GB 9251-88 Test Method for Hydrostatically Testing the Cylinders of the Sealed Liquefied Petroleum Gas
Introduction
The use of liquefied petroleum gas (LPG) cylinders has become increasingly popular in the developed countries due to the convenience, personalized and efficient mode of transportation it offers. To ensure the safety of these cylinders, proper testing and maintenance is essential, this includes proper hydrostatically testing. A standardized hydrostatic pressure test procedure must be followed in order to ensure the safety of the containers and to confirm their performance under different operating and emergency conditions. This document sets out the requirements for the hydrostatically testing the cylinders of the sealed liquefied petroleum gas, as prescribed in GB 9251-88.
Scope
This standard defines the requirements for the hydrostatic testing of the cylinders of the sealed liquefied petroleum gas. Testing must be conducted in accordance with the procedure as prescribed in GB 9251-88 and any applicable local laws and regulations.
Requirements
LPG cylinder testing is mandatory and must be conducted by qualified personnel in accordance with the criteria defined in GB 9251-88. Cylinders must be pressure tested at a minimum design pressure equal to seventy percent (70%) of the stated test pressure. If the stated test pressure is unknown, then the pressure test must be performed at the maximum design pressure. The design pressure specified in the certificate of test must be exceeded during the test. The testing must be conducted using appropriate hydrostatic testing equipment capable of accurately measuring the pressure. Cylinders must be fully inspected for dents, non-original material, excessive corrosion, damage to external or internal threads, and any other defects that may affect the safety of the cylinder. The test system must include the required guard and relief valves and be operated in a safe manner. The hydrostatic test pressure must be maintained for a period of not less than 15 minutes. When the cylinder is opened, its internal surface temperature should not exceed 70o Celsius. Any cylinder that has obviously been affected by high pressure or temperature must be discarded and replaced.
Conclusion
The testing of sealed liquefied petroleum gas cylinders is a crucial process to maintain the safety of the cylinders. It is essential that qualified personnel follow the standardized procedure as prescribed in GB 9251-88 when conducting the hydrostatic tests. The cylinders must be inspected for defects before testing, and the hydrostatic pressure must be maintained for a period of not less than 15 minutes to ensure its safety and performance. When the cylinder is opened, the internal temperature should not exceed 70o Celsius. Any cylinder that has been affected by high pressure or temperature must be discarded and replaced.
