Which category space indicates an area where system failure is unlikely to have any physical impact on a patient?

Category 4 spaces are designated areas where the failure of medical gas systems would not result in any physical harm or adverse effects to patients. These spaces are typically used for utility or support rooms that do not directly impact patient care or safety, hence the risks associated with a system failure are minimal.

In the context of the NFPA 99 guidelines, each category is defined based on the risks involved with medical gas systems. Category 1 spaces are critical to patient care, where failures could cause serious harm. Category 2 spaces also support patient care, but they are slightly less critical than Category 1. Category 3 spaces, while they provide essential services, still have a degree of patient-related impact that necessitates reliability.

On the other hand, Category 4 spaces have been designed with the understanding that a system failure in these environments would not compromise patient safety, making them fundamentally different. This classification helps in guiding the installation and maintenance standards necessary for different types of medical gas systems.