5 replies to this topic

[AMPIR]

Hi everybody, I do not have experience in the pre-commissioning stage of a plant but now I have to prepare a pre-commissioning manual for 2nd phase of a plant with using the manual of the 1st phase . Can you please help me to find answer for:

1. Except class break and Package limits, what is the key point to define subsystems of pre-commissioning in a plant?
2. If two sub systems have same condition (e.g.: piping class), which of the manual valve or blowdown/shutdown valve should be considered as boundary point between two subsystems?
3. Is there any standard colour code for pre-commissioning drawings?
4. How can select the flushing media?
5. How can select the pressure test media?
6. Is there any guideline for pre-commissioning procedures?

[ricky]

1. Except class break and Package limits, what is the key point to define subsystems of pre-commissioning in a plant?
4. How can select the flushing media?
5. How can select the pressure test media?

Based on my experience so far,

1. Other key points which is usually can't be seen earlier in the project is time.
Some projects have strict time limit. Even worse, not all packages or facilities are completed in orderly manner as predicted before. I have experienced this many time. To tackle this problem, one may consider to build different 'operating' pre-commissioning procedure and time schedule. Generally, make the procedure as flexible as possible. If necessary, forget about facilities limit and go for them simultaneously.

4. Usual flushing media is water (not brackish). But in some facilities like lube plant, lube oil itself is used to flush the pipes. If working fluid of the pipe is a common one, water can be used. Check compatibility of flushing media and working fluid.
However, do not use brackish water since the inner wall of pipe can undergo premature corrosion due to ambient air expose after flushing. Air plus remained salt minerals are perfect match for metal corrosion.

5. Usually is water except when pneumatic test is mandatory.

Hope will help

[AMPIR]

Thanks Ricky;

Do you know:
1. What is limitation to use of water as media for flushing and pressure test?
2. a general guideline for pre commissioning procedure?

[astro]

Thanks Ricky;

Do you know:
1. What is limitation to use of water as media for flushing and pressure test?
2. a general guideline for pre commissioning procedure?

For 1, chlorides are an obvious concern for stainless steel pipework and systems. The allowable chloride level will depend on the risks. I don't have a guideline immediately to hand, I'll let you search the internet.

For 2, you could search this forum. Here's a post I found by using the search function:
Commissioning References
If you haven't heard it before, Engineering has a much used saying, "don't reinvent the wheel". Have a good attempt at eliminating the possibilities that are placed at your ready disposal. By doing a bit of research you'll be able to ask more focused questions.

[AMPIR]

Dear Astro;
Thanks for your reply. But as you know per-commissioning is one step before commissioning and they have different activities so I try to find specific guideline for pre-commissioning.

[astro]

I recognise that key point and so does the content of the post that I referred you to.