Why process safety is vital for net zero

United Kingdom | 12 April 2021

By Peter Hunt – Business Development Director, Industry, WSP

Process safety is a framework for managing the integrity of operating systems and processes handling hazardous substances by applying good design principles, engineering, and operating practices.

Those of us working in process safety strive to prevent and control incidents that can cause the release of hazardous materials. Over five decades, the IChemE Loss Prevention Bulletin has documented many incidents, using stories to illustrate some of the lessons learnt and improve corporate memory. In the UK, an example of this is the Buncefield Fire and Explosion on 11 Dec 2005, which resulted in numerous injuries and damage to assets and the environment.

Our work is about learning from such events and using this knowledge to prevent serious injuries, property damage, lost production, and environmental impact in the future. We do this by trying to make processes inherently safe. As my university lecturer and process safety guru Trevor Kletz used to say in summing up inherent safety: “What you don’t have, can’t leak.”

How to make processes inherently safe

Minimise – reduce the amount of hazardous material present
Substitute – replace one material with another of lower hazard
Moderate – reduce the strength of an effect
Simplify – eliminate problems by design rather than adding additional equipment or features to deal with them
Error tolerance – design to withstand faults and deviations from design
Resilience – limit consequences of failure by designing:
Against knock-on effects
To make incorrect assembly impossible
To make status clear
For ease of control.

Another key message from Trevor’s book, Lessons from Disaster, is that: “Organisations have no memory – only people have memories and after a while they move on taking their knowledge and experience with them.” Because of this, process safety needs continuous attention.

The net zero economy will require key industrial chemicals, such as hydrogen and ammonia, which can be considered inherently unsafe. But they can still be used in processes that are themselves inherently safe. This is done by building process safety into every aspect of a project, from management systems to human factors, and every stage of a project, from inception to decommissioning.

This continuity is crucial because it’s during times of change that mistakes can happen. For example, with the introduction of new environmental laws in the 1990s to reduce emission of volatile organic compounds (VOCs), some companies linked vents together through collection systems to form a single vent from which to remove contaminants. But the plant components weren’t originally designed to be connected and joining them together magnified any potential incident. The risks weren’t always assessed and mitigated, leading to several explosions at plants around the world.

Net zero process safety: capturing CO2

Capturing CO2 from industrial processes is an important part of net zero and requires fitting additional equipment to existing plant. While for some industries this is familiar technology, for other sectors it is something they have not previously encountered, and the associated hazards are unfamiliar. Our process safety team at WSP is working on a project that will capture CO2 at a plant and feed it into a pipeline network. We are ensuring all the modifications are designed rigorously and carrying out process safety studies to ensure there is no additional risk.

Net zero process safety: hydrogen and ammonia

Hydrogen and ammonia are being considered both as decarbonised energy vectors and as transport fuels, for example in the maritime sector. This means that these chemicals will be handled and utilised in settings that are unfamiliar and out with current practice. We have performed safety studies for a proposed large-scale green hydrogen and ammonia production, storage and export facility, considering potential hazards, their mitigation and requirements for spatial segregation from other industries and vulnerable receptors.

A focus on process safety can prevent and control incidents in the processes at the heart of the UK’s plans for net zero – and by doing so build and maintain social acceptance of them. Such a focus has been achieved after past incidents, with companies appointing directors responsible for process safety and creating separate departments to focus purely on process safety, irrespective of timescale and cost.

As we move towards net zero, and new companies deploy new technologies, we must not let this focus slip; we must not forget the process safety lessons of the past. The processes we need for net zero can be inherently safe, if we design, engineer and operate them that way.