In which landings do standpipe connections exist in scissor stairs?

In scissor stairs, standpipe connections are typically found on alternating floors. This design serves to enhance accessibility and ensure that standpipe systems, which are crucial for fire suppression, are readily available at strategic points throughout the building's vertical space. By placing connections at alternating floors rather than on every floor, the system can reduce the overall amount of piping needed while still providing effective coverage for fire suppression across different levels.

The design also considers safety and operational effectiveness, as having too many connections could lead to confusion and reduce response efficiency during emergencies. This approach allows firefighters to access the standpipe at various locations within the stairwell without overcrowding any single point, facilitating smoother operations in high-stress situations.

The other options do not align with standard practices for scissor stairs, where standpipe connections are strategically placed to enhance their functionality and accessibility. This method meets building code requirements while optimizing the use of space and resources in fire safety planning.