Piping Systems are closed tubular arrangements that move gases, liquids, and solids (as slurries) through industrial processes (especially in refining); to users (distribution of natural gas, oil, and water); and from users back to treatment (sewage). Piping systems include compressors and pumps to keep material moving, valves to control and direct flows, and sensors to track volumes/deliveries. Engineering concerns in piping systems are materials, safety, security, and seismic risks.ping Systems are closed tubular arrangements that move gases, liquids, and solids (as slurries) through industrial processes (especially in refining); to users (distribution of natural gas, oil, and water); and from users back to treatment (sewage). Piping systems include compressors and pumps to keep material moving, valves to control and direct flows, and sensors to track volumes/deliveries. Engineering concerns in piping systems are materials, safety, security, and seismic risks.
Piping engineering is an emerging engineering science, although it has been there for years. Pipes are crucial for any plants, so are the individuals who help in creating plans and designs to make the sufficient piping system for a facility. The article draws light on the importance of piping engineering and piping engineers.
A piping system is crucial to any process plant; hence it needs to be designed with precision and care. The efficiency of a plant highly depends on its ability to transport fluid through the pipes to various equipment that function collectively. In order to create a piping system, it requires a systematic analysis of various engineering methods. In the past years, many standard practices for piping system has emerged, and today piping system is considered to be one of the major engineering sciences. As a result there is a continuous need for trained piping engineers to design piping system in every engineering and construction company.
As an academic discipline, piping engineering is rarely taught in universities. However, it is extremely important for the safety of plant, safety of the personnel, public, and also for maintaining the level of consistency in a facility.
Pipes on the surface are simple to comprehend; they are a cylindrical bar with a hole in it to allow the flow of fluid or gaseous substance. Pipes in a plant are subjected to numerous loading conditions in their life span. Piping systems can fail, hence it is important for the engineers to consider possible outcomes and work their way out to prevent the failure of the piping system and other hazards.
The Role of a piping engineer in an engineering company:-
Pipes do fail, and sometimes with disastrous outcomes. A piping engineer at the plant understands the potential risks, can aid in troubleshooting the issues.
A piping engineer is a mechanical engineer whose expertise lies in disciplines which deal with planning, design and implementation of various piping systems (including plumbing system) for broad spectrum of industrial plants. Industries such as: manufacturing, oil and gas, energy, agriculture and food, residential and commercial construction, chemical, etc. are the major industries which take the help of piping engineering consultants and professionals to implement the apt piping system for better functioning of their plants. The piping engineer's duties and responsibilities vary depending on the position in a specific industry. The companies prefer piping engineers who have a degree in mechanical engineering, civil engineering, or pipe engineering. Pipe engineers are expected to have excellent drafting and analytical skills, in order to ensure that the planned piping projects are documented and designed well, and built to meet the desired functions. These professionals are expected to have strong management skills for both supervising the team and executing specific tasks. The main responsibility of a piping engineer is to create fundamental drawings that define the functions of a piping system and to decide what materials should be used to create them. They help in choosing the appropriate materials to be used for pipes. Also, engineers conduct huge amount of research and development activities while creating the piping systems.
As we have seen that pipes are an inevitable part of any process plants, hence it is equally important to have the right piping engineer or piping engineering consultant before setting up a facility.
How to make critical line list or flexibility log? How will you decide critical line list with help of ASME B31.3?
How to decide Stress critical systems for analysis using Caesar II?
Which lines can be eliminated from formal Stress analysis?
Can you make a typical Sketch & supporting for column piping? How to decide how many load bearing clip supports to be used?
Draw a typical Sketch & supporting arrangement for tank farm piping? How tank Piping analysis is different from normal pressure vessel connected piping system analysis?
What is SIF? Formulas for In plane, outplane sif for elbow (B31.3)?
Value of sif, flexibility factor for Bend?
What are the necessary documents required for stress analysis?
Why a Spring hanger is used? Can you write the formula for spring HL, CL & variability?
What are the different types of supports used in piping systems?
What do you know about Expansion joints and their types? When these come into picture?
What are the normal types of load cases? Write the load cases for a typical stress system using static method of seismic and wind?
What is slug flow? What parameters are required to calculate Slug force?
What are the dynamic restraints? What is snubber and when do you use a snubber?
What is the minimum swing allowed in top mounted hanger? What will you do if that amount exceeds in a typical piping system?
What is cold pull and why it is used?
What is difference between Variable Hanger and Constant Hanger? What is the variability of Constant Spring hanger?
What are the inputs required for stress analysis? What do you check in Caesar analysis of a piping system?
What do you mean by the term “liberal stress”?
What is hot-cold philosophy for pump? Have you heard the term Pump alignment?
Write equation for SE in terms of Sb and St from ASME B 31.3?
What are the major difference between WRC 107 and WRC 297?
How Anchor load for a rack is calculated at the initial phases of project? What are the normal guidelines assumed?
Draw a typical control station layout and show its supporting?
How pump piping is routed and supported?
How you will decide the position of anchor bay in rack piping?
Which side (suction or discharge) in case of pump piping system is more critical from stress point of view? Justify the answer?
28) What are the main factors that decides support span?
29) What does API610 explains about aloowable nozzle loads for a Centrifugal Pump?
Can you show the typical layout and supporting for PSV lines?
What is the effect of friction in Piping stress analysis?
How layout of a pump piping changes with changes in temperature?
Why the allowable for primary stress is different from that of secondary stress?
Is the stress due to seismic anchor movement an occasional stress ? Explain with proper reason?
What is meant by the sentence ”primary stress is not self relieving but secondary stress is”? Explain in detail the meaning of the term “ self relieving”.
Will SIF increase or decrease with increase in pressure, other parameters kept constant? Justify your answer.
What is the role of Y factor in the pressure thickness eqn. of B31.3 and B31.1?
Is the pressure thickness eqn. for bends same as that of straight pipe in B31.3?
How B31.3 defines the terms Weldolet, Sweepolet?
Between a short and a long radius bend, which one has higher flexibility and why?
What does B31.3 tell about SIF for sockolet and reducer?
Explain the role of Appendix V of B31.3?
Does B31.3 allow a stress limit of 1.33Sh in PSV pop up case or is it 1.20 Sh?
Explain how to model snubber in CAESAR II.
Briefly explain the modeling of Sway Brace is CAESAR II.
What is the basic difference between a snubber and a sway brace in terms of applicability?
Explain with reason as to what should happen to the SIF and Flexibility factor of a bend when a trunnion is attached to it?
Explain the terms SIF and FLEXIBILITY factor.
Why SIF is “not so significant” with primary loading?
What happens to SIF of a reinforced connection if thickness of reinforcement increases beyond 1.5 times header thickness?
What special note B31.3 provides for SIF of welding tees (B16.9) ?
Explain with reasons as to which one is having higher SIF: a 45 bend or a 90 Bend?
Explain with reasons as to whether for a non 90 degree branch the same SIF can be taken as that for a 90 branch?
If thickness of the header of a branch connection increases, what happens to its SIF, other parameters kept constant?
What are the methods for flange leakage checking? Write euations used for flange leakage checking in pressure equivalent method?
What are the major difference between ASME B 31.3 and B31.1?
Place the following lines in Rack and show the placement of expansion loop?
A 16 inch High pressure steam line
A 6 inch Low pressure steam line
A 10 inch Medium pressure steam line
A 30 inch flare line
A 8 inch process line and
A 24 inch cooling water line.
How to decide the Spring height for a top mounted Spring hanger? What are the attachments used?
How do you calculate SIF for 45 degree lateral connections entering into flare header?
What are the transfer lines? Why does the stress analysis of transfer lines considered critical?
If a power plant is designed inside a Process refinery then where the specification break between ASME B31.1 & ASME B31.3 should occur?
What is category M fluid service? Provide some examples?
What will be the consequences of a steam piping having low pocket but not having a steam trap?
When and why the reducer of a pump suction piping is installed in bottom flat condition?
If you found a specification break (at flange) between carbon steel and stainless steel in a typical P&ID. What are the additional arrangements which a piping engineer should make for this?
Assume a straight pipe of length L anchored at both ends. When a temp change occurs the anchor force at one anchor becomes F1. Now the length of the same pipw increased to L2 and with similar temp change anchor force becomes F2. What is the relation between F1 and F2?
What is Piping Speciality item? How many types of piping speciality items are used in piping engineering? Can we include them in standard piping specification, explain with reason?
Why does the sustained sagging for steam lines are limited within 3-5 mm?
What is a “Double block & Bleed” valve? When such type valves are required?
In a normal tie-in where do you insert the spectacle blind? a) before block valve and towards new plant or b) after block valve and towards existing plant . Explain why.
What is the difference between a pipe elbow and a bend?
Among the following which material have the highest co-efficient of thermal expansion?
Carbon steel
Cast Iron
Duplex steel
Stainless steel
Galvanized Carbon steel
What are the major parameters to be reported in support tag for a Shoe/Saddle type support?
What are the Metallic expansion joints? When they are used and when they could be avoided?
What is hot sustained stress? Why do we check it? Do we need to chech expansion stress for hot sustained case?
What is the philosophy of arranging pipes in the Pipe rack and why? Normally what % of area is kept reserved for future expansion?
What are the major difficulties faced by a stress engineer while analysis two vertical rebolers connected with a single column?
What are the different types of combination methods available is Caesar II? What is the difference between Scalar and Absolute method?
Are process plant water lines considered pressure piping systems?
For what fluid service category may a hydro test be waived off as per B31.3?
Check the following load cases and tell me what is the difference between load case L3 and L4?
L1. W+T1+P1 OPE
L2. W+P1 SUS
L3. L1-L2 EXP
L4. T1 EXP
Which comes first?–Stress or Strain?
What is the difference between Stress and Pressure?
What are the major differences between a Pipe and a Tube?
What is seismic co-efficient? How this is decided?
What is wind shape factor? How the value of wind shape factor is decided?
Why does the manufacturer produce pipes with OD constant for a specific size and varying ID?
What are the major responsibilities of a stress engineer?89. What are the major differences between primary and secondary stresses in Piping?
Do you consider the vertical thermal growth for modelling fired heater in Caesar II? Explain with reason?
Why does the dummy of a piping system is also insulated for cold insulated piping system but not insulated for hot insulated piping system?
What are the major parameters and process inputs required for performing dynamic slug flow analysis?
Which parameters do you seek from civil department for performing underground piping analysis in Caesar II? Describe briefly the method of performing underground piping analysis using caesar II?
What are the outputs to check and what to interpret from caesar results?
How to calculate pipe thickness for externally pressured piping system?
What do you mean by the term flexibility ? How to ensure that the flexibility of a piping system is appropriate? What are the means for increasing flexibility? What will happen if more flexibility is provided to a piping system?
96. As per code ASME B 31.3 how many types of fluid service is available?
97. What are the code cases for ASME B 31.3?
98. Describe step by step methods for modelling a sway brace in caesar II?
99. In which way PDS, PDMS and SP3D differs? Which one is the best user friendly?
How to calculate the piping stress manhour for a specific project?
Can we exceed the design pressure of a piping system more than its design pressure. If yes then in what condition?
What is the limitation of using PTFE slide plate? What can be done in such situation?103. How to decide whether hydrotest or pneumatic test will be performed for a piping system?
What is bourdon effect of Piping system? When this effect become critical?
How do you check dummy ot trunnions for any project? Can you write the formulas used for this checking?
What is the difference between pressure safety valve and pressure relief valve?
Why do you consider slug flow in a piping system as critical?
What is the function of a gasket in flanged joint?
Why sustained stress is considered as a primary stress?
What are the major differences between SIF and SCF (Stress Concentration Factor)?
Lets assume from a 24 inch pipe header two tapping, one 2 inch and other one 4 inch, are taken. At the interconnection point in which case the SIF will be higher?
What is the industry accepted procedure for transferring anchor load for intermediate anchors (anchor in between two loops) where normally caesar shows very less value?
How to analyze stress packages when D/T ratio for the pipe exceeds 100?
Arrange the following piping elements with respect to flexibility and SIF (either increasing or decreasing order). Assume pipe size and thickness are constant.: 1.5D bend, 1D bend, Straight Pipe, 4D bend, 10D bend.
What is primary membrane stress?
Which one is more flexible : 45° bend or 90° bend? Which one is having more SIF?
Can we call piping shoe a pipe component as per code? Explain with reason. What is your opinion about RF pad in this respect?
What does the piping code says about the operation and maintenance of piping system?
You want to make some changes in the existing plant and want to add a new line by hot tapping. From which point the ASME B 31.3 code will be applicable?
What are the terms Code Case and Code Interpretation signifies?
How to model Air fin Fan Cooler in Caesar II? Why do you consider equipment weight in AFC modeling while for other heat exchanger we do not consider? What code need to be followed for nozzle load checking and what the code says about nozzle load checking? Why do we need thrust blocks for air fin fan cooler?
Can you write the NEMA equipment nozzle equation sets? What are the major differences in between API 617 and NEMA SM 23 from stress point of view? Draw a typical steam turbine piping layout?
Which standard is used for designing plate fin heat exchanger? Which table is normally followed for nozzle load checking?
How do you consider tank settlement while stress analysis? Is it a primary or secondary stress? Do you add tank settlement with sustained load cases? If yes why? What code says about tank settlement? What is tank bulging and why does it happen?
Draw a typical layout of a line connected with fired heater (Heater Piping)? Which standard is used for allowable nozzle loads?
What are the major differences in between B 31.3 edition 2012 and 2010?
Which standard says about rotary equipment alignment check? What is the criteria mentioned in that standard? While alignment checking spring will be in locked or design condition?
Calculate the number of loops for a 400 meter long carbon steel pipe having a temperature of 400 degree centigrade running over a pipe rack?
How do you calculate PSV reaction forces in absence of reaction force in vendor data? What is the major difference in between pressure safety valve and pressure relief valve?
Do you perform trunnion check while analysing a stress system? What are the associated formulas for trunnion checking?
What is the equation for calculating seismic coefficient?
How to calculate the wind force?
What is guided cantilever method? What is the importance of this method?
What does the Appendix F of API 610 ensures? What are the equations? What the standard says for vertical inline pumps?
What do you mean by weld joint strength reduction factor and quality factor? What is the importance of these factors?
While providing preliminary rack loading what assumptions do you consider?
What was the most critical system you analysed in the last company? Draw the layout? What changes you recommended? What is temperature of that line?
What are the minimum load cases required to consider while performing stress analysis of a vertical reboiler connected piping system?
Have you performed stress analysis of reciprocating compressor connected line? What are the considerations? What is the minimum frequency you achieved before sending for pulsation study? How do you consider upto what length of piping is to be send for pulsation study?
What actually do you check during flange leakage checking by NC 3658 method?
Can we reduce the hydrotest pressure of pipe to less than 1.5 times the line design pressure? If yes then in what condition?