Part E4 Visibility in an emergency, exit signs and warning systems (DtS)
E4.0 Deemed-to-Satisfy Provisions
E4.1 to E4.9; and
for additional requirements for Class 9b buildings, Part H1; and
To clarify that compliance with EP4.1 to EP4.3 will be achieved by compliance with E4.1 to E4.9 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 H1 in the case of theatres, stages and public halls and Part H3 for farm buildings and farm sheds.
Where a solution is proposed to comply with the Deemed-to-Satisfy Provisions, E4.0 clarifies that, for most buildings, if compliance can be demonstrated with E4.1 to E4.9, then compliance has been achieved with EP4.1 to EP4.3. The exceptions to this general rule are as follows:
- If the building contains an occupiable outdoor area, it must comply with Part G6 in addition to E4.1 to E4.9.
- Farm buildings and farm sheds must comply with Part H3 in addition to E4.1 to E4.9.
E4.1 * * * * *
This clause has deliberately been left blank.
In accordance with the decision not to change the numbering of the BCA from that of the previous edition, the space previously occupied by this provision has been left blank. The previous E4.1 provisions are now located in the BCA Performance Requirements.
E4.2 Emergency lighting requirements
An emergency lighting system must be installed—
in every passageway, corridor, hallway, or the like, that is part of the path of travel to an exit; and
in every passageway, corridor, hallway, or the like, having a length of more than 6 m from the entrance doorway of any sole-occupancy unit in a Class 2 or 3 building or Class 4 part of a building to the nearest doorway opening directly to—
a road or open space; and
in every room or space to which there is public access in every storey in a Class 6 or 9b building if—
in every Class 9c building excluding within sole-occupancy units; and
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.
See the comment on EP4.1.
E4.2 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 E4.2 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.
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:
- E4.2(e) specifies that emergency lighting is not required in each sole-occupancy unit (note that the 300 m2 minimum in E4.2(e)(i) applies to an individual sole-occupancy unit); but
- E4.2(f) specifies that every room or space to which there is public access (in this case, each entire sole-occupancy unit—note that the 300 m2 minimum in E4.2(f)(i) applies to the entire storey) must have emergency lighting.
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.
Emergency lighting is required in every storey with a floor area over 300 m2 in a Class 5–9 building, as follows:
- Every passageway, corridor, hallway, or the like forming part of a path of travel to an exit, because these areas are unlikely to be provided with sufficient amounts of natural lighting for safe evacuation.
- Any room larger than 100 m2 which does not open to a corridor or other space containing emergency lighting, or a road or open space.
- Any room larger than 300 m2. Note that this size of room is relatively large, and E4.2(b)(iii) applies irrespective of whether or not the room opens to a corridor or other space containing emergency lighting or a road or open space.
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:
- a fire-isolated exit;
- an external stairway used in lieu of a fire-isolated stairway;
- an external balcony leading to a fire-isolated exit; or
- a road or open space.
This provision reflects the likelihood that such buildings will be occupied at night, when the occupants are likely to be asleep.
Emergency lighting is required to be installed in all required non-fire-isolated stairways (note that E4.2(d) applies even if the other provisions of E4.2 do not require the installation of emergency lighting).
Emergency lighting is required to be installed in a sole-occupancy unit of a Class 5, Class 6 or Class 9 building if:
- the area of the unit is larger than 300 m2; and
- the exit from the unit does not open to the specified areas or spaces which are likely to have adequate natural lighting.
Emergency lighting is required to be installed in every publicly accessible room or space in a Class 6 or Class 9b building if:
- the area of the storey is relatively large (i.e. greater than 300 m2);
- any point on the floor is more than 20 metres from the specified doorways (which is a distance compatible with Section D requirements);
- egress requires a vertical rise of 1.5 metres;
- egress requires any vertical rise, if insufficient light is not admitted from outside the building; or
- the storey provides a path of travel from another storey included in E4.2(f)(i)–(iii). In this case, once a person enters an area with emergency lighting, then that lighting must be maintained throughout the remainder of the egress path.
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.
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.
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.
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.
E4.3 Measurement of distance
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 E4.2.
See the comment on EP4.1.
E4.4 Design and operation of emergency lighting
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.
See the comment on EP4.1.
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. F4.4(a)(i) requires artificial lighting to be provided within required stairways, passageways and ramps, but does not require such lighting to be illuminated at all times.
E4.5 Exit signs
door from an enclosed stairway, passageway or ramp at every level of discharge to a road or open space; and
horizontal exit; and
To minimise the risk of death or injury to occupants during an emergency because of an inability to find an exit.
See the comment on EP4.1.
E4.5 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.
E4.6 Direction signs
If an exit is not readily apparent to persons occupying or visiting the building then exit signs must be installed in appropriate positions in corridors, hallways, lobbies, and the like, indicating the direction to a required exit.
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.
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.
E4.7 Class 2 and 3 buildings and Class 4 parts: Exemptions
E4.5 does not apply to—
a Class 2 building in which every door referred to is clearly and legibly labelled on the side remote from the exit or balcony—
with the word “EXIT” in capital letters 25 mm high in a colour contrasting with that of the background; or
by some other suitable method; and
an entrance door of a sole-occupancy unit in a Class 2 or 3 building or Class 4 part of a building.
To specify some circumstances where risk levels do not warrant compliance with E4.5.
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:
- the layout of their unit;
- the layout of the building within which the unit is located; and
- Class 4 parts attached to parts of a building with different (and usually greater) fire loads.
With regard to E4.7(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 E4.7(a)(ii), if a suitable alternative means of notification can be found to the requirements of E4.7(a)(i), it may be used. The decision is made by the building proponent, who must satisfy the appropriate authority.
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 E4.7(b) to grant an exemption so that exit signs are not required above what is described as the “entrance door”, being either:
- the main door from the unit into the remainder of the building; or
- the door leading directly outside from the unit.
E4.8 Design and operation of exit signs
AS/NZS 2293.1; or
be clearly visible at all times when the building is occupied by any person having the right of legal entry to the building.
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.
E4.8 sets out the provisions for required exit signs, which must meet the following criteria:
- they must be visible at all times when the building is occupied by a person who has a legal right of entry. Exit signs have a function during normal periods to make occupants aware of the location of exits; and
- the system must comply with—
- AS/NZS 2293.1; or
- for photoluminescent exit signs, Specification E4.8, which varies some of the requirements of AS/NZS 2293.1.
E4.9 Emergency warning and intercom systems
An emergency warning and intercom system complying where applicable with AS 1670.4 must be installed—
in a building with an effective height of more than 25 m; and
in a Class 3 building used as a residential care building, except that the system—
must be arranged to provide a warning for occupants; and
in areas used by the residents, may have its alarm adjusted in volume and content to minimise trauma consistent with the type and condition of residents; and
must be arranged to provide a warning for occupants; and
in a ward area, may have its alarm adjusted in volume and content to minimise trauma consistent with the type and condition of patients; and
To minimise the risk of death or injury to occupants through lack of knowledge that an emergency exists or an evacuation is required.
See the comment on EP4.3.
E4.9 sets out the types of buildings requiring the installation of an emergency warning and intercom system.
Building proposals using the Deemed-to-Satisfy Provisions to achieve the Performance Requirements must comply with AS 1670.4, where applicable.
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.
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.
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.
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:
- must be arranged to warn occupants, including staff, residents and patients; and
- may be adjusted to take account of any special issues regarding residents or patients.