On issue might by that they can only have one tank per smoke compartment other than small ones.
Reference:
NFPA 99, 2015
11.3.3 Storage for nonflammable gases with a total volume equal to or less than 8.5 m3 (300 ft3) shall comply with the requirements in 11.3.3.1 and 11.3.3.2.
11.3.3.1 Individual cylinder storage associated with patient care areas, not to exceed 2100 m2 (22,500 ft2) of floor area, shall not be required to be stored in enclosures.
11.3.3.4 Individual small-size (A, B, D, or E) cylinders available for immediate use in patient care areas shall not be considered to be in storage.