1104.2 Refrigerant Concentration Limit.

The concentration of refrigerant in a complete discharge of an independent circuit of high-probability systems shall not exceed the amounts shown in Table 1102.3, except as provided in Section 1104.3 and Section 1104.4. The volume of occupied space shall be determined in accordance with Section 1104.2.1 through Section 1104.2.3. Exceptions: (1) Listed equipment containing not more than 6.6 pounds

(2.99 kg) of refrigerant, regardless of the refrigerant

(1) Listed equipment containing not more than 6.6 pounds

(2.99 kg) of refrigerant, regardless of the refrigerant safety classification, provided the equipment is installed in accordance with the listing and with the manufacturer’s installation instructions. (2) Listed equipment for use in laboratories with more than

100 square feet (9.29 m ² ) of space per person, regardless

2019 CALIFORNIA MECHANICAL CODE 211

REFRIGERATION any other purpose or distributed to any other persons or parti es.

1104.2.1 Volume Calculations. The volume used to convert from refrigerant concentration limits to refrigerating system quantity limits for refrigerants in Section 1104.2 shall be based on the volume of space to which refrigerant disperses in the event of a refrigerant leak.

[ASHRAE 15:7.3] 1104.2.2 Nonconnecting Spaces. Where a refrigerating system or part thereof is located in one or more enclosed occupied spaces that do not connect through permanent openings or HVAC ducts, the volume of the smallest occupied space shall be used to determine the refrigerant quantity limit in the system. Where different stories and floor levels connect through an open atrium or mezzanine arrangement, the volume to be used in calculating the refrigerant quantity limit shall be determined by multiplying the floor area of the lowest space by 8.2 feet (2499 mm). [ASHRAE 15:7.3.1] 1104.2.3 Ventilated Spaces. Where a refrigerating system or a part thereof is located within an air handler, in an air distribution duct system, or in an occupied space served by a mechanical ventilation system, the entire air distribution system shall be analyzed to determine the worstcase distribution of leaked refrigerant. The worst case or the smallest volume in which the leaked refrigerant disperses shall be used to determine the refrigerant quantity limit, subject to the criteria in accordance with Section 1104.2.3.1 through Section 1104.2.3.3. [ASHRAE 15:7.3.2] 1104.2.3.1 Closures. Closures in the air distribution system shall be considered. Where one or more spaces of several arranged in parallel are capable of being closed off from the source of the refrigerant leak, their volume(s) shall not be used in the calculation. Exceptions: The following closure devices shall not be considered: (1) Smoke dampers, fire dampers, and combination

smoke and fire dampers that close only in an

(249.5 kg) in the occupied areas and machinery rooms of institutional occupancies. Exception: The total of all Group A2L refrigerants shall not be limited in machinery rooms of institutional occupancies. Rooms.1104.4 Industrial Occupancies and Refrigerated Section 1104.2 shall not apply in industrial occupancies and refrigerated rooms where in accordance with the following: (1) The space(s) containing the machinery is (are) separated

from other occupancies by tight construction with tight

(1) The space(s) containing the machinery is (are) separated

from other occupancies by tight construction with tightfitting doors. (2) Access is restricted to authorized personnel. (3) The floor area per occupant is not less than 100 square

feet (9.29 m ² ).

(3) The floor area per occupant is not less than 100 square

feet (9.29 m ² ). Exception: The minimum floor area shall not apply where the space is provided with egress directly to the outdoors or into approved building exits. (4) Refrigerant detectors are installed with the sensing loca tion and alarm level as required in refrigeration machin

(4) Refrigerant detectors are installed with the sensing loca tion and alarm level as required in refrigeration machinery rooms in accordance with Section 1106.2.2.2. (5) Open flames and surfaces exceeding 800°F (427°C) shall

not be permitted where a Group A2, B2, A3, or B3 refrig

(5) Open flames and surfaces exceeding 800°F (427°C) shall

not be permitted where a Group A2, B2, A3, or B3 refrigerant, is used. (6) Electrical equipment that is in accordance with Class 1,

Division 2, of the California Electrical Code where the

(6) Electrical equipment that is in accordance with Class 1,

Division 2, of the California Electrical Code where the quantity of a Group A2, B2, A3, or B3 refrigerant in an independent circuit is capable of exceeding 25 percent of the lower flammability limit (LFL) upon release to the space based on the volume determined in accordance with Section 1104.2.1 through Section 1104.2.3. (7) Refrigerant containing parts in systems exceeding 100

horsepower (74.6 kW) compressor drive power, except

(1) Smoke dampers, fire dampers, and combination

smoke and fire dampers that close only in an emergency not associated with a refrigerant leak. (2) Dampers, such as variable-air-volume (VAV)

boxes, that provide limited closure where airflow

(7) Refrigerant containing parts in systems exceeding 100

horsepower (74.6 kW) compressor drive power, except evaporators used for refrigeration or dehumidification, condensers used for heating, control and pressure-relief valves for either, and connecting piping, are located in a machinery room or outdoors. [ASHRAE 15:7.2.2]