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. 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. 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 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. 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, 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 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. • 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? 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. Before you move further, please like and share
this video because it helps in YouTube ranking. This is a PFD of the ATF system shows the
entire system of ATF Supply to MEROX Unit. The function of MEROX unit is to remove sour
gases from the AFT. This process is also known as a sweeting process. This is a simplest system with just one cone
roof tank and two centrifugal pumps. Here ATF is coming from CDU. You can see here that ATF is coming from ATF
rundown line to the tank and with the help of pump it is supplied to the MEROX Unit. 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. I will explain you the OSBL part of the system. I have full course on how to read P&ID with
lots of other types P&ID such as pumps, vessel, exchanger, column any many more. If you want to be as expert, you can check
my course. Link is given in the description. 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 this video for better understanding 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 ATF is coming from CDU; you can see that. You can see the line number. The diameter of incoming line is 6-inch NPS
which is equivalent to 150 mm DN. 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 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, 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
ATF line is divided into two strim. We follow this strim. 6” line is getting reduced to 4”. 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 different. This is 4” line number. 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. From the piping point of view, you can see
that there is 1-inch 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. Note that if it is a vent, it will be shown
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. Reading P&ID is nothing but reading P&ID symbols. So, if you are aware of symbols, you can easily
understand the P&ID. If you want to be an expert in reading P&ID,
you can buy my course How to read P&ID like an Expert that has may different types of
P&ID example that makes you confident to read any type of P&ID that you will come across. Link is given in the description. 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. 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. The last two instrument bubbles show the potions
and status of the valve. From field, you can set and see the % of the
valve opening and you can also check that valve is open or close. 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 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 ATF it will go to COC system. 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. 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. 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 20 meter in height with 9 meter
diameter. 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 show the tentative location of the nozzle
and also shows the size of the nozzle. Manholes are shown as M1 to M3. The broken line shows internal piping. There is a vortex breaker with N7 nozzle connected
to pump suction line with a Normally Closed gate valve. This is because the main suction line is N2. N7 will use only when you want to drain the
tank completely. There are two more nozzle N5 and N6 that used
to drain the tank to COC. 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. 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 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. 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 control panel for the pressure, level and temperature instrument
that I have explained to you. You may have noticed that there is tank gauging
system which received all input signal from these 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. In the last part of this video, let check
what is going out of the tank. ATF from the tank is supplied to the pump
with the help of 6” inch 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 control panel. If you know the instrument legends and symbol,
you can read and understand any P&ID. As said earlier, if you want to be an expert
in reading P&ID, you can buy my course How to read P&ID like an Expert that has may different
types of P&ID example that makes you confident to read any type of P&ID that you will come
across. Link is given in the description. 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. See you soon goodbye take care.
