In a cryogenic liquid cylinder manifold system, the reserve header shall have no fewer than how many cylinder connections?

• A. 3
• B. 2
• C. 4
• D. 5

Answer: (A)

The key idea is redundancy to keep the gas supply uninterrupted during cylinder changes. The reserve header serves as a backup bank, so you can swap cylinders without cutting off flow. Having at least three cylinder connections provides enough capacity and flexibility to maintain continuous supply: one cylinder (or group) can be feeding the system, another can be in the process of being changed or isolated, and a third acts as a standby reserve. With only two connections, a changeover could interrupt flow or leave you without a ready replacement during switching. Three connections give you a safe, practical buffer to ensure uninterrupted operation.