A proposed
change to the
NCC could allow
exit signs to be
99.8% dimmer
What are Emergency Exit Signs?
Emergency exit signs are a crucial part of a building’s fire safety. Emergency evacuations can cause panic, and visibility can be poor due to smoke or power outages. That’s why it is essential that emergency exit signs are clearly visible at all times to direct people to the nearest fire exit.
Self-Contained Exit Signs
This is the most common type of exit sign in Australia. Its 3 main components are:
- A green pictogram indicating the direction of nearest exit.
- An LED backlight to enhance visibility and provide a distinct contrast between the white and green sections.
- An inbuilt battery-backup to continue powering the LED backlight in the event of a power loss.
Photoluminescent (PL) Exit Signs
A photoluminescent exit sign absorbs light during normal operation. In the event of a power outage, it emits the stored light as a visible glow.
It requires a light source to sufficiently charge the photoluminescent material under normal conditions. This light source can be ambient natural light when installed in well-lit outdoor areas, or a dedicated external light source in dimly lit areas.
Hybrid Exit Signs
A hybrid exit signs combines features from both self-contained and photoluminescent exit signs.
Similar to a self-contained exit sign, a hybrid exit sign uses an internal, integrated light source as a backlight during normal operation.
It also contains a photoluminescent material that is constantly charged by the backlight, similar to a photoluminescent exit sign. This allows it to remain visible during a power outage without needing batteries.
Are Photoluminescent Exit Signs Legal?
Photoluminescent exit signs can not be used in most Australian buildings due to non-compliance with AS/NZS 2293:2018. AS/NZS 2293:2018 is the governing standard for exit signs and describes the installation, operation, maintenance and product requirements. Almost all buildings will list AS/NZS 2293:2018 as a minimum requirement for exit signs in their fire safety schedule and a fire safety schedule can not be changed unless there are errors or omissions in the schedule that require correction.
However, for buildings that do not list AS/NZS 2293:2018 as a requirement in their fire safety schedule, the NCC (National Construction Code) offers a pathway to compliance for PL exit signs. Specification 25 specifically exempts PL exit signs from AS/NZS 2293:2018 requirements such as a minimum luminance level of 8 cd/m2. In exchange, it imposes strong limits such as a constant 100 lux minimum charging brightness and strict performance testing requirements. Ultimately, specification 25 is based on and directly references AS/NZS 2293.1:2018.
What is the proposed change to the NCC?
Now, there is a Proposal to Change the NCC to allow hybrid exit signs to bypass both AS/NZS 2293.1:2018 and Specification 25. Instead, hybrid exit signs will only need to comply with a new technical specificationSA-TS-5367:2021, which is not based on AS/NZS 2993.1:2018.
SA-TS-5367:2021 has not been sufficiently tested and important sections such as the system maintenance and operation information note that “Requirements for periodic inspection and maintenance procedures are under development.” Allowing this proposed change to the NCC could allow hybrid exit signs to undo the increasing fire safety requirements developed over decades.
The Three Biggest Impacts of the Proposed Changes
1. Minimum luminance requirement decreased by up to 99.8%
It's crucial for exit signs to be clearly visible in any emergency. Luminance levels play a significant role, ensuring adequate backlighting and enhancing contrast between the white and green areas of the pictogram for easy direction to the nearest exit. The new SA-TS-5367:2021 standard significantly reduces these luminance requirements.
Luminance is measured in candela per square metre (cd/m2) or nits, and it measures how bright a surface will appear. For comparison, a typical movie theatre screen operates at around 50 nits. That would be 800 times brighter than the minimum requirement specified by SA-TS-5367:2021.
Minimum Luminance Under Power Loss Conditions
| AS/NZS 2293:2018 | SA-TS-5367:2021 | ||
|---|---|---|---|
| Green background of sign | Green background of sign | 8 cd/m2 | No minimum |
| White foreground of sign | White foreground of sign | 32 cd/m2 | 0.06 cd/m2 (99.8% decrease) |
Minimum Luminance Under Normal Power Conditions
| AS/NZS 2293:2018 | SA-TS-5367:2021 | ||
|---|---|---|---|
| Green background of sign | Green background of sign | 8 cd/m2 | 2 cd/m2 (75% decrease) |
| White foreground of sign | White foreground of sign | 32 cd/m2 | 20 cd/m2 (37.5% decrease) |
2. Removed Standard Testing and Maintenance Requirements
To ensure that a building’s exit signs are always in good condition, AS/NZS 2293.2 outlines detailed testing and maintenance procedures. However, SA-TS-5367:2021 does not define any testing and maintenance requirements. This allows the manufacturer to specify maintenance methods without any guidelines or restrictions. To name a few changes, buildings will no longer be required to:
- Keep routine service and maintenance records.
- Inspect, clean and ensure exit signs are not obscured.
- Check the luminance of Hybrid Signs under power loss and normal conditions.
- Check the light source life and service life of Hybrid Signs. SA-TS-5367:2021 claims that:
…there is no basis to assign an end-of-life to the PL material
3. Removed Existing Product Requirements
- Removed requirement for hybrid signs to be constantly charged at 100 lux.
- Removed lux requirements from compliance testing procedures.
- Reduced normal operating temperature range from 10-40°C to 20-30°C.
- Maximum viewing distance marking reduced from 5-10mm to 3-8mm.
- Removed requirement for a charging indicator.
- Removed requirement for a light source life marking.
Conclusion
The current version of the SA-TS-5367:2021 is incomplete and significantly degrades the current exit sign safety standards. SA-TS-5367:2021 must be updated to include important information such as testing and maintenance procedures, and it must uphold the same level of safety requirements that we have today. If you would like to voice your opinion, please submit a public comment, or join our petition by 11:59 PM AEST Monday 1 July 2024.