Building standards - ministerial view: compartmentation and escape (ref. V2024/1)

Functional standard 2.1 - Compartmentation

Every building must be designed and constructed in such a way that in the event of an outbreak of fire within the building, fire and smoke are inhibited from spreading beyond the compartment of origin until any occupants have had the time to leave that compartment and any fire containment measures have been initiated

Clause 2.1.7 - Basements

Where a building has a basement storey, the floor of the ground storey should be a compartment floor. However where the building comprises one basement storey and not more than 2 other storeys, and no storey has an area more than 280 m2, a compartment floor need not be provided.

Where a building has a basement storey at a depth of more than 10 m, every basement storey should form a separate compartment.

Functional standard 2.9 - Escape

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 the fire, are provided with the opportunity to escape from the building, before being affected by fire or smoke.

Clause 2.9.14 - Openings in floors

In the event of a fire, there is always a risk that an opening in a floor could result in a proportion of fire or smoke and toxic fumes arising from a fire flowing up through the opening leading to a build-up of smoke on the upper storeys. This can pose a threat to life safety, particularly when the occupants are unfamiliar with the building. Smoke and flames rising through such an opening in a floor may impede evacuees from leaving the building. It is important when such a design is considered that it does not impair the ability of the occupants to escape. Occupants should be able to move directly away from the opening or continue their evacuation at a safe distance away from the edge of the opening.

Escape routes should not be compromised by openings between floors, such as at an escalator and fire safety measures are necessary to compensate for this increased level of hazard.

In a building where there is an opening in any floor, not being a compartment floor or separating floor, an escape route should not be within 4.5 m of the openings unless:

• the direction of travel is away from the opening
• there is an alternative escape route, which does not pass within 4.5 m of the opening
• a wall or screen with a short fire resistance duration for integrity is provided between the opening and the route of escape

Clause 2.9.34 - Escape stairs in basements

The limited natural ventilation available in a basement can lead to rapid heat and smoke build up. The heat and smoke generated can be forced up through any opening such as a door into a stairway. This means that fire-fighting in under-ventilated compartments must be approached with caution before opening the door to the basement storey. There is also a risk that disoriented occupants could continue their escape to the basement storey instead of escaping through the ground storey. In order to minimise these risks, a wall or screen (including a self-closing fire door) with a medium fire resistance duration should be provided between the ground storey of the protected zone and the basement storey.

Functional standard 2.14 - Fire and rescue service facilities

Every building must be designed and constructed in such a way that facilities are provided to assist fire-fighting or rescue operations.

Clause 2.14.3 - Fire-fighting stairs

At least 1 fire-fighting stair should be provided to assist fire-fighters to access the fire and if necessary escape from the fire in relative safety. The fire-fighting stair should be at least 1.0 m wide measured between handrails to provide fire and rescue service personnel sufficient room to carry fire-fighting and rescue equipment.

A fire-fighting stair should be contained within a protected zone. The enclosing structure of the protected zone should have at least a medium fire resistance duration and should have a long fire resistance duration where it serves:

• a basement storey at a depth of more than 10 m below the fire and rescue service access level
• a shop, factory, storage building or an open sided car park where the area of any storey is more than 900 m2
• any building where the topmost storey is more than 18 m above the fire and rescue service access level

However where the elements of structure in a building have a medium fire resistance duration, the protected zone need only have a medium fire resistance duration. A self-closing fire door in the enclosing structure of a protected zone should have at least a medium fire resistance duration. In some cases an escape stair can be used as a firefighting stair. For example, in single stair buildings.

Verifier

City of Edinburgh Council

Technical context

The building warrant application is for alterations to an existing barber shop and the referral relates to Mandatory Standards 2.1, 2.9 and 2.14. Specifically, to guidance clauses 2.1.7, 2.9.14, 2.9.34 and 2.14.3 in respect of compartment ground floor, escape past opening in floor, escape from basement and fire-fighting safety and operational provisions.  The guidance states that a compartment floor should be provided, the floor opening should not impede escape, any risk with escape related to basement stairs and fire safety (in basement fires) and operational duties are considered. 

The premises comprise the ground and basement floors of a barber’s shop within a tenement block of traditional construction. Currently the ground floor forms the main shop with staff room and storage located at basement level. Both ground and basement floors each have a floor area of 53m2. The shop has a current capacity for approximately 6 customers at any one time and it is proposed to carry out alterations in order to provide two additional chairs within the basement area.

The local authority is of the view that; “An alternative method of compliance should demonstrate how the proposals are equal to a design which demonstrates compliance with the Technical Handbooks. Engineer’s document does not demonstrate how the proposals are equal to the two fully complaint escape routes and associated protected zones, which are required by standard 2.9 to convert a basement to an area to be used frequented by members of the public.”

The applicant has stated: “The proposed works are to a small building where we have had a fire engineering report carried out which was submitted to the Scottish Fire and Rescue Service who had no objections to the report and ultimately the proposal plans. We feel as this is to an existing compact building we cannot reasonably/ practically meet all the standards under regulation 2 however informed by the fire engineering report along with the said report and the proposal plans not being objected to by SFRS we feel no fire safety concerns will exist as a result of the proposals and they should be approved.”

The view of Scottish Ministers

The key area of doubt is in relation to compliance with standards 2.1 and 2.9 and whether occupants are provided with the opportunity to escape from the building, before being affected by fire or smoke. Therefore, the focus of this Ministerial View is on whether the proposal adversely affects occupant’s opportunity to escape should they wish to evacuate.

Scottish Fire and Rescue Service (SFRS) have raised no concerns related to fire-fighting safety or operational provisions in relation to Mandatory Standard 2.14, therefore a view is not given on compliance with this standard.

On behalf of Scottish Ministers, the Building Standards Division has considered all the information submitted in this case and their view in relation to standards 2.1 and 2.9 is set out below:

• the proposed category L1 fire detection and alarm system in accordance with BS 5839: Part 1: 2017 will provide enhanced protection and the earliest possible warning to the occupants in the event of an outbreak of fire within the property
• the premises is single occupancy and does not communicate or share escape routes with other parts of the building
• the premises is small providing good visibility and short travel distances, with occupants being awake and alert
• occupancy numbers are low
• there are two alternative routes from the basement staff room to the ground floor level exit

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 Standards 2.1 and 2.9.