Industry Standard Update 122

This Industry Standard Update (ISU) provides an overview of the key areas of change arising from the revised British Standard 5440-2:2009 Flueing and ventilation for gas appliances of rated input not exceeding 70kW net (1st, 2nd and 3rd family gases) – Part 2: Specification for the installation and maintenance of ventilation provision for gas appliances.

Introduction
During December 2023, BSI published a revised version of British Standard 5440-2:2023 Chimneys, flue pipes and ventilation for gas appliances of rated input not exceeding 70kW net (1st, 2nd and 3rd family gases) – Part 2: Installation and maintenance of ventilation provision for gas appliances – Specification⁽¹⁾.

The new standard came into effect on 31 December 2023 and supersedes the previous edition⁽²⁾ (December 2009), which is now withdrawn.

The following is a brief overview of the areas of significant change to the revised BS 5440-2.

General
Legislation, normative, references and current standards have been updated throughout where necessary. The scope of the document now excludes cooking appliances in catering or educational establishments, as well appliances fuelled by 100 per cent hydrogen.

Figures and tables
Figures and tables in the new standard have been updated and, in some cases, renumbered. For instance, Table 6 – Minimum permanent opening equivalent free area for flueless appliances – in the previous edition is now Table 4. The information contained in these tables remains unchanged.

Ventilation provision
Air vents passing through a fire-rated compartment are permitted only where the ventilation opening is direct to outside, and no vent shall penetrate a protected area, as per Section 5.4.

Section 7.2.2 states that any new air vent shall not communicate with a roof space. Existing air vents communicating with a roof space may be deemed acceptable, as long as the total free area is satisfactory, and any opening is checked to ensure it is free of any obstruction.

In the previous version of the standard, a ventilation outlet connected to a cooker extract or gas tumble drier would not be considered an opening into the building, provided that the terminal was fitted with non-return flaps. This provision has now been removed, and therefore the ventilation outlet would now be considered an opening.

The method of measuring the equivalent free area of an air vent has been moved to Annex A.

 Bibliography
(1) BS 5440-2:2023 Chimneys, flue pipes and ventilation for gas appliances of rated input not exceeding 70kW net (1st, 2nd and 3rd family gases) – Part 2: Installation and maintenance of ventilation provision for gas appliances – Specification
(2) BS 5440-2:2009 Flueing and ventilation for gas appliances of rated input not exceeding 70kW net (1st, 2nd and 3rd family gases) – Part 2: Specification for the installation and maintenance of ventilation provision for gas appliances