Size of emergency lights vs viewing distance in Australia

Exit Light

In Australia, the size of an exit sign is intricately linked to its viewing distance, a critical factor determined by the Australian Standard AS 2293.1 - Emergency escape lighting and exit signs for buildings. This standard offers guidelines on the minimum size and lettering height of exit signs, with a direct correlation to their intended viewing distance.

Key considerations outlined by AS 2293.1:

1. Viewing Distance Determination: The maximum viewing distance of an exit sign, defined as the farthest point where it needs to be visible for guiding occupants to the exit, plays a pivotal role in determining its size. This factor ensures that exit signs remain effective in various building configurations.

2. Lettering Height Formula: AS 2293.1 introduces a formula for calculating the minimum lettering height based on the maximum viewing distance. The formula is expressed as: Lettering height (mm) = Viewing distance (m) / 8. This formula helps establish a proportional relationship between the size of the exit sign and its intended viewing distance.

3. Practical Example: For instance, if the maximum viewing distance of an exit sign is 16 meters, the minimum lettering height would be calculated as 16m / 8 = 2m. Therefore, the minimum lettering height for this particular sign would be 200mm. This exemplifies the practical application of the formula in determining the appropriate size of exit signs.

4. Varying Lettering Heights: Utilizing the formula for different viewing distances results in varying minimum lettering heights. For a viewing distance of 10m, the minimum lettering height would be 10m / 8 = 1.25m or 125mm. Similarly, for a viewing distance of 24m, the minimum lettering height would be 24m / 8 = 3m or 300mm. This flexibility ensures adaptability to diverse building layouts.

5. Formula Limitations: It's crucial to recognize that the formula provides a baseline for the minimum lettering height, and the actual size of the exit sign may need to be larger based on specific requirements stipulated by building codes and regulations. The formula offers a standardized approach, but compliance with regional standards should be confirmed.

6. Regional Standards and Consultation: Recognizing the regional differences in building codes and regulations across states and territories in Australia, consulting with a qualified professional is advisable. Fire safety engineers or licensed electricians can provide valuable insights to ensure that exit signs align with the relevant standards and regulations in a specific locale.

7. Application of the Formula: The formula's application is not only a mathematical exercise but a practical consideration in enhancing the effectiveness of exit signs. It ensures that these signs are appropriately sized to fulfill their crucial role in guiding occupants to safety during emergencies.

8. Integration with Building Layouts: Tailoring the size of exit signs based on viewing distance allows for seamless integration with diverse building layouts. This adaptability ensures that exit signs remain visible and effective, regardless of the architectural configuration.

9. Continuous Compliance: As building codes and standards evolve, ensuring continuous compliance with the latest regulations is essential. The interplay between viewing distance and exit sign size underscores the dynamic nature of emergency lighting standards.

10. Occupant Safety Focus: The sizing considerations for exit signs emphasize a fundamental focus on occupant safety. By aligning the size of exit signs with their intended viewing distances, building owners and managers contribute to creating safer environments for occupants.

11. Customization for Specific Applications: Recognizing that different buildings may have unique requirements, the formula allows for customization. Tailoring exit sign sizes based on the specific viewing distances within a building enhances the overall efficacy of the emergency lighting system.

12. Visibility Enhancement Strategies: The correlation between viewing distance and exit sign size prompts the exploration of visibility enhancement strategies. Implementing optimal lighting conditions and clear sightlines further augments the effectiveness of exit signs in guiding occupants during emergencies.

13. Interdisciplinary Collaboration: Achieving an optimal balance between viewing distance and exit sign size often requires interdisciplinary collaboration. Involving professionals with expertise in fire safety engineering, electrical systems, and building design ensures a comprehensive approach to emergency lighting design.


This information is provided with the expectation that individuals will independently evaluate and validate all inforrmation with accredited experts. Exiting assumes no responsibility for any harm, losses, or damages resulting from the utilization or dependence on this information .