p&Id

It is easy to prepare a MTO (Material Take-Off) depending on and from the P&ID for some materials such as : equipment, vessels, pumps, valves and instruments. But no way you are capable to estimate the piping materials such as pipes, flanges, fittings, supports, ... etc.

And the P&ID (not p&id) must be completed to include all main processes and utilities, and not as a PFD (Process Flow Diagram) nor a Schematic Drawing.

My job, these days, has become one of read a P&ID and price a quote to build the system for a customer. Therefore, I have a bit of experience with this.

You better have a good spec package with this to describe what is desired for various symbols on the P&ID. For example, an automated ball valve symbol tells you basically what is required, but not what brand and model is preferred, nor whether it is a two piece or three piece valve, if the ball is a vee notch or not, what connections to the piping is required, unless the P&ID shows a flange connection. But then, what is the required pressure rating of the flange? Some customers want 300# rating flanges in systems that will never exceed 100#. The spec package should cover this. Also, if limit switches are shown, then without a spec package, you will be at a loss to determine if they want standard contacts or proximity switches. If possible, get a spec package form the originator of the P&ID.

After the spec package you also need a piping schedule to tell you what piping is required for the different runs. (schedule 40 304 ss, .065 wall 316L tubing, etc.) The P&ID seldom gives you this directly, but has a line symbol that is referenced in a piping schedule to determine the piping and the connecting means required for each run. This also helps to determine the connecting means for the various instruments. Better get a piping schedule form the P&ID originator.

For reading the symbols, the ISA symbology is usually used, but not always, especially outside of North America. You will need to determine what the various symbols mean. Possibly there is an included lead sheet that describes the various symbols and line markings. If not, and you don't know what some symbols are, since they don't match accepted ISA symbols, you will have to find the originator of the drawing and have him tell you what he used for various instruments.

That is a 2 minute synopsis of 15 years experience, and I know it is not very helpful. This really is a case where one has to have a bit more details.

Good luck.