Testing and Commissioning of Instrumentation

[TomosSmith]

Hello,

We have various field instrumentation, such as pressure, temperature and level switches and transmitters on our project which have been installed but are yet to be tested and commissioned.

Can anyone give me a few bullet points for general items that should be checked during the testing and commissioning of instrumentation? I aim to write some checklists for each type of instrument on our plant.

Thanks,
Tom

 

[IceStationZebra]

The most important item would probably be how to determine if the readings are accurate. You can simulate different sensor outputs at the junction box, then see if the display/plc gives the correct readings. ISZ

 

[gerhardl]

Note: Some of the instruments will probably have instructions that will require adjustment at site under actual conditions.

The reason for this is that the instruments are constructed as 'switches', not actual measurement instruments.

Even if the instrument have very precise 'repeatability' (e.g. in/out at the same points of the scales with very little variation), the actual 'scale' given or the pre-set adjustment need not necessarily be exact actual measured temperature, pressure or needed switching point at site.

For actual measurement additional instrumentation or procedures might be necessary.

Suggestion:
All instrumentation to be controlled for installation (orientation, layout, (mechanical placement (orientation and distance from other equipment, straight stretches etc) and quality, tubular/mechanical protection, electrical protection and connections, mounted depth in pipeline (if relevant), leakage of connection (obs max pressure and other limits for the instrument allowed!), suitability for service and design parameters checked.

Correct electrical current, voltage (to/from) and input/output signals checked.

All installation control and adjustment according to each instruments manufacturor's instruction. Adjustment and tests done with additional measurement devices or other devices if necessary.

Issue of instruction checked to be correct for the actual instrument. Instruction (with relevant data) (and instrument itself) to be clearly marked and instructions easily presented (not a whole book or mixed with other instruments without clear marking).

In addition: datasheets and instructions filled out and/or in original and present (physical or electronical) as required.

Note: some of the instrument might have protection tubes as an option (not necessarily installed) or exposed membrane, tubes, floats etc. in materials other than supplied. To be checked for possible improvement, longer life possibillity or deviations from requirement and description?

 

[pmover]

TomosSmith,

test/calibrate each and every sensor/switch/transmitter from each end device to the PLC/DCS or other controller type. this will ensure that the entire electrical loop operates as designed. be sure to apply the appropriate pressure, temperature, liquid level, etc. at the sensor/switch/transmitter to ensure proper operation of each end device.

from experience, i have never trusted the calibration/settings of switches, transmitters, etc. directly from the mfg. it should be the operator's responsibility (possibly the contractor too, depending upon contract requirements) to ensure proper operation of all sensors/switches/transmitters. afterall, the operation of the facility greatly depends upon those sensors/switches/transmitters.

hope this helps and good luck!
-pmover