This standard specifies safe design, construction, installation, and operation of refrigerating systems. 2.1 This code establishes safeguards for life, limb, health, and property; and prescribes safety standards. 2.2 This code applies to the following new installations and to modifications of existing installations made after adoption of this code: (a) to mechanical refrigerating systems and heat pumps used in the occupancies defined in Section 4, (b) to parts or components added, (c) to parts or components replaced only if they are not identical in function, and (d) to substitution of a refrigerant having a different number designation. ANSI/ASHRAE Standard 34 provides refrigerant number designations. 2.3 This code does not apply where water is the primary refrigerant.