Eliminating or Controlling System Risks via Effective System Safety Requirements and Standards

Abstract

When addressing system risks, an overly simplistic supposition exists when an analyst assumes that once single hazards are identified and hazard controls are applied, the job of the safety engineer is complete. Such a mindset is literally dangerous in that potential system accidents may not have been identified and mitigated. System accidents may be the result of many hazards that under specific circumstances form an adverse progression, resulting in harm. Consider that there may be systemic and synergistic risks associated with a system.

Designers are generally concerned with meeting a customer’s needs; however, in many situations, neither the customer nor the designer may be aware of systemic and synergistic risks related to a particular design. Experience shows that more than 50 percent of requirements are either not defined or not articulated clearly by the customer.

Given that there may be non-apparent system hazards that present systemic and synergistic risks, how then are effective system safety requirements and standards developed to assure that system risks are eliminated or controlled to acceptable levels? The following discussion provides concepts, criteria and considerations to provide context and answer the proposed question.