Wednesday, November 23, 2016

Construction Procedure for Instrument Loop-Check / Testing !!


1           PURPOSE

2                        SCOPE

3                        REFERENCE, CODE & STANDARD

4                       DEFINITIONS

5                       RESPONSIBILITY AND AUTHORITY

6                        WORK PROCEDURE

7                        SAFETY

8                         QUALITY CONTROL

1          PURPOSE

The purpose of this procedure is to specify responsibilities and describe the
    steps Instrument Loop check / Testing work for ..... Project.

2          SCOPE
  This method statement (M/S) shall be applied to Instrument Loop Check / testing work.


 3.1 Subcontractor document
 3.2 Work index, symbol and detailed drawing
        3.3 Process Control and Automation Engineering Standard Specification.
          European (IEC and EN) standards shall be adopted throughout,
          unless otherwise Specified in the technical specification.

4          DEFINITIONS

4.1                    Within this document following definitions shall apply.
                  OWNER / COMPANY     
                  CONTRACTOR                                            SUBCONTRACTOR          


5.1             Site Manager

5.1.1      Site manager bears the responsibility and authority on work and quality related to this method statement.
                        51.2      Site manager approves work plans.

5.2 Construction Superintendent

5.2.1      A construction Superintendent bears the responsibility and authority to train their staff and subcontractor’s after preparing work plan according to this method statement.
5.2.2      A construction team manager takes the responsibility of all Instrument Loop check/testing work execution and preparation. 

5.3            Construction Supervisor

5.3.1      Construction Supervisor shall execute inspections and tests to secure quality materials, take adequate measures, manage results as quality records, and utilize checklist.

5.3.2    Construction supervisor bears the responsibility of Instrument Loop check 
       /testing according to the dimensions specified in specifications or drawings,
       and submits reports to the owner for approval

5.4            Quality Manager

5.4.1      Site Quality Manager is responsible for management and supervision of implementing inspection work as specified in this method statement.

5.4.2      Inspection request to QC when portions of the work are ready for inspection, as depicted in the ITP’s.

5.4.3      Responsible for preservation and maintenance of equipment at site.
6.1       General Requirements

6.1.1       All instruments in a loop are calibrated, installed and inspected prior to commencing loop check in accordance with the applicable procedures and specifications.

6.1.2       The loop testing shall be witnessed by QC group in accordance with approved ITP.

6.1.3       Documents compiled for loop checking (loop folder) should contain but not be limited to the following:
- Piping & Instrument Diagram
- Instrument Data Sheet
- Instrument Installation Acceptance Checklist
- Instrument Loop Acceptance Certificate
- Instrument Calibration Record
- Instrument Piping / Tubing Test Record
- Instrument Cable Test Record
- Instrument Hook-up Drawing    
6.2   Procedure

6.2.1       Pressure testing of signal or process piping is to be completed, witnessed and signed-off by the responsible authorities prior to the commencement of loop checking.

6.2.2       Prior to loop testing, instrument cable shall be checked for continuity & insulation resistance test.

6.2.3       Prior to loop testing, check all components for correct zeroing and adjust if necessary except for those indicated in calibration procedure to be zeroed during commissioning.

6.2.4       Completed loops are to be tagged in accordance with approved ITP on pre-loop and final-loop check.
6.2.5       All wires are checked for correct tagging and termination. Any wires disconnected for purposes of the loop check are to be reconnected to the proper terminals upon completion of activities.

6.2.6       Instrument tubing disconnected for loop check will be covered with protective tape / plugs at the ends to prevent entry of foreign materials.

6.2.7       Instrument tubing disconnected during the loop check is to be re-inspected to ensure proper reconnection as per instrument drawing.

6.2.8       The completed instrument loop shall be tested as one system and adjustment shall be made to ensure that the loop is fully operational as a system and is correctly calibrated. Associated alarms shall be checked during loop testing.

6.2.9       Loop testing of remote control loops is a two groups operation, one in the field and one in the control room. They must be provided with adequate means of remote Two-way RADIO communication system suitable for the area classification of the site of work.

6.2.10     Loop testing shall not be carried out on electronic equipment until an adequate warm up period has elapsed. Where possible instruments shall be energized for at least 24 hours prior to testing or as recommended by the manufacturer.

6.2.11      On completion of loop testing, all controllers shall be left with correct action and with 100% proportional band setting. Derivative & Integral function shall be set at minimum time value (Set by DCS Vendor).

6.2.12     Inspect the loop setting air / electrical supplies where appropriate. Check in particular the control valve air supply pressure at site in accordance with the specification.

6.2.13     For electronic loops, check the polarities to be correct at field instrument.

6.2.14     Each loop must be tested from the field signal input through to the receiving instrument and in the case of controllers; the output of controller shall be checked through to the final control element operation. During a loop test all ancillary items in the loop ex. signal converters, alarms, switches, etc. shall be tested.

6.2.15     Each loop will be checked as per the following documents :
          a)  Instrument Data Base (IDB) printout (range, configuration, etc.)
          b)  Graphic display (the point shall appear in the designated Graphics)
      c)  Alarm summary.

6.2.16     Signals shall be generated equivalent to 0, 25, 50 and 100% of the instrument range and the loop function checked for correct operation at each point in both rising and falling modes. Any  adjustments found necessary shall be carried out during loop check in accordance with approved calibration procedure and manufacturer’s instruction and using approved and certified field calibrators.

6.2.17     For controller applications the following test also apply :

a)     Switch the controller to manual mode and by applying the appropriate signal, ensure that the control valve or valves stroke correctly. Valve positioner gauges also be checked during this stage.

b)    Apply an actuating signal to the controller equivalent to 50% of the instrument range
   and adjust the manual regulator output to 50%. Adjust the controller set point to 50% and, by switching the auto / manual transfer switch, check for “bumpless” transfer. Following  the manufacturer’s instruction, adjust where necessary until satisfactory “bumpless” transfer is achieved.

c)     Check alarm by varying the actuating signals and adjust as necessary.

d)    After each loop is satisfactory tested the controller shall be switched to manual and identified.

e)     For three and four wire resistance detector installations, care must be taken to ensure the correct connections. Trips and alarms e.g. initiating devices which stop / start pumps etc. shall be checked.

f)     All system shall be checked for fail / safe operation which will include the checking of
  “ burn out “ features on thermocouple installations.

6.2.18    For gas alarm system:

a)     Sensors shall be tested in accordance with the manufacturer’s instruction.

b)    Where voting logic is involved then each combination of the activities inputs shall be
          tested and all resultant outputs is also be checked.

          NOTE : The testing of field audible and visual alarms shall be carried out on an
          individual basis plus a check that the audible can be heard in all areas and that the
          visual alarms provide coverage as necessary. All systems shall be subjected to thorough
          fault testing, e.g. open circuits of each field loop, card removal, power isolation to section
          of a system, earth faults etc.

6.3.1    Loop Test Methods

6.3.2     Flow Loop

 Simulate appropriate input signal as follows :

         Transmitter Type                                                 Input Source
                         Differential Pressure Type                                 FF/Hart Communicator
                         Vortex Flow meter                              
                         Ultrasonic Flow Meter
                         Mass Flow Meter

a)       FF/Hart Communicator will be used to simulate signals. In case FF/Hart Communicator
is not applicable, portable simulator will be applied.

b)       Simulate signal 0%, 50% and 100% of full scale & check indication of local indicator
and DCS indicator.

c)       If the flow loop includes consist with control output, manually output 0%, 25%, 50%,
75% and100% of valve operating signal and check valve stroke. Check tight closing of control valve if necessary.

6.3.3   Pressure Loop

  Simulate appropriate input signal as follows :

Transmitter Type                               Input Source
                  Pressure                                     FF/Hart Communicator
                  Differential Pressure  
a)     FF/Hart Communicator will be used to simulate signals.

b)    Simulate signal 0%, 50%, 75% and 100% of full scale & check indication of local indicator and DCS indicator.

c)     If the pressure loop includes control output, manually output 0%, 25%, 50%, 75% and 100% of valve operating signal and check valve stroke. Check tight closing of control valve if necessary.

6.3.4    Level Loop

     Simulate appropriate input signal as follows:

     Transmitter Type                                           Input Source
                          Differential Pressure Type                       FF/Hart Communicator
a)     FF/Hart Communicator will be used to simulate signals. In case FF/Hart Communicator is not applicable, portable millampere simulator will be applied.

b)    Simulate signal 0%, 50% and 100% of full scale & check indication of local indicator and DCS indicator.

c)     If the level loop is consist with control output manually output 0%, 25%, 50%, 75% and 100% of valve operating signal and check   valve stroke. Check tight closing of control valve if necessary.

6.3.5    Temperature Loop
Simulate appropriate input signal as follows:
    Measuring Element Type                                Input Source
                                                 Thermocouple Type                               Accurate Millivolt Generator
                    RTD Type                                                          Decade Resistance Box   
                        Misce llaneous Type              As per Vendor’s Instruction   

a.     Inject input signal 0%, 50% and 100% of full scale and check the DCS indication and indication of transmitter. If there will be system equipment with burn out function, check it by opening the temperature element circuit while observing the output.

b.    If the temperature loop includes control output, manually output 0%, 25%, 50%, 75% and 100% of valve operating signal and check valve stroke. Check tight closing of control valve, if necessary.

c.     Reassemble the temperature element to the original condition.

6.3.6   Switching Loop

 Simulate appropriate input signal as follows:

 Using a wire jumper, short out the input terminals or disconnect wire termination to simulate
           switching signal.

Switching Type                                                      Input Source
                                  Level Switch                                 Wire jumper
                  Miscellaneous Type Level Switch               Disconnect wire termination
                  Miscellaneous Type

          Valve having limit switch for Open/Close condition.
    Check DCS graphic, alarm etc. Actuate switching action and check all related system such as
    alarm, trip, trip signal, indicating lamp etc.

6.3.7   Integrated Control System

a)  The Programmable Logic Controller (PLC), H I M and associated peripheral equipment are generally completely configured and tested in the supplier’s factory includes complete  
    hardware and software test, Including simulation of input / output signals. as well as  
    carrying function checks once the system is integrated and I/O signals are terminated.

      b)   After installation of equipment in the control room, the system is checked for grounding plan,
    grounding scheme etc. at the supplier representative prior to applying power to system.

c)  The system is loaded and checked for required displays and operation of auxiliary devices by the supplier’s representative with direct manpower assistance. System alarms, operation of redundant modules, and back-up power supplies are checked at this time.    

d)  During loop check, the input /output display is checked for correct engineering units, control
    functions, controller action and alarm locations. Group and alarm displays are checked for

e)  Alarm set Report print outs and auxiliary recorders or other devices are checked for correctness. the loop check document shall be filled out for control loop.

f)  After the tests have been completed, the instrumentation shall be identified with a colour sticker.

g)  Results will be filed and recorded on applicable test form per approved ITP.

6.3.8   Analyzer and Miscellaneous Loop

 The Analyzer and miscellaneous loop shall be checked as per Vendor’s instruction
 If special techniques required checking out the specific instrumentation,
 the vendor representative or the specially trained technician should attend
 during pre-commissioning activities

6.4       FUNCTIONAL TEST           
6.4.1       Function test will be carried out after completion of loop test.
6.4.2       The field Instrument can be simulated from field through HART/ FF communicator.
6.4.3        Pump operation interlock check will be carried out based on HIM, function test will be
           carried  out based on Cause & Effect Matrix.

   Pump auto START/STOP condition checking, /Control Valve Open/Close
   checking depends upon the process condition. 

6.4.4       Documents compiled for function check should contain to the following:

a)    Piping & Instrument Diagram.
b)   Instrument Specification Data Sheet.
c)    Instrument Loop Acceptance Test Record.
d)   Loop Test Sing-Off From Sheet.
e)    Instrument Index..
7      SAFETY

7.1.1     To ensure best practice HSE control is being implemented throughout all Instrument Loop check work, Contractor Instrument Supervisors and HSE Supervisor with Sub contractors Instrument Supervisors and HSE Supervisor shall carry out inspections prior to Work commencing and at regular intervals during the activities.

7.1.2         Persons working at height (above 1.8 meters) shall be protected from falling by the installation of safe access/ egress and working platforms.

7.1.3         Persons involved in Instrument Loop check work shall be provided with and use the necessary PPE and as a standard each person shall wear a Safety Helmet and Safety footwear. The requirement for additional PPE shall be identified in the Risk Assessment and may include the use of the following:

7.1.4        Eye protection.
7.1.5        Hand Protection.
7.1.6        Dust masks.
7.1.7        Reflective jackets if working in the vicinity of moving traffic.
7.1.8        Any other necessary PPE

Note: - The issue and use of PPE is the final step in protecting people and must not be see as the only safety control method. Risks must be reduced to the smallest amount possible and the PPE is the back up equipment.

8.1         ITP is a document submitted to the owner or owner’s representative formulated in an orderly manner by the construction supervisor or site quality manager to record main working processes for tests and quality inspections, and to enable the owner or owner’s representative to assign inspection points.
     8.2         Witness Point
 8.2.1               Point where permission to the next level is granted without Owner’s agreement.

     8.3            Hold Point
8.3.1      Point where further progress is not allowed without Owner’s written permission

     8.4         Inspector

8.4.1      Person that inspects whether processes quality of materials or specifications are consistent with prescribed or desired requisites.

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