NFPA99 Medical Gas Practice Exam

The number of cylinders in an Instrument Air Standby header is designed to last for a period of 1 hour. This duration provides a sufficient safety buffer for medical facilities to maintain uninterrupted service in the event of a primary source failure. The 1-hour timeframe is based on industry standards and best practices, ensuring that there is adequate time to address any issues that may arise and to implement contingency plans without jeopardizing patient care or operational integrity.

While other durations, such as 30 minutes, 2 hours, or 4 hours, might seem reasonable, they do not align with the standard guidelines that support an effective and immediate response to emergencies involving medical gas supply systems. Specifically, a 1-hour supply aligns well with operational needs while allowing enough time for maintenance, inspection, or potential replacement of the primary air supply.