Instrument Tubing Layout shows routing of instrument tubing according to plant layout and the location of source and destination points connected by tubing. In addition, instrument tubing layout shows the details related to instrumentation tubing such as:
- Tubing number/identification
- Tubing going up/down
- Type of fluid carried inside the tubing i.e hydraulic or pneumatic (air/gas) by appearance of different tubing symbol
Instrument tubing layout covers the following scope, but not limited to:
- Tubing from instrument air distribution manifold or instrument air header to control valve and actuated valve
- Tubing for utility air from instrument air header to vendor package
- Tubing for panel purging from instrument air header to panel enclosure
- Tubing from chemical injection to process tapping point
- Tubing for fusible plug loop
Those tubing may be drawn in separate instrument tubing layouts for convenience
Reference drawing: Instrument Location Plan, Piping Plot Plan
- From Instrument Location Plan, disregard the instrument which does not require tubing. Point out the instrument which requires instrument air such as control valve, actuated valve and utility air such as vendor package, outdoor panel requiring purging
- Instrument air header pipe could be extracted from piping plot plan
- Location of process tapping could be obtained from piping plot plan
Routing should be as short as possible, however consider some factors which should be avoided such as hot source, fire, accidental mechanical abuse, etc. Tubing slope shall also be considered and pocket shall be avoided.
The purpose of instrument tubing layout
Instrument tubing layout is to be used as a reference for preparing instrument tubing schedule in determining the following:
- List of the tubing required and its length
- The point of source and destination of tubing
Instrument tubing layout is also a reference to identify the existence of all instruments tubings in the plant or platform.
No example is provided here since instrument tubing layout depends on plant or platform layout. However below symbols may be used for items retaled to instrument tubing layout.
Note that, above example shows symbols which may differ among projects. The important thing is one should be consistent with the symbol in the entire instrument tubing layout drawing and listed the symbol in the legend section.