Part C1 Fire resistance

Basis of Objective

This Objective is based on the belief that a building should:

• provide people with an environment which, during a fire, will minimise the risk of them suffering illness or injury;
• provide people with an evacuation route which will minimise the risk of them suffering illness or injury while escaping a fire;
• facilitate the role of emergency services personnel, such as the fire brigade, if it becomes necessary for them to undertake such operations as fire-fighting and search and rescue;
• assist in minimising the risk of fire spreading from one building to another; and
• not have a structural failure during a fire that results in damage to another building, allotment or road.

Spread of fire

There is a continuing debate regarding the means by which the BCA should minimise the risk of fire spreading from one building to another. Should the greater degree of fire protection be in the building on fire, or should it be in the building at potential risk of the fire spreading?

Generally, the BCA provisions aim to minimise the spread of fire from the building on fire, but there are some provisions that limit the spread of fire from an adjacent building.

Consequently, C1O1(d) states that the spread of fire is to be avoided “between buildings” — that is, in either direction.

Protection of other property

The BCA is principally designed to maximise (within reasonable bounds) the safety, health and amenity of people in and around buildings. Protection of property, either the subject building or what is termed “other property”, is not generally a primary aim of the BCA—although it may sometimes be a consequence of the provisions of the BCA.

However, there are some exceptions to this rule, and the inclusion of “other property” in C1O1(e) is one of these. In this context, a building is expected to maintain the level of structural sufficiency necessary to prevent it causing damage to any other property as a result of fire. The reason C1O1(e) concerns itself with the protection of other property is primarily because fire from a building should not pose a serious risk to the health, safety and amenity of the public or occupants of another building. See Schedule 1 for definition of “other property”.

Structural stability

A building must remain structurally stable during a fire to:

• allow the occupants to safely evacuate;
• allow the fire brigadeto undertake searchand rescue, if necessary, and fire-fighting operations; and
• avoid damage to anotherbuilding, allotment or road.

Instability may not contravene the BCA

So long as a building does not endanger life or other property, and the BCA’s structural stability criteria have been satisfied,

then the building may become structurally unstable after a fire and still comply with the objectives of Section C. It could even collapse, providednone of the building falls in a way that endangers the public or causes damage to anotherbuilding. For example, if a buildingfalls onto a road, it could endangerthe safety of the public and would therefore not achieve the Functional Statement.

Spread of fire

A building must have in-builtsafeguards to preventthe spread of fire:

• to allow sufficient time for the occupants to safely evacuate;
• to allow the fire brigade to undertake search and rescue,if necessary, and fire-fighting operations;
• in Class 2 or Class 3 buildings or Class 4 parts used as sole-occupancy units that provide sleeping accommodation to allow sufficient time for the occupants to safely evacuate;
• to an adjoining fire compartment; and
• from one building to another building.

Spread of fire may not contravene BCA

So long as a buildingfire does not endanger life or other property, and the BCA’s spread of fire criteriahave been satisfied, then the building may burn and still comply with the aims of Section C.

C1P1 sets structural stabilityrequirements for buildingelements during a fire.

C1P1 does not make any reference to a fire-resistance level (FRL). FRLs are only included as part of the Deemed-to- Satisfy Provisions.

It may be found by a building proponentusing a Performance Solution that FRLs to building elementsare not necessary as other means, such as the use of active systems, satisfy the Performance Requirements.

“To the degree necessary”

C1P1 uses the term “to the degreenecessary”. This word usage is designed to provide flexibility in the way this provision is implemented. The intended meaning of the term “to the degree necessary” in C1P1 and other Performance Requirements, is explained in explanatory information to A1G4(3)(c).

It means that the BCA recognises that different building elements require differing degrees of structural stability during a fire. The expression is intended to allow the appropriate authority to determine the degree of compliance necessary in each particular case.

Any decision made in this context can extend to not requiring an item to be installed or a particular level of performance to be achieved, if that is the appropriate action to be taken.

“Appropriate to”

The structural stability must be “appropriate to” the criteria listedin C1P1, which relateto such factors as:

• the likelihood or risk of a fire occurring in the building;
• the load, intensity and potential dangerof any fire in the building;
• the difficulty of evacuation and/orrescue;
• a structural element’s exposure to fire in another building,or risk of spreading a fire to another building;
• the fire safety systems in the building,which can affect the rate of fire spread (e.g. if a sprinkler system is installedin a building, it could either extinguish the fire or reduce its growth rate);
• the size of a fire and the difficulties in effecting an evacuation;
• the fire-fighting operations of the fire brigade;and
• the consequences of the failureof the element (another way of expressing this is to consider that if the element fails, could it result in the failure of another element).
• the time taken from the startof the emergency to the occupants reachinga safe place.

While assessment of a building proposal must have regard to the differing needs of each building element, the proposal must make sure that the elements have an appropriate structural stability during a fire so that:

• the fire does not endanger the occupants by entering escape routes; and
• the fire does not endanger firefighters while they are undertaking search and rescue operations.

The following are two examples of what may or may not be “appropriate”. They should not be regarded as absolute, or applicable in all circumstances.

Examples

The building concerned is a commercial poultry building which is single storey and occupied by only a few workers, who are likely to know the buildingwell. The buildingis situated a long distancefrom any other building and has direct routes to the exit doors.

In such a case,the building elementsmay not need to be fire protected under C1P1 becausethe occupants wouldbe able to evacuate quickly and if the building collapses, there is little likelihood of it damaging another building.

Note that for the example above, it is assumed that the buildingin question has not met the criteriato be considered a farm building or farm shed in the Deemed-to-Satisfy Provisions.

Examples

The building concerned is a centralcity high-rise officebuilding. It is located on the streetalignment and closeto other similar buildings. In such a case, the structural failure of any of the building elements could lead to danger to building occupants and the general public, failure of building elements intended to protect another building, or the collapse of another element which relies on the first element for structural support.

In this example,building elements may require a high level of protection under C1P1.

In both cases, the ability of the fire brigade to control a fire also needs to be considered when considering the implications of C1P1.

If the proposal being considered involves a solutionthat is taking advantage of the Deemed-to-Satisfy Provisions, the Deemed-to-Satisfy Provisions contain detailed requirements for the fire protection of building elements.

If a Performance Solution is being used, it may be appropriate to assess it using the Section C Deemed-to-Satisfy Provisions (Parts C2, C3 and C4) for guidance purposes. It is stressed, however, that compliance with the Deemed-to- Satisfy Provisions is not compulsory if alternative means can be found to satisfy the appropriate authority that the Performance Requirements will be achieved. The building proponent should refer to A2G2 for guidance on acceptable assessment methods for determining compliance with the Performance Requirements.

C1P2 deals with the spread of fire both within and between buildings (including risk of spread of fire via the external walls of the building), and which does not only result from the structural failure of a building element.

C1P2 does not make any reference to non-combustibility or a fire-resistance level (FRL). Non-combustibility and FRLs are only included as part of the Deemed-to-Satisfy Provisions. However, proponents of a Performance Solution should note these requirements, as part of developing the Performance Solution, if considered to be applicable. See C1F2.

C1P2(1)(a) aims to avoid a situation where fire either endangers occupants evacuating by way of exits, or impedes the capacity of emergency services personnel to access the building and fight the fire or rescue occupants.

C1P2(1)(b) aims to minimise the risk of people in Class 2 and Class 3 buildings and Class 4 parts, for example, if they were sleeping and consequently having difficulty escaping a fire. For this reason,C1P2(1)(b) requires that sole-occupancy units and corridors used for escaping be provided, to the degree necessary, with protection to avoid the spread of fire.

C1P2(1)(c) aims to minimise the risk of fire spreading from one building to another that could endanger the occupants of both buildings and impede the actions of the fire brigade. See C1V1 and C1V2 for two means of verifying, under certain circumstances, whether or not the requirements of C1P2(1)(c) will be achieved. Other assessment methods for determining compliance with the Performance Requirements are in A2G2.

C1P2(1)(d) aims to minimise the risk of fire spreading through a building that could endanger the occupants and impede the actions of the fire brigade. C1P2(1)(d) requires that a building must have elements that will avoid the spread of fire in a building. This includes avoiding the risk of fire spread via the external walls of the building. C1P2(1)(d) covers the risk of fire spread across the building facade due to the increased risk of spread to other compartments of the building, to other adjacent buildings, and the difficulty of firefighting external fires occurring at higher levels.

C1P2(1) uses the term “to the degree necessary”. This word usage is designed to provide flexibility in the way this provision is implemented.

It means that the BCA recognises that different building elements require differing degrees of protection to avoid the spread of fire. The expression is intended to allow the appropriate authority to determine the degree of compliance necessaryin each particular case after considering each building scenario.

Any decision made in this context can extend to not requiring an item to be installed or a particular level of performance to be achieved, if that is the appropriate action to be taken.

Building elements must be appropriate to avoid spread of fire, taking into consideration the matters listed in C1P2(2) including:

• the likelihood or risk of a fire occurring in the building;
• the size, load or intensity of any fire in the building;
• the difficulty of evacuation and/orrescue;
• the building’s exposure to fire in another building, or risk of spreading a fire to another building;
• the fire safety systems in the building,which can affect the rate of fire spread (e.g. if a sprinkler system is installedin a building, it will either extinguish the fire or reduce its growth rate);
• the size of a fire and the difficulties in effecting an evacuation;
• the fire-fighting operations of the fire brigade and the resources available to it;
• the consequences of the failure of the element (another way of expressing this is to consider that if the element fails, could it result in the failure of another element); and
• the time taken from the start of the emergency to the occupants reaching a safe place.

If a Performance Solution is being used, it may be appropriate to assess it using the Section C Deemed-to-Satisfy Provisions (Parts C2, C3 and C4) for guidance purposes. It is stressed, however, that compliance with the Deemed-to- Satisfy Provisions is not compulsory if alternative means can be found to satisfy the appropriate authority that the Performance Requirements will be achieved. The building proponent should refer to A2G2 for guidance on acceptable assessment methods for determining compliance with the Performance Requirements.

The following are two very simple examples of what may or may not be “appropriate”. They should not be regarded as absolute or applicable in all circumstances.

Examples: Commercial poultry building

The building concerned is a commercial poultry building whichis single storeyand is occupied by only a few workers, who are likely to know the building well. The building is situated some distance from any other building and has direct routes to the exit doors.

In such a case,the building elements may not need to be protected against the spread of fire under C1P2(1) because the building is:

• only one fire compartment;
• people are not sleeping in the building; and
• there is little likelihood of the spread of fire to another building because of the large distance to any other building.

Note that for the example above, it is assumed that the building in question has not met the criteria to be considered a farm building or farm shed in the Deemed-to-Satisfy Provisions.

Examples: High-rise office building

The building concerned is a central city high-rise office building. It is located on the street alignment and close to other similar buildings.

In such a case, the spread of a fire needs to be avoided because:

• the occupants will take some time to evacuate the building, so there is a need to protect the escape routes;
• there is a need for protection from the spread of a fire between each storey, including the risk of fire spread via the external walls of the building where each storey is a separate fire compartment; and
• a fire could easily spread between buildings because they are close together.

In this example,building elements may require a high level of protection against the spread of fire under C1P2(1).

In both cases, the ability of the fire brigade to control a fire would also need to be considered when considering the implications of satisfying C1P2(1).

If the proposal being considered involves a solution that is taking advantage of the Deemed-to-Satisfy Provisions, the Deemed-to-Satisfy Provisions contain detailed requirements for the fire protection of building elements.

C1P3 deals with the spread of fire and smoke withina patient care area of a Class 9a building.

If a fire occurs in a health-care building, most patients would be unable to leave their beds, or may require assistance to evacuate the building. It is therefore important that the areas of the health-care building used by patients in beds be protected from fire in another part of the building.

See definition of “health-care building”in Schedule 2.

C1P3 also applies in Class 9c buildings. In this case it applies throughout the whole building, not just in the resident use areas. This is because if a fire occurs in an aged care building, some residents would be unable to leave their beds, or may require assistance to evacuate the building.

C1P4 deals with the fire hazard properties of materials used in the construction of a building. These include such matters as their smoke, toxic gas and heat generation capacities.

C1P4 uses the term “to the degree necessary”. This word usage is designed to provide flexibility in the way this provision is implemented.

It means that the BCA recognises that different materials and assemblies must resist the spread of fire to limit the generation of smoke, heat and toxic gases to differing degrees, depending on the circumstances of their use. The expression is intended to allow the appropriate authority to determine the degree of compliance necessary in each particular case after consideration of the building scenario.

Any decision made in this context can extend to not requiring an item to be installed or particular level of performance to be achieved, if that is the appropriate action to be taken.

The materials used in the building must be appropriate to avoid the spread of fire and the generation of smoke, heat and toxic gases after consideration of the matters listed in C1P4. The reason for each of these matters is as follows:

• If the occupants can evacuate in a short time, then the smoke, heat and toxic gases generated prior to the completion of the evacuation will be less likely to have an impact on the safety of the occupants than if a longer evacuation time is required.
• The number, mobility and other characteristics of the occupants influence the time taken for the evacuation of the building. If the number of occupants is large, or they are not mobile, such as patients in a hospital or residents of an elderly people’s home, the evacuation time could be long. Such an evacuation time may allow the fire to develop and generate greater amounts of smoke, heat and toxic gases that will endanger the safety of the occupants trying to evacuate.
• The function or use of the building has an impact on the types of materials and linings that are part of the building’s fire load. This directly influences the rate of spread of any fire in the building.
• Any active fire safety system installed in the building, such as a sprinkler system,may limit the spread of fire and allow additional time for the evacuation of the occupants.

The Deemed-to-Satisfy Provision applicable to C1P4 is C2D11. C2D11 limits the early fire hazard characteristics of materials susceptible to the effects of flame or heat, particularly during the early stages of a fire.

If a Performance Solution is being used, it may be appropriate to assess it using the Section C Deemed-to-Satisfy Provisions (Parts C2, C3 and C4) for guidance purposes. It is stressed, however, that compliance with the Deemed-to- Satisfy Provisions is not compulsory if alternative means can be found to satisfy the appropriate authority that the Performance Requirements will be achieved. The building proponent should refer to A2G2 for guidance on acceptable assessment methods for determining compliance with the Performance Requirements.

C1P5 is intended to overcome a problem observed when a fire has occurred in a building of “tilt-up construction”, and the panels have collapsed outwards,either during the fire or shortly after with little or no warning, endangering public safety, health, amenity and fire fighting operations.

A wide variety of structural systems and materials are possible to achieve this.

C1P5 is only applicable to walls that could collapse as complete panels and, therefore, is not applicable to concrete and clay masonry walls, and the like, because such walls tend to fail in portions, rather than as complete panels.

The height limitation of 2 storeys is based upon the observation that the problem only seems to occur in low-rise buildings. This is due to taller buildings usually having fire rated floors and other building elements to restrain wall panels during a fire.

Certain types of equipment installed in buildings, such as boilers and the like, have a high fire potential. Other types of equipment, such as transformers and batteries, have a high potential for explosion. C1P6 aims to minimise the risk of a fire spreading from such equipment to other parts of the building.

C1P6 uses the term “to the degree necessary”. This word usage is designed to provide flexibility in the way this provision is implemented.

It means that the BCA recognises that different equipment requires differing levels of protection, depending on the circumstances within which it is used and installed. The expression is intended to allow the appropriate authority to determine the degree of compliance necessary in each particular case.

Any decision made in this context can extend to not requiring an item to be installed or a particular level of performance to be achieved, if that is the appropriate action to be taken.

C1P7 is intended to protect emergency equipment from the spread of fire within a building. It is important that emergency equipment continues to operate to the required level during an emergency. The length of time it should continue to operate will depend on the particular equipment.

Examples

C1P7 requires that the emergency equipment continue to operate for as long as it is needed. Some examples of where protection may be required include:

• the protection of central smoke control plant required to operate in a fire for sufficient time for the occupants to evacuate; and
• the protection of the power supply to emergency lifts for sufficient time for the use of the lifts.

C1P7 uses the term “to the degree necessary”. This word usage is designed to provide flexibility in the way this provision is implemented.

It means that the BCA recognises that different emergency equipment requires differing levels of protection, depending on the circumstances within which it is used and installed. The expression is intended to allow the appropriate authority to determine the degree of compliance necessary in each particular case.

Any decision made in this context can extend to not requiring an item to be installed or a particular level of performance to be achieved, if that is the appropriate action to be taken.

C1P8 requires openings and penetrations in building elementsto resist the spread of fire.

C1P8 should be read in conjunction with C1P2. C1P8 deals with any opening or penetration within a building element, and C1P2 deals with the building element itself.

C1P8 uses the term “to the degreenecessary”. This word usage is designed to provide flexibility in the way this provision is implemented.

It means that the BCA recognises that different building elements require differing levels of protection, depending on the circumstances within which they are used and installed. The expression is intended to allow the appropriate authority to determine the degree of compliance necessary in each particular case.

Any decision made in this context can extend to not requiring an item to be installed or a particular level of performance to be achieved, if that is the appropriate action to be taken.