Section 7.2.1/Machinery Room Requirements
ASHRAE 15 Section 7.2 covers machinery room requirements for refrigeration equipment including ventilation, detection, and alarms.
A machinery room is required when the refrigerant charge exceeds the allowable quantity for the occupied space or when the refrigerant is in a higher toxicity or flammability class. The machinery room must have mechanical ventilation capable of exhausting the room in an emergency at a rate sufficient to prevent the refrigerant concentration from exceeding the specified limits. A refrigerant detector must be installed that activates an alarm and starts the emergency ventilation when the refrigerant concentration reaches the threshold. Access must be restricted to authorized personnel.
Why this section exists
Refrigerant leaks in enclosed spaces can create health hazards (toxicity, asphyxiation) or fire/explosion risks depending on the refrigerant type. Machinery rooms contain the refrigerant charge within a restricted, ventilated space where a leak can be detected and exhausted before it reaches occupied areas. The ventilation, detection, and alarm requirements form a layered safety system that protects building occupants from refrigerant exposure.
What plan reviewers look for
Plan reviewers check whether a machinery room is required based on the refrigerant type and charge size. They verify the emergency ventilation rate calculation, exhaust fan sizing, refrigerant detector location, and alarm connections. They check that the room has self-closing doors, restricted access signage, and no openings to occupied spaces. They verify the room is not used for storage or other purposes.
Common violations
Related ASHRAE 15 requirements
Section 8.11 covers refrigerant pipe and vessel requirements. Section 7.3 covers refrigerant detection requirements in detail. IMC Section 1105 covers refrigeration system requirements in the International Mechanical Code. ASHRAE 34 covers refrigerant safety classifications.