In the framework of a testing program for glass-reinforced epoxy (GRE) pipes, the long-term material strength properties at a high temperature of 150°C are determined through the pressurization of test spools. These spools, comprising pipes, fittings, and end caps, are pressurized with water at a pressure of 250 bar and a temperature of 150°C. The tests are conducted within a protective container. Due to the high pressure involved, which poses a risk to personnel and equipment near the test facility, DRG conducts a Risk Assessment and Evaluation in accordance with the requirements of the governing control agency.
Risk Assessment Analysis
Despite the water in the test spool being heated well above its atmospheric boiling point of 100°C, it does not boil due to the high pressure. However, if the test spool fails, the pressure drops to atmospheric level, causing a significant portion of the water to evaporate almost instantly in an explosive manner. This leads to a substantial pressure increase and a potential shock wave within the test container. Thermodynamic analyses are carried out to evaluate these effects. Additionally, fragments of the test spool may be propelled by the explosive development of steam. The kinetic energy of these fragments is calculated to assess their impact on the surrounding test container and the protective spool that encloses the test spool. Based on these analyses, specific measures are proposed.
Results And Conclusions
An explosion hatch is appropriately sized to quickly relieve overpressure and prevent damage to the container. A GRE material protection spool is designed to shield the environment from the shock wave resulting from the explosive steam formation. The spool’s sizing also considers the impact energy of the test spool fragments. Furthermore, a check valve is specified to prevent the uncontrolled return flow of hot water and steam into the pump house adjacent to the test facility, which could occur if a hose breaks or disconnects from the pump.
Comprehensive Risk Assessment
DRG’s specialized analysis and comprehensive Risk Assessment and Evaluation provide time and cost savings. The thermodynamic and strength assessments are complemented by an evaluation of all other technical and non-technical risks associated with the test facility. Various measures to eliminate these risks are proposed. The detailed analysis and findings are documented in a Risk Assessment and Evaluation report submitted to the local authorities.
