Section 1 Introduction

  1. Section 1

    Section 1


    This guide provides detailed guidance to help persons comply with requirements in building regulations for installation, inspection, testing, commissioning and provision of information when installing fixed ventilation systems in new and existing dwellings. The aim is to ensure the provision of adequate ventilation while minimising energy use and environmental problems such as noise and thermal discomfort.

    It is important to note that the guide covers a range of frequently occurring situations but it is not exhaustive and alternative means of achieving compliance with the ventilation requirements in the Building Regulations may be possible.

    1.1 Status of guide

    Building regulations contain functional requirements, such as requirements that buildings must be structurally stable, must be constructed and fitted out to ensure reasonable levels of fire protection, and must be reasonably energy efficient. These functional requirements are often drafted in broad terms, and so it may not always be immediately clear to a person carrying out building work how to comply with the relevant requirements. Consequently documents are often issued by the government department responsible for building regulations which provide practical guidance on ways of complying with specific aspects of building regulations in some of the more common building situations. In England and Wales, these documents are called Approved Documents.

    Approved Documents are intended to provide practical guidance but they are not intended to be comprehensive. Consequently there may be references in Approved Documents to other documents which will provide more detailed information and assistance on parts of the guidance. This guide is one of those documents. It provides additional detail in relation to the guidance about compliance with the requirements for installation, inspection, testing, commissioning and provision of information in Approved Documents F, L1A and L1B which apply when installing fixed ventilation systems in new and existing dwellings.

    It is important to note that following the guidance in an Approved Document or any guidance referred to by that document does not guarantee compliance with building regulations. If you follow relevant guidance in an Approved Document and in any document referred to which provides additional advice or information to help you follow that guidance (such as this guide), there is a legal presumption that you have complied with building regulations. However, in every case it is for the building control body, whether a private sector approved inspector or the local authority, to decide whether work complies with building regulations. So, you should always check with the building control body before you start work what they consider it is necessary for you to do to comply with building regulations.

    1.2 Requirements on air flow testing, commissioning and information provision

    In England and Wales, requirements for ventilation and energy efficiency are contained in Part F, Ventilation, and Part L, Conservation of fuel and power, of Schedule 1 to the Building Regulations. This guide provides appropriate guidance for the four types of ventilation system discussed in detail in Approved Document F. It is referenced by Approved Document F (ADF), Approved Document L1A (ADL1A), and Approved Document L1B (ADL1B) as providing guidance on meeting those requirements for ventilation systems.

    Specific statutory requirements in the Building Regulations for England and Wales which this guide addresses are:

    • The requirement to commission mechanical ventilation systems (where they can be tested and adjusted) in accordance with an approved procedure, and to provide a notice confirming that commissioning has been carried out to the
    building control body not later than five days after the work has been completed where a person has had to submit a building notice or full plans or, in other cases, not later than 30 days after the completion of work.

    • For mechanical ventilation systems in new dwellings only, the requirement to measure air flow rates in accordance with an approved procedure, and to
    provide a notice recording the results and the data on which they are based in an approved manner to the building control body not later than five days after the final test is carried out.

    • The requirement to provide sufficient information about the ventilation system and its maintenance requirements to owners or occupiers so that the ventilation system can be operated to provide adequate air flow. This guide contains recommendations on the range of information that could be given to dwelling owners on completion to satisfy this requirement.

    The approved procedures for commissioning mechanical ventilation systems in dwellings and air flow testing of such systems in new dwellings are set out in Tables 2, 6 and 8 according to which ventilation system has been adopted.

    The manner in which the results of air flow testing and the data on which they are based are to be recorded and given to the building control body is given in Part 3 of Section 5 of this document. A downloadable copy of this form is available at > Part F (Ventilation) > Associated documents, for the use of those carrying out the air flow testing.

    In addition to specifying how the above statutory requirements in the Building Regulations should be met, this guide also contains recommendations for an inspection checklist and for recording the equivalent area of background ventilators.

    The inspection checklist and air flow measurement test and commissioning sheet in Section 5 should be completed by installers and test and commissioning engineers, and should form part of the information pack given to dwelling owners to satisfy the information requirement.

    1.3 How to use this guide

    The guide refers to Systems 1 to 4 as specified in Approved Document F.

    Section 2 provides guidance on installation, inspection and testing of natural ventilation and intermittent extract systems; and Section 3 provides guidance on installation, inspection, testing and commissioning of continuous mechanical ventilation systems.

    The testing and commissioning procedures set out in this guide are the approved methods by which a system must be checked and assessed before handover to the end user. For mechanical ventilation (both intermittent and continuous), air flow measurement tests are included as part of the commissioning process. For natural ventilation openings, the recommendation is to carry out a visual inspection and record the equivalent area.

    Supplementary information appears in some places in the guide in italic font with a grey background. It is intended to assist understanding of the guidance or to direct readers to sources of additional information, but is not part of the guidance. In some cases there are links to best practice guidance that goes beyond the recommended minimum requirements.

    BS EN 14134: 2004 Ventilation for buildings – Performance testing and installation checks of residential ventilation systems may be referred to for further guidance on installation, inspection, testing and commissioning procedures.

    Section 4 details the information that it is recommended should be left with the building owner on completion of the installation of the system. This information is to aid the user to correctly operate and maintain the system.

    Section 5 contains in Part 1 a form for recording details of the installation; in Part 2a an installation checklist; in Part 2b a form for recording the results of a visual inspection of the installation; and in Part 3 the air flow measurement test and commissioning sheet to be given to the building control body.

    1.4 Key terms

    The following key terms where used in this guide are shown in bold italic font. For other terms, reference should be made to Approved Document F.

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

    BCB or building control body is a local authority or an approved inspector.

    Continuous mechanical extract ventilation (MEV) is a ventilation system comprising a central ducted continuously running extract fan (or a set of local continuously running extract fans in the wet rooms for de-centralised systems), air being supplied via background ventilators into the habitable rooms.

    Continuous mechanical balanced ventilation with heat recovery (MVHR) is a ventilation system that comprises central ducted supply and extract fans, air being supplied into the habitable rooms via a heat recovery unit.

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

    Free area is the geometric open area of a ventilator or terminal.

    Intermittent extract fan is a mechanical ventilator that does not run all the time, usually only running 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.

    Passive stack ventilation (PSV) is a ventilation system using ducts from terminals in the ceilings of rooms to terminals on the roof that extract air to outside by a combination of the natural stack effect and the pressure effects of wind passing over the roof of the building.

    Single room heat recovery ventilator (SRHRV) is a ventilation system comprising local continuously running balanced supply and extract fans in a single room.