NCC 2022 Volume One - Building Code of Australia Class 2 to 9 buildings
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E4
Part E4 Visibility in an emergency, exit signs and warning systemsThis Part is intended to provide a minimum level of visibility in evacuation routes in an emergency, including emergency lighting and signage to assist in locating and identifying exits. This part also includes requirements for emergency warning and intercom systems to alert occupants and assist evacuation.
This Objective covers three of the basic elements required to help occupants evacuate a building in an emergency:
Visibility in an emergency—E4F1(a)
Artificial lighting is often one of the first things to fail during a building emergency. This can significantly impair the ability of the occupants to evacuate the building. Accordingly, a building must provide adequate visibility on the failure of artificial lighting in an emergency.
Warning of occupants—E4F1(b)(i)
Many of the emergency protection systems built into the BCA are time related, particularly those designed to protect occupants from a fire. The effectiveness of this protection may be negated if occupants are not made aware of the need to evacuate. It is essential that adequate early warning systems advise of the need to evacuate the building as soon as possible.
Evacuation management systems—E4F1(b)(ii)
Emergency evacuation requires all evacuations to maximise the opportunity for occupants to reach a place of safety. Since the BCA generally relates to the construction of a building, rather than its on-going use, it can only require the installation of a system to assist in the management of the evacuation process. It cannot demand, for example:
Identification of exits and paths of travel—E4F1(b)(iii)
Occupants need to be able to identify their route to safety without hesitation. The emergency route must be signed in a way which is clear and unambiguous.
To facilitate safe evacuation in an emergency, a building must be provided with a system that—
E4P1 does not apply to the internal parts of a sole-occupancy unit in a Class 2, 3 or 9c building or Class 4 part of a building.
The intent of E4P1 is to provide occupants with satisfactory visibility in an emergency. Sufficient visual conditions must be provided in a building to aid safe evacuation during an emergency. Accordingly, visibility must be sufficient to:
E4P1 Limitations
E4P1 does not apply within sole-occupancy units of Class 2, 3 or 9c buildings or within the Class 4 part of a building.
Operation when artificial lighting fails
A system to provide visibility in an emergency within a building only needs to operate on the failure of the normal artificial lighting system (see E4F1(a)).
“To the degree necessary”
E4P1 uses the expression “to the degree necessary”. The BCA recognises that not all buildings need the same level of visibility in an emergency.
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.
Criteria for visibility in an emergency
As set out in E4P1, a system to provide visibility in an emergency must be installed when necessary, and be appropriate to a number of factors, including:
“Appropriate to”
The system to provide visibility in an emergency must be “appropriate to” the matters listed in E4P1, which relate to the amount of visibility in a particular building, and which is necessary to enable evacuation in an emergency.
Examples
The following are two examples of what may or may not be “appropriate” in this case. They should not be regarded as absolute.
Examples
A commercial poultry building:
In such a case, it may be reasonable for no system to provide visibility in an emergency in this particular 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
A cinema, unlike the commercial poultry building in the previous example:
In such a case, even having no regard to the floor area or the distance of travel to an exit, it is probable that the building will require a system to provide visibility in an emergency such as an artificial illumination system and/or a way guidance system.
Deemed-to-Satisfy Provisions
E4D2 provides a number of examples where emergency lighting systems must be installed if the proposal being considered involves a solution which utilises the Deemed-to-Satisfy Provisions.
Performance Solutions
If a Performance Solution is being used, it may be appropriate to assess it using E4D2 for guidance purposes.
Stand-by lighting and safety lighting
If the system to provide visibility in an emergency is an emergency lighting system, it should not be confused with the following:
Examples
A generator may be used to provide a “working” level of light in case of a power failure. Such a level of light may be directed to different locations than the emergency routes required to achieve a safe evacuation. This would be considered stand-by lighting. The safe operation of specific equipment may require a level of lighting beyond that normally required for work conditions, and significantly beyond that required for safe evacuation. This would be considered safety lighting.
To facilitate evacuation, suitable signs or other means of identification must, to the degree necessary—
E4P2 does not apply to the internal parts of a sole-occupancy unit in a Class 2 or 3 or Class 4 part of a building.
The intent of E4P2 is to provide occupants with clear and concise information on what route to take to evacuate a building in an emergency. This may require the installation of emergency signage or other suitable means to identify egress routes and exits and assist in orderly evacuation.
This information must be easily obtainable, despite the reduced lighting conditions, even though emergency lighting systems have been provided.
E4P2 Limitations
E4P2 does not apply within sole-occupancy units of Class 2 or 3 buildings or within the Class 4 part of a building.
“To the degree necessary”
E4P2 uses the expression “to the degree necessary”. The BCA recognises that not all buildings need signs or markers to facilitate evacuation.
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.
Criteria for identification of exits
A building proposal must make sure that the means used to identify egress routes and exits are sufficient to enable occupants:
Examples
The following are two examples of what may or may not be suitable exit identification. They should not be regarded as absolute.
Examples
A commercial poultry building:
In such a case, occupants will be able to easily find the way to the exits. Accordingly, exit signs would not be necessary.
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
A cinema, unlike the commercial poultry building in the previous example:
In such a case, clear and illuminated signage would be required, located in common view points to encourage evacuees to continue travelling in a specific direction.
Deemed-to-Satisfy Provisions
If a builder is undertaking a solution using the Deemed-to-Satisfy Provisions, there are a number of relevant provisions regarding:
Performance Solutions
If a Performance Solution is being used, it may be appropriate to assess it using the Part E Deemed-to-Satisfy Provisions for guidance purposes.
To warn occupants of an emergency and assist evacuation of a building, an emergency warning and intercom system must be provided, to the degree necessary, appropriate to—
Early warning and communication
The intent of E4P3 is to maximise the opportunities for occupants to evacuate. This may include giving them as early a warning as possible and providing means of communicating both the need for evacuation and the process of evacuation.
Evacuation management systems
Emergency evacuation requires that the evacuation maximises the opportunity for occupants to reach a place of safety. Since the BCA relates to the construction of a building it can only require the installation of a system. It cannot require:
“To the degree necessary”
E4P3 uses the expression “to the degree necessary”. The BCA recognises that different buildings require differing types and degrees of emergency warning and intercom systems for occupants.
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.
Criteria for emergency warning and intercom system
As set out in E4P3, to warn occupants and assist with an evacuation, an emergency warning and intercom system must be appropriate to a number of factors, including:
“Appropriate to”
The emergency warning and intercom system must be “appropriate to” the matters listed in E4P3, which principally relate to the type of system which is necessary to enable evacuation in an emergency.
The BCA recognises that different emergency warning and communication needs may exist, depending on the size of the building, its function, use and height.
Examples
The following reveal what may or may not be “appropriate”. They should not be regarded as absolute.
Examples
A commercial poultry building:
In such a case, the ability of occupants to notice an emergency starting, particularly a fire, and their capacity to easily notify other occupants and exit quickly may mean that there is little or no need for emergency warning and intercom systems.
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
In a cinema, however, there is a large number of people who do not know the building or its evacuation routes. In such a case, the building’s occupants may be:
of the building beyond the auditorium; and
Accordingly, there may be a need for specialised emergency warning and intercom systems.
Deemed-to-Satisfy Provisions
If the proposal being considered involves a solution which utilises the Deemed-to-Satisfy Provisions, the Deemed-to- Satisfy Provisions provide a number of situations where emergency warning and intercom systems must be installed.
Performance Solutions
If a Performance Solution is being used, it may be appropriate to assess it using the Part E4 Deemed-to-Satisfy Provisions for guidance purposes.
E4V1 does not verify full compliance with E4P1. E4V1 is a means of verifying if a proposed emergency lighting system achieves the level of visibility for safe evacuation and the instantaneous activation required by E4P1 in an emergency. The appropriate authority will still need to be satisfied that the proposed emergency lighting system is appropriate to:
It is not compulsory for a designer to use E4V1. The designer has the choice of using:
If E4V1 is used to verify compliance, a designer may choose the method used to determine the:
To clarify that compliance with E4P1 to E4P3 will be achieved by compliance with E4D2 to E4D9 in the case of all buildings, Part G3 in the case of buildings with an atrium, Part G4 in the case of buildings in alpine areas, Part G6 in the case of occupiable outdoor areas, Part I1 in the case of theatres, stages and public halls and Part I3 for farm buildings and farm sheds.
Where a solution is proposed to comply with the Deemed-to-Satisfy Provisions, E4D1 clarifies that, for most buildings, if compliance can be demonstrated with E4D2 to E4D9, then compliance has been achieved with E4P1 to E4P3. The exceptions to this general rule are as follows:
Where a Performance Solution is proposed, the relevant Performance Requirements must be determined in accordance with A2G2(3) and A2G4(3) as applicable. (See commentary on Part A2).
An emergency lighting system must be installed—
An emergency lighting system must be installed—
To minimise the risk of death or injury to occupants during an emergency because of an inability to see their way along an exit path of travel.
Reasons for emergency lighting
See commentary for E4P1.
Locations for emergency lighting
E4D2 sets out the locations in buildings, and in some cases the classes of building, in which emergency lighting must be installed.
Each sub-provision of E4D2 must be considered separately. It is possible that more than one may apply to any single building. Where any sub-provision requires emergency lighting, such lighting must be provided, even though another sub- provision may appear to provide an exemption.
Examples
Consider a single storey building comprised of three open plan Class 6 sole-occupancy units of 150 m2 each, where each sole-occupancy unit has one exit direct to open space:
In this case, as E4D2(f) requires emergency lighting, such lighting must be provided despite the fact that the sole- occupancy units do not require such lighting under E4D2(e).
Extent of emergency lighting
The following sections outline the extent of emergency lighting required in each of the different scenarios listed under E4D2.
All fire-isolated exits—E4D2(a)
Emergency lighting is required to be installed in all fire-isolated exits, because it is unusual for them to be provided with sufficient amounts of natural lighting for safe evacuation.
Storeys over 300 m2 in Class 5–9 buildings—E4D2(b)
Emergency lighting is required in every storey with a floor area over 300 m2 in a Class 5–9 building, as follows:
Class 2, Class 3 and Class 4—E4D2(c)
Emergency lighting is required in any passageway, corridor, hallway, or the like in Class 2 and Class 3 buildings and Class 4 parts, if the distance of travel from the door leading from a sole-occupancy unit is greater than six metres to:
This provision reflects the likelihood that such buildings will be occupied at night, when the occupants are likely to be asleep.
Non-fire-isolated stairways—E4D2(d)
Emergency lighting is required to be installed in all required non-fire-isolated stairways (note that E4D2(d) applies even if the other provisions of E4D2 do not require the installation of emergency lighting).
Sole-occupancy unit in Class 5, Class 6 or Class 9—E4D2(e)
Emergency lighting is required to be installed in a sole-occupancy unit of a Class 5, Class 6 or Class 9 building if:
Publicly accessible room in Class 6 or Class 9b—E4D2(f)
Emergency lighting is required to be installed in every publicly accessible room or space in a Class 6 or Class 9b building if:
This provision reflects the likelihood that such buildings are used by large numbers of the public who do not have any knowledge of the building or its exits.
Class 9a—E4D2(g)
Emergency lighting is required to be installed in the specified areas in Class 9a buildings, because such buildings are used by patients who may require assistance to evacuate.
Class 9c—E4D2(h)
Emergency lighting is required to be installed throughout Class 9c buildings excluding within the sole-occupancy units. The requirement is generally aligned with the principles for emergency lighting in Class 9a buildings as described above.
Required fire control centres—E4D2(i)
Emergency lighting is required to be installed in required fire control centres, because they are designed for use by the fire brigade during an emergency, such as a fire.
Distances, other than vertical rise, must be measured along the shortest path of travel whether by straight lines, curves or a combination of both.
To clarify how distance must be measured for the purposes of emergency lighting required under E4D2.
Reasons for emergency lighting
See commentary for E4P1.
To which distances does E4D3 refer?
While not specifically stated, the intention is that the distances referred to in E4D3 are to be those calculated in accordance with E4D2(c) and E4D2(f)(ii).
Most direct route
The E4D2(c) and (f)(ii) distances are required to be measured the same way as those specified in clause D2D20.
Every required emergency lighting system must comply with AS/NZS 2293.1.
To specify how an emergency lighting system must operate, to minimise the risk of death or injury to occupants during an emergency because of an inability to see their way along an exit path of travel.
Reasons for emergency lighting
See commentary for E4P1.
Emergency lighting system and safe evacuation
An emergency lighting system must provide the visual conditions necessary for safe evacuation during an emergency such as a fire. It must be installed in accordance with AS/NZS 2293.1.
It should be noted that this is an emergency lighting system which is only required to operate during an emergency. F6D5(1)(a) requires artificial lighting to be provided within required stairways, passageways and ramps, but does not require such lighting to be illuminated at all times.
An exit sign must be clearly visible to persons approaching the exit, and must be installed on, above or adjacent to each—
An exit sign must be clearly visible to persons approaching the exit, and must be installed on, above or adjacent to each—
To minimise the risk of death or injury to occupants during an emergency because of an inability to find an exit.
Reasons for exit signs
See commentary for E4P1.
Locations of exit signs
E4D5 sets out the locations in a building requiring the installation of exit signs. Signs must be clearly visible to occupants approaching the exit. They need to be located on, above or adjacent to the specified exits and doors.
Some exemptions to E4D5
If an exit is not readily apparent to persons occupying or visiting the building, then exit signs must be installed—
To minimise the risk of death or injury to occupants during an emergency because of an inability to find their way along an exit path of travel.
Reasons for direction signs
Exits may not be visible from all locations within a building. In such cases, exit signs with directional indicators (such as arrows) are required to clearly indicate the direction of travel to required exits.
E4D5 does not apply to—
To specify some circumstances where risk levels do not warrant compliance with E4D5.
Class 2 buildings—E4D7(a)
The BCA considers that the risks to occupants of units within a Class 2 building are less than those to occupants of Class 3 buildings and Class 4 parts. This is because occupants of Class 2 buildings are assumed to be more familiar with:
Consequently, E4D7(a) grants an exemption for Class 2 buildings from the need to comply with E4D5, on the condition that the buildings comply with certain specific provisions.
With regard to E4D7(a)(i), while the size and wording of the exit sign are specified, the structure, method of attachment, or colour and the like are not specified. However, the colour of the word must contrast with that of the background. The building proponent can make this decision as long as the appropriate authority is satisfied.
With regard to E4D7(a)(ii), if a suitable alternative means of notification can be found to the requirements of E4D7(a)(i), it may be used. The decision is made by the building proponent, who must satisfy the appropriate authority.
Entrances to Class 2, Class 3 or Class 4—E4D7(b)
The BCA assumes that the occupants of units in Class 2 or Class 3 buildings, or in Class 4 parts of a building are familiar with the layouts of their units to allow E4D7(b) to grant an exemption so that exit signs are not required above what is described as the “entrance door”, being either:
Every required exit sign must—
To specify how exit signs must be designed and operate, to minimise the risk of death or injury to occupants during an emergency because of an inability to find an exit.
Criteria for exit signs
E4D8 sets out the provisions for required exit signs, which must meet the following criteria:
An emergency warning and intercom system complying, where applicable, with AS 1670.4 must be installed—
To minimise the risk of death or injury to occupants through lack of knowledge that an emergency exists or an evacuation is required.
Reasons for emergency warning systems
See commentary for E4P3.
Types of buildings requiring such a system
E4D9 sets out the types of buildings requiring the installation of an emergency warning and intercom system.
AS 1670.4
Building proposals using the Deemed-to-Satisfy Provisions to achieve the Performance Requirements must comply with AS 1670.4, where applicable.
Building with an effective height of more than 25 metres—E4D9(a)
In a building with an effective height of more than 25 metres, if a fire starts on one floor, there is a considerable risk that occupants of the other floors might not be aware it has started. Co-ordination of the evacuation process is important. This reduces confusion and congestion in the stairways and accordingly the time taken for the evacuation.
The people most at risk
In a building fire, the highest degree of risk is attached to such people as the very young, people with certain types of disability (such as a mobility disability), the elderly, and those asleep.
The BCA cannot address all possible permutations of people who are likely to be in any particular building. Nonetheless, it does attempt to address the risks that are most likely to be attached to the people most likely to be in particular types of building.
Installation for larger buildings
In most cases, the need to install an emergency warning and intercom system only applies to larger buildings. The reason for this requirement is the heightened risk that occupants may not be aware of a fire in another part of the building.
Residential care and Class 9a buildings
In Class 3 residential care buildings and in Class 9a buildings, many of the occupants or patients are unable to evacuate without assistance. There is also an enhanced risk in many of these buildings that residents or patients will be traumatised by loud or insistent alarms. To minimise this risk, the sound system and intercom system: