The Oil and Gas Engineering Guide


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Published Friday 17/02/2012

- precise definition of interface between disciplines, through procedures, responsibility matrixes etc, to avoid "waiting on others",


- close coordination between disciplines, such as piping and civil: engineers and designers to be grouped by work areas rather than by disciplines,


- a good system in place for design changes. First, develop a strong resistance to design change and habit to strive to find alternatives. For changes that cannot be avoided, early implementation by means of identifiation of all impacts, prompt actions (E, P, C) and precise dedicated follow-up of implementation of all actions,


- focus and control of key vendor drawings (interface dwgs: GA, foundation and loads, piping connection, load list, PID, control narrative, C&E), avoiding engineering hold up ydue to vendor information,


- proper organization for spooling, reducing the lag between design and shop ISOs, such organization integrates both engineering and the construction contractor,


- definition of relevant early work packages, with construction, during constructability workshop,


- maintain up-to date bill of quantities, e.g., list of steel structures to be erected, with dwgs and material delivery dates, for Site to plan adequate resources,


- provide Site with adequate and updated list of items, material take-of, item count etc. to enable an accurate monitoring of the construction progress. The Construction progress shall indeed be measured against the up-dated work volumes. The later, which constitutes the "100%" will keep changing up to the end of Engineering. It is necessary that such changes are incorporated in the Construction progress measure in order to reflect the progress against the actual work volume,


- Implement a precise Engineering progress monitoring. Such as precise progress monitoring is one where steps are precisely and indisputably identified, such as with a binary status 0/1 (document not issued/document issued). Intermediate statuses, such as "document started" etc. shall not not considered. The individual document status is weighted by the number of documents to give the progress of a task consisting of the issue of multiple documents, such as P&IDs.


Published Thursday 02/02/2012

The purpose of the Piping Line diagrams

A Piping Lead Discipline engineer colleague of mine recently explained to me the purpose of the Piping line diagrams (page 106).


As we know, the P&IDs are not geographical hence do not give any idea of the length of lines. The Line Diagram does. It therefore allows to measure the length of lines and to produce the first piping material take-off.


In addition, the line diagram shows the number of lines on each pipeway/piperack. It will therefore allow to determine the width of the pipe ways, width and number of levels of pipe-racks etc. Such width is not directly shown on the line diagram as the latter is, after all, a "diagram" and not a "drawing" hence it is not to scale. It does not take into account the space taken by each line (depending on its diameter) and their spacing. This will have to be determined in a second step, by making typical sections. Once this will have been done the footprints of pipe ways and pipe-racks whill be known, which have to be fed into the Plot Plan.


Another purpose of the line diagram is to identify the density of lines in the various areas. It will then be used to split the piping routing study work in different areas, of same work volume, to each of which will be assigned a different lead engineer producing the piping studies (page 107).


Lastly, the line diagram allows piping to identify the order of the connections on a header, such as a flare header, and to provide such information to Process, in the form of comments on P&IDs. With such information, Process can size the header with properly positioned diameter increases throughout its route.