3 replies to this topic

[A mukherjee]

HI all,
There is a dilemma which I am facing currently.We were commissioning a plant.But due to some technical problem we have to abandon the process in middle.Now after 2 months we are again planning to commission the plant. Now I am confused whether blowing/flushing of the process lines is required.
Can any one help me in this account?

[Art Montemayor]

Arpan:

This is a very sensitive and potentially hazardous topic.

My experience and recommendations can be summarized as:

Unless you are directly in charge of Project Management you should not be held responsible for that decision. The integrity and safety of the startup is at risk due to any possible infiltration of external effects and causes taking place in the last 2 months while the system was moth-balled. This is a management decision.

Unless you can substantiate that the system has been maintained EXACTLY AND PRECISELY in the same, documented condition as it was abandoned (and sealed) 2 month ago, then you are taking a risk and should proceed cautiously and consider the possible outcomes. From what you describe I cannot recommend that you proceed, taking credit for what has previously been done in precommissioning. In my experience, the work, effort, and costs expended 2 months ago should be considered as wasted and the pre-commissioning should be done once again, in detail, starting as if nothing had occurred before.

I cannot place any trust or confidence on a state of equipment unless I have personally been responsible and 100% present/aware of its condition and state of preparation. Since that is not usually the case, then I have to assume a secure, 100% conservative stance. You will probably find strong management opposition to this stance, but this is natural since their interest is to save money and time while they are not participants in the ultimate risks and hazards involved out in the field.

[sheiko]

HI all,
There is a dilemma which I am facing currently.We were commissioning a plant.But due to some technical problem we have to abandon the process in middle.Now after 2 months we are again planning to commission the plant. Now I am confused whether blowing/flushing of the process lines is required.
Can any one help me in this account?

Hi,

I faced the same problem some time ago, but i had taken care documenting the precommissioning activities, sign (user and contractor) the precommissioning documentation so that the hand over had been done before starting the commissiong activities. Doing the hand over (tranfer of responsability from contractor to user) at the end of each phase help avoiding this kind of situation.

In your case (hand over apparently not made) i would follow Art's advice.

[kkala]

Unless you are directly in charge of Project Management you should not be held responsible for that decision....I cannot place any trust or confidence on a state of equipment unless I have personally been responsible and 100% present/aware of its condition and state of preparation. Since that is not usually the case, then I have to assume a secure, 100% conservative stance. You will probably find strong management opposition to this stance, but this is natural since their interest is to save money and time while they are not participants in the ultimate risks and hazards involved out in the field.

What I observe locally is that high technical management have a growing tendency to consider themselves as contract administrators rather than responsible project executioners, passing the buck of "difficult time-consuming details" (e.g. of safety, not to say all hard tasks) to others; so that these "others" are responsible for delays etc. This has to be discouraged, although the specific case does not have an indication that it is so.
Nevertheless I would ask revised written procedure from higher technical management, to clarify what commissioning activities should be repeated, what should not and what new has to be added (if any). This is not limited to blowing of lines only. E.g. there might have been piping modifications in these two months, needing hydrostatic test. Electrical arrangements may have changed, needing new tests. Corrosive liquids might have remained in lines, etc. Finally I would comment the revised procedure, only on points that I would certainly judge wrong (if any).
Besides, it is assumed that blowing of lines may also depend on specific conditions, for instance:
(α) A tested compressed air line may not need a new test. An instrument air line may need humidity check of produced air and purging to atmosphere for few hours to remove any humidity concentrated in piping.
(β) A strong sulfuric acid steel line may need blowing to remove humidity, that would dilute the newly produced acid causing corrosion & H2 production.
(γ) A hydrocarbon line may need blowing, if downstream process require hydrocarbon free of water. E.g. a hot tar line to a tank needs blowing before use.
Only humidity removal has been mentioned, yet blowing may serve also other needs. Let those in charge (knowing all conditions) decide.
Generally unexpected situations can occur, try to use experience as much as possible in addition to pure logic.

Edited by kkala, 26 December 2010 - 05:18 AM.