Failure

It refers to the status in which manufactured items and purchased parts don't meet the quality standards, and such items are called defected goods. According to the severity of influence which have on the product's function, failure is classified as follows:

Fatal failure

It refers to the deadly flaws, including the gas leak in gas appliances and the brake problems in cars, which probably pose some danger to the users or damage the product's function itself.

Severe failure

It refers to the flaws, including the disconnecting of electrical appliances, which causes the product's function not to work as intended or to be inoperable.

Mild failure

It refers to the flaws which deteriorates the product's function, decreases the efficiency, or shortens its lifetime.

Negligible failure

It refers to such flaws that do not meet the product standards or specifications including scratches in appearance or unevenness in painting, although, unlike mild failures, it has no influence on the product lifetime, performance, and efficiency.