Final answer:
Reusable refrigerant containers that are under pressure above 15 psig must be hydrostatically tested and date stamped every 5 years.
Step-by-step explanation:
Reusable refrigerant containers that are normally under any pressure above 15 psig must be hydrostatically tested and date stamped every 5 years.
Hydrostatic testing involves filling the container with water and pressurizing it to the specified test pressure. The container is then inspected for leaks or other issues.
By date stamping the container every 5 years, it ensures that the container is regularly tested for safety and compliance.