Building Standards technical handbook 2017: non-domestic buildings

The Building Standards technical handbooks provide guidance on achieving the standards set in the Building (Scotland) Regulations 2004 and are available in two volumes, Domestic buildings and Non-domestic buildings. This publication is available in html and also in PDF format (in 'supporting documents' ).

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2.3 Structural protection

Mandatory Standard

Standard 2.3

Every building must be designed and constructed in such a way that in the event of an outbreak of fire within the building, the load-bearing capacity of the building will continue to function until all occupants have escaped, or been assisted to escape, from the building and any fire containment measures have been initiated.

2.3.0 Introduction

In order to prevent the premature collapse of the load-bearing structural elements of a building, appropriate levels of fire resistance duration (see annex 2.D) should be provided to all element of structure. The purpose of structural fire protection is:

  • to minimise the risk to the occupants, some of whom may not evacuate the building immediately, and

  • to reduce the risk to fire-fighters who may be engaged in fire-fighting or rescue operations.

An element of structure may perform more than one function and it is important that the appropriate guidance related to the different standards is followed.

The added benefit to structural fire protection means that the risk to people in the vicinity of the building or in adjoining buildings from collapse of the structure is reduced.

An element of structure is part of a building which is part of a structural frame (beams and columns), load-bearing (other than part which is only self-load bearing), a floor, or supports a floor. An example of part of the structure that is only self load-bearing could be a lintel in a non load-bearing wall. A roof structure should not be considered as an element of structure unless the roof provides support to an element of structure or which performs the function of a floor.

Conversions - in the case of conversions, as specified in regulation 4, the building as converted shall meet the requirement of this standard (regulation 12, schedule 6).

2.3.1 Elements of structure

It is essential that during a fire the elements of structure should continue to function. They should remain capable of supporting and retaining the fire protection to floors, escape routes and fire access routes, until all occupants have escaped, or assisted to escape or been rescued by the fire and rescue service. In practice, the fire and rescue service could remain in the building long after it has been evacuated. For this reason, an additional level of protection is built into the guidance for non domestic buildings that varies depending on the height of the topmost storey of the building.

The element of structure in a building should have at least the fire resistance duration as set out in the tables to clause 2.1.1.

However the following element of structure need not be provided with any fire resistance for structural protection:

2.3.2 Combustibility

An element of structure may be constructed from combustible material i.e. material which is low, medium, high or very high risk, (see annex 2.E) provided the element of structure has the appropriate fire resistance duration.

Where an element of structure provides support to another element of structure (or a protected route of escape, see clause 2.0.6) which should be constructed from non-combustible products, the supporting element of structure should also be non-combustible (see annex 2.E).

2.3.3 Supporting structure

Where an element of structure provides support to another element of structure (or provides support to a protected route of escape) which attracts a higher period of fire resistance, the supporting element of structure should have at least the same period of fire resistance.

2.3.4 Openings and service penetrations

In general, openings and service penetrations in elements of structure need not be protected from fire unless there is the possibility of structural failure. However where a large opening or a large number of small openings are formed, careful detailing particularly at the edge of the opening or service penetration should be carried out in order to maintain the load-bearing capacity of the element of structure. If in doubt, edge protection should be provided.

2.3.5 Junctions

The detailing of junctions between relevant parts of a building is described in clauses 2.1.15, 2.1.16, 2.2.7, 2.4.9 and 2.9.28. Fire-stopping of other junctions is generally not necessary. The important criteria to consider is the ability of the element of structure to maintain its load-bearing capacity in a fire in accordance with the fire resistance duration set out in the tables to clause 2.1.1 (see also annex 2.D).

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