Enhancing Safety Through Risk Management

Use This Nine-Step Plan for Every Process

The handling, use, processing, and storage of hazardous materials will always present risk. The goal of process safety management is to consistently reduce risk to a level that can be tolerated by all concerned — by facility staff, company management, surrounding communities, the public at large, and industry and government agencies.

A systematic, risk-based approach to safety design is discussed below. Such an approach can help eliminate those hazards that pose intolerable risk and mitigate the potential consequences of such hazards. Guidance for identifying tolerable risk levels is also provided.

In recent years, industrial standards for tolerable risk have become increasingly stringent. This trend reflects a convergence of public opinion, government regulations, and industry initiatives. In fact, to contain long-term costs and minimize liability, many leaders throughout the process industries are setting standards for their own companies that are well more than what is required.

At the same time, managers at many chemical process companies face unremitting pressure to run their activities “lean” and control and justify costs. The ability to reach rational decisions about process safety design based on a clear understanding of both the risk-reduction options and costs can greatly strengthen a manager’s ability to meet the needs of internal and external stakeholders.

The Concept of Risk

To achieve a consistent approach to risk reduction, process designers must define “tolerable” and “intolerable” risks and document how risk is addressed in the design process. To meet a company’s business needs, the process safety solutions that designers propose must be as cost-effective as possible. The goal is to enable designers to answer the needs of all process-safety stakeholders, without compromising on safety or spending too much on excessive prevention or mitigation measures.

In chemical process safety design, risk is understood in terms of the likelihood and consequences of incidents that could expose people, property, or the environment to the harmful effects of a hazard. Risks that are likely to occur should be addressed; those that are unlikely to occur need not be.

For example, it is always possible to identify scenarios that would be catastrophic for the system being designed. However, process and emergency relief system (ERS) design does not necessarily need to address the worst scenario someone can imagine. Rather, a line must be drawn (or at least a gray area defined) between likely scenarios and unlikely ones.

A process might use an alkyl chloride, which is known to react vigorously with water. If water is not present at the site, there is no need to address that potential reaction scenario in ERS design. Similarly, if water is on site, but is not used in the same process as the chloride, there is still no need to ad­dress it in the ERS design. However, if water is not used in the same process as chloride, but is stored in the same, or an adjacent, storage facility, then, de­pending on the circumstances, it might make sense to include a chloride-water reaction scenario in the ERS design.