The EPC Contractor will normally be responsible for some or all of the Pre-Commissioning activities, if required these activities can be provided by us as part of an integrated service. Commissioning Experts will identify the required equipment and resources to be managed and supplied under an integrated service by us.
Specification and Name Plate Data
Prior to Pre-Commissioning of any component, the specification of the nameplate data on the equipment should be verified against the design documentation.
All Equipment and Systems should be tested to the applicable specifications of the project. The EPC Contractor will ensure a list of the technical specifications for equipment and systems is available.
All Equipment must be properly lubricated before it can be commissioned. The EPC Contractor must follow the manufacturer’s instructions in the vendor manual. Equipment will likely be received with a factory-installed lubricant, which will protect the equipment during shipping and storage. The EPC Contractor must replace these lubricant with a charge of the normal lubricant. While the rotating equipment is in the warehouse, it is a good idea to follow the recommendation of the various vendors, and rotate the equipment by hand periodically. This ensures the shafts don’t become bowed, and keeps lubricants in the bearings. All lubrication documents are inserted into the turnover package.
Flushing is normally undertaken on the following systems:
- Lubricating Oil (using oil as the flushing medium)
- Fuel oil (using fuel oil as the flushing medium)
- Hydraulic oil (using hydraulic oil as the flushing medium)
- Cooling water (using water as the flushing medium, or at some projects the system is chemically cleaned)
- Raw water and service water (using water as the flushing medium)
- Fire protection (using water as the flushing medium)
- Feed water and condensate (sometimes chemically cleaned)
When Flushing a piping system, Our Commissioning Experts must be present witness and identify potential flushing problems. If possible, the piping internals should be inspected prior to fit up using CCTV inspection, to guarantee there are no foreign objects in the pipe. Water and oil piping systems are usually flushed using the installed pumps. In some cases, temporary pumps are used during the flushing. High Pressure Water Jetting can also be used with special lances and nozzles, to blast debris and rust from pipe interiors. Where possible all flushing water should be recycled by temporary filtration and ion exchange. Before flushing, all orifice plates, control valves, or other restrictions must be removed. Sometimes, a check valve needs to have its disc or plug removed to allow flow in the opposite direction.
Valves should be inspected prior to System Flushing, and should be monitored during the period of initial operation. Manuel valves must be inspected, in addition to the air, motor, or hydraulically operated valves. Packing glands should be adjusted, but tightened only as necessary to preclude leakage. Every check valve must be inspected to insure the flow is in the correct direction. Some globe or plug valves also have a flow orientation, which must be observed. Look for the arrow or marking that indicates the direction of flow.
Direction of rotation of the pump and the driver should be verified. Usually there is an arrow on the equipment, but sometimes you need to check the vendor drawing. Review the vendor manual for any special operating characteristics or additional hardware requirements. During the Flushing, after some time of regular operation is achieved, the pump performance and vibration data can be collected.
Normally all turbine and engine lubricating oil systems will require Oil Flushing. These activities would normally be undertaken by Our Commissioning Experts or a specialist contractor, using temporary flush skids with pumps, filters, and heat exchangers.
Chemical Cleaning of those lines specified will take place after Hydrostatic Testing. Our Commissioning Expert can undertake Chemical Cleaning and we will provide the necessary chemicals, equipment, and manpower, customarily performs the Chemical Cleaning of critical systems.
Some systems are required to be completely dry with a required dew point demonstrated, Air Drying or Blowing is used for this purpose and involves undertaking the flow and volume to reduce the system to the required dew point which in turn will determine the required equipment set up to achieve the specification of dryness required.
Internal heaters on large motors, generators, and motor-operated-valves should be energized with temporary power. On projects which have a long duration, the heaters may be energized in the warehouse or laydown area. Large motors and generators are megger-tested during the construction period to verify insulation integrity.
Testing Cables, Switchgear and Controllers
All cables and switchgear/MCC buses are tested prior to energization; Cables are tested for continuity and insulation resistance. For switchgear and MCCs, hi-pot testing (using very high voltage) to test high voltage feeders and switchgear/buses requires special test equipment.
Transformers and Switchyards
Transformer and switchyard tests are performed according to the manufacturers instructions. Transformers, bushings, circuit breakers, and disconnect switches are commonly inspected and tested by Our Commissioning Experts, Oil-filled transformers, HV bushings, and circuit breakers may require conditioning of the insulating oil to remove vapors and water. Special equipment is required for this conditioning and testing process, and normally provided by Our Commissioning Experts.
Electrical Meters and Relays
Power transformers, switchyard equipment, generators, switchgear, and load centers are protected by sophisticated relay systems. If the protective relays detect faults, they will re-route or trip the circuits in order to protect personnel and equipment. Meter and relay testing must be coordinated with the local utility, for those circuits that interact with the utility grid. Special equipment and expertise is required for setting the meters and relays and will usually be undertaken by Our Commissioning Experts.
All instrumentation devices must be calibrated and installed prior to Commissioning. Instrumentation devices will be initially inspected and calibrated in a workshop environment, but final calibration will take place in the field, in the installed configuration. Calibration set points are provided by the design engineer, or by the vendor.
All signal and sensor instrumentation will be tested by simulating a specific parameter, which is then converted to an electrical signal and displayed on the control system graphics. The Instrument will be tested through a range of settings and certified as accurately tuned. There could be thousands of loops combined in any plant, with the total number dependent upon the design philosophy and degree of automation. Alarm, runback, and trip signals are all functionally tested during Commissioning.
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