This means that systems with a capacity of 20,000ft³ or more (connected and in storage) are considered to be bulk systems, and must conform to bulk oxygen system requirements set forth by the NFPA 50.

 

To be compliant, central supply systems for oxygen must contain less than 20,000ft³.

 

H-Cylinders contain 244ft³ per cylinder.

To be under the maximum allowable limit, you can have 81 H-Cylinders connected and in storage. Technically, you could have a 40 by 40 manifold configuration with these cylinders, but it would be unadvisable, since changing one cylinder bank would be extremely labor intensive and would increase the risk for physical injury.

 

Small Liquid Portable Containers (Chart 160 HP) contain 4,577ft³ per container.

To be under the maximum allowable limit, you can have 4 containers connected and in storage. Since the requirements are to have a reserve header with an average day supply, you would only be able to have 6 high pressure cylinders connected to a reserve header, and still be under the maximum allowable limit. Most likely the 6 cylinders would not be enough for an average day supply. If this is the case, then you would only be able to have a one by one system with these containers in order to allow for the reserve cylinder connections to meet the average day supply requirement.

 

Large Liquid Portable Containers (Chart 265 HP) contain 5,769ft³ per container.

To be under the maximum allowable limit, you can have 3 containers connected and in storage. Since the code requires two equal headers, you would only be able to have a one by one configuration with these containers.
 

There are other things to remember when trying to size a new system or keep an existing system compliant. Be sure to follow NFPA 99 guidelines to stay within the allowable limits and stay code compliant.

 

Don’t forget: All cylinders and containers for oxygen in the room, whether connected or in storage, count toward the total amount.