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Decommissioning Safety Critical Elements

Decommissioning Safety Critical Elements

Decommissioning Safety Critical Elements


My company (oil & gas) have invested a substantial amount of time and recourses into an operating integrity project which has reviewed pressure relief/blowdown and depressuring performance of plant units and updated our safeguarding memorandum.

We've identified some process vessels which have more than adequate pressure relief coverage and we are considering removing some relief valves to save on maintenance costs and generally improve maintenance productivity.

My experience of industry is that it is often very easy to install/implement barriers to hazards but particularly difficult to take them away once already existing. It's seems to be a large reputational risk should an unforeseen scenario develop where this piece of equipment could have prevented an incident.

The example I've shared above is on relief valves but my question relates to general safety critical plant equipment...thus what are people's opinions on removing barriers to save money (decisions based on an engineering always of course)? Should we remain ultra conservative or should we out our mouths where our money has already gone?

RE: Decommissioning Safety Critical Elements

Surely this is covered by Change Control in your organisation, noting that it is not only a cost saving measure, it is removing more points of failure.

If the correct level of engineering justification is done (HAZOP and calculations), then the risks assessed for removing and not removing the PSVs, it should be simple and defendable in court (I guess this is one of the reputational risks you are talking about). I guess the costs for completing the project need to be approved and offset against the potential cost savings proposed.

RE: Decommissioning Safety Critical Elements

To build on tickle's question about change control, do you have documentation about why each of the different safety devices were added? Perhaps some items were added after a "one-off" incident and may seem redundant without knowing the history. This scenario is fresh in my mind because my friend and his colleagues made this mistake and had to undo two weeks worth of work after someone brought up a long forgotten issue.

RE: Decommissioning Safety Critical Elements

What does the PSFM say about these relief scenarios which these RVs' are meant for; and how have you / your company justified removing them - have you beefed up on alternate instrumented safeguards also ?

RE: Decommissioning Safety Critical Elements



These RVs were added as per the original design of the plant circa 1970. Over the years the facility operating envelope, fluid conditions etc have changed as well as our technical expertise in the area of design (dynamic simulations etc). Personally I do think we have done the necessary engineering work to justify their removal...but as with everything safety related, it is impossible to foresee all circumstances hence why the industry as a whole continues to hurt/kill people. Thus the only real risk in my opinion is a reputational risk - thus I was interested to hear peoples thoughts on this.


They are fire case RVs. There are multiple RVs in service and we have demonstrated we have adequate relief capacity with the adjacent valves.


Thanks for the thoughts. Seems like the general consensus is that by following an MoC process it is sufficient to cover one's backside :)

RE: Decommissioning Safety Critical Elements

If the project has the money, get some contractors to do an independent review of your reports and calcs. Follow your process, if you have a PE on the project make sure they are on the same page as the rest of the team if they have been hands off. If you and your team are confident in the work and diligence, there isn't much more that can be done. May the entropy be ever shifting in your favorthumbsup2

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