Decoding P&ID Drawings

How to Read P&ID Drawing - A Complete Tutorial

AI-generated summary and notes. Check quotations, numbers, and important claims against the source video. Captions may contain errors.

Watch the source video on YouTube

Estimated reading time: 17 minutes for the text on this page.

Summary

In this comprehensive tutorial by HardHat Engineer, viewers are guided through the intricacies of reading Piping and Instrumentation Diagrams (P&ID). Varun Patel, the narrator, differentiates P&IDs from simpler Process Flow Diagrams (PFDs) and explains their critical role across the plant's lifecycle, from design to operation. The tutorial covers the detailed information a P&ID provides, including equipment details, piping components, and instrumentation, while also clarifying what it doesn't include, such as process conditions and streamflow details. The video also offers practical guidance on interpreting symbols and instrument legends crucial for understanding P&IDs, ensuring viewers can effectively read and apply these diagrams in the field.

Highlights

Understand the complexity of P&ID compared to PFDs and the importance of watching the tutorial till the end. 🎥
Learn about the various elements that a P&ID covers, such as equipment details, valves, and piping information. ⚙️
Discover what data is missing from P&ID, like process conditions and equipment locations. ❓
Follow along with Varun Patel’s explanation on reading and interpreting P&ID symbols for practical understanding. 📘
Get insights into operational practices, such as maintaining P&ID for safety and compliance. 🔐

Key Takeaways

P&ID diagrams are essential for comprehensively representing the process of a plant, far more complex than PFDs. 🚀
Symbols and legends are crucial for understanding P&ID, as they define elements and equipment within the system. 🔍
P&ID is a pivotal document throughout the plant's life cycle, important for designing, constructing, and operating phases. 📜
Reading P&IDs requires familiarity with industry standards and terminologies, essential for engineers and operators. 🛠️
Varun Patel emphasizes the educational value of subscribing to engineering content on platforms like YouTube. 🧑‍🏫

Overview

Piping and Instrumentation Diagrams (P&ID) are essential to the workflow within any engineering project, offering a detailed graphical representation of the physical aspects of a process system. This tutorial simplifies their otherwise complex setup, inviting engineers to delve into the specifics of reading and applying P&ID effectively.

Varun Patel, a knowledgeable guide, navigates through the layers of information depicted in P&IDs, detailing the critical components they map, including equipment specifics, piping, and instrumentation requirements. He also emphasizes the missing information in these diagrams, offering a realistic guide for on-field application and comprehension of these essential tools.

Highlighting the necessity for solid foundational knowledge in symbols and terminologies, this tutorial is a crucial resource for engineers and operators alike. Varun's engaging instructional style ensures viewers can grasp these complexities effectively, applying their learning across various stages of plant design, operation, and maintenance.

Chapters

00:00 - 00:30: Introduction and Importance of P&ID The chapter provides an introduction to Piping and Instrumentation Diagrams (P&ID) and their significance in process engineering. It highlights that P&ID is also referred to as Process Engineering Flow Scheme (PEFS). The chapter aims to teach readers how to read and interpret P&ID and PEFS using actual plant drawings, presented by Varun Patel on Hardhatengineer.com.
00:30 - 01:00: Definition and Complexity of P&ID P&ID is more intricate compared to PFD, encompassing numerous details. The video aims to cover all aspects of this complex drawing and invites viewers to stay engaged until the end for a comprehensive understanding. Additionally, the creator encourages subscribing to the channel for updates on new content.
01:00 - 01:30: Understanding P&ID Details Understanding P&ID Details: P&ID, or Piping and Instrumentation Diagram, is a detailed graphical representation of a process plant. It uses various symbols to depict actual equipment. Compared to a Process Flow Diagram (PFD), a P&ID is more complex and detailed. While a single PFD can illustrate a system, multiple P&IDs may be required to represent the same system comprehensively.
01:30 - 03:30: Use of P&ID During Plant Lifecycle The chapter 'Use of P&ID During Plant Lifecycle' covers the essential role of Piping and Instrumentation Diagrams (P&ID) throughout the stages of a plant's lifecycle. It begins with the importance of P&ID as a crucial deliverable in the Front-End Engineering and Design (FEED) phase. These diagrams are indispensable from the pre-EPC phase through to the EPC and operation phases. A specific focus is given to their use during the pre-EPC phase, highlighting how P&IDs assist in deriving project capital cost estimates.
03:30 - 04:30: Components and Symbols in P&ID P&ID is crucial for developing EPC contract specifications and plotting plant development, taking inputs from both P&ID and the physical site location.
04:30 - 08:00: In-depth Explanation of P&ID Symbols and Example Piping and Instrumentation Diagrams (P&IDs) are essential tools used to develop piping layouts and prepare bulk material take-offs for various disciplines including piping, electrical, instrumentation, and civil engineering. They serve as key documents for several types of reviews such as HAZOP (Hazard and Operability Study), SIL (Safety Integrity Level), and operability reviews. It's crucial to maintain P&IDs in a state that accurately reflects the plant's current conditions, updating them as physical changes occur to ensure ongoing compliance.
08:00 - 16:30: Mechanical and Instrumentation Details in P&ID This chapter focuses on the details of mechanical and instrumentation aspects in Piping and Instrumentation Diagrams (P&IDs). The significance of these diagrams lies in their role as essential documents within industrial operations. They ensure compliance with codes, standards, and specifications, and verify that operations can proceed safely under specified process conditions. Emphasizing their educational purpose, P&IDs facilitate the training of operators and engineers prior to commencing plant work. Key information conveyed by P&IDs includes a comprehensive outline of all the equipment—such as installed spares—and the associated piping, detailed further by inclusion of drain and vent lines.
16:30 - 18:00: Conclusion and Additional Resources The 'Conclusion and Additional Resources' chapter encapsulates the key topics covered in the form of piping and instrumentation details. It outlines the importance of insulation, jacketing, instrumentation, heat tracing, and specific utilities information. The chapter offers insights into piping components detailing their size, class, and tag number, and provides essential data required for design, construction, and operation, including the slope of lines, permissible distances from equipment or instruments, and necessary straight lengths post-instrumentation. It concludes with a note on what aspects are not covered in a Piping and Instrumentation Diagram (P&ID).

How to Read P&ID Drawing - A Complete Tutorial Transcription

00:00 - 00:30 Welcome to Hardhatengineer.com. I am Varun Patel. In this video, you will learn about how to read P&ID. Piping and instrumentation diagram is also known as Process engineering flow scheme which is PEFS. You will learn how to read P&ID and PEFS with the help of the actual plant drawing.
00:30 - 01:00 P&ID is more complex than of PFD and includes lots of details, because of this you have to watch the video till the end to understand all the aspects of this drawing. Please subscribe to my channel because it helps me to increase my reach on YouTube and you will also get regular updates on a new video. You can subscribe right now by just clicking the subscribe button on the right-hand side of the screen.
01:00 - 01:30 What is P&ID? P&ID is a graphical representation of the actual process plant using various symbols that represent actual equipment. As said earlier it is complex than PFD. A single PFD can have multiple P&ID. This means if some system is shown on single PFD, to show the same system on P&ID, it may
01:30 - 02:00 require multiple P&ID sheets. It is one of the main deliverables of FEED. That is front-end engineering and design. It is used during entire life-cycle of the plant. That means during pre-EPC, EPC and operation. Use of P&ID/PEFS During Pre- EPC Phase P&ID is used to derive Project capital cost estimate.
02:00 - 02:30 It is also used to develop EPC contract specification. Plot plant is developed considering various inputs from P&ID and physical site location. Use of P&ID/PEFS during EPC phase During EPC phase, P&ID is used to develop the individual unit layout. It used to identify hazardous areas classification, preparing data sheets of equipment, valves,
02:30 - 03:00 and instrument. P&ID are used to develop the piping layout and preparing bulk material take-off for piping, electrical, instrumentation and civil. It is key documents for various review such as HAZOP, SIL and operability review. During Operation, you have to maintain P&ID in such a condition that it will show actual plant conditions at any time. It should be updated when any physical change is made so that the unit will remain compliant
03:00 - 03:30 with codes, standards, and specification, and can be operated safely under the defined process conditions. P&IDs are used to train operators and engineers before they start work in the plant. What information does P&ID provide? • All the equipment, including installed spares, and associated piping including drain and vent line.
03:30 - 04:00 • Insulation or jacketing requirements. • Instrumentation • Heat tracing and insulation detail • Information about utilities • Piping components including their size, class and tag Number • Information required for design, construction, and operation such as  Slope of the line  Minimum and maximum distance from the equipment or instruments  Minimum straight lengths after instruments What is not included in a P&ID?
04:00 - 04:30  Process conditions and physical data  Operating conditions  Streamflow details  Equipment locations  Pipe routing, length, and fittings  Support and structural details are also not included in p&id Ok, now you know what P&ID is and types of information you’re going to get from the drawing. Let’s confirm this with the help of actual P&ID.
04:30 - 05:00 Before you move further, please like and share this video because it helps in YouTube ranking. This is a PFD of the flushing oil system shows the entire system of pump seal flushing oil. This is a simplest system with just one cone roof tank and two centrifugal pumps. The pump used in a heavier product such as crude, fuel oil required flushing oil to keep
05:00 - 05:30 the pump seal clean. Here Ultra low sulfur diesel is used as flushing oil. You can see here that ULSD is coming from diesel rundown line to the tank and with the help of pump it is supplied to the various pump of ISBL and OSBL units’. Hope the function of the system is clear to you. Now let’s move to P&ID. There are two P&IDs for OSBL part of this system and may more for ISBL parts.
05:30 - 06:00 I will explain you the OSBL part of the system. Reading P&ID is nothing but the reading of symbols. So, if you have not seen the earlier videos on P&ID symbol and how to read PFD, it will be difficult for you to understand this drawing. Links of these videos are given in the description. So, if have not seen these videos, please watch these video for better understanding
06:00 - 06:30 of P&ID. If possible, get a print of this P&ID in A3 and follow the video. You can download this P&ID by visiting my website. The link is given in the description. It is always a good practice to start reading P&ID from the main incoming lines and follow the fluid path. Here ULSD is coming from DHT; you can see that.
06:30 - 07:00 Remember the black head on the arrow? You have learned this in how to read PFD video. It means Diesel is coming from the different unit. Here you can see the line number. It is 150 mm diameter line as per DN standard which is equivalent to 6” NPS. The different company follows different terminology for the line number. But it contains same information such as line size, unit number, commodity code that identify
07:00 - 07:30 fluid inside the line, circuit number, line sequence number, piping class that gives all detail about piping components and their materials, insulation, and coating requirement. Here N means there is no insulation. If there is H than hot insulation, C is for cold insulation, A for acoustic reduction,
07:30 - 08:00 P for personal protection, F for fireproofing. It also gives information about whether the line is steam trace or electric trace. Normally ET is used for electric tracing and ST is used for steam tracing. Let’s move ahead, here you can see that diesel line is divided into two strim. We follow this strim. 6” line is getting reduced to 4”.
08:00 - 08:30 Don’t get confused with reducer symbol; it is just indication of line size change. In piping, it can be a reducing tee as it is 6” to 4” concentric reduction. Now, this triangle with line indicates a line break. A line break is the demarcation of the line number change. So, whenever this symbol is used it indicates that from that point onward line number is
08:30 - 09:00 different. This is the bypass loop for the flow transmitter. You can see that venturi-type flow transmitter provided in between the two gate valves. Why did I say it is a venture type flow transmitter? Letters VM indicates the type of flow transmitter. It gives flow indication on the control plane. You can see the connection shown between FT and FI.
09:00 - 09:30 From the piping point of view, you can see that there is 25 mm drain valve is given in between the two gate valves. The letter D indicates that it is drain valve and if it is V than it is vent valve. Offcourse if it is a vent, it shows on the topside, not on the bottom. The bypass valve is also a gate valve which will remain closed during normal operation. You can see the letters NC which indicates the same.
09:30 - 10:00 Reading P&ID is nothing but reading P&ID symbols. So, if you are aware of symbols, you can easily understand the P&ID. Here you can see the motor-operated butterfly valve. Lots of instruments are shown here. But it is not that complicated. If you are aware of MOV, you know that it can be operated locally or from the control penal.
10:00 - 10:30 You can read AT VALVE label that means this instrument function is available on the valve itself. HS indicates hand switch, with these switches you can put MOV on manual control or remote control that means on panel control. You can also start or stop the valve from the field. HS-O means open, and HS-C means close. The data link indicates this valve is connected to the control panel.
10:30 - 11:00 The last two instrument bubbles show the potions of the valve. From field, you can set and see the % of the valve opening. Next is drain valve that is located at the lowest point. This is the spectacle blind with normally closed configuration. If the dark ring is towards the valve, as in this case, it indicates that solid ring
11:00 - 11:30 covers and isolate the joint during normal operation. If the only circle is towards the valve, as shown here, that means the hollow ring is there, and the line is live during the normal operation. Below the drain valve, the funnel is shown. So, when you drain ULSD it will go to COC system.
11:30 - 12:00 COC means continues oil contaminated that used to drain hydrocarbon. The second type of drain is AOC that means accidentally oil contaminated system. After dike wall, there is pneumatically controlled globe valve is there. You can see the pneumatic line symbol. Like MOV, the pneumatic valve also has various switch to operate the valve locally and from the control panel.
12:00 - 12:30 You can also see the three-way valve connected to the pneumatic line to operate the actuator. You can refer the abbreviation table to understand the meaning of all these instrument bubbles. I have attached this table with a free download. The link is given in the description. You can see that there is a relief valve in bypass. It used to protect the actuator from the surge. Next is a tank.
12:30 - 13:00 First, I will explain mechanical parts and then instrumentation. As you can see, this is a fixed roof tank. On the top of the P&ID, you can see the detail of the each of the equipment shown in the drawing. Let see the detail of this tank. The tank is 17.5 meter in height with 8.25-meter diameter.
13:00 - 13:30 You can also see the operating pressure and temperature of the tank. The material of construction is carbon steel, and there is no insulation. Now let go back to the tank. N1 to N17 are nozzle number. P&ID don’t show the exact location of the nozzle, but it shows the size of the nozzle. Manholes are shown as M1 to M3. The broken line shows internal piping.
13:30 - 14:00 There is a vortex breaker with N8 nozzle connected to pump suction line with a Normally Closed gate valve. This is because the main suction line is N2. N8 will use only when you want to drain the tank completely. There are two more nozzle N9 and N10 that used to drain the tank to COC.
14:00 - 14:30 This is open type liquid seals that prevent air ingress into the tank. Now let’s check the instrumentation. For safe operation of any equipment, you have to monitor pressure, temperature, and level. Here you can see the Pressure Transmitter near the tank bottom plate. On the top of the roof, you can see the radar type level indicator and transmitter. The temperature gauge is shown as TE that is temperature elements.
14:30 - 15:00 This arrangement shows multiple thermocouples installed at a different height of the tank. This will ensure that you will get an average temperature of the tank as the liquid has a different temperature at a different level. LZT is level safety transmitter. Here you can see the value for LLL, HLL and HHLL. LLL means low liquid level, HLL means high liquid level and HHLL means high high liquid
15:00 - 15:30 level. LLL protects your pump and when tank level reached to LLL, it gave the alarm in control penal and based on the logic configuration it may trigger to switch off command to the pump. HLL and HHLL will use to protect the tank from over filling.
15:30 - 16:00 When liquid level reached to the HLL it gives the alarm and when it reached to HHLL it will trigger the safety logic and stop the fluid supply to the tank. There is a breather valve on the tank. It will protect the tank from the overpressure and vacuum. Now, these all instrument bubbles are sending the information to the local and main control panel for the pressure, level and temperature instrument that I have explained to you.
16:00 - 16:30 You may have noticed that there is tank gauging system which received the all input signal from the instruments. Tank gauging system is used to calculate the quantity of the liquid stored in the tank at any given time. Based on the diameter, level, and temperature it will calculate the quantity of the liquid stored in the tank. QI is quantity indicator.
16:30 - 17:00 In the last part of this video, let check what is going out of the tank. ULSD from the tank is supplied to the pump with the help of 150 mm pipeline. You can see that inside dike there is a manual gate valve with bypass arrangement. There is safety relief valve on the bypass. Outside the dike, you can see the motor-operated butterfly valve. This MOV has similar switches as I explained earlier to operate the valve locally and from
17:00 - 17:30 control penel. If you know the instrument legends and symbol, you can read and understand any P&ID. You can download this P&ID with the instrument code table by visiting my website hardhatengineer.com. Don’t forget to subscribe to my channel to get regular updates on a new video. Please like and share my video with your friends. If you want to request a video, write in the comment.
17:30 - 18:00 See you soon goodbye take care.