A transportation refrigeration system comprising: a single distinct compartment to be conditioned; a refrigeration circuit associated with an enclosure including a compressor, a condenser, an expansion valve upstream of a first evaporator, a first evaporator inlet shut-off valve, a first evaporator outlet shut-off valve, a second evaporator, a second evaporator inlet shut-off valve and a second evaporator outlet shut-off valve, wherein the first evaporator is in parallel with the second evaporator, wherein when the first evaporator inlet and outlet shut-off valves (62, 64) are closed, the first evaporator becomes fluidly isolated from the rest of the refrigeration circuit, and when the second evaporator inlet and outlet shut-off valves (66, 68) are closed, the second evaporator becomes fluidly isolated from the rest of the refrigeration circuit; a first enclosure surrounding the first evaporator, wherein the first enclosure includes a first refrigerant detection sensor in communication with a controller; and a second enclosure surrounding the second evaporator, wherein the second enclosure includes a second refrigerant detection sensor in communication with the controller; wherein the first refrigerant detection sensor is configured to identify the presence of refrigerant in an atmosphere of the first enclosure and the second refrigerant detection sensor is configured to identify the presence of refrigerant in an atmosphere of the second enclosure; wherein the isolating function of the first evaporator inlet and outlet shut-off valves (62, 64) and the second evaporator inlet and outlet shut-off valves (66, 68) allows a non-isolated evaporator to continue to function in the refrigeration circuit; and wherein the first and second evaporator condition the single distinct compartment. a single distinct compartment to be conditioned; a refrigeration circuit associated with an enclosure including a compressor, a condenser, an expansion valve upstream of a first evaporator, a first evaporator inlet shut-off valve, a first evaporator outlet shut-off valve, a second evaporator, a second evaporator inlet shut-off valve and a second evaporator outlet shut-off valve, wherein the first evaporator is in parallel with the second evaporator, wherein when the first evaporator inlet and outlet shut-off valves (62, 64) are closed, the first evaporator becomes fluidly isolated from the rest of the refrigeration circuit, and when the second evaporator inlet and outlet shut-off valves (66, 68) are closed, the second evaporator becomes fluidly isolated from the rest of the refrigeration circuit; a first enclosure surrounding the first evaporator, wherein the first enclosure includes a first refrigerant detection sensor in communication with a controller; and a second enclosure surrounding the second evaporator, wherein the second enclosure includes a second refrigerant detection sensor in communication with the controller; wherein the first refrigerant detection sensor is configured to identify the presence of refrigerant in an atmosphere of the first enclosure and the second refrigerant detection sensor is configured to identify the presence of refrigerant in an atmosphere of the second enclosure; wherein the isolating function of the first evaporator inlet and outlet shut-off valves (62, 64) and the second evaporator inlet and outlet shut-off valves (66, 68) allows a non-isolated evaporator to continue to function in the refrigeration circuit; and wherein the first and second evaporator condition the single distinct compartment.