scope:

Purpose. This handbook provides guidelines for Environmental Stress Screening (ESS) of electronic equipment, including environmental screening conditions, durations of exposure, procedures, equipment operation, actions taken upon detection of defects, and screening documentation. These guidelines provide for a uniform ESS process that may be utilized for effectively disclosing manufacturing defects in electronic equipment caused by poor workmanship and faulty or marginal parts. It will also identify design problems if the design is inherently fragile or if qualification and reliability growth tests were too benign or not accomplished. The most common stimuli used in ESS are temperature cycling and random vibration. A viable ESS program must be dynamic; the screening program must be actively managed, and tailored to the particular characteristics of the equipment being screened. It should be noted that there are no universal screens applicable to all equipment.

ESS is part of a viable engineering development, manufacturing corrective action and overhaul process rather than a test in the normal accept/reject sense. Guidance in developing a screen can be found in figure 1. Those participating in the effort, including the contractor should never be led to believe that a "failure" is bad and would be held against them. ESS is intended to stimulate defects, not to simulate the operating environment, and therefore, factory failures are encouraged. The root causes of ESS failures need to be found and corrected before there is a complete process. This handbook cannot be cited as a requirement. If it is, the contractor does not have to comply.

intended Use:

This document provides guidance for establishing, documenting and implementing an ESS program.