Which of the following is not a requirement for refrigerant cylinders?

Refrigerant cylinders are designed with specific standards to ensure safe handling and storage of refrigerants. One of these standards includes incorporating pressure relief devices to prevent the cylinder from bursting due to excessive internal pressure. Color coding is also mandated to allow for easy identification of the type of refrigerant contained within the cylinder, facilitating proper handling and use.

While temperature regulation is important in the overall management of refrigerants, specifically, there is no requirement stipulating that refrigerant cylinders must be kept at a regulated temperature. Instead, it's crucial to store cylinders in an appropriately ventilated area and protect them from excessive heat. Evacuation before disposal is also necessary to ensure that no refrigerants are released into the atmosphere, aligning with environmental regulations.

Thus, while the other options pertain to essential safety requirements for refrigerant cylinders, temperature regulation is not mandated as a standard requirement for the cylinders themselves.