Section 1104 System Application Requirements
Except as provided in Sections 1104.2.1 and 1104.2.2, all components containing the refrigerant shall be located either outdoors or in a machinery room where the quantity of refrigerant in an independent circuit of a system exceeds the amounts shown in Table 1103.1. For refrigerant blends not listed in Table 1103.1, the same requirement shall apply where the amount for any blend component exceeds that indicated in Table 1103.1 for that component. This requirement shall also apply where the combined amount of the blend components exceeds a limit of 69,100 parts per million (ppm) by volume. Machinery rooms required by this section shall be constructed and maintained in accordance with Section 1105 for Group A1 and B1 refrigerants and in accordance with Sections 1105 and 1106 for Group A2, B2, A3 and B3 refrigerants.
Exceptions:
- Machinery rooms are not required for listed equipment and appliances containing not more than 6.6 pounds (3 kg) of refrigerant, regardless of the refrigerant's safety classification, where installed in accordance with the equipment's or appliance's listing and the equipment or appliance manufacturer's installation instructions.
- Piping in conformance with Section 1107 is allowed in other locations to connect components installed in a machinery room with those installed outdoors.
This section applies only to rooms and spaces that: are within industrial occupancies; contain a refrigerant evaporator; are maintained at temperatures below 68°F (20°C); and are used for manufacturing, food and beverage preparation, meat cutting, other processes and storage. Where a machinery room would otherwise be required by Section 1104.2, a machinery room shall not be required where all of the following conditions are met:
- The space containing the machinery is separated from other occupancies by tight construction with tight-fitting doors.
- Access is restricted to authorized personnel.
Refrigerant detectors are installed as required for machinery rooms in accordance with Section 1105.3.
Exceptions:
- Refrigerant detectors are not required in unoccupied areas that contain only continuous piping that does not include valves, valve assemblies, equipment, or equipment connections.
- Where approved alternatives are provided, refrigerant detectors for ammonia refrigeration are not required for rooms or areas that are always occupied, and for rooms or areas that have high humidity or other harsh environmental conditions that are incompatible with detection devices.
- Surfaces having temperatures exceeding 800°F (427°C) and open flames are not present where any Group A2, B2, A3 or B3 refrigerant is used (see Section 1104.3.4).
- All electrical equipment and appliances conform to Class 1, Division 2, hazardous location classification requirements of NFPA 70 where the quantity of any Group A2, B2, A3 or B3 refrigerant, other than ammonia, in a single independent circuit would exceed 25 percent of the lower flammability limit (LFL) upon release to the space.
- All refrigerant-containing parts in systems with a total connected compressor power exceeding 100 horsepower (hp) (74.6 kW)—except evaporators used for refrigeration or dehumidification, condensers used for heating, control and pressure relief valves for either, low-probability pumps and connecting piping—are located either outdoors or in a machinery room.
Group A2 and B2 refrigerants shall not be used in high-probability systems where the quantity of refrigerant in any independent refrigerant circuit exceeds the amount shown in Table 1104.3.2. Group A3 and B3 refrigerants shall not be used except where approved.
Exception: This section does not apply to laboratories where the floor area per occupant is not less than 100 square feet (9.3 m2).
MAXIMUM PERMISSIBLE QUANTITIES OF REFRIGERANTS
| TYPE OF REFRIGERATION SYSTEM | MAXIMUM POUNDS FOR VARIOUS OCCUPANCIES | |||
| Institutional | Assembly | Residential | All other occupancies | |
| Sealed absorption system | ||||
| In exit access | 0 | 0 | 3.3 | 3.3 |
| In adjacent outdoor locations | 0 | 0 | 22 | 22 |
| In other than exit access | 0 | 6.6 | 6.6 | 6.6 |
| Unit systems | ||||
| In other than exit access | 0 | 0 | 6.6 | 6.6 |
For SI: 1 pound = 0.454 kg.
Where any device having an open flame or surface temperature greater than 800°F (427°C) is used in a room containing more than 6.6 pounds (3 kg) of refrigerant in a single independent circuit, a hood and exhaust system shall be provided in accordance with Section 510. Such exhaust system shall exhaust combustion products to the outdoors.
Exception: A hood and exhaust system shall not be required where any of the following apply:
- The refrigerant is R-717, R-718 or R-744.
- The combustion air is ducted from the outdoors in a manner that prevents leaked refrigerant from being combusted.
- A refrigerant detector is used to stop the combustion in the event of a refrigerant leak (see Sections 1105.3 and 1105.5).
Where an evaporator or condenser is located in an air duct system, the volume of the smallest, enclosed occupied space served by the duct system shall be used to determine the maximum allowable quantity of refrigerant in the system.
Exception: If airflow to any enclosed space cannot be reduced below one-quarter of its maximum, the entire space served by the air duct system shall be used to determine the maximum allowable quantity of refrigerant in the system.