- Where the refrigerant is carbon dioxide or water.
- Fuel-burning appliances shall not be prohibited in the same machinery room with refrigerant-containing equipment or appliances where combustion air is ducted from outside the machinery room and sealed in such a manner as to prevent any refrigerant leakage from entering the combustion chamber, or where a refrigerant vapor detector is employed to automatically shut off the combustion process in the event of refrigerant leakage.
Machinery rooms shall be mechanically ventilated to the outdoors.
Exception: Where a refrigerating system is located outdoors more than 20 feet (6096 mm) from any building opening and is enclosed by a penthouse, lean-to or other open structure, natural or mechanical ventilation shall be provided. Location of the openings shall be based on the relative density of the refrigerant to air. The free-aperture cross section for the ventilation of the machinery room shall be not less than:
|F||=||The free opening area in square feet (m2).|
|G||=||The mass of refrigerant in pounds (kg) in the largest system, any part of which is located in the machinery room.|
During occupied conditions, the mechanical ventilation system shall exhaust the larger of the following:
- Not less than 0.5 cfm per square foot (0.0025 m3/s • m2) of machinery room area or 20 cfm (0.009 m3/s) per person; or
- A volume required to limit the room temperature rise to 18°F (10°C) taking into account the ambient heating effect of all machinery in the room.
|Q||=||The airflow in cubic feet per minute (m3/s).|
|G||=||The design mass of refrigerant in pounds (kg) in the largest system, any part of which is located in the machinery room.|