Abstract:
The journey of developments in instrumentation has been very exciting. From pneumatic (3 to 15 psi) to voltage (0 to 5 V DC) or current (4 to 20 mA) to hardwired relays/PLC/DCS, HART/Modbus/Foundation Fieldbus/Profibus, etc… further to wireless and other technologies; the developments and their practical application have been very fascinating and at times challenging to implement. The growing trend of application of Safety Instrumented Systems and Industrial Cybersecurity is the best that can happen in Instrumentation. It is very difficult to know the intricate details of every instrumentation aspect as the subject is infinite and one needs to know the area of his/her interest and expertise so as to be the best. The need of the hour is to know the issues related to instrumentation that are still prevalent in the industry and that these issues need to have a firm solution.
In this article we attempt to highlight some issues related to documentation and drawings; in particular P&IDs – the very basic platform on which the fundamentals of instrumentation stand. The author tries to share his experience (related to P&IDs) gained during site visits/audits of various operating companies in India.
Introduction
The industrial sector in India has grown rapidly in the past few years and the usage of automation has seen an exponential rise. Though there has been tremendous advancement in automation, still, even today, one key issue that is prevalent is the correct and up-to-date updation of documentation and drawings (henceforth called as documentation in this article) that are maintained at the end-users operating facility. This is applicable for green field projects and even brown field projects. Though, in any project there are thousands of documentation that are required to be referred even after the plant is commissioned and set into production mode but very few of them see the face of updation and correct record maintenance. This may appear to be a trivial matter but in reality poor documentation is one of the very big causes of constant issues for operations, maintenance and safety that actually affects productivity, profitability and business sustainability.
Site documentation (as related to instrumentation) is varied like: P&IDs, instrument index, I/O list, Functional Specifications, JB/Cable schedule, Hook-ups, Interface drawings, Control / Shutdown system related documentation, O&M manuals, SOPs, maintenance/calibration schedules, vendor certificates/catalogues, etc. However, in this article, we discuss through case studies, the issues with the mother of all documentation, i.e. P&IDs (Process and Instrumentation Drawings or Piping and Instrumentation Diagrams).
The Details
There are many operating companies that have their facilities running quite smoothly till date but the mother document “P&IDs” are either completely/partially missing or they have not been updated since decades. Barring a few companies that believe in truly following the Management of Change (MoC) procedure and maintaining documentation up-to-date and enforce strict control to prevent misuse, many others believe in maintaining strong commercials and making profits while some of them have a mixed approach. The need to invest time and money in maintaining P&IDs up-to-date is lacking and that is a big gap to be bridged.
This common issue is applicable across all industries like oil and gas, chemicals, refineries, pharmaceuticals, etc. The bigger and complex the facility is, more is the need to have each and every P&ID (and of course all documentation) updated and in easily accessible and retrievable place.
The author has many case studies that can be discussed but would like to highlight one recent example.
Case Study
The author while conducting a Process Safety Management (PSM) gap analysis observed a strange case of issues with P&IDs.
The operating facility was running past 25 years and involved in manufacturing Highly Hazardous Chemicals (HHC). The plant personnel knew that they were sitting on a live bomb ready to explode but they were habituated to procrastinate because they were complacent in the fact that nothing could go wrong in their facility as nothing major hard happened in the past 15 years.
On document review it was found that the P&IDs were not available for all the unit areas in the facility and for the areas where P&IDs were available they were last updated in the year 1998 and only a few had been updated in the year 2000 so as to close the observation highlighted in one of the safety audits. This good attempt however never became a habit due to prevalent site culture. The prints of some of them were very dull and were not readable at all. Many operating personnel in the facility were unaware that P&IDs did exist and what was actually the use for it. Plant personnel believed in verbal communication and sign language was heavily used.
Many who were interviewed had raised a strange concern; the company has changed many hands and there is no set guideline or management procedure that can be followed. Most of the procedures were still under management approval (since 5 years).
Personnel at site believed that P&IDs were never referred as the site had umpteen modifications and for all modifications P&IDs were not updated or even required.
However, with one clear P&ID a site round was conducted for a small unit area. But it was astonishing to see that almost 50% of the instrumentation as depicted on the P&ID was not available and even some of the pipeline numbers. were not matching. On further interaction, the site personnel revealed their management beliefs, that P&IDs were meant for the design and detail engineering phase only and after As-Built their updation made no difference as such as the senior personnel on site were working since the time the facility was built. Hence they were the ‘Masters’ on site and so no modification / updation on site would proceed without their consensus.
Though taking consensus of Seniors/Management is absolutely correct and a must requirement, however, without formal documentation and that too P&IDs in place the ‘so called verbal method’ adopted should not be accepted. There are umpteen chances of verbal communication being misinterpreted and incorrect implementation may have catastrophic consequences. It is fair to understand that during design and engineering stage, the P&IDs are actually under the ownership of Process engineering. However after the handover at site and once the site is up and running, it usually comes under custody of the instrumentation team and proper P&ID ‘take-care’ shall always be ensured.
Key Notes
Some of the instrumentation pointers that shall always be available on a P&ID are:
1. Use of correct instrumentation symbols as per ISA S5.1/ client specific standards (field, control room, local, packages, etc.)
2. Use of correct identification of signals (electrical, pneumatic, hydraulic, soft link, etc.)
3. Representation of scope demarcation between various parties (if applicable)
4. Specific notes to be referred (like: requirement of split range control, etc.)
5. Interface between DCS, ESD, package PLCs, etc.
6. Applicable Interlocks and their description
7. Equipment numbering, pipeline numbering, legend sheets, set points/trip limits, etc…
8. Other key parameters depending on the project scope, process criticality and requirements.
Summary
The need to have the facility P&IDs on site shall be understood by all required site personnel (including top management) and that P&IDs be always readily accessible and easily retrievable should be developed as a habit and a culture in any organization.
Additionally, all instrumentation engineers in colleges be precisely taught how to read/draw/develop/understand/maintain (and everything) about P&IDs including the interlocks, field & control instrumentation and symbols used. This will help engineers carry the habit and influence to develop a positive culture in the organization that they work, in true spirit.
