The following checklist shows instrumentation items that should be checked in the PDMS model. There are several types of checks that need to be made.
- Datum points assigned by the Designer
- Verifying that instrumentation names match those on the P&IDs
- Checks of in-line/equipment-mounted devices placed by the Process designer via categories & specifications
- Checks of off-line instrumentation placed by the Instrument designer and verification that instruments are placed on stands
- Instrument cable trays built by the Electrical designer
- Verification that data integrity and data transfers were made correctly
Mandatory Checklist for All Instruments
- Check that all datum points have been placed in the model. There should be a datum point at every column and every floor, required for location and elevations. The Civil Designer is responsible for placing these datums. Remember that even existing columns will need datum points if there is instrumentation nearby.
- Check and verify that every instrument has been correctly named in PDMS. Names are available from the categories & specifications database. Note that instruments coming from categories & specifications have the loop, function, and class concatenated without hyphens or slashes.
- Check that the loop number is defined as individual fields in the Loop Number window in PDMS. Assign each loop component separately as Loop, Function, and Class. This convention will be used for the named item that will be in the transfer file.
- Check which attributes are required. Understand ahead of time which attributes will and will not transfer from PDMS. Tray Access Points are required on Instrumentation that has a cable going to it. Both Electrical and Instrument trays are needed in some cases.
Assign the Support Description in PDMS for all instruments. The Support Description for stand-mounted instruments should read "Std Mtd." If more than one instrument is mounted on the same stand enter "mtd w/1234FT" Support Description field so the material takeoff person doesn't buy two stands.
Electrical Arrangement, Instrument Arrangement Drawings, and Electrical and Instrument Installation Details can be assigned in PDMS.
Process Design Checklist
- Have all in-line/equipment- mounted instruments been placed in the pipelines or on the equipment as needed?
- Have the position and orientation of control valves and on-off valves been checked for maintenance and accessibility?
- Have all in-line flowmeters been checked for orientation and maintenance accessibility? Have the upstream and downstream requirements been followed? Is proper support provided, especially for mass flowmeters?
- Has the position of Thermowells been checked for full flow contact maintenance, and accessibility? Is there room to remove the well and/or thermal element from the pipeline or nozzle?
- Have pressure and temperature gauges been checked for proper placement, operability, and maintenance?
- Have level probes and/or chambers placement been checked for operability, maintenance, or removal?
- Are conductivity or pH probes located to insure that the electrodes are flooded at all times?
- Have orifice taps been checked for proper installation?
- Are instrument service headers and taps provided and in the correct locations? Are they adequate?
- Have all widgets been removed from the model and replaced with actual in-line device before ISOs are generated? (Use the QA Widget report in PDMS to find the Widgets.)
- Has the QA - Categories & Specifications report in PDMS been run and checked?
Instrument Designer Checklist
- Have stand-mounted instruments (sub-equipment in PDMS) been checked for proper naming? Are they assigned as an Instrument?
- Have off-line instruments been placed on the instrument stands and located at the appropriate height for liquid, gas, or vapor installations? Are they close to their process taps?
- Are instruments with filled capillaries mounted within the length of the capillary per the purchase order? Is the instrument elevation at or below that of the diaphragm seal?
- Has the installation been checked versus field Instrument Installation Detail? Is the correct Installation Detail assigned and appropriate?
- Has the installation been checked versus the field Support Description? Is the correct Support Description assigned?
- Have Tray Access Points (for both E & I tray in some cases) been defined for all instruments that will require cabling?
- Are all instrument enclosures shown with their supports? Has adequate reserve space been left for door swing, tubing, and conduits?
- Are all DCS cabinets and junction boxes that are not shown on P&Is located on the model?
Electrical Designer Checklist
- Has all instrument cable tray been checked and verified to make sure it's placed where needed?
- Have you done a preliminary data transfer? Have you reviewed any error report generated for mis-named instruments?
- Have you used FTP to transfer the PDMS file in binary format?
- Have you checked the PDMS transfer Error report for other errors?