What are the Safety Parameters Followed by Pressure Vessel Manufacturers
Safety has always been a huge priority where pressure vessels are concerned. The use of poorly designed and manufactured pressure vessels has resulted in the deaths of millions of men and women over the years. To reduce the staggering number of fatalities, pressure vessel manufactures are required to adhere to the standards and guidelines laid down by Government bodies.
API and OSHA Regulations
While there are a variety of codes and standards regarding various types of vessels, the most well-known guidelines that companies adhere to are:
• API 572 for inspection
• ASME Boiler and Pressure Vessel Code
• API 510 Vessel Code for maintenance, alteration, and repair
• OSHA 1915 Subpart K for vessels, drums, and containers
Safety Parameters for Pressure Vessels
While standards, codes, and regulations are essential for the industry, it is also the responsibility of pressure vessel manufacturers to use certain safety parameters for the manufacturing process. All manufacturers know that corrosion is the biggest factor for the weakening of the pressure vessel. For this reason, manufacturers place immense importance on the type of construction materials, the welding processes, and testing procedures, when it comes to designing and producing pressure vessels.
• Materials: Pressure vessel safety concerns begin right from choosing the raw materials. If the raw materials are not of proper grade, then the pressure vessel cannot be considered fit for use. For the fabrication process, manufacturers use only high grade stainless steel and alloy materials including Hastelloy, aluminum, nickel, and carbon steel. Nuts and bolts of particular sizes and specifications are chosen to provide the metal further strength. A few manufacturers also provide skid assemblies for better safety in industrial applications.
• Welding: All manufacturers are required to follow welding guidelines laid down by ASME in Section 9 of Pressure Vessel Safety. Manufacturers formulate a welding procedure that adheres to the standards of Section 9. They employ pressure welders who have passed the ASME P1-F3 qualification test. Welders are required to stamp the work using a symbol provided by the manufacturer.
• Testing: The testing process is a pivotal stage as this will ascertain whether a pressure vessel is ready for delivery and use. The process begins with testing the mechanical strength and thickness of the steel plates. The quality of the welding joints is tested by conducting Non Destructive Examinations (NDE) using ultrasonic devices, magnetic particle tests, and even radiography.
The final test that is used to determine whether the vessel can withstand the required industrial pressures is the hydrostatic test. The vessel is completely filled with water and is pressurized 1.5 times the maximum allowable working pressure. If the vessel maintains the pressure for at least an hour, then it is ready for use.
All these processes ensure that pressure vessels sent for industrial applications meet the safety requirements, and will work under extreme conditions.