Ventilation: Approved Document F, Volume 1 — Dwellings

F1(1) O N L I N E V E R S I O N 3.5 When a building undergoes a material change of use, Part F of Schedule 1 to the Building Regulations applies to the building or part of the building that has changed use. Guidance in Section 1 should be followed. NOTE: Ventilation equipment is considered to be a ‘controlled service or fitting’ and providing or extending this 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. Details of such work are set out in the Manual to the Building Regulations. Installing energy efficiency measures 3.6 Many existing dwellings are ventilated through infiltration rather than purposeful ventilation. Energy efficiency measures carried out on existing dwellings might reduce infiltration and cause the dwelling to become under-ventilated. Building work should not reduce the ventilation provision of the dwelling unless it can be demonstrated that the ventilation provision after the work is carried out meets the minimum standards of requirement F1(1). 3.7 When carrying out energy efficiency measures to an existing dwelling, an assessment should determine what, if any, additional ventilation provision is needed, based on the estimated impact of the work. The assessment should be carried out by one of the following means. a. Applying the simplified method in paragraphs 3.8 to 3.13. b. Seeking expert advice, which may include carrying out an air permeability test that follows the procedures given in Approved Document L, Volume 1: Dwellings. NOTE: Following BSI PAS 2035 is considered to be an adequate means of demonstrating compliance with paragraph 3.6. Simplified method NOTE: The simplified method set out in paragraphs 3.8 to 3.13 is designed to apply to an existing dwelling that is assumed to have adequate means of ventilation through a combination of purpose- provided ventilation and infiltration. If the property differs significantly from this assumption, the requirements of paragraph 3.6 must still be met. This should be demonstrated through seeking expert advice or using another suitable method. 3.8 When carrying out energy efficiency measures on an existing dwelling, Table 3.1 should be used to calculate the number of major and minor energy efficiency measures involved. This calculation should include all of the following. a. Energy efficiency measures fitted since the original dwelling was constructed, to consider accumulation of measures. b. Energy efficiency measures planned. NOTE: Where specific energy efficiency measures are not included in Table 3.1, the most similar category should be chosen instead. 3.9 Diagram 3.1 should then be used to determine the category that the works result in. 22 Approved Document F Volume 1, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N