RE: Line numbering

From: <Richard>
Date: Sat Jan 05 2008 - 13:54:00 EST

Hi Sanjib basu
The standard for line numbering varies from company to company, and I have seen it done both ways. My own preference is to change line numbers when there is a reduction in header size. I believe this to be clean and concise and avoids Line Lists with notation such as: 1001 A 3"/2" 40/80 or the same line number being listed twice for the differing NPS and schedules, and sometimes insulation thicknesses. Having worked with both, I have not experienced any issues with preliminary MTO's either way, as these come from the studies and rough isometrics. And while the bulk purchase valve count is generally a take off from the P&IDs, these are by spec and not line number. Later on down the line during detailed design and construction is where I think the benefits of separate line numbers come into play for MTO/valve reports and progress monitoring.

It is my understanding (not being at all literate in databases) that automatic Line List generation from a database, populated as the drafter creates the "smart P&ID", cannot work without a change of line number (Paul, any comments now that you're a CAD guru?). So as more and more companies adopt these softwares the industry will be forced as a whole to do it this way.

When all's said and done what are we saving by not changing line numbers? A few line numbers is all. And what are we risking by not changing? Potential mistakes in my opinion. One line number used for varying NPS sizes equates to many variables within the documentation generated for that line, and hence the possibility of mistakes, whereas changing the line number can avoid this potential for mistakes.

Richard B
Calgary, Canada

-----Original Message-----
From: PipingDesign@yahoogroups.com [mailto:PipingDesign@yahoogroups.com] On Behalf Of sanjib basu
Sent: January 4, 2008 6:43 PM
To: Piping Design
Subject: [PipingDesign] Line numbering

Dear Experts,

The question below is asked by one of my friends:

"We have a situation wherein lines having different dia are assigned same line numbers.

I am informed, here, that its easy for process design & Piping work (initially), but I believe that this makes execution more complicated in terms of :

• Initial estimates, Initial Inch-dia, insulation, tracing quantities etc based on prelim MTO where P&ID is the source.
• Based on line list, its confusing to associate a size for the valves.
• More importantly from a database perspective, it cannot be captured.

My question is " Is it a common practice to have line numbers with different dia or is it non-standard? "

With regards
Sanjib basu

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[Non-text portions of this message have been removed] Received on Sat Jan 05 13:54:00 2008