NCC 2019 Volume One
Search the National Construction Code editions
Filter
Part E4 Visibility in an emergency, exit signs and warning systems
Performance Requirements
EP4.1 Visibility in an emergency
To facilitate safe evacuation in an emergency, a building must be provided with a system that—
(a)
(b)
activates instantaneously upon the failure of an artificial lighting system, to the degree necessary, appropriate to—
(c)
the function or use of the building; and
(d)
the floor area of the building; and
(e)
the distance of travel to an exit.
Limitation:
EP4.1 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 Objective of this Part is, in an emergency, to safeguard occupants from injury by—
(a)
having adequate visibility; and
(b)
having adequate identification of exits and paths of travel to exits; and
(c)
being made aware of the emergency.
Provision of visibility, signage and warning
This Objective covers three of the basic elements required to help occupants evacuate a building in an emergency:
- visibility to see the evacuation route;
- signage to indicate the evacuation route; and
- warning of the emergency, so they know they need to evacuate.
A building is to be provided with—
(a)
adequate visibility upon failure of normal artificial lighting during an emergency; and
(b)
adequate means—
(i)
of warning occupants to evacuate; and
(ii)
to manage the evacuation process; and
(iii)
to identify exits and paths of travel to an exit.
The intent of EP4.1 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:
- minimise the risk of panic;
- make the safe route to an emergency exit visible;
- identify obstacles within the path; and
- otherwise assist in the orderly and safe evacuation of the building.
EP4.1 Limitations
EP4.1 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 EF4.1(a)).
“To the degree necessary”
EP4.1 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 EP4.1, a system to provide visibility in an emergency must be installed when necessary, and be appropriate to a number of factors, including:
- the use of the building will affect the fire load in the building;
- the size of the building's floor area which is a measure of the size of any potential fire, and the area through which occupants must travel to reach safety; and
- the distance of travel to an exit which is a measure of the distance occupants must travel to reach safety (and therefore the time necessary to reach safety).
“Appropriate to”
The system to provide visibility in an emergency must be “appropriate to” the matters listed in EP4.1, which relate to the amount of visibility in a particular building, and which is necessary to enable evacuation in an emergency.
Examples
Examples
The following are two examples of what may or may not be “appropriate” in this case. They should not be regarded as absolute.
Commercial poultry building
A commercial poultry building:
- has a high level of natural light;
- is occupied by only a few workers, likely to know the shed well;
- is rarely occupied by humans at night;
- is without a substantial floor space accessible by humans; and
- has short and direct routes to the exit doors.
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.
Cinema
A cinema, however:
- has no natural light; and
- is occupied regularly by large numbers of people who do not know the building or its evacuation plan well.
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
E4.2 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 E4.2 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:
Stand-by lighting
This is a term used to describe a lighting system providing a relatively high lighting level to allow normal activities to continue in case of a failure of the normal lighting system.
Example
Example
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.
Safety lighting
This is a term used to describe a lighting system provided for the safety of occupants working near hazardous equipment or processes.
Example
Example
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.
EP4.2 Identification of exits
To facilitate evacuation, suitable signs or other means of identification must, to the degree necessary—
(a)
be provided to identify the location of exits; and
(b)
guide occupants to exits; and
(c)
be clearly visible to occupants; and
(d)
operate in the event of a power failure of the main lighting system for sufficient time for occupants to safely evacuate.
Limitation:
Limitation:
EP4.2 does not apply to the internal parts of a sole-occupancy unit in a Class 2 or 3 building or Class 4 part of a building.
The intent of E4.2 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.
EP4.2 Limitations
EP4.2 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”
EP4.2 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:
- to locate the exits;
- to find their way to the exits;
- to clearly see any signs or other markers; and
- to be able to continue to see any signs or markers during their evacuation, in case of a failure of the normal lighting system.
Examples
Examples
The following are two examples of what may or may not be suitable exit identification. They should not be regarded as absolute.
Commercial poultry building
A commercial poultry building:
- has a high level of natural light;
- is occupied by only a few workers, who are likely to know the shed well;
- is rarely, if ever, occupied by people at night; and
- has direct routes to the exit doors.
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.
Cinema
A cinema, however:
- has no natural light; and
- is occupied regularly by large numbers of people who do not know the building or its evacuation routes.
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:
- the installation of exit signs; and
- the size, colour and wording of signs.
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.
EP4.3 Emergency warning and intercom systems
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—
(a)
the floor area of the building; and
(b)
the function or use of the building; and
(c)
the height of the building.
Early warning and communication
The intent of EP4.3 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:
- training, so that the evacuation process is undertaken automatically;
- allocation of staff to assist with evacuation, particularly if the building is likely to contain occupants who have been unable to benefit from prior training; or
- a detailed evacuation plan.
“To the degree necessary”
EP4.3 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 EP4.3, to warn occupants and assist with an evacuation, an emergency warning and intercom system must be appropriate to a number of factors, including:
- the floor area of the building which is a measure of the size of any potential fire, the area to be covered by a warning sound or signal, and the difficulty of intercommunication;
- the function of the building will affect the fire load in the building, and the difficulty such a load may cause in evacuating occupants; and
- the height of the building which is a measure of the difficulty of evacuation, search and rescue, and communication.
“Appropriate to”
The emergency warning and intercom system must be “appropriate to” the matters listed in EP4.3, 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
Examples
The following reveal what may or may not be “appropriate”. They should not be regarded as absolute.
Commercial poultry building
A commercial poultry building:
- has a comparatively small floor area accessible by occupants;
- is occupied by only a few workers, who are likely to know the shed well; and
- has good sight lines around the 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.
Cinema
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:
- unlikely to notice the commencement of an emergency, which could involve electrical or equipment failure in parts of the building beyond the auditorium; and
- unlikely to automatically know when or how to exit the building.
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.
Verification Methods
EV4.1 Emergency lighting
Compliance with EP4.1 is verified for the level of visibility for safe evacuation in an emergency and instantaneous activation, when an emergency lighting system satisfies the requirements below:
(a)
The calculated horizontal illuminance is not less than—
(i)
0.2 lux at floor level in the path of travel to an exit; and
(ii)
1 lux at each floor level or tread in every required—
(A)
(B)
(C)
(D)
non-fire-isolated stairway; or
(E)
non-fire-isolated ramp.
(b)
The emergency lighting provides a level of illuminance not less than—
(c)
(d)
An emergency lighting system must operate at not less than the minimum required level of illuminance for not less than 90 minutes.
EV4.1 does not verify full compliance with EP4.1. EV4.1 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 EP4.1 in an emergency. The appropriate authority will still need to be satisfied that the proposed emergency lighting system is appropriate to:
- the function or use of the building;
- the floor area of the building; and
- the distance of travel to an exit.
It is not compulsory for a designer to use EV4.1. The designer has the choice of using:
- EV4.1 to verify that the proposal achieves EP4.1;
- the Deemed-to-Satisfy Provisions of E4.2 to E4.4; or
- another means of verifying that EP4.1 will be achieved.
If EV4.1 is used to verify compliance, a designer may choose the method used to determine the:
EV4.2 Fire Safety Verification Method
Compliance with EP4.1, EP4.2 and EP4.3 is verified when a building is designed in accordance with Schedule 7.