According to NFPA 1192 5.2.1.1, what is not allowed regarding the installation of propane cylinders?

The correct answer highlights that, according to NFPA 1192 5.2.1.1, there are specific limitations regarding the number of propane cylinders that can be installed together. This standard establishes safe practices for the storage and use of propane cylinders, and it specifically states that a maximum of three cylinders can be installed together, ensuring that safety and accessibility are maintained.

This limitation helps prevent potential hazards associated with gas leaks or cylinder malfunctions, as a higher number of cylinders could complicate maintenance, inspection, and emergency response situations. This requirement is part of ensuring safe installation practices in environments where propane is used.

The context of the other choices provides clarity on why they do not fit the standards set by NFPA 1192. More than five cylinders would exceed the safety guidelines, making it a riskier option. The installation of portable cylinders could also have safety implications if not properly managed in a designated space. Lastly, stating that there are no restrictions would directly contradict the established safety protocols, which are designed to minimize risks associated with propane cylinder installation.