NFPA-99 Practice Exam

The reserve header in a cryogenic liquid cylinder manifold system shell has significant cylinder connections for an average day supply. What is the minimum number of connections required?

1. 1

2. 2

3. 3

4. 4

The correct answer is: 2

In a cryogenic liquid cylinder manifold system, the integrity and reliability of gas supply are critical, particularly for medical and industrial applications where uninterrupted service is essential. The minimum number of connections required, which is two in this case, ensures that there is redundancy in the system. This allows for continuous supply from the manifold while one connection could potentially be serviced, or if one cylinder runs out. Having two connections means that if maintenance is required on one cylinder or if one fails, the other can still provide the necessary supply. It also supports the system’s ability to share the load between cylinders, which can improve efficiency and reduce the risk of rapid depletion of a single source. This design consideration reflects best practices in safety and operational continuity, ensuring users have enough capacity available to meet average daily demands without compromising the availability of the cryogenic liquid. Other options imply a different approach to supply reliability which may not guarantee the same level of operational integrity.