The Weekly Reflektion 03/2022

Research and Development can lead to new understanding that can change the way safety systems are designed and operated. One example is the release of water deluge in the event of a gas leak.

Do you systemically review the way you carry out tasks to ensure the hazards are controlled and the risks managed?

On one of the installations I was working on in the 1990s, the operator introduced the ISRS system (International Safety Rating System). The ISRS system consisted of several elements or processes that the organisation should follow and there was a scoring system to monitor development. One of the elements was ‘task analysis’. Here the person normally carrying out a task would discuss the procedure/process for the task with a colleague and then carry out the task with the colleague observing and noting the steps. The person doing the work was encouraged to explain each step and why it was being done. For anyone who has participated in a defensive driving course this technique of explaining your thinking and actions underway should be familiar.

One of the tasks was to acid wash the hydrocyclones that were used to remove oil from produced water before it was discharged. The acid wash was required to remove scale (salt deposition) that reduced the cyclone efficiency. At one of the steps the production technician carrying out the task opened a vent valve that was not part of the procedure and did not explain why it was done. ‘Why did you open that valve?’ the observer asked. ‘Well, if you don’t open that valve before proceeding to the next step then you may get a release of hydrosulphide gas. It happened to me a couple of months ago and wasn’t pleasant’. ‘Why didn’t you tell anyone and get the procedure updated’ the observer asked. ‘Everyone knows about it, and you know what a hassle it is no get these procedures changed’ was the reply. The observer was also a production technician although he had never done this task before and was not aware of the potential hazard.

The particular scale that deposited in the hydrocyclones was zinc sulphide and it reacted with the hydrochloric acid to produce hydrogen sulphide (H2S) gas. H2S is highly toxic and can be fatal even at low concentrations. Ensuring a closed system and an adequate vent during the acid washing was an important safety factor. The acid washing was only required intermittently and not many of the production technicians had been involved in the task and were unaware of the potential hazards. The person that wrote the acid washing procedure used the procedure from another installation as the start point. On the other installation the scale in the hydrocyclones was a different type and did not react with the acid to produce H2S.

Cut and paste can be a useful start to preparing procedures for a new installation or for procedures for new operations on an existing installation. However, there may be differences between the installations and the material being produced that mean the pasted-in procedure may not be adequate to control the hazards and manage the risks. Task analysis is a useful technique to promote discussion and to discover holes in the procedures. Are you sure there are no holes in your procedures?   

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