equipment in or in connection with a building is considered to be building work.

Note: Some building work does not need to be notified to the local authority. This is set out in Schedule 4 of the Building Regulations 2010.

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3.5If the existing windows have background ventilators, the replacement windows should include background ventilators. The new background ventilators should both:

3.6Replacing windows is likely to increase the airtightness of the building. If ventilation is not provided via a mechanical ventilation system, then increasing the airtightness of the building may reduce beneficial ventilation in the building. In these circumstances, it should be ensured that the ventilation provision in the building is no worse than it was before the work was carried out. This may be demonstrated in any of the following ways:

i.occupiable rooms:

a.for floor areas up to 10 m2 – minimum 2500 mm2 equivalent area

b.for floor areas greater than 10 m2 – minimum 250 mm2 equivalent area per m2 of floor area

ii.domestic-type kitchens - minimum 8000 mm2 equivalent area

iii.bathrooms (with or without a toilet) and shower rooms - minimum 4000 mm2 equivalent area per bath or shower

iv.sanitary accommodation (and/or washing facilities) – minimum 2000 mm2 equivalent area per WC

Section 3

Replacing windows

Existing windows with background ventilators

a.not be smaller than the background ventilators in the original window

b.be controllable either automatically or by the occupant.

If the size of the background ventilators in the existing window is not known, the ventilator sizes in paragraph 3.6 may be applied.

Existing windows without background ventilators

a.Incorporating the following background ventilators in the replacement windows equivalent to the following:

b.Other ventilation provisions provided they can be demonstrated to a building control body that they comply with the requirements of paragraph 3.2.

Note: If it is not technically feasible to adopt the minimum equivalent areas set out in paragraph 3.6, the background ventilators should adopt equivalent areas as close to the minimum value as is feasible.

Note: If an exposed façade is close to an area of sustained and loud noise (e.g. a main road), then a noise attenuating background ventilator should be fitted.

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Section 3

Requirement F1(2) and Regulations 39 and 44

This section deals with the requirements of Part F1(2) of Schedule 1 and regulations 39 and 44 of the Building Regulations 2010.

Note: Where the building control body is an approved inspector, see regulation 20 of the Building (Approved Inspectors etc.) Regulations 2010 (as amended).

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Section 3

Intention

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

a.All fixed mechanical ventilation systems for which testing and adjustment is possible are tested and commissioned.

b.Commissioning results show that systems are operating as required to achieve adequate ventilation, including achieving the flow rates specified in this approved document.

c.Commissioning results show that controls are operating as required to achieve adequate ventilation.

d.The person carrying out the work gives notice to the building control body and building owner that commissioning has been carried out in accordance with the procedure given in this document.

In the Welsh Minister’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 their ventilation system, as per paragraphs 4.4 to 4.9.

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Section 4

Section 4

Commissioning and providing information

Commissioning of ventilation systems

4.1Mechanical ventilation systems must be commissioned to provide adequate ventilation. A commissioning notice must be given to the building control body.

4.2Commissioning should be carried out in accordance with CIBSE’s Commissioning Code M.

4.3Ventilation ductwork commissioning should take account of guidance in BESA’s DW/144 for metal ductwork, DW/154 for plastic ductwork and DW/143 for ductwork leakage testing.

Note: When mechanical ventilation is commissioned, the use of fuel and power should also be considered in accordance with Part L of the Building Regulations (L1(b) of Schedule 1). Installers may provide notice of commissioning to cover Part F (F1(2) of Schedule 1) and Part L in the same document.

Operating and maintenance instructions

4.4Sufficient information about the ventilation system and its maintenance requirements must be given to the building owner so that the system can be operated effectively. This should include both design flow rates and maintenance requirements. The information should be provided in a clear manner, for a non- technical audience.

4.5For new and existing buildings other than dwellings, information should be provided in a new or existing building log book. The log book should follow the guidance in CIBSE’s TM31. Guidance on building log books is given in Approved Document L, volume 2: Buildings other than dwellings.

4.6A copy of the completed commissioning sheet should be provided to the owner of the building.

4.7The operation and maintenance information should contain specific instructions for the end user on how and when to use the ventilation system, including information on the intended use of available fan settings. Information should also be provided to suggest when, and how, the system components should be cleaned and maintained.

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Section 4

4.8The following information should be provided where relevant:

a.manufacturer’s contact details

b.that background ventilators allow fresh air into the building and should be left open

c.the location of automatic controls and how to set them

d.the location of manual controls for the on/off and high rate settings for a mechanical ventilation system and how to use them

e.How cleaning and maintenance of the system and its components should be carried out. This includes the location and specification of filters and how to assess when to replace filters.

f.how to access ducts for cleaning, how to undertake cleaning of plant and ducts and the intervals at which cleaning should be undertaken.

g.the location of sensors and how to recalibrate them

h.design flow rates

i.The use of and interpretation of results from CO2 or other air quality monitoring sensors.

j.Adjustment of outdoor air rate for recirculating systems.

k.Operation, maintenance and safety of any UV-C germicidal irradiation system installed.

4.9The operation and maintenance information should also contain relevant manufacturers' literature, including the following, where relevant:

a.components specification

b.installation guidance

c.operating instructions

d.maintenance schedules

e.guarantees

f.registration card

g.spare part lists

h.instructions for obtaining spare parts.

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Appendix A

Appendix A

Key Terms

Except for the items marked * (which are from the Building Regulations 2010), these definitions apply only to Approved Document F, Volume 2: Buildings other than dwellings.

Air permeability The measure of airtightness of the building fabric. It is defined as the air leakage rate per hour per m2 of envelope area at the test reference pressure differential of 50Pa.

Airtightness The resistance of the building envelope to infiltration when ventilators are closed. The greater the airtightness at a given pressure difference across the envelope, the lower the infiltration.

Automatic controls A system whereby a ventilation device is adjusted by a mechanical or electronic controller that responds to a relevant stimulus. That stimulus usually relates to the humidity of the air in a room, pollutant levels, occupancy of the space or pressure difference across the device.

Background ventilator A small ventilation opening designed to provide controllable whole building ventilation.

Bathroom A room that contains a bath or shower and which can also include sanitary accommodation.

Building control body A local authority or an approved inspector.

Common space A space where large numbers of people are expected to gather (e.g. a shopping mall or foyer of a cinema or theatre) or which is used mainly for circulation in buildings which do not contain dwellings (e.g. a corridor or lift lobby in an office building). This does not include areas used solely or principally for circulation in buildings containing dwellings, including corridors or lift lobbies in blocks of flats.

Continuous operation Uninterrupted running of a mechanical ventilation device, such as mechanical extract ventilation or mechanical supply and extract ventilation. The air flow rate provided by mechanical ventilation need not be constant but may be varied, under either manual or automatic control, in response to the demand for removal of pollutants or water vapour.

Dwelling A self-contained unit designed to accommodate a single household.

Equivalent area A measure of the aerodynamic performance of a ventilator. It is the area of a sharp-edged circular orifice through which air would pass at the same volume flow rate, under an identical applied pressure difference, as through the opening under consideration.

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Appendix A

Expert advice Advice from a suitably qualified competent person. Examples from the ventilation industry of a person competent to give expert advice include a chartered or professional engineer, a building services specialist, a specialist ventilation manufacturer or members of professional trade bodies.

Extract ventilation The removal of air directly from an internal space or spaces to the outside. Extract ventilation may be by natural means or by mechanical means (e.g. by an extract fan or a central system).

Free area The geometric open area of a ventilator.

Habitable room A room used for dwelling purposes but which is not solely a kitchen, utility room, bathroom, cellar or sanitary accommodation.

Infiltration The uncontrolled exchange of air between the inside and outside of a building, through gaps and cracks.

Intermittent operation When a mechanical ventilator does not run all the time, usually running only when there is a particular need to remove pollutants or water vapour (e.g. during cooking or bathing). Intermittent operation may be under either manual control or automatic control.

Manual controls A system whereby a ventilation device is opened and closed, or switched on and off, or its performance is adjusted by the occupants of a room or building (see automatic controls).

*Material change of use Defined in regulation 5 as: Where there is a change in the purposes for which or the circumstances in which a building is used, so that after that change:

a. the building is used as a dwelling, where previously it was not;

b. the building contains a flat, where previously it did not;

c. the building is used as an hotel or a boarding house, where previously it was not;

d. the building is used as an institution, where previously it was not;

e. the building is used as a public building, where previously it was not;

f. the building is not a building described in classes 1 to 6 in Schedule 2, where previously it was;

g. the building, which contains at least one dwelling, contains a greater or lesser number of dwellings than it did previously;

h. the building contains a room for residential purposes, where previously it did not;

i. the building, which contains at least one room for residential purposes, contains a greater or lesser number of such rooms than it did previously;

Source page 37

Appendix A j. the building is used as a shop, where it previously was not; or k. the building is a building described in regulation 7(4)(a), where previously it was not.

Mechanical supply and extract ventilation Any mechanically driven ventilation that both continuously supplies outdoor air to the inside of the building and continuously extracts indoor air and discharges it to the outside. This includes decentralised supply and extract ventilation, and mechanical ventilation with heat recovery (MVHR, a mechanical supply and extract ventilation system that includes a heat recovery mechanism).

Natural ventilation Ventilation provided by thermal, wind or diffusion effects through doors, windows or other intentional openings without the use of mechanically driven equipment. For the purposes of this approved document, a natural ventilation strategy may include decentralised extract ventilation from rooms where water vapour or pollutants are likely to be released to minimise their spread to the rest of the building.

Occupiable room A room in a building other than a dwelling that is occupied by people, such as an office, workroom, classroom or hotel bedroom. The following are not occupiable rooms: bathrooms, sanitary accommodation, utility rooms or rooms or spaces used solely or mainly for circulation, building services plant or storage purposes.

Passive stack ventilation (PSV) A ventilation system using ducts from terminals in the ceiling of rooms to terminals on the roof that extract air to the outside by a combination of the natural stack effect and the pressure effects of wind passing over the roof of the building. (The stack effect is the pressure differential between inside and outside a building, caused by differences in the density of the air due to an indoor/outdoor temperature difference.)

Purge ventilation Manually controlled ventilation of rooms or spaces at a relatively high rate to rapidly dilute pollutants and/or disperse water vapour. Purge ventilation may be provided by natural means (e.g. an openable window) or mechanical means (e.g. a fan).

Purpose-provided ventilation That part of the ventilation of a building provided by ventilation devices designed into the building (e.g. background ventilators, PSV, extract fans, mechanical ventilation or air-conditioning systems).

*Room for residential purposes Defined in regulation 2(1) as a room, or a suite of rooms, which is not a dwelling-house or a flat and which is used by one or more persons to live and sleep and includes a room in a hostel, an hotel, a boarding house, a hall of residence or a residential home, but does not include a room in a hospital, or other similar establishment, used for patient accommodation.

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Appendix A

Sanitary accommodation A space containing one or more flush toilets (WCs) or urinals. Sanitary accommodation containing one or more cubicles counts as one space if there is free circulation of air throughout the space.

Shared communal rooms Rooms in buildings containing dwellings, which provide facilities for the residents, for example a laundry room, occupied lobby or gym. This does not include areas used solely or principally for circulation in buildings containing dwellings, including corridors or lift lobbies.

Surface water activity A measure of the availability of water to micro-organisms. Surface water activity is determined from the ratio of the vapour pressure of the water in the substrate to the vapour pressure of pure water at the same temperature and pressure. This ratio, in steadystate conditions, is numerically equal to the equilibrium relative humidity of the air, except that the latter is commonly expressed as a percentage.

Thermal envelope The combination of thermal elements of a building which enclose a particular conditioned indoor space or groups of indoor spaces.

Utility room A room containing a sink or other feature or equipment that may reasonably be expected to produce significant quantities of water vapour.

Ventilation The supply and removal of air (by natural and/or mechanical means) to and from a space or spaces in a building. It normally comprises a combination of purpose- provided ventilation and infiltration.

Ventilation opening Any means of purpose provided ventilation (whether permanent or closable) that opens directly to external air, such as the openable parts of a window, a louvre or a background ventilator. It also includes any door that opens directly to external air.

Whole building ventilation (general ventilation) Nominally continuous ventilation of rooms or spaces at a relatively low rate to dilute and remove pollutants and water vapour not removed by extract ventilation, purge ventilation or infiltration, as well as to supply outdoor air into the building.

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Appendix B

Appendix B

Performance-based ventilation

Introduction

B.1 This Appendix sets out the levels of moisture and other pollutants that the provisions in this approved document are designed to control. The provisions are designed to control all of the following:

a.Bio-effluents as described in paragraph B.2 (a)

b.Moisture levels as described in paragraph B.2 (b)

c.Indoor air pollutants as described in paragraph B.2 (d)

Note: the guidance in this approved document may not be adequate to address pollutants from flueless combustion space heaters. This approved document does not directly address contamination from outdoor sources.

Note: A strategy for achieving good indoor air quality includes reducing the release of water vapour and air pollutants. This approved document does not provide guidance on such strategies.

Performance criteria for buildings other than dwellings

B.2 The main guidance within this document has focused on offices. For this, the main performance criteria applied are as follows:

a. There should be a supply rate, in the absence of tobacco smoke or other excessive pollutants, of 10 litres per second per person. This will also satisfy the requirement of 8 litres per second per person needed to control higher levels of bio-effluents.

b. There should be no visible mould on the inner surfaces of external walls of a properly heated building with typical moisture generation.

c. Mould can grow whether the building is occupied or unoccupied, so the performance criteria for surface water activity (as given in Table B.2) should be met at all times, regardless of whether there are occupants. The other pollutants listed in Table B1 are only of concern when the building is occupied.

d. The performance criteria for indoor air pollutants are given in Table B.1.

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Appendix B

Table B.1 Indoor air pollutants guidance values(1) (2)

Notes:

1.No safe levels can be recommended for benzene or trichloroethylene so they have not been considered in the definition of ventilation rates in buildings. The best strategy for reducing their concentration indoors may be to control them at source.

2.Even if the designer and builder choose to reduce volatile organic compound (VOC) levels in buildings by controlling them at source, the ventilation requirements must still be met.

3.The total volatile organic compound (TVOC) metric is representative of all airborne indoor air VOC concentrations and should not be used as a direct indicator of health. The simplified metric is used as an indicator for the purposes of ventilation control strategies. As an alternative to the TVOC limit, individual VOC limits may be used where justified in accordance with the guidance in paragraph B.3.

B.3 As an alternative to using TVOC, the individual VOCs may be used, where their use is supported by robust independent evidence. Public Health England’s Indoor Air Quality Guidelines for selected Volatile Organic Compounds (VOCs) in the UK should be used. Testing against these metrics is likely to be more complex than testing against TVOC.

Where the Health and Safety Executive gives guidance for specific situations, it should be followed in preference to the guidance given here.

Source page 41

a.25 mg/h for TVOC

b.3 mg/h for ozone.

Appendix B

Assumptions used in applying performance criteria for offices in Section 1

General

B.4 For the purposes of this approved document, for all offices (both new and existing, where Part F applies), the moisture criteria are likely to be met if, during the colder months of the year, the moving average surface water activity of the internal surfaces of external walls is always less than the value in Table B.2, evaluated over each moving average period.

Table B.2 Surface water activity

Extract ventilation

B.5 Office equipment can emit pollutants, including ozone and organic compounds. For example, a study by Black and Wortham (1999) suggests the following emission rates for laser printers and dry paper copiers assuming 30 minutes use in an hour:

To meet the performance criteria for these pollutants requires an extract rate of 20 litres per second per machine during use.

B.6 For sanitary accommodation, the extract rates used for dwellings have been applied.

B.7 For food and beverage preparation areas, the extract rates used for dwellings have been applied.

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Appendix C

Appendix C

CO2 monitoring

Note: The guidance in this appendix is based on the Scientific Advisory Group for Emergencies (SAGE) EMG/SPI-B advisory group paper Application of CO2 monitoring as an approach to managing ventilation to mitigate SARS-CoV-2 transmission.

People exhale carbon dioxide (CO2) when they breathe out. If there is a build-up of CO2 in an area it can indicate that ventilation needs to be improved.

Checking levels of CO2 using a monitor can help to identify areas that are poorly ventilated.

Types of CO2 monitor to use

Many different types of CO2 monitor are available. The most appropriate portable devices for use in the workplace are non-dispersive infrared (NDIR) CO2 monitors.

How to use a CO2 monitor

The level of CO2 in the air will vary within an indoor space. It is best to place CO2 monitors at head height and away from windows, doors or air supply openings.

Monitors that are positioned too close to people may give a misleadingly high reading due to the CO2 in exhaled breath. Monitors should therefore be positioned at least 500mm away from room occupants.

Measured levels of CO2 within a space can vary throughout the day due to changes in number of occupants, activities being performed or ventilation rates in the space. The opening and closing of doors and windows can also have an effect.

The amount of CO2 in the air is measured in parts per million (ppm). If measurements in an occupied space seem very low (far below 400ppm) or very high (over 1500ppm), it is possible that the monitor is not in a suitable location. The monitor may need to be moved to another position within the space, to get a more accurate reading.

Instantaneous or ‘snapshot’ CO2 readings can be misleading, so several measurements should be taken throughout the day. The frequency of measurements should be sufficient to ensure that changes in the use of the room or space throughout the day are represented in the readings. Levels of CO2 may also vary throughout the year, as outdoor temperatures, and therefore behaviour relating to opening windows and doors, change.

How to get the most accurate readings

a. Check that monitors are within the recommended calibration period.

b. Follow the manufacturer’s instructions, including allowing the appropriate warm-up time for the device to stabilise c. Know how to use the monitor correctly, including the time needed to provide a reading.

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Appendix C d. Take measurements at key times throughout the working day.

e. Record CO2 readings, number of occupants, the type of ventilation in use at the time and the date. These will help you use the CO2 records to decide if an area is poorly ventilated.

How the measurements can help you take action

CO2 measurements should be used as a broad guide to ventilation within a space, rather than treated as ‘safe thresholds’.

Outdoor levels are around 400ppm. A consistent indoor CO2 value of less than 800ppm is likely to indicate that a space is well ventilated.

An average CO2 concentration of 1500ppm over the period when a space is occupied is an indicator of poor ventilation. Action should be taken to improve ventilation if CO2 readings are consistently higher than 1500ppm.

However, in locations where continuous talking or singing takes place, or there are high levels of physical activity (such as dancing, playing sport or exercising), providing ventilation sufficient to keep CO2 levels below 800ppm is recommended.

Where CO2 monitors will be less effective

CO2 monitors may not be suitable for use in areas that rely on air-cleaning units because these remove contaminants from the air but do not remove CO2 .

In large, open spaces and spaces with high ceilings, such as food production halls or warehouses, air may not be fully mixed and the measurements made by CO2 monitors may not be representative.

CO2 monitors are of limited use in less populated areas.

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Appendix D

Appendix D

Standards referred to

BS 4971 Conservation and care of archive and library collections [2017]

BS 5502 Buildings and structures for agriculture. Various relevant parts, including:

BS 5502-33 Guide to the control of odour pollution [1991 + AMD 10014]

BS 5502-52 Code of practice for design of alarm systems, emergency ventilation and smoke ventilation for livestock housing [1991 + AMD 10014]

BS EN 378-3 Refrigerating systems and heat pumps. Safety and environmental requirements – Installation site and personal protection [2016 + A1: 2020]

BS EN 13141-1 Ventilation for buildings. Performance testing of components/products for residential ventilation. Externally and internally mounted air transfer devices [2019]

BS EN 16893 Conservation of Cultural Heritage. Specifications for location, construction and modification of buildings or rooms intended for the storage or use of heritage collections [2018]

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Appendix E

Appendix E

Documents referred to

Legislation

Air Quality Standards (Wales) Regulations 2010, SI 2010/1433

Ancient Monuments and Archaeological Areas Act 1979, Chapter 46

Control of Substances Hazardous to Health Regulations 2002, SI 2002/2677

Dangerous Substances and Explosive Atmospheres Regulations 2002, SI 2002/2776

Education (School Premises) Regulations 1999, SI 1999/2

Factories Act 1961, c. 34 Health and Safety at Work etc. Act 1974, c. 37

Planning (Listed Buildings and Conservation Areas) Act 1990, c. 9

The Welfare of Farmed Animals (Wales) Regulations SI 2007 No. 3070

Other Documents

American Conference of Government Industrial Hygienists (ACGIH)

Industrial Ventilation: A Manual of Recommended Practice for Design. Thirtieth Edition [2019] Industrial Ventilation: A Manual of Recommended Practice for Operation and Maintenance. Second Edition [2020]

American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE)

ASHRAE Handbook – HVAC Applications [2019]

Association of Petroleum and Explosives Administrations (APEA)

Code of Practice for Ground Floor, Multi Storey and Underground Car Parks. Second Edition [1995]

Building and Engineering Services Association (BESA)

BESA DW 143 Guide to Good Practice – Ductwork Air Leakage Testing [2013]

BESA DW 144 Specification for Sheet Metal Ductwork [2016]

BESA DW 154 Specification of Plastics Ductwork [2000]

BESA DW 172 Specification for Kitchen Ventilation Systems [2018]

BESA TR 40 Guide to Good Practice for Local Exhaust Ventilation [2020]

Building Research Establishment (BRE)

Ventilation for Healthy Buildings: Reducing the Impact of Urban Air Pollution [2011]

Source page 46

Appendix E

Building Services Research and Information Association (BSRIA)

BG 43 Flexible Ductwork: A Guide to Specification, Procurement, Installation and Maintenance [2013]

Chartered Institution of Building Services Engineers (CIBSE)

AM10 Natural Ventilation in Non-domestic Buildings [2005]

AM13 Mixed Mode Ventilation [2000]

Commissioning Code M Commissioning Management [2003]

Guide A Environmental Design [2015]

Guide B2 Ventilation and Ductwork [2016]

TM31 Building Log Book Toolkit [2006]

TM40 Health and Wellbeing in Building Services [2020]

TM64 Operational Performance: Indoor Air Quality – Emissions Sources and Mitigation Measures [2020]

Department for Environment, Transport and the Regions (DETR)

Expert Panel on Air Quality Standards: Ozone [1994]

Department of Health Estates and Facilities Division (part of NHS Digital)

HTM 03-01 Specialised Ventilation for Healthcare Premises: Part A – Design and validation [2021] HTM 03-01 Specialised Ventilation for Healthcare Premises: Part B – Operational Management and Performance Verification [2007]

Health Building Notes (various). Available at: https://www.england.nhs.uk/estates/health- building-notes

Education and Skills Funding Agency (ESFA)

Building Bulletin 101: Guidelines on Ventilation, Thermal Comfort and Indoor Air Quality in Schools [2018]. Available at: https://www.gov.uk/government/publications/building- bulletin-101-ventilation-for-school-buildings

European Concerted Action (ECA) on Indoor Air and its Impact on Man

Guidelines for Ventilation Requirements in Buildings. Working Group Report No. 11. EUR 14449 EN [1992]

Health and Safety Executive (HSE)

HSE Catering Information Sheet No. 10, Ventilation in catering kitchens [2017]

EH40/2005 Workplace Exposure Limits. Containing the list of workplace exposure limits for use with the Control of Substances Hazardous to Health Regulations 2002 (as amended). Fourth Edition [2020]

Source page 47

Appendix E

HSG 258 Controlling Airborne Contaminants at Work. A Guide to Local Exhaust Ventilation (LEV). Third Edition [2017]

HSG 202 General Ventilation in the Workplace – Guidance for Employers [2000]

Home Office

Code of Practice for the Housing and Care of Animals Bred, Supplied or Used for Scientific Purposes [2014]. Available at: https://www.gov.uk/government/publications/code-of-practice-for-the-housing-and-care- of-animals-bred-supplied-or-used-for-scientific-purposes

McGraw-Hill Education

John Spengler, John McCarthy and Jonathan Samet, Indoor Air Quality Handbook [2001]

Ministry of Justice

PSI 17/2012 Certified Prisoner Accommodation [2012]

National Health Service

Activity DataBase. Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment _data/file/148547/ADB_2012_Getting_Started_Guide.doc

Public Health England (PHE)

Indoor Air Quality Guidelines for Selected Volatile Organic Compounds (VOCs) in the UK [2019]

Scientific Advisory Group for Emergencies (SAGE)

EMG/SPI-B advisory group. Application of CO2 monitoring as an approach to managing ventilation to mitigate SARS-CoV-2 transmission [2021]

Sport England

Sports Halls Design and Layouts: Updated and combined guidance [2012]

Design Guidance Note: Fitness and Exercise Spaces. Issue 002 [2008]

Welsh Government

Approved Document F, Volume 1: Dwellings (2022 Edition)

World Health Organization (WHO)

WHO Guidelines for Indoor Air Quality, Selected Pollutants [2010]

Other publications

Black MS and Wortham AW. Emissions from Office Equipment. Proceedings of the 8th International Conference on Indoor Air Quality and Climate, Indoor Air 99 [1999]

Source page 48

Appendix E

Approved Documents

This approved document is one of a suite of approved documents that have been published to give guidance on how to meet the Building Regulations. You can find the date of the edition approved by Welsh Ministers at

Building regulations: approved documents | GOV.WALES