Section 1 Introduction

  1. What is an Approved Document?
    1. Consideration of technical risk
      1. How to use this Approved Document
      2. Where you can get further help
        1. Responsibility for compliance

          What is an Approved Document?

          1.1 This document has been approved by the Secretary of State to provide practical guidance on ways of complying with the requirements in Part F of Schedule 1 to, and regulations 39, 42 and 44 (in so far as it relates to fixed systems for mechanical ventilation) of, the Building Regulations 2010 (SI 2010/2214) for England and Wales, and regulations 20(1) and 20(6) (in so far as it relates to fixed systems for mechanical ventilation) of the Building (Approved Inspectors etc) Regulations 2010 (SI 2010/2215) for England and Wales. The Building Regulations 2010 and the Building (Approved Inspectors etc) Regulations 2010 are referred to throughout the remainder of this document as ‘the Building Regulations’ and ‘the Approved Inspectors Regulations’ respectively.

          1.2 The intention of issuing Approved Documents is to provide guidance about compliance with specific aspects of building regulations in some of the more common building situations. They set out what, in ordinary circumstances, may be accepted as reasonable provision for compliance with the relevant requirement(s) of building regulations to which they refer.

          1.3 If guidance in an Approved Document is followed there will be a presumption of compliance with the requirement(s) covered by the guidance. However, this presumption can be overturned, so simply following guidance does not guarantee compliance; for example, if the particular case is unusual in some way, then ‘normal’ guidance may not be applicable. It is also important to note that there may well be other ways of achieving compliance with the requirements. There is therefore no obligation to adopt any particular solution contained in this Approved Document if you would prefer to meet the relevant requirement in some other way. Persons intending to carry out building work should always check with their Building Control Body, either the local authority or an approved inspector, that their proposals comply with building regulations.

          1.4 It is important to note that this Approved Document, as well as containing guidance, also contains extracts from the Regulations. Such regulatory text must be complied with as stated. The guidance contained in this Approved Document relates only to the particular requirements of building regulations that the document addresses (set out in Section 2). However, building work may be subject to more than one requirement of building regulations. In such cases the work will also have to comply with any other applicable requirements of building regulations.

          1.5 There are Approved Documents that give guidance on each of the Parts of Schedule 1 and on regulation 7. A full list of these is provided at the back of this document.

          Consideration of technical risk

          1.6 The construction of new buildings, and building work to existing buildings, must satisfy all the technical requirements set out in the Building Regulations. When considering the incorporation of ventilation measures in dwellings, attention should also be paid in particular to the need to comply with Part B (fire safety), Part C (site preparation and resistance to contaminants and moisture), Part E (resistance to the passage of sound), Part L (conservation of fuel and power), Part J (combustion appliances and fuel storage systems) and Part P (electrical safety), as well as Part F. The adoption of any particular ventilation measure should not involve unacceptable technical risk of, for instance, creating a cold bridge. Designers and builders should refer to the relevant Approved Documents and to other generally available good practice guidance to help minimise these risks.

          How to use this Approved Document

          1.7 This Approved Document is subdivided into eight sections as detailed below.

          This introductory section sets out the general context in which the guidance in the Approved Document must be considered.

          Section 2 sets out the relevant legal requirements as published in the Building Regulations.

          Section 3 contains key terms and general guidance on the types of building work covered by Approved Documents, how to deal with ‘special’ areas of buildings that contain dwellings, procedures for notifying work, materials and workmanship, certification and standards, and health and safety issues.

          Section 4 details the principles of ventilation and its control.

          Section 5 details the guidance for ventilation of dwellings.

          Section 6 details the guidance for ventilation of buildings other than dwellings.

          Section 7 details the guidance for ventilation of existing buildings.

          Section 8 lists standards and other publications referred to in the text.

          Note: A reference to a publication is likely to be made for one of two main reasons: either the publication contains additional or more comprehensive technical detail, which it would be impractical to include in full in the Approved Document but which is needed to fully explain ways of meeting the requirements; or it is a source of more general information. The reference will be to a specified edition of the document. The Approved Document may be amended from time to time to include new references or to refer to revised editions where this aids compliance.

          1.8 In this document the following conventions have been adopted to assist understanding and interpretation:

          a. Regulations extracted from the Building Regulations or the Approved Inspectors Regulations as amended are printed under ‘The Regulations’ heading. There is a legal obligation to comply with the requirements in these regulations. In contrast, the technical guidance in the Approved Document shows one or more ways of complying with ventilation requirements in typical situations.

          b. Key terms are defined in paragraph 3.1 and are printed in bold italic text.

          c. Additional commentary in italic text appears after some numbered paragraphs. This commentary is intended to assist understanding of the preceding paragraph or sub-paragraph, or to direct readers to sources of additional information, but is not part of the technical guidance itself.


          Where you can get further help

          1.9 If you do not understand the technical guidance or other information set out in this Approved Document and the additional detailed technical references to which it directs you, there are a number of routes through which you can seek further assistance:

          • the CLG website:;
          • the Planning Portal website:;
          • if you are the person undertaking the building work you can seek assistance either from your local authority building control service or from your approved inspector (depending on which building control service you are using, or intend to use, to certify compliance of your work with the requirements of the Building Regulations);
          • businesses registered with a competent person self-certification scheme may be able to get technical advice from their scheme operator;
          • if your query is of a highly technical nature you may wish to seek the advice of a specialist, or industry technical body, in the area of concern.


          Responsibility for compliance

          1.10 It is important to remember that if you are the person (e.g. designer, builder, installer) carrying out building work to which any requirement of building regulations applies you have a responsibility to ensure that the work complies with any such requirement. The building owner may also have a responsibility for ensuring compliance with building regulation requirements and could be served with an enforcement notice in cases of non-compliance.