What are the regulatory requirements for “drop and swap” storage at hydrogen refueling stations? NFPA 2 is clear that no flexible hoses are allowed except the ones connecting to the vehicle being refueled. A drop and swap approach obviously needs to use flexible hoses to connect to the tube trailers.

A "drop and swap" delivery system using tube trailers is a common and accepted method of supply for both industrial and fueling station applications. While NFPA 2 - 2023, paragraph 10.6.3.5 states, "The use of hose in a hydrogen dispensing system shall be limited to vehicle fueling hose," this is intended for the dispenser itself, not the entire fueling station. This does not limit the use of a hose for other portions of the system where applicable. Examples where hoses are appropriate are tube trailer connections, compression equipment connections for vibration isolation, and purge connections. 

This requirement is under review by the NFPA 2 Technical Committees for clarification.