Part E4 Visibility in an emergency, exit signs and warning systems

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.

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:

• 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.

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.

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:

• 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.

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:

• 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 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:

• 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.

Examples
A cinema, unlike the commercial poultry building in the previous example:

• 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

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:

• 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.
• Safety lighting: This is a term used to describe a lighting system provided for the safety of occupants working near hazardous equipment or processes.

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.

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:

• 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

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:

• 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.

Examples
A cinema, unlike the commercial poultry building in the previous example:

• 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.

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:

• 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”

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:

• 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 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:

• 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.

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:

• 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.

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:

• 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 E4V1. The designer has the choice of using:

• E4V1 to verify that the proposal achieves E4P1;
• the Deemed-to-Satisfy Provisions of E4D2 to E4D4; or
• another means of verifying that E4P1 will be achieved.

If E4V1 is used to verify compliance, a designer may choose the method used to determine the:

• calculated horizontal illuminance at E4V1(2);
• illumination and delay at switch-on at E4V1(3) and (4); and
• operation time at E4V1(5).

Compliance for E4P1, E4P2 and E4P3 is verified when a building is designed in accordance with C1V4. C1V4 is a Verification Method that stipulates a method of demonstrating compliance with E4P1, E4P2 and E4P3 among other Performance Requirements.

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:

• If the building contains an occupiable outdoor area, it must comply with Part G6 in addition to E4D2 to E4D9.
• Farm buildings and farm sheds must comply with Part I3 in addition to E4D2 to E4D9.

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).

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:

• E4D2(e) specifies that emergency lighting is not required in each sole-occupancy unit (note that the 300 m2 minimum in E4D2(e)(i) applies to an individual sole-occupancy unit); but
• E4D2(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 E4D2(f)(i) applies to the entire storey) must have emergency lighting.

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:

• 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 E4D2(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.

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:

• 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.

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:

• 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.

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:

• 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 E4D2(f)(i), (ii) and (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.

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.

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.

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.

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

E4D7 provides some exemptions to E4D5 See E4D7.

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.

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:

• 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.

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:

• the main door from the unit into the remainder of the building; or
• the door leading directly outside from the unit.

Criteria for exit signs

E4D8 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 25, which varies some of the requirements of AS/NZS 2293.1.

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:

• 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.