Some pressure vessels such as fire extinguishers may be re-qualified by means of a proof pressure test. This method, also known as a modified hydrostatic test, consists of subjecting a pressure vessel to a specified internal pressure and inspecting the pressurized container for leaks, bulges or other defects. This method is permitted only when the applicable regulations do not require the determination of volumetric expansion measurements in order for the container to pass the hydrostatic test.
High pressure cylinders must be requalified periodically in compliance with Transport Canada, UN and CGA standards. Testing of pressure vessels for transport and storage of gases is important because they can catastrophically fail under pressure if they are damaged or defective.
WATER JACKET TESTING
After the cylinder passes an internal and external visual inspection it is placed inside a test jacket filled with water, water is used as it is almost in-compressible. The applied internal pressure which is typically 150% of the operating pressure causes an expansion of the container being tested, the total and permanent expansion that the cylinder undergoes are measured. These volumetric expansion measurements are used to determine if a pressure vessel is safe for continued use, or has suffered from a degradation in its structural integrity and must be condemned. After hydrostatic testing, it's common for the cylinder to remain slightly larger than it was prior to testing, this is referred to as permanent expansion.
Majestic Hydrotest & Fire Extinguisher Services Inc is a Transport Canada and Intertek certified hydrostatic testing facility and cylinder requalifier. We use computer controlled hydrostatic testing equipment capable of testing from 2500-9000 psi. Our large test jacket can accommodate up to 22" in diameter and 66" tall. We also offer CO2 filling, proof testing, UN cylinder testing, acetylene tank recertification, fire extinguisher sales and service.
Majestic Hydrotest & Fire Extinguisher Services Inc