Table of Contents
1. Scope
2. Definition
3. General
4. Materials
5. Testing and Calibration
6. Commissioning
7. Administration
Attachments:
I Facilities and Equipment for Testing and Calibration
II Classification of Instruments for Testing and Calibration
III Checklist for the Verification of Instrumentation
IV Loop Check Requirements
V Instrument Calibration and Loop Check Progress Recording
Reference Specifications:
BN-SP-K8 Specification for the Installation of Instruments
BN-SP-K2 Engineering Design Specification for the Accessibility of Instruments and Instrument Connections
- Requisition for Installation of Instrumentation.
1. Scope
1.1 This specification outlines the technical requirements and procedures for the inspection, verification, testing, calibration and loop check of instrument installations. For the scope of work reference is made to the requisition for instrument testing and calibration.
2. Definition
2.1 Loop
A loop will be defined in accordance with ISA 5.1 as a combination of one or more interconnected instruments arranged to measure or control a process variable or both.
To this extent a loop also comprises dedicated systems such as alarm systems, safety and interlocking systems, scanners, process computers, PLC systems, logging systems, ICS, DCS, etc.
2.2 Inspection
Examination of equipment for any physical defect or damage.
2.3 Verification
A visual examination to ensure that each instrument has been correctly installation is satisfactory.
2.4 Testing
To prove that the equipment stands the environment and functions in the manner expected.
2.5 Calibration
Comparison with approved standards of adequate precision and subsequent adjustment to meet the manufacturer’s specification or the functional requirement.
2.6 Loop Check
A check of the instrument loop to prove the syncronization of components and the functional performance of the system.
3. General
3.1 Contractor shall provide sufficient skilled labour and technically capable supervision to complete all aspects of the testing and calibration within the agreed schedule for the contract.
3.2 The testing must be considered inclusive of all the operations necessary to have the instrumentation perfectly operating.
3.3 Although it should be unnecessary for engineer’s personnel to participate in or witness every aspect of the work described, the engineer shall have the right to do so without the need for justification. Engineer shall be able to see a repeat of any particular test on request.
3.4 Attachment mentioned in the index form part of this specification.
4. Materials
4.1 Handling of Materials
Instrument materials shall be stored and handled in accordance with the specification for the installation of instrumentation, BN-SP-K8.
4.2 Facilities and Equipment
4.2.1 Contractor shall supply and maintain all required test and calibration facilities including but not limited to items listed in Attachment I of this specification.
4.2.2 All test apparatus used for calibration must be checked regularly against standards of at least comparable quality to the apparatus.
Discrepancies shall be noted, recorded and the source of discrepancy established. The discrimination and absolute accuracy of the test apparatus for a given test must be better than the accuracy and discrimination value quoted by the instrument manufacturer for the particular equipment under test.
Test equipment shall be approved by the engineer before use.
4.3 Materials Supplied by the Contractor
4.3.1 The contractor shall provide all tools, jigs, plastic tubing, compression ffittings, pipe fittings, valves, wire, electrical terminals, plugs and sockets, and any other equipment necessary to follow the procedures contained in this specification. Further, adequate provision for consumable material such as PTFE tape, thread compound, solvent, contact cleaning fluid, graphite grease, lubricating oil, etc shall be made.
5. Testing and Calibration
5.1 General
5.1.1 Plastic sealing plugs should be kept firmly fixed in process connections, electricals entries, air supply input, output and other connections, except during testing and calibration and immediately before final plant connection.
5.1.2 Any air system, permanent or temporary used for instrumentation purposes should be blown down throughly before use.
5.1.3 Any connection between any air supply system and an instrument under test shall be via an adequate filter and regulator. Pneumatic instrumentation and related equipment requires a clean and dry instrument air supply at all times. Excessive air supply pressure shall be avoided.
5.1.4 Care should be observed when connecting electrical power supplies to electric and electronic instrumentation. Ensure correct voltage and frequency on AC suppliers, and where DC is used check that the voltage regulation and any superimposed ripple is within the instrument manufacturer’s specification.
Disconnect all circuitry before the execution of HV cable insulation test (meggering), and point-point identification (ringing out).
5.1.5 Filling, test and drain plugs of instruments etc, should be put in place after use and checked for leakage.
5.1.6 Where a part of plant is deemed to be a hazardous or remotely hazardous area (zone 0, zone 1, and zone 2) caution is necessary if testing is performed after introduction of hydrocarbons, or other potentially hazardous material into the plant, observe permit systems.
Where field devices are made safe by means of suitable enclosures (i.e. flameproof, explosionproof) some restriction may be met in simulation if direct operation of float, displacer, pressure element, etc, is not possible, due to the possible need to remove safety covers for access.
The appropriate codes, permits and local regulations should be followed in these circumstances, normally involving a periodic gas test in the area where covers are to be removed from enclosures.
Note that in any case power should be switched off prior to removing, and prior to replacing enclosure covers. Contractor to provide portable gas test equipment.
5.2 Warehouse Inspection
5.2.1 Prior to the installation of field instruments the contractor shall inspect the instrument data plate information against the equipment requisition to confirm correct model number, option, action, range, supply voltage, hook-up requirements, etc.
5.2.2 Instruments not calibrated in accordance with the documents shall be readjusted.
5.2.3 Pressure switches shall be checked for the correct switch point and differential.
5.3 Flushing, Pickling and Pressure Testing
Prior to flushing and pickling operations of the main process lines all inline instrument components shall be removed from the line and precautions shall be taken to avoid damage to instruments.
These will include but shall not be limited to:
- Flow measurement devices
- Control valves
- Analyzer probes thermowells, etc.
Control valves, pressure regulators, etc, shall not be hydrostatically tested with the line, as such testing can damage the packing and diaphragms.
5.3.2 The contractor shall observe the correct handling of instrument components, avoid abuse and disconnect/reconnect instrument tubing and cabling.
5.3.3 All process piping connections to instruments shall be removed and reinstalled before/after pickling, flushing and pressure testing operations. Instrument primary block valves to in line instrument shall be closed. Instrument process piping shall be subject to the same test pressure as the piping or equipment to which they are connected. During this test any leakage and/or faults shall be eliminated.
The contractor shall verify that all instrument process lines and fittings are clean and free from obstruction before connection to the instrument.
5.3.4 Pneumatic piping shall be tested for leaks in accordance with ISA-RP. Final instrument connections shall be tested with a corrosion free soap solution. The normal instrument air supply pressure shall be used for testing piping upstream of regulators, normally 4 to 7 bar.
5.4 Bench Test and Calibration
5.4.1 All instruments defined in Attachment II (paragraph 1.0) shall be calibrated in the field work shop for bench calibration. This list is indicative not restrictive.
Instrument calibration shall be performed prior to mechanical completion.
5.4.2 The vendor’s published instructions for test and calibration shall be followed.
5.4.3 The calibration of indicating, recording and/or transmitting instruments shall be made at five points (10, 0,25, 50, 75 x 100 percent of range).
5.4.4 The instrument shall be suitably supported on the test bench (or in a dummy panel rig as appropriate) in the position it would normally assume when installed. The applicable test equipment shall be connected to the instrument and in the case of pneumatic instruments all external connections tested for leaks before commencing calibration. Only those adjustments provided for the purpose of calibration shall be used to effect correct calibration. Should calibration by means be impossible then the manufacturer should be consulted by the engineer.
5.5 Field Test and Calibration
5.5.1 The primary purpose of field calibration is to calibrate those instruments which, because of their nature (weight, size, etc.) do not easily lend themselves to bench calibration, and which may be adequately and easily calibrated in their installed position.
An indicative list of which may be field calibrated is presented in Attachment II, Section 2.0.
5.6 Panel and Panel Instrument Testing
5.6.1 All instruments mounted on panel front or integral with panels, cabinets and racks have been functionally checked in the panel work shop.
Detailed testing of these instruments should therefore not be necessary unless the loop check reveals an abnormal behavior or demonstrates misalignment.
5.7 Special Instruments
5.7.1 The calibration and testing of special instruments as identified in the requisition will be manufacturer’s responsibility.
Procedure and prescriptions agreed with the manufacturer will be followed.
However, contractor is requested to supply assistance as required to the manufacturer for the field testing and calibration.
5.7.2 When testing of special instruments have been included in contractors scope but the contractor does not have the skills required to test or calibrate special instruments the contractor must obtain the assistance of an outside source, such in agreement with the engineer.
5.8 Verification
5.8.1 The instrument installation shall be verified to ensure that each instrument has been correctly installed in accordance with the documents issued for the project.
5.8.2 Verification shall include the following:
- Visual examination to determine the good state of field instruments, accesories, supports, mounting stands, process piping, air piping, electrical installation, etc.
- Visual examination of the correct installation of inline instruments.
- Visual examination of the correct installation of instruments in the control room, panel, and accesories.
- Visual examination of the completion of wiring and cabling.
An indicative list of instruments to be verified is included in Attachment III.
5.9 Loop Check
5.9.1 When all individual loop components have been tested and calibrated a complete functional check of the instrument loop shall be made.
Loop checks are an oportunity to demonstrate that the instrumentation system performs satisfactorily. Each loop check therefore should be witnessed by the engineer.
All calibration, wherever carried out, and all aspects of field inspection, verification and testing shall have been satisfactorily completed before loop checks are performed.
For loop check requirements refer Attachment IV.
5.9.2 The following operations shall be performed during loop checking:
- Check against flowsheet to enclosure that all instruments and components are installed in the right place, right direction of flow, etc.
- Check availability and performance of utility supply systems (electrical, pneumatic, )
- Apply a calibrated signal to the transmitter primary and check loop operation
- Check for correct action and synchronization of all the components
- Activate primary devices
- Check on the functional performance of alarm, safety and sequence systems
- Any other check required to have the instrumentation working properly.
5.9.3 All defects in apparatus, wiring, tubing and connection errors, etc. should have been eliminated during the various tests, prior to final loop check.
Loop checks are functional checks, and if an inoperative or badly calibrated or otherwise unsatisfactory loop check result is encountered, all results for that loop should be considered null and void, and the relevant earlier tests repeated, as necessary, after rework, replacement or repair. The loop check shall then be repeated completely for that particular loop.
6. Commissioning
6.1 Commissioning includes all instrument activities associated with the initial start-up of the plant such as but not limited to:
- The observance of instrument performance
- Zero checking/calibration under operating pressure
- Tuning of control loops
- Emergency repair and modifications
6.2 Control loops shall be commissioned in close cooperation with the plant operators.
Note: Commissioning belongs only to the scope of work of contractor if specifically stated so in the requisition for instrument installation work.
Commission shall only proceed after a written order has been given to the contractor indicating coordination procedures with plant operations department.
7. Administration
7.1 Contractor shall arrange for accurate and continuously record and keep engineer informed of progress by regular formal reports, including an updated copy of the critical path diagram, and by cooperative day to day communication when requested.
7.2 Contractor shall maintain his own filing system and organize the calibration and loop check recording as detailed in Attachment V.
7.3 Engineer to be notified of the planned commencement of each major activity, if different from latest published time schedule.
Engineer shall be given the opportunity to review methods and procedures for the first test of a major type, first inspection of a common type installation, etc.
7.4 Contractor shall pursue anomalies, clarify discrepancies in results, identify faulty instruments/materials, progress replacement or repair of defective items and expedite/initiate rework or modification of unacceptable installations with vendors or other contractors.
Attachment I
Facilities and Equipment for Testing and Calibration
1. Facilities
1.1 The contractor shall provide a mobile or temporary site workshop suitably clean and equipped for instrument calibration.
1.2 Test Air Compressor
It shall be assumed that in the early stages of construction, instrument air will not be available, and therefore a compressed air cylinder or small air compressor system shall be provided by contractor. An adequate storage receiver, cooling provisions and facilities to remove any oil and water from the air shall be included.
1.3 Local/Temporary Electricity Supplies
When temporary electrical supply is being utilised on site for construction purposes, it should be ascertained that the voltage, frequency and stability characteristics of the temporary supply are adequately similar to the permanent supply which is to energize instrumentation equipment.
1.4 Workshop Transformers
Where necessary an isolation transformer of adequate rating should be available to step down (or up as necessary) from the existing power supply voltage to the required voltage level.
1.5 Instrument Power Packs
Similarly where a special electrical supply is required for instrumentation, such as 24, 60 V AC, etc, the contractor shall provide suitable power supplies for workshop use where it is not feasible or realistic to utilize the supply equipment of the final system.
1.6 Electronic and Clean Instrumentation Facility
The site workshop should include suitable work benches and mounting facilities, and a separate clean section for electronic and pneumatic instrumentation isolated from the area used for the test of heavy equipment, pressure and leak testing, etc.
1.7 Mercury Handling Precautions
Mercury manometers and any other equipment utilizing mercury should be well separated from all electronic test gear and instrumentation.
If possible vendor to avoid using these instruments.
1.8 Basic Cleaning Facilities
To cover the situation where heavy instrumentation (level switches, displacer transmitters, control valves) requires attention during the plant startup period, and has been exposed to process,at least rudimentary cleaning facilities, including a drainage through and steam/water hoses, shall be provided by contractor.
A vacuum cleaner shall be available for the maintenance of dustfree shop cleanliness, when electronic and pneumatic instrumentation is to be tested.
1.9 Satisfactory Storage
The site workshop shall incorporate clean, dry and secure storage for instrumentation waiting test or installation after test.
1.10 Lifting and Handling Gear
A suitable lifting and weight handling facility shall be provided for handling control valves, large regulators, large level switches, ball float level transmitters, displacer transmitter (when fitted to their stilling tube) and similar heavy equipment.
1.11 Radioactive Radiation Sources
Where radioactive materials are utilized for level, density measurement etc, properly qualified personnel and safe and plainly marked storage should be available.Proper handling and installation practices should be observed.
1.12 Communication Equipment
Contractor shall provide for his own communication equipment for loop testing.
Radio transmitters/receivers shall comply with local and site regulations.
Where digital ICS or DCS systems or mV/phase equipment is used no ratio transmission is allowed within 3 m of ant panels. This may necessitate the use of external (remote) arials for the control room end of radio systems.
2. Test and Calibration Equipment
Following equipment shall be provided as far as applicable.
2.1 Pressure Testing Equipment
2.1.1 Bucket Pump.
2.1.2 Air Pump (hand operated).
2.1.3 Vacuum Pump.
2.1.4 Test Gauges.
2.1.5 Hand-held Hydraulic Pumps.
2.2 Calibration Equipment for Pressure/Pneumatic Instruments
2.2.1 Dead weight tester.
2.2.2 Air filter regulator sets for use as sources of air signals.
2.2.3 Precision mercury manometer range 0-800 mm Hg.
2.2.4 Absolute pressure gauge.
2.2.5 ‘’Wallace and Tiernan’’ pneumatic calibrator (dual scale), calibrated in mbar and bar.
2.2.6 ‘’Wallace and Tiernan’’ precision low pressure gauge 0-250 mbar.
2.2.7 Precision inclined manometer (water).
2.2.8 Certified test gauges with an accuracy of 0.1% of range, calibrated for the required units of the following ranges (barg) 0-1/0-2, 5/0-6/0-10/0-25/0-60/0-100.
2.3 Calibration Equipment for Electronic and ElectricalInstrumentation
2.3.1 Digital voltmeter with an accuracy of ± 0.1% of range or better and with a discrimination of 10 mV or better and incorporating an internal calibration/standardization feature.
2.3.2 Digital multimeters, ‘’Fluke’’ or equivalent, (Exi) type preffered.
2.3.3 Portable pressure calibrator, 0-1 barg.
2.3.4 250 volts insulation resistance testers.
2.3.5 Cable continuity testers, as required.
2.3.6 Vendor’s recommended calibration and test gear where this is unique to his equipment.
2.3.7 Stopwarch.
2.3.8 Oscilloscope portage frequency generator (sine square).
2.3.9 Test leads complete with clips, etc.
Note: For testing of circuits and cables within an operating plat, test equipment must have appropriate safety certification.
2.4 Temperature Test and Calibration Equipment
2.4.1 Thermostatic temperature bath for use with oil.
2.4.2 High temperature bath for use with salt, or sand.
2.4.3 Standard (precision) thermometers.
2.4.4 Portable potentiometer and millivolt generator for field use, accuracy 0.05%.
2.4.5 One decade box 0.1-100.000 ohms accuracy ± 0.05% on any resistance value.
Attachment II
Classification of Instruments for Testing and Calibration
1. Bench Test and Calibration
1.1 Flow Instruments
1.1.1 Orifice Plates
All orifice plates should be checked visually for:
- Smooth perfectly flat surfaces without scratching or bowing
- A sharp nonreflecting edge on the upstream face where relevant, or radius on quadrant edge type orifices
- The correct bore, as measured by inside micrometer
- Correctly stamped identification and bore dimensions on upstream face of tag handle.
1.1.2 Other Differential Pressure Producers
These include nozzles (of various designs), venturis, dall tubes and inserts.
It is normally impracticable to validate exactly the dimensions of these elements under site conditions. However, every effort should be made to estimate dimensions internally and equipment should be visually checked to ensure a good finish and freedom from damage.
1.1.3 Variable Area Flowmeters
Check for freedom damage, rough internal surfaces, the ability of the float to move freely and the correct operation of indication and remote transmission (if any) when the float is operated by hand.
1.1.4 Turbine Meters
Check for damage, metal dust, rough internal surfaces, improper noise on bearings when the rotor is spun (avoid overspeed).
Check for any damage to the pick-up head and electrical/mechanical connections.
In case of transmitting devices check the output signal as detailed for miscellaneous instruments.
1.1.5 Positive Displacement
Examine as for turbine meters including register head or linkage. Ensure free movement of mechanism. Handle with care and avoid interference with inernal mechanism.
1.1.6 Vortex Meters
Check for damage to flange faces, buiff body and terminal housings.
1.1.7 Magnetic Flow Meters
Check for damage to flange faces, linings, electrodes and electrical housings, ensure earthing rings provided, if required.
1.2 Level Instruments
1.2.1 Calibration testing of level measurement devices with sonic, conductivity, radiation, capacitance, etc. measuring elements as detailed for miscellaneous instruments.
1.3 Pressure Instruments
(Including differential pressure for flow and level).
1.3.1 Transmitters
Apply calibrated hydraulic pressure or vacuum to the measuring element(s) at 0, 25, 50 and 100% of full range.
Observe and record output corresponding to each calibrated input both going up and down scale. Adjust as necessary, to obtain correct indicated process variable. After adjustment repeat above procedure until calibration is within the tolerance stated by the manufacturer. Adjustment and alignment procedures shall be carried out in accordance with the manufacturers’ instruction book.
1.3.2 Switches
Apply a test pressure in a similar manner as under paragraph 1.3.1. The switch point may be sensed by multimeter or ohmmeter. The repeatability and hysteresis (differential) shall be determined and shown to lie within the manufacturer;s published specification. The calibration shall be made with respect to the function (high or low trip setting).
1.4 Temperature Instruments
1.4.1 Filled Systems
A constant temperature bath shall be used to calibrate all filled system, bi-metallic, and similar types of thermal elements where used on transmitters, controllers, switches, etc.
The procedure shall be the same as above for transmitter calibration, except that two calibration points (temperatures) only may be arranged, and they need not be at 0 and 100% of scale. The two temperatures selected should, however, be sufficiently different to ensure satisfactory calibration. For temperature switches, the tests should demonstrate the capacity of the device to sense and switch at any desired point within its specified range. The repetability and differential should be checked to ensure that they are within the manufacturers’ published specification. Adequate immersion of the sensing element, and steady conditions within the temperature bath, is essential for accurate calibration.
1.4.2 Thermocouple Type Instruments
Use a millivolt source input, and follow the procedure detailed for pressure transmitters.
Conventional ‘’wire in ceramic bead’’ thermocouples require no more than an inspection of the junction and check on the material type by means of a magnet and/or visually. Mineral insulated, insulated junction thermocouples require no such check if a factory certification label is attached for the specified T/C material.
However, an insulation resistance test from thermocouple to metal sheath should be performed. Insulation resistance should exceed 20 M at 20 ºC measured at 500 volts DC. Lower values may be indicative of moisure ingress through a faulty seal of a batch of thermocouples check one for correct output whilst performing temperature bath test as 1.4.1.
1.4.3 Resistance Bulbs
A digital multimeter shall be connected to the RTD, and the resistance measured compared with the specification figure for the bench temperature at the time. Check insulation resistance.
1.5 Miscellaneous Instruments
1.5.1 Transducers/Converters/Relays, etc
Connect the input terminals to an adjustable precision source and calibrate the output signal to its nominal range. Check linerarity and hysteresis at the five cardinal points (0, 25, 50, 75 and 100%) which should be within the manufacturer’s quoted specification.
1.5.2 Electronic Trip/Alarm Devices
The calibration shall be made in correspondence with the set point as detailed for pressure switches and transducers.
2. Field Test and Calibration
Following instruments may be tested in the field. Unless otherwise indicated, the same procedures as detailed for bench calibration (as far as applicable) shall apply.
2.1 Final Elements
2.1.1 Control Valves and Positioners
a. Valves shall be examined without dismantling
The data plate shall be checked against the requisition sheet
b. The action on air failure to be correct
If the action is incorrect it shall be changed
c. The lubricator, if fitted, shall be charged with the correct lubricant
d. The action of the handwheel shall be checked by manual operation
e. Air shall be applied to the valve and starting pressure and stroke checked and adjusted as necessary. Stroking time shall be checked on applications with speed adjusters and quick release pilots
f. The valve positioner shall be checked and adjusted if necessary for correct stroking of the valve. All pivots on the feedback mechanism shall be lubricated and checked that it is securely fastened to the valve stem
g. The stroke indicator shall be checked for readings 0, 25, 50, 75 and 100% on correctness and readability
h. Valve testing shall only be done after a specific check to determine that valve or solenoid is not under process pressure.
2.1.2 Solenoid Valves (Air Service)
A functional test shall be applied to each valve by connecting an air supply to its inlet port and energizing the coil with the appropriate electrical power supply. Test pressure should equal the maximum differential pressure for which the valve is rated by the Manufacturer. Drop out voltage should be no higher than 90% minimal voltage.
If vertical orientation is specified by the vendor the valve should be so mounted during the test. If orientation is not specified, it should be varied during the test to anticipate any field mounting problems that may arise.
Application or removal, depending on mode, of electrical power should close the valve or close and divert the pressure, depending on whether a two or three port valve is involved. Check valve porting arrangement with pneumatic hook-ups. Air leakage through the closed-off port should be virtually zero.
2.1.3 Solenoid Valves (Gas Service)
Test procedure shall follow 2.1.2. Additionally an inspection for suitable materials of construction shall be made.
2.1.4 Solenoid Valves (Liquid Service)
Test procedure shall follow 2.1.2 except that a water supply shall be used to simulate the liquid service.
Where normal city water pressure does not equal or exceed the working pressure on which the valve will be used, temporary means of raising a higher pressure shall be provided by means of a small rotary pump.
2.1.5 Miniature Pneumatic Valves
Pneumatic valves should be tested in a like manner to solenoid valves but with air, rather than electric, actuation.
2.2 Level Instruments
2.2.1 Level and Interface Switches (Float, Displacer)
Level switches shall be checked by partial immersion of the displacer or float with water in the float or displacer chamber or stilling tube. Due recognition should be given, when appraising results, to the difference in gravity between water and the application fluid. Interface level switches shall be checked by the total immersion of the displacer or float in water to a depth calculated by equating the upthrust to an equivalent volume. All test liquids should be fully drained from the system after test. The trip of the switch should be checked for both a rising and a falling level (and/or interface). Normally the trip point should be at the centre of the float chamber or some other well defined points.
2.2.2 External Displacer Level and Interface Transmitters/Controllers
Procedure should be similar to that level and interface switches but it will be necessary for the level (or interface) to be raised and lowered over the calibrated length of the displacer. 5 Point calibration is preffered but as a minimum the calibration should be checked at 1,50 and 100% of span, measurement of output change, either pneumatic or electronic, shall be by calibration apparatus according to the requirements detailed for pressure transmitters.
Where location or circumstances prohibit the use of water and/or other fluids for the calibration of displacement transmitters/controllers, testing may be performed by removing the displacer from the torque or equivalent suspension and hanging carefully calculated precision weights on the suspension. Weight combinations should check the transmitter/controller at 0,50 and 100% of span.
Where weight calibration is used, displacers shall be tested for leaks by immersing in cold water and heating towards, but not to, boilding point. Any released bubbles, particularly at welding lines, is an adequate cause for rejection to the manufacturer. If such tubes are weighed before immersion, and weighed again after allowing the immersion water to cool before removing the displacer, any increase in weight is a clear indication of leakage. Check knife edges for clean lines.
2.2.3 Tank Level Indicators
Floats to be raised and lowered using test facilities in accordance with manufacturers instructions.
Floats to move freely and synchronization of read-out system shall be checked.
Calibration should be made during plant start-up unless otherwise prescribed by the engineer.
2.3 Analytical Instruments
2.3.1 Procedure and prescriptions agreed with manufacturer shall be followed.
In general analytical instruments have been functionally checked in the manufacturer’s workshop.
Detailed checking of the associated electronics, transducer, programmer and read-out systems is not required unless loop checking reveals abnormal operation.
2.3.2 The analytical section shall receive an operational field test. When calibration references/standards are not available the calibration shall be made during plant start-up.
2.4 Miscellaneous Instruments
2.4.1 General testing and calibration procedures to be followed.
Attachment III
Checklist for The Verification of Instrumentation
1. Visual Examination
1.1 Location
Contractor shall check that:
1.1.1 The right instrument is in the right location and correctly identified.
1.1.2 The location and instrument is accesible in accordance with BN-SP-K2.
1.1.3 The junction boxes are fabricated and located per specification.
1.1.4 Supporting of equipment, cable trays, piping and tubing is adequate and vibration free.
1.2 Installation
Contractor shall check that:
1.2.1 The instrument is installed in accordance with the process, air- and purge-piping details including any recommendation given by the manufacturer.
1.2.2 Connections of piping and process equipment confirm to specification and instrument design.
1.2.3 Drains, purges, winterizing and isolation valves are properly installed.
1.2.4 The process instrument tubing and fittings meet specifications.
1.2.5 The necessary instrument bypass, shutoff, process block valves are provided as specified.
1.2.6 Each instrument item, controller, transmitter, motor valve, pressure switch, etc, meets purchase specifications (check power supply level).
1.2.7 Instrument protection is completed (winterizing, purges, seals, fireproofing, etc).
1.2.8 All covers are installed and openings plugged (where required).
1.2.9 Check each thermocouple to verify type of metal used and polarity of couple.
Check length of each thermocouple and thermometer, and corresponding depth of thermowell. Make sure thermocouple bottoms in well.
1.2.10 Verify mechanical completion of the installation including the correct installation of nameplates.
1.3 In Line Instruments
Contractor shall check that:
1.3.1 In line instruments are installed in the right location and properly oriented.
1.3.2 Check supporting of vessel mounted instruments.
1.3.3 All thermowells are sealed against the entrance of water.
1.3.4 Check direction of flow through:
- Valves
- Flow meters such as variable area meters, positive displacement meters, turbine meters, orifice plates, sight flow glasses, flow switches, etc.
1.4 Control Room
Contractor shall check that:
1.4.1 All scales and charts are correct as specified.
1.4.2 All instruments are properly supported.
1.4.3 Panel installation checked for mechanical completion.
1.5 Wiring and Cabling
This aspect covers all wiring and cabling and extends up to the field cable terminations and connections at control panels and consoles including those in the main control center.
Contractor shall check that:
1.5.1 All cable, wiring, ducting, tray, conduit and fittings should be complete and secured in position.
1.5.2 All cables and wiring, completely disconnected from any equipment, shall have been checked for continuity from end and for insulation resistance from core to core and each core to earth, using a 500 volt insulation resistance tester. Correct routing of each conductor/pair shall be checked. Screens shall be checked as common conductor.
1.5.3 Check for correct installation of cable glands.
Attachment IV
Loop Check Requirements
1. Structure
On large plants (grater than 1000 input/output) it is considered time saving to perform loop check in two stages, viz:
1.1 Stage 1 - Preliminary or Internal Loop Check
A check of the control room(s) or central control facilities first to the outgoing terminals of field marchalling racks, where the field (multicore) cables are (or will be) connected. The field devices are simply simulated with transmitter simulators, switches, mV sources or multimeters, per both inputs and outputs.
This achieves the following:
a. Enables the verification of all control room components including cross wiring, system cabling, ICS, logic inputs/outputs, I/I converters, etc.
b. Often the control room(s) can be made ready before field equipment is installed, thus partial loop check can be performed early
c. Trip devices can be set or checked
d. ICS,DCS and PLC configurations can be installed/checked/modified
e. A better indication can be obtained as to where any faults found at final loop check lie
f. Witnessing requirements at (final) loopcheck can be reduced
g. Loop check packages can be prepared in advance and partially marked up.
1.2 Stage 2 - Final (or overall) Loop Check
The check of the total loop from process, through the control room equipment back to process, as described in paragraph 2.0 and 3.0 below.
2.1 Power Supply Systems
2.1.1 Check designation and function of each isolator and fuse.
2.1.2 Check operation of automatic transfer systems, earth fault detection systems, reset mechanisms,etc, and monitor performance.
2.1.3 Check fuse selectivity.
2.1.4 Determine in-rush current.
2.2 Instrument Air Supplies
2.2.1 Check supply system.
2.2.2 Check designation of air supply valves.
2.2.3 Adjust air supply to the required levels.
2.3 Steam Supply and Tracing Test
A functional test should ensure that a steam supply is available, that no noticable leaks appear with steam at full pressure and that condensate is adequately disposed of. Checks for leaks shall be made by putting steam on and off several times. Where main condensate headers are inoperative for one reason or another, a parallel activity should seek to make the main condensate system operational and at the same time prove the tracing system by draining condensate temporarily (and safely) to atmosphere.
2.4 Electrical Tracer Test
Electrical tracing, where used, should be energised circuit by circuit, to prove operability and validate individual circuit isolation.
2.5 Purge Medium Test
A functional test of gasious and liquid purge systems should prove availability of the purge medium, correct operation of regulatory and indicating devices and a pressure tight piping system.
2.6 Analyzer Utility Systems
All analyzer utility, sample recovery, vent gas and purge systems shall be functionally tested.
3. Measurement and Control Loops
3.1 Apply an appropriate reference source consistent with those described under calibration procedures to the transmitter input.
Allow for filled legs on level applications. Zero adjustment is allowed at this stage, but for recalibration and frange, transmitter must be returned to a workshop. Transmitter simulators may be used for remote seal transmitters.
3.2 Check each loop component at 1,50 and 100% of transmitter range.
Where a recorder forms part of the loop it should also be checked at this time.
3.3 Set any trip or alarm in the loop at the desired value. Adjust the transmitter output to initiate the device and check the action of the interlock/alarm circuit.
3.4 Set transmitter output to say 50%. Switch to automatic and check, and if necessary set the correct action of the controller.
3.5 On pneumatic controllers check, in seal position, for leaks.
3.6 On pneumatic loops perform bubble testing of pneumatic transmission lines from field to control room to check for leaks.
3.7 Switch to manual, check controller output and control valve action. Check open and closed position and any override control forming part of the control loop.
3.8 Correct any wiring or piping defect and adjust any faulty component as required.
3.9 Check that the instrument in the panel is in the correct location, that the nameplate is affixed. Leave all controllers with conservative control mode settings prior to start-up.
3.10 Check burn-out protection, polarity and continuity of thermocouple and resistance bulb installations. Verify correct indication and point selection of multipoint/datalogger systems.
4. Alarm, Shutdown and Interlocks
4.1 Check the action of the annunciator against its specification, i.e. fleeting contacts, first failure etc. Alarm locations not already verified during measurement and control loop tests, should be completed.
4.2 Activate, or simulate, all inputs and observe system response.
Where interlock inputs have already been proved during measurement and control loop tests these inputs shall be bypassed.
All other inputs shall be proven. The complete interlock system shall then be checked for correct sequence of operation and all output devices shall be proven to work satisfactorily.
Attachment V
Instrument Calibration and Loop Check Progress Recording
1. General
1.1 Accurate records are essential for the satisfactory, timely completion of the calibration and loop check.
In order to keep accurate records of all settings and work carried out, and subsequent re-work and re-test where applicable, an acceptable and mutually agreed form of documentation is necessary.
Although the standard format of contractors may differ, a document shall be selected for use which is convenient and appropriate for each type of inspection or test involved.
1.2 Record documentation of test and calibration is likely to be of only transident value to the ultimate customer or operating company, once a plant is fully commissioned. However, value exists, at or about such a time, for the purposes of ensuring accurate, as-built drawings and instrument schedules.
2. Recording Procedures
2.1 Instrument Schedule
The ‘’instrument schedule’’ or ‘’instrument index’’ or ‘’instrument data sheet’’ prepared for the job is a reference document that contains all components of the loops with location of instruments and reference to relevant instrument requisition.
This document will be used for overall record purposes by keeping a master copy and signing-off instruments and instrument loops as checked.
2.2 Recording of Verification Operations
2.2.1 Verification of field and other cable connections to the panel and rack instruments can be conveniently recorded on wiring diagrams, again ‘’marking up’’ as progress is made.
2.2.2 For field verification a meaningful record of installation, process piping, steam tracing, etc, can be made by the use of relevant hook-up drawings.
2.3 Recording of Testing and Calibration
2.3.1 Each test shall be resumed in a report signed by contractor.
Contractor shall submit a form which has to be approved by the engineer. However, the engineer has the right to prescribe the use of particular documents.
2.3.2 Test reports shall be submitted not later than 40 hours after the date of testing.
2.3.3 Revisions to ranges, alarm and shutdown settings, etc, shall be recorded on appropriate documents.
2.4 Loop Checking
2.4.1 The recording of loop tests may convently be carried out on process and instrument flow diagrams provided that all instrument functions are clearly marked.
2.4.2 For special loops on such diagrams which are grossly simplified, additional documentation may be necessary in order to provide a checklist for every detail, setting, test, etc. This may take the form of the loop sheet, with or without supplementary sheets, and/or control/shutdown/interlock schematic diagrams.
3. Marking
3.1 Marking Project Documentation for Record
The use of colour is recommended in the marking up of all test results. It is possible to easly read most detail drawings, although heavily marked-up with a yellow feltpen or equivalent. Other colours may normally be acceptable on P&I diagrams, particularly when used outside.
3.2 Marking Instrumentation
Following the completion of each step labels shall be applied to identify the status of inspection, calibration, verification and loop checking.
Labels shall be supplied by contractor but the application will be supervised by the engineer.
Labels should be installed on visible and fixed parts of the instrument so they will not become removed during the installation and connection of instruments.
3.2.1 Incoming Inspection (Apply Label 1)
Instrument has been inspected by contractor after it has been unpacked, against the data sheets and manufacturer’s model, material, range, size, etc, are correct. This step is done normally at the warehouse.
3.2.2 Instrument Calibration (Apply Label 2)
Instrument is calibrated in the shop. Special instruments will be calibrated as per manufacturer’s instructions. In special cases such as some analyzers, calibration will be done by vendor representatives. Calibration will normally be done before instrument is installed.
3.2.3 Verification of Installation (Apply Label 3)
When 3 is on the instrument it indicates that the instrument is checked against the flowsheet for location and direction of flow, that it is installed correctly according to the mounting drawings, tubing and fittings are correct, the instrument is accesible, air or electronic connections are completed and instrument is ready to be energized for loop checking.
3.2.4 Loop Checking (Apply Label 4)
Instrument loop system has received a functional check and is fully operational.
At this stage the loop is completed and the instrument bears following information.
This sticker can only be applied after agreement with engineer’s instrument installation supervisor.