Nfpa 99 does not define the point where a cylinder is considered empty.
Compressed gas cylinder storage nfpa.
Section 6 16 of nfpa 55 states that indoor storage and use areas and storage buildings for compressed gases and cryogenic fluids are to be provided with mechanical exhaust ventilation or natural ventilation where natural ventilation can be shown to be acceptable for the material as stored.
For the purpose of segregating empty and full cylinders the facility should establish a level of where this delineation would be made.
The occupational safety and health administration osha addresses the storage and handling of lp gas in 29 code of federal regulations cfr 1910 110 the national fire protection association nfpa standard on lp gas nfpa 58 liquefied petroleum gas code covers the storage handling transportation and use of lp gas.
Because of this nfpa guidelines require that all compressed gas cylinders of all sizes are restrained securely at all times so that they don t fall or tip over.
It is recommended that you only use approved storage racks so that the cylinders are adequately secured by metal chains straps or other approved materials to prevent cylinders from being knocked over.