Why we are Wrong to Overlook the Cinderella of Hazard Studies

Britest’s Rob Peeling argues that despite its reputation as a dowdy workhorse, Hazard Study One is a risk assessment tool fit for a prince

ONCE upon a time, and I am old enough to remember it, a venerable, not to say imperious, kingdom called ICI produced something they called Process SHE Guide 13. This handsome document proposed a six-stage hazard study programme for all projects spanning everything from process development to operation post-commissioning. The guide’s fame travelled far and wide, and it became the de facto standard expected by the UK’s Health and Safety Executive and other regulatory bodies around the world.

Recent experience, however, acquired in the course of my work at Britest, suggests the six-stage process may now be less widely known than it once was. While a romantic disappearance into the mists of legend may have the makings of a good fairy story, for me this is a cause for concern and regret.

Not everything in the guide is consigned to long, long ago, however. Table 1 summarises the classic six stages of the study programme. Stages two through five are alive and well. Hazard Identification (HAZID) is Hazard Study Two, and the universally recognised HAZOP is Hazard Study Three. Checking the design and pre-commissioning checks are an integral part of project implementation, though these are not necessarily known these days as Hazard Study Four and Five. Hazard Study Six (essentially confirming the basis of safety is still sound post-commissioning) was often omitted as the commissioning team was hastily redeployed to their next job.

Hazard Study One, although still frequently completed, was always a bit of a Cinderella. The problem lies, I believe, in the way it was originally structured, which led to the study getting a reputation as a mere form-filling, box-ticking exercise. In other words, a necessary chore. For many, unlike its more glamorous stepsisters HAZID and HAZOP, it was unclear what the value was in terms of better process safety. Surely such a drudge could never be belle of the ball? I beg to differ, however. For many, if not most, projects, Hazard Study One is a great missed opportunity. Here is why:

Before the chime of midnight strikes

The original ICI documentation states: “The purpose of Hazard Study One is to ensure that the understanding of the project, the process, and the materials involved is sufficient to enable safety, health and environmental issues to be properly assessed,” and “to agree the extent and timing of further hazard studies and the need for any additional specific studies or assessments”.

It is these two statements, together with the timing of the study, that capture the potential power and value of Hazard Study One as a process safety risk assessment tool.

No leaving it until just before the clock strikes midnight here.

The importance of the timing is simply that it should be very early in the project life cycle, during process development. This is the stage of the project where making timely changes can have the greatest impact at the minimum cost of implementation on safety, health, and environmental impacts and reaching beyond that to operability and sustainability.

At this point, the gaps in a process definition become an opportunity to develop a simpler, more robust process and make better informed equipment selections. Ideally the time when the perils of using a pumpkin for a coach would be identified.

A good example of the value derived from making an early assessment of this sort arose during the scaleup of a two-phase chemical synthesis to a kilo lab. In the original version, the required product was in the heavier, organic phase. The project team were aware at the time of the study that the reaction could proceed just as well in another organic solvent which was lighter than the aqueous phase. Since the study revealed this early in the project, it was possible to change solvents and realise a process that was both inherently safer and of improved operability with respect to product work-up and isolation.

“Understanding of the project, the process and the materials,” encourages us to consider a broader range of risks that goes beyond process safety. Do we understand how business and technical risks (particularly those associated with scaleup and technology transfer) are going to be mitigated? The relevance to process safety of secure process understanding is clear and represents a first chance to work with the operability element in HAZOP. Mixing challenges, for instance, can be identified and any impact these will have on process safety or scaleup. How tight are the operational windows for a biotechnology process? Identifying mitigation measures to resolve such issues early on, potentially saves considerable expenditure later when corrective action is much harder to take.

I have found that the approach has been successful in making Hazard Study One a much more insightful probe of a process, adding real value to the activity