Are your people protected by your isolation process? - Hidden factors in complex process plants.

A real example of hidden factors that could have had fatal consequences and how you need a technical expert to diagnose these problems or you could be solving the wrong problems.

I have recently shared a post and some material on the subject of isolation of equipment to prevent the unwanted release of energy. This is normally referred to as Lock-Out - Tag-Out (LOTO). This is a follow on from that article, but relates to another article I posted recently about the dangers of choosing a safety consultant without the right capabilities for the job. The case below is an example of both.  

Failure to properly isolate (LOTO), is a complex problem, made more complex with increased use of automated / programable logic-controlled equipment in more industries. This requires more process safety, process engineering and technical safety expertise in workplaces traditionally focussed on personal health and safety. 

A modern processing plant had been experiencing recurring incidents related to machines not being isolated during both planned and unplanned maintenance. The operation had previously engaged an OHS consultant (not me), who performed an audit to identify the problems and any non-compliances with OHS law. The audit criteria were a combination from AS/NZS 4801 and general OHS regulations for the jurisdiction, with some checks against an isolation checklist. The consultant provided a 20-page report with findings primarily relating to worker behaviours, procedural breaches, poor safety culture (not defined in the report) and a few non-compliances with regulations, not related to isolations. The consultant also provided a new OHS management system (off the shelf) and an isolation procedure, that was largely generic. This took about 7 days consulting time. The isolation incidents continued not long after the consultant had finished the work, despite the implementation of the new system and procedure. I was engaged by the client to investigate the isolation problems, referred to them by another company within the same group of companies, who had engaged me previously for similar problems. I performed a full diagnostic for the isolation process at the plant. In doing so, I worked primarily with people from operations and maintenance. We reviewed incident investigations; read circuit, piping and instrumentation diagrams (yes I can read them); checked equipment operating modes; inspected isolators and isolation points; tested isolations; and reviewed control room operations, indications and monitoring. We talked to many operators and maintainers, asking focussing questions and walked through various isolation processes a number of times. This included working through how: areas / equipment were secured; isolation devices, locks / keys and devices were issued; equipment move / test / bypass procedures were carried out; and how the authority or permit to work system operated.

I then facilitated a problem definition and problem solving workshop involving maintenance, operations and safety personnel. In that session, we came to a common understanding of the problems and the recommended solutions. What we found were a number of problems that could have resulted in permanent or fatal damage to people that were simply not identified by the previous consultant’s audit. The key findings of the diagnostic included:

• Changes to equipment configuration, power / control logic making some isolations no longer effective at all times when carried out to the procedure.
• Unmanaged wiring and logic control changes also rendered some emergency stops inoperative.
• The logic control for some equipment, meant that control room tests for zero energy in the system were invalid, as permissible signals to operate the equipment were not present / absent at the time of testing.
• Isolation points were not well identified, some people were mistakenly isolating the wrong equipment.
• The isolation procedures were generic, not equipment, configuration, system or task specific, which invited mistakes and incorrect isolations.
• All isolations were “individual isolations”, making everyone responsible for their own isolation (every person for themselves). In a complex plant, with many tasks interfacing, this situation led to constant unwanted interactions and people were only communicating by accident not by design.
• The authority or permit to work system executed by the control room did not properly control task interfaces, keys, locks and bypasses.
• Move / test procedures and up-stream / down-stream energies / tasks were not properly understood and resulting in equipment moving / operating with people in the line of fire.

We also revealed that several people in the workforce had identified parts of these problems previously, but this had not been captured effectively. Simply, no one had asked the right questions and had not brought operators, maintainers and safety personnel together and enable them to come to a common understanding.

This is a perfect example, of where a safety consultant, without the right experience and technical expertise to understand the problems they are attempting to solve, has jumped straight to a broad-brush solution. An unplanned release of energy or energisation of equipment in the plant during maintenance, cleaning or clearing blockages could easily result in permanent or fatal damage to people working on or near the equipment or those up-stream / downstream.

It is also a good example of how isolation of hazardous energy can be a very complex problem with many component problems interacting, needing to be properly defined.

Please, don't assume if you are having near misses / incidents involving isolations that it is just people making mistakes. If you cannot be 100% certain that your equipment is in a zero energy state when isolated, have the problems properly diagnosed and defined by an expert.

If you need any assistance form an expert on the isolation of hazardous energy in processing, manufacturing or during maintenance in any industry, please don't hesitate to contact me. Even if it is just a phone call from some free advice, I would be more than happy to help if I can.