1. Controlling Interests Editors' Blog Control's editors weigh in with timely insights and tidbits on goings-on in the process automation world, mostly news and technology but also interesting perspectives gleaned from our daily conversations with end users and the challenges of the craft. Loop Checking and Field Instrument Testing Procedure Category: Implementation Loop Analysis Loop Performance Usability Submitted by Katherine Bonfante on Thu, 10/04/2012 - 10:00 Everybody knows that loop checking and field instrument testing is the last piece of the puzzle in each project before commencing the commissioning of any system. It is time- consuming and depends upon the completion of other systems like piping, electrical equipment, control valves etc. Each contractor or company has its own procedure and common practices for instrument loop checking and functional testing. I found this forum is good place to discuss this topic in more detail, for example: 1. Can we have a common or guide line procedure for loop checking? 2. Can we illustrate all the required drawings, specification and forms required for loop checking? 3. Can we build a flow chart for loop checking which illustrates the rule of operation, maintenance, engineering and inspection for example? Login or register to post comments 41755 reads Permalink 6 Comments Join the discussion We welcome your thoughtful comments. Please comply with our Community rules. All comments will display your user name. Want to participate in the discussion? Register for free Log in for complete access. Comments Submitted by santhiraj sathanna on Fri, 09/06/2013 - 08:58 This is a very good topic for discussion. We do the following in our organisation
2. 1.A detailed loop check format is prepared for each project 2.Above is based on latest I/O list , P&ID and process narrative. 3.For each I/O point, all connected details/elements like PLC/DCS I/O module,Panel Terminal Block, Marshalling panel Terminal Block, Junction Box Terminal Block,Instrument/Final Control element tag, Service description,calibration range,cable tag.... 4.We do this testing by involving owner's as well as prime EPC bidder's Engineer as witnesses. After successful completion, the document gets signed by them. We follow the same procedure for commissioning the logic as well as to demonstrate the same to end user! This is time consuming and we do it religiously to eliminate last minute surprises. Reply Submitted by on Tue, 10/29/2013 - 12:24 I fully agree with all 3 points. A guide is really needed. I takes much time to get agreed such procedure in every new project and a unified approach would be very effective here. To the second point I may add that a list of such documents would be very useful as well to avoid creating of a huge dossier and got all needed papers in place. Templates for certificates would be fine. As to the third point I'd a recommended list of personal of performing and witnessing parties. Mikhail Aravin, Senoir Instrument Commissioning Engineer. Reply Submitted by Edward Smigo on Fri, 12/27/2013 - 10:45 The loop testing procedure can vary depending on the instrumentation and I/O infrastructure. A foundation fieldbus or Profibus PA based system would be different from a system using conventional or HART instrumentation on a system with HART I/O cards. While one can perform a loop test with a handheld communicator when HART I/O is not present on the automation system that process would require multiple people similar to performing loop tests with conventional instruments. One benefit HART instrumentation has over conventional is the non intrusive nature of the testing. One does not need to break the loop to insert a mA simulator. HART instruments have a Loop Test method that allows the tester to drive the mA output of the instrument from a hand held communicator or an Asset Management Software application, When using Asset Management software, testing can be done more efficiently because a single person can be commanding devices from one window and observing results on another. An additional benefit when using Asset Management software is that multiple instruments can be put into loop test simutaneously which allows one to incorporate interlock logic checks along with the loop tests which further streamlines the comissioning process.
3. Since loop tests are often the final step before start-up, and projects schedules often slip, there is always pressure on the loop testing team to gain efficiencies to pull in the plant startup milestone. Reply Submitted by Tom Dotts on Tue, 12/30/2014 - 08:30 Unfortunately, even today's large manufacturers have lost qualified process control specialists and engineers, leaving sometimes, unqualified personnel to decide how a "system" should be validated. A systematic approach is necessary and a legitimate step towards ensuring the "completeness" of even the smallest of project, upgrade or change to or within a BPCS or SIS on the plant floor. Of course regulations apply to safeties, but many times the even the fundamentals of instrumentation go unchecked and now become a liability. Standardization is needed - especially within chemical and petro-chemical applications. T.Dotts, Contract EI&C Technician / Project manager. Reply Submitted by Charles Palmer on Wed, 01/14/2015 - 03:23 I would like to share some perspectives : Loop testing and plant commissioning done in- house is one aspect. Naturally the requirement for policies and procedures is mandatory ( as in both cases) Things change slightly when this work is been done under contract by a 3rd party. Once again the policies and procedures are required. FAT and SAT procedures should be issued to the supplier/contractor within 30 days of contract signature. As a Consultant, I have witnessed so many poor FAT and SAT company procedures in many different countries ( Cultures if you like). This has compounded poor FAT testing into total SAT failures as the fault could not be isolated to Panel or Field . Many hours could have been saved if the bookwork had been done up front. Reply Submitted by Sankar Kumar R on Tue, 02/24/2015 - 03:43 I would like to summarize the requirement prior to start the loop check activity as follows: 1. SAT of DCS/ESD/F&G and IAMS system shall be completed and ready with all pre- requisites completed. 2. Total IO's shall be divided into loops & Loop Folder shall be prepared and approved from PMC/Client. 3. Loop folder shall contain the following documents as a minimum : a) Loop test record format (To enter the details of the Instrument subjected to loop check and the master instrument used). b) Instrument Data sheet(s) related with the loop. c) P&ID sheet related to the Instrument(s) d) Instrument(s) loop drawing (derived from Intools which shall contain termination details from Field through JB's to Rack Room) e) C&E sheet (For logic checks) f) IO Point Database (To refer : Ranges, Alarm Points, Controller action etc) g) Calibration sheet of Instruments in
4. loop. h) Observation sheet (To note down any observations during loop check/logic check activity for necessary corrective action). 4. Prerequisites like HVAC, Utilities shall be ensured 5. Loop check shall be carried with Handheld communicator / Calibrators or from IAMS system (For both FF & HART devices). 6. The checks shall be witnessed & loop folder documents shall be signed by DCS contractor, EPC contractor, PMC & Client. The preparation of above said document is time consuming but these will ease the loop / logic checks as all data's will be available in a single folder. This is the procedure we are following in our Greenfield Petrochemical Project. Instrument Calibration, Loop Testing and System Start Up Instrument Calibration is a necessary and important part of any instrument system. The accuracy of the information produced by any instrument is dependent on it. Instrument Sciences and Technologies Inc. recognizes the importance of calibration and has tailored the company policies and procedures to ensure you receive the highest level of quality and accuracy your process requires. After all, your end-product quality and customers count on it. We have a full, experienced staff of highly qualified Instrument Technicians ready to serve you. All technicians performing calibrations and loop check are EPRI level II and/or ISA level III qualified. We own over 400 individual pieces of NIST (National Institute of Standards and Technology) traceable calibration and test equipment. This inventory is meticulously logged, tracked, and evaluated per our Quality Manual's documented procedures. All equipment is either annually or semi-annually recalibrated and certified by an independent testing laboratory to NIST standards. Any instrument calibrated with this equipment is NIST traceable. Some of our calibration services include: Custom tailored customer/site specific recurring calibration program. Inventory is taken of your instruments to determine the condition and frequency of calibration required. A Technician arrives at your site when required to perform these calibrations, leaving you with a Calibration Certificate and up to date Calibration sticker affixed to the instrument. If the instrument needs repair, replacement, or relocation, this service can be performed during this process. Project specific calibration. We are an unlimited resource of Certified Instrument Technicians for your project. Our technicians are experienced in all the industries we serve, whether it is a Class 100 clean room, the top of a smokestack, or a confined space. Field and Bench Calibrations. One way to save time and cost during construction of your project is to have your instruments calibrated prior to installation. We call this "Bench Calibration". Our calibration facility is set up on site and staffed with technicians. We take care and custody of your i