In an EPC project after how much percentage progress of civil work, should piping work be started?

Piping work will start after completion of 50 % civil work .

Soil compaction and leveling shall be finished. Main Pipe rack installation work shall be started.

We can start piping works after 30% complition of the civil work.

It should be after around 30%

It is not only Civil, but also structural works . The percentage progres should be about 25 to 28%

We can start piping work after 30% of civil work completion.