High probability systems shall not be allowed in areas of institutional occupancy.
Exception: High probability systems shall be allowed in areas of institutional occupancy where the amount of refrigerant in the largest refrigerant circuit does not exceed the lesser of:
1. 50 percent of the pounds of refrigerant allowed in Table 18-28-1103.1, or
2. 30 pounds. The value of cubic feet used to calculate the maximum amount of refrigerant allowed by Table 18-28-1103.1 shall be based on the smallest contiguous space where refrigerant can collect in the vent of a discharge.
The total of all Group A2, B2, A3 and B3 refrigerants shall not exceed 550 pounds (250 kg) in occupied areas or machinery rooms.