Moving Towards Inherently Safer Plants

In the early days of social networks and even for some process manufacturers and producers today, IT departments blocked these social networks including YouTube. I recommended that engineers point to sites such as the U.S. Chemical Safety and Hazard Investigation Board (USCSB) YouTube channel as reasons why these networks should be available. The USCSB performs accident investigations and shows the root causes of the accidents and ways they could have been prevented.

If you’ve seen any of the videos, you know that often missing measurements could have prevented the accident. In one video, a vessel was isolated from its pressure relief valve causing an explosion when the pressure could not be safely dissipated.

Emerson's Jonas Berge


I caught up with Emerson’s Jonas Berge who noted that instrumentation is typically added for equipment being controlled. Wireless instrumentation has opened the ability to easily add measurement for monitoring. In the accident mentioned above, wireless isolation valve position feedback could have warned operators that the vessel was in a potentially dangerous state before the overpressure condition occurred.

Vessel fouling leading to late, unplanned switchovers was another condition cited in some of the accident investigations. By adding wireless flow, temperature and differential pressure (DP) measurements as well as condition monitoring sensors on mechanical equipment surrounding the vessel, these measurements could provide early warning of fouling conditions to allow time to plan orderly switchover and maintenance activities.

Of course, adding missing measurements is not the answer to avoid all accidents. But in many cases, the hierarchy of process safety management can be reviewed to see where manual procedural safeguards can be augmented with active safeguards including these missing measurements. The book, Inherently Safer Chemical Processes: A Life Cycle Approach, included this hierarchy from most effective to least effective:

The most effective approach is an inherently safer design. The least effective are manual procedures to try to spot abnormal or dangerous conditions.

Rapid advancement of technologies and Industrial Internet of Things based sensors around traditional measurements such as pressure, flow, temperature, level, etc. and more recent innovations including vibration, acoustic, corrosion & erosion, etc. make safer, more effective strategies possible.

As these technologies are deployed, procedures reassessed, and processes made inherently safer, let’s hope that sites like the USCSB YouTube channel become ones with really stale, never-updated content.

You can connect with other wireless and safety experts in the Wireless and Safety Instrumented Systems groups in the Emerson Exchange 365 community.