2015 UMC §1102.1 General.
Refrigeration systems shall comply with this chapter and ASHRAE 15.
Exception: Ammonia refrigeration systems shall comply with IIAR 2, IIAR 3, and IIAR 5.

2015 IMC §1101.6 General.
Refrigeration systems shall comply with the requirements of this code and, except as modified by this code, ASHRAE 15. Ammonia-refrigerating systems shall comply with this code and, except as modified by this code, ASHRAE 15 and IIAR 2.

ANSI/ASHRAE 15-2013 §8.11.2
Each refrigerating machinery room shall have a tight-fitting door or doors opening outward, self-closing if they open into the building, and adequate in number to ensure freedom for persons to escape in an emergency. With the exception of access doors and panels in air ducts and air-handling units conforming to Section 8.11.7, there shall be no openings that will permit passage of escaping refrigerant to other parts of the building.

ANSI/IIAR 2-2008 Addendum B §13.3.3 Access and Egress
13.3.3.1 Machinery rooms shall have tight fitting doors which open outward and are provided with panic type hardware.
13.3.3.2 Any door(s) communicating with the building shall be approved, self-closing fire door(s).
13.3.3.3 At least one exit door shall open to the outdoors directly or through a vestibule type exit equipped with self-closing, tight fitting doors.