Leak
Types of leak openings include a puncture, gash, rust or other corrosion hole, very tiny pinhole leak (possibly in imperfect welds), crack or microcrack, or inadequate sealing between components or parts joined together.
Also possible are leaks of engine coolant - particularly in the radiator and at the water pump seal, transmission fluid, motor oil, and refrigerant in the air conditioning system.
Batteries are at risk of leakage, because their operation inherently involves chemical corrosion.
A system holding a full or partial vacuum may have a leak causing inleakage of air from the outside.
Hazmat procedures and/or teams may become involved when leakage or spillage of hazardous materials occurs.
Leaks while transporting hazardous materials could result in danger; for example, when accidents occur.
A leak could even be inside a living body, such as a hole in the septum between heart ventricles causing an exchange of oxygenated and deoxygenated blood, or a fistula between bodily cavities such as between vagina and rectum.
Leaks can occur from the outset even during construction or initial manufacture/assembly of fluid systems.
Pipes, tubing, valves, fittings, or other components may be improperly joined or welded together.
Wearing out of packing around a turning valve stem or rotating centrifugal pump shaft could develop into fluid outleakage into the environment.
Similarly, wearing out of seals or packing around piston-driven pumps could also develop into outleakage to the environment.
Helium testing may be done to detect for any very small leakage such as when testing certain diaphragm or bellows valves, made for high purity and utra high purity service, requiring low leak rate capability.
Leak testing is part of the non-destructive test NDT portfolio that can be applied to a part to verify its conformity; depending on material, pressure, leak tightness specifications, different methods can be applied.
For example, BS EN 1779:1999; it applies to assessment of leak tightness by indication or measurement of gas leakage, but excludes hydrostatic, ultrasonic or electromagnetic methods.
Sometimes a damaged but not yet leaking tube is pre-emptively plugged to prevent future leakage.
