Building standards - ministerial view: escape (ref. V2019/3)

Functional standard: 2.9. Escape

Standard 2.9 (Escape) states: “Every building must be designed and constructed in such a way that in the event of an outbreak of fire within the building, the occupants, once alerted to the outbreak of fire, are provided with the opportunity to escape from the building, before being affected by fire and smoke.”

Verifier

City of Edinburgh Council

Technical context

The subject of the view is a conversion from a hotel to 9 residential dwellings comprising 7 flats and 2 maisonettes. The height of the topmost storey is 13.6m above the lower ground level and approximately 11.7m above ground floor level. Flats 14, 14A and 15A do not communicate with the common escape stairs and have independent escape routes. Flats 15/1, 15/2 and 15/3 are accessed from one common escape stair and maisonettes 16/1, 16/3 and flat 16/2 are accessed from the other. Maisonette 16/3 has an alternative escape route from the upper level direct to the common escape stair. A BS 5839 - 6 Category LD1 fire detection and alarm system is provided in all flats and maisonettes.

The view of Scottish Ministers

On behalf of Scottish Ministers, the Building Standards Division has considered all the information submitted in this case and their view is set out below.

The building is designed on the principle of ‘stay put’ other than the dwelling of fire origin. The key area of doubt in relation to compliance with standard 2.9 is the non-provision of ventilated protected lobbies due to the constraints in the existing building. Therefore, the focus of this Ministerial View is not the dwelling of fire origin but the potential for fire and smoke spread into the common stairs, denying all other occupants the opportunity to escape should they wish to evacuate. The guidance in clause 2.9.10 confirms that ventilated protected lobbies should be provided between the flats/maisonettes and the escape stair where the topmost storey is more than 7.5m above the adjoining ground. The intent is to limit the number of dwellings to a maximum of 12 where reliance is placed upon fire safety measures within a dwelling that also protects the common escape stair. Mitigation measures:

• both common escape stairs provide access to only 3 dwellings therefore minimising the risk of fire and smoke spread
• FD60s entrance doors are provided to all 6 dwellings that enter the common escape stairs. It is considered that the provision of FD60S fire door sets to flat and maisonette entrances in lieu of FD30S doors will greatly enhance the fire protection to the escape stairs provided they are installed correctly
• a small protected lobby (unventilated) is provided between maisonette 16/1 and the common escape stair on the ground floor. This is considered reasonable given the space available
• protected enclosures and automatic fire suppression system to BS 9251-2014 is provided to Flats 15/2, 15/3 and maisonette 16/3
• protected enclosures are provided to flats 15/1, 16/2 and maisonette 16/1
• automatic opening ventilators are provided to the common escape stairs actuated by smoke detection to BS 5839-1 Category L5. Note: Since evacuation sounders will be provided to the common areas it is recommended that specialist advice is sought to minimise the risk of unwanted fire alarm signals.

Having carefully considered all the information submitted in this case, it is the view of Scottish Ministers that the proposals do meet the requirements of Standard 2.9.

Escape functional standard (ref. V2019/3): ministerial view

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