Event Tree Analysis

Event trees in the process and energy industries

Overview

Event Tree Analysis (ETA) uses the same logical and mathematical techniques as Fault Tree Analysis. However, whereas a fault tree analyzes how an undesirable top event may occur, an event tree considers the impact of the failure of a particular component or item in the system, and works out the effect such a failure will have on the overall system risk or reliability. Event trees use an inductive approach, whereas fault trees are deductive. Event trees were developed for the nuclear industry. They are much less widely used in the process industries.

Safety and Environmental Management Systems (SEMS)

The SEMS rule applies to oil and gas operations in U.S. waters. It is administered by the Bureau of Safety and Environmental Enforcement (BSEE). The rule holds the facility accountable for the overall safety of the offshore facility, including ensuring that all contractors and subcontractors have safety policies and procedures in place that support the implementation of the operator's SEMS program and align with the principles of managing safety set forth in API RP 75.

Standard Examples

Worked examples for Sutton Technical Books

We have developed a set of process safety management standard examples that are used to illustrate some of the concepts and ideas developed in our publications. 

Example 1 - Facility Design

A process consists of four operating units and a utilities section. A schematic of the system is shown in Figure 1.

 

Equipment Isolation Methods

Isolation of equipment for safe work

Isolation Methods

Positive isolation methods are those which remain effective even if there is equipment failure or operator error. These techniques apply not only to vessels, piping and tanks but also to pneumatic and hydraulic equipment.

The sketch shows some of the various isolation techniques that can be used to protect workers in the process industries. The process containing toxic or flammable chemicals under pressure is on the left; the open system, where the workers are present, is on the right. The order is from the least to the most secure.