Final answer:
The question about the maximum practical number of storeys to travel is not answerable without additional context or specific guidelines; it could relate to engineering, building design, or safety considerations.
Step-by-step explanation:
The question you are asking about doesn't specify a context for what is considered the maximum practical distance to travel. If the question pertains to the height of the buildings and the number of storeys, it could be related to engineering and building design, where practical travel distance may imply the maximum number of floors people would typically walk up before opting to use an elevator. Without additional context, it is not possible to give a definitive answer to your question. However, if you're looking for general practice or comfort levels in building design or maximum height a fire department's ladder can reach, it might be lower than the numbers provided. Please provide more context or refer to the specific study or guideline that the question is based on.