The Joint Commission addresses aisle width requirements
Effective immediately: Aisle widths in hospital and critical access hospital suites must be 36 inches at minimum
On April 21, The Joint Commission issued a release that all Life Safety Code® surveyors will “cite noncompliance in suites with aisles that have less than 36 inches of clearance from side to side to facilitate egress.” The Joint Commission quotes The National Fire Protection Association’s (NFPA) Life Safety Code (NFPA 101–2012), Section 188.8.131.52 (2) which states:
(2) Not less than 36 in. (915 mm) where another part of this chapter and Chapters 11 through 43 do not specify a minimum width.
This reference however addresses egress that is not “provided in 184.108.40.206.1 through 220.127.116.11.3.” The 2012 NFPA 101 18.104.22.168.1 actually addresses the aisle width of “exit access that is formed by furniture and movable partitions” that should be referenced for this standard. The 2012 NFPA 101 22.214.171.124.1 (2) states:
(2) A width of not less than 36 in. (915 mm) for new exit access, and not less than 28 in. (710 mm) for existing exit access, shall be capable of being provided without moving permanent walls.
To read more about the requirement, check out The Joint Commission Online.