Risk Assessment: Tools, Techniques, and Their Applications

8.1 Risk Assessment Data

8.1.1 Introduction

Finding data to populate risk assessments can sometimes be problematic. For example, an analyst is in the process of performing a failure mode and effect analysis on a new, complicated system. When the analyst begins to populate the data tables with failure rates for various failure modes, he/she hits a brick wall. No failure rate data. The question becomes what to do next? Do a SWAG (“scientific” wild ass guess), make it up (worse than a SWAG), or find a subject matter expert (SME) and have that person do a SWAG?

Data are available in many forms for hardware failure rates and for human error probabilities (HEPs), and this chapter provides examples of how to find data and/or how to develop it.

8.1.2 Hardware Failure Rate Data

In the truest sense, hardware failure data are much easier to obtain, than are HEPs. In many cases, failure rate data are available at the system as well as the subsystem and component levels. Hardware failure rate data can be obtained from the manufacture, historical data, government and military handbooks, and accident data or can be generated from testing by the user (1).

8.1.3 Manufacture

Failure rate data can be obtained from the manufacturer for certain pieces of industrial equipment, for instance, pumps, valves, motors, electrical panels, controllers, and even for components such as chips, diodes, and resistors. These data are usually supplied on a product data sheet or can be requested from the manufacture. ...