8. Assessing Product Reliability
8.1. Introduction
8.1.1. Why is the assessment and control of product reliability important?

8.1.1.3.

Safety and health considerations

Some failures have serious social consequences and this should be taken into account when planning reliability studies

Sometimes equipment failure can have a major impact on human safety and/or health. Automobiles, planes, life support equipment, and power generating plants are a few examples. 

From the point of view of "assessing product reliability", we treat these kinds of catastrophic failures no differently from the failure that occurs when a key parameter measured on a manufacturing tool drifts slightly out of specification, calling for an unscheduled maintenance action. 

It is up to the reliability engineer (and the relevant customer) to define what constitutes a failure in any reliability study. More resource (test time and test units) should be planned for when an incorrect reliability assessment could negatively impact safety and/or health.