The most important consideration when preparing any type of chart as a visual aid is size and:

When preparing any type of chart as a visual aid, legibility is crucial because it ensures that the information presented can be easily read and understood by the audience. If a chart is not legible, the intended message may be lost, and the effectiveness of the visual aid is compromised. This means that factors such as font size, clarity of text, and overall design are all important considerations to ensure that viewers can quickly grasp the key points at a glance.

While portability, colour, and location may have their significance in specific contexts—such as ease of transport for portable materials, the psychological impact of colour on engagement, or the visibility of a chart in different settings—none of these can substitute for the core requirement that the audience must be able to read and comprehend the information presented. Thus, emphasizing legibility ensures that the visual aid serves its primary function of enhancing understanding and communication of fire and life safety information.