QC INSPECTOR - Welding and Piping Interview Review Question+++ PDF [PDF]

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QC INSPECTOR WELDING & PIPING INTERVIEW REVIEW QUESTIONS RAMENDRA NATH BISWAS (Welding Engineer)

2019

[TYPE

THE COMPANY ADDRESS]

PART-I

WELDING & PIPING INTERVIEW REVIEW QUESTIONS

1. What is the standard for process (or) plant piping systems? ➢ ASME B 31.3 2. What is the standard for power piping systems? ➢ ASME B 31.1 3. What is the standard for liquid petroleum transportation and distribution piping systems? ➢ ASME B 31.4 4. What is the standard for gas transmission and distribution piping systems? ➢ ASME B 31.8 5. What is the code for welding of pipelines and related facilities? ➢ API 1104 6. What is the standard for welding rods Electrodes and filler metals? ➢ ASME SEC-IIC 7. What is the standard for Non-destructive examination? ➢ ASME Sec-V 8. What is the standard for welding and brazing qualifications? ➢ ASME Sec-IX 9. Which type of process we are using in field/shop fabrication shop? ➢ Fusion welding

10. What is the specification/classification for carbon steel filler wire? ➢ AWS 5.18/ER70-Sx 11. What is the specification/Classification for carbon steel Electrode? ➢ AWS 5.1/E-XXXX 12. Where we can use E-6010 type electrode? ➢ We can use at root pass for deep penetration 13. What is the meaning for ASME? ➢ American society for Mechanical Engineering 14. Which type of electrode we are using in GTAW process? ➢ Non-consumable Tungsten Electrode 15. How do handle the electrode? ➢ Different grades of electrodes shall be stored separately. ➢ It shall be kept clean, dry and properly stored according to manufacturer’s recommendations. ➢ Before use all low hydrogen electrodes shall be baked and stored in heated containers ➢ Electrodes used shall be free from rust, oil, grease, earth and other foreign matter 15A. How many times we can dry the electrodes? ➢ Only one time 16. Why we are baking the electrodes? ➢ To remove the moisture content from the Electrodes 17. What is the standard for structural steel fabrication? ➢ AWS D1.1 18. What is the standard for welding symbols? ➢ AWS A2.4

19. What is the hydro test pressure? ➢ 1.5 times of design pressure 20. What is the drying temperature for stainless steel electrodes? ➢ 120 to 250 degree temperature 21. What is the drying procedure for low hydrogen electrodes? ➢ 260 to 430 degree temperature baking for two hours 22. What are the defects we can find visual inspection? ➢ Porosity, Undercut, Surface crack (HIC), Side wall fusion on fusion boundary 23. What is the procedure for Fit-up inspection? ➢ Base metal classification, cleaning, alignment, root gap, root face, bevel angle & mismatch or overlap 24. What is the internal overlap or mismatch for piping? ➢ 1.5mm 25. How much root face is allowed? ➢ As per WPS or 0.8mm to 1.6mm 26. What is the meaning for F-number? ➢ F-is filler metal grouping number 27. What is the meaning for P-number? ➢ P-is base metal grouping number 28. What is the meaning for A-number? ➢ A-is electrode chemical analysis number 29. How much bead width we can allow? ➢ Max 3 times of electrode diameter 30. How much area is required for preheat? ➢ 75mm minimum from both end of the joint.

31. Which section we are using for NDT? ➢ ASME Sec-V 32. What are the essential variables for SMAW process? ➢ In base metal thickness, P-number, die of pipe, preheat, post weld heat treatment ➢ In Filler metals F, A- numbers, dia of filler metal 33. What are the essential variables for GTAW process? ➢ In base metal thickness, P-number, die of pipe, preheat, post weld heat treatment ➢ In Filler metals F, A-numbers and dia of filler metal 34. If welder made test by 2” die, what is his range qualified? ➢ He has qualified 1”-dia and above 35. If welder test by 14mm thickness, what is the thickness range qualified? ➢ He has qualified unlimited thickness 36. What is carbon % in low carbon steel? ➢ Max 0.30 % 37. What is the interpass temperature for carbon steel materials? ➢ Max 315 degree C 38. What is the meaning for SAES, SAEP and SAMSS? ➢ Saudi Aramco Engineering Standards 39. How much undercut depth allowed in piping? ➢ 0.8mm 40. How much percentage is allowed more than test pressure in pressure relief device? ➢ Test pressure plus 10% (10% should be lesser than 50Psi)

41. How much gap is allowed in socket weld? ➢ 1.5mm minimum before welding 42. What is the minimum fillet weld in socket weld? ➢ Minimum 3mm fillet size. 43. What is the purpose of High frequency unit in GTAW process? ➢ To avoid Tungsten inclusion and arc strike 44. What is mean by suffix letter ‘G’ in electrode AWS specification? ➢ Such type of electrode is using in LTS materials. In that chemical content is less than 1% any one follows Mn, V & Mo. 45. What is the means for WPS? ➢ Collection of data which produce sound weld. (Essential, NonEssential & Sublimentry variables) 46. What is the P-number for Cr, Mo materials? ➢ It comes under P4 & P5 47. Explain essential variables? ➢ If we adjust or change any variable in weld process, it affects mechanical properties those are called Essential variables. 48. What are the types of supports? ➢ Anchor supports, T-supports, Shoe supports, Guide supports, Pedestal supports, candy lever supports, Hanging supports, Dummy supports, Trunion supports, Wear pad supports. 49. Tell some types of flanges? ➢ Weld neck flange, Slip on flange, Blind flange, Threaded flange, Socket flange, lap joint flange 50. Tell some types of classes & purpose? ➢ 150, 300, 400, 600, 900, 1500 & 2500

➢ Based on the class only we have to identify suitable gasket OD & ID, bolt length, nut, and torque 51. What are the types of pipes and schedules? ➢ Welded type, Seamless pipe and tubes SCH-10,20,30,40 ,60,80,XS,100,120,140,160 & XXS ➢ Based on the schedule we have to identify the suitable pipe thickness 52. Tell some gaskets? ➢ Spiral wound gasket, Composite gasket, corrugated gasket, Die cut gasket, solid metal gasket 53. Material familiar with? ➢ LTS, CS, SS, Duplex, cupper Nickel, Low alloy steel 54. Fluid service familiar with? ➢ Normal fluid, D, M-fluid services. 55. What is the string bead? ➢ Straight motion of welding, No side to side motion example-SAW weld 56. What is weave bead? ➢ Side to side motion while welding 57. How we approve the WPS? ➢ The weld should be sound weld: it has to fulfill the minimum requirement of mechanical, chemical and physical properties 58. What are the parameters required to prepare a WPS? ➢ Pipe diameter, thickness, welding position, current, voltage, electrode and base metal 59. Which is the standard using using in ARAMCO for welding requirements of pressure vessels? ➢ SAES-W-010

60. Which is the standard using in Aramco for on-plot piping? ➢ SAES-W-011 61. Which is the standard using in Aramco for welding requirements of pipelines? ➢ SAES-W-012 62. Which is on-plot piping? ➢ Inside plant piping are called on-plot piping 63. Which is off-plot piping? ➢ Outside plant piping are called off-plot piping 64. What are the specifications used for pipe manufacturer? ➢ API 5L and ASTM 65. Why we are doing PWHT? ➢ To release the stresses 66. What is the hardness Method acceptable in procedure qualification? ➢ Vickers, Brunel’s, Rockwell hardness method 67. What are some ways of visually identifying piping materials on the shop floor? ➢ Color code, Stamping. 68. How would you ensure radiograph have been taken on specific pipe welds? ➢ Identification which has been on films and sometimes drawings. 69. What information should be contained in a radiograph of a pipe weld? ➢ Penetrameter ➢ Joint Number ➢ Welder Id

70. What are some of the precautions which should be taken when welding piping materials of alloy material such 1.25Cr, 5Cr etc? ➢ Preheat ➢ Interpass Temperature ➢ PWHT requirements are to be complied with.

PART-II WELDING & PIPING INTERVIEW REVIEW QUESTIONS ❖ Duties and Responsibilities of Welding Inspector. ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢

Perform material inspection. Perform consumable inspection. Application of inspection gauges, instruments and tools. Check equipment and accessories. Witness procedure qualification test. Witness welder qualification test. Perform visual inspection. Review / witness NDT Witness mechanical test. Monitor heat treatment Observe production and fabrication welding. Interpret and assure compliance to Code / Standard / Specification. ➢ Review technical drawing. ➢ Witness weld repair. ➢ Prepare and compile inspection records. 1) What is the formula for heat input? ➢ Heat Input (j/cm)= Voltage x Amperage x 60 / Travel Speed(cm/min)

2) How do you calculate the weld repair percentage? ➢ % RR = (Lr/Lw) X 100 Where, % RR – Percent repair rate Lr -- Total length of repair in one week Lw --Total length of weld radiographed in one week 3) What should be the distance b/w two parallel welds? ➢ 20mm or three times the wall thickness of the joint, whichever is greater. 4) What are the types of thermocouples in PWHT? ➢ Type K (Chromel-Alumel) ➢ Type J (Iron-Constantan. 5) What is HIC? ➢ HIC – Hydrogen Induced Crack 6) Different categories of fluid services in ASME B 31.3? ➢ Category D ➢ Category M ➢ High pressure fluid service. ➢ Normal fluid service 7) What is ocv and ccv? ➢ OCV - open circuit voltage ➢ CCV – closed circuit voltage 8) What are the types of olets? ➢ Weldolet ➢ Sockolet ➢ Threadolet ➢ Nippolet 9) What factors (give at least four) are taken into account when selecting and designing a joint for a welding application? ➢ Strength ➢ Accessibility for welding ➢ Minimize distortion ➢ Cost of welding ➢ Accessibility for inspection

10) What is the P no for SS & CS? ➢ SS – P No. 1 ➢ CS – P No, 8 11) What are supplementary essential variables? ➢ The change in a welding condition which will affect the notch toughness properties of a weldment is known as supplementary essential variable. 12) What are essential variables? ➢ Essential Variable (Procedure) – A change in a welding condition which will affect the mechanical properties (other than notch toughness) of the weldment. ➢ Essential Variable (Performance) – A change in a welding condition which will affect the ability of a welder to deposit sound weld metal. 13) Which standard do you refer for the welding equipment calibration? ➢ BS 7570. 14) What are the tests required for verifying supplementary essential variables? Notch toughness tests➢ Charpy V- Notch test ➢ Drop weight. 15) What is a welding procedure specification (WPS)? ➢ The WPS is a written document that provides direction to the welder for making production welds in accordance with Code/Standard requirements. 16) How is the Procedure Qualification Record (PQR) different from the WPS (Welding Procedure Specification)? ➢ Procedure Qualification Record certifies that test welds performed in accordance with the WPS meet Code requirements and summarizes the specific test results.

17) What is a “Weld Map” and how is it used? ➢ It is an isometric drawing showing the location and numerical identification of each weld used in the construction of a process piping system. Each weld when completed is labeled with the weld number indicated on the weld map, the date completed, and the welder/welding operator identification number or code. 18) What are the welder qualification limits? ➢ Base metal qualification limits. (P no. and Thickness) ➢ Filler material qualification limits. (F No.) ➢ Pipe diameter and position qualification limits. ➢ Weld metal thickness qualification limits. 19) What is the chemical composition of a low hydrogen electrode – E7018? ➢ E7018 – C 0.15, Mn 1.60, Si 0.75, P 0.035, S 0.035, Ni 0.30, Cr 0.20, Mo 0.3, V 0.08. 20) How can you verify that the received electrode has the chemical composition as per MTC? ➢ By verification of chemical composition of filler materials through chemical analysis method. ➢ By verifying the heat no. and Lot no. of welding consumables.

21) What are the tests required for analysis of consumables and the standard for this analysis? Tests➢ Chemical analysis method ➢ Positive Material Identification (PMI) Standard➢ ASME Sec IIC 22) How do you calculate the weld repair percentage? ➢ % RR = (Lr/Lw) X 100 Where, % RR - Percent repair rate Lr - Total length of repair in one week Lw - Total length of weld radiographed in one week

23) JERES standard for consumable storage & handling procedure for low hydrogen electrode? ➢ JERES-W-011. Appendix A 24) What does L stands for 316L and the composition? ➢ Low Carbon. 26)

What are the criteria for selecting welding consumables? ➢ Welding consumables shall be selected based on their mechanical properties, compatibility with the materials to be joined, their suitability for the intended service, and consideration of polarity, position, and direction of welding.

27)

What do you meant by low hydrogen consumables? ➢ Low hydrogen consumables are defined as less than or equal to 8 ml of hydrogen per 100 g of deposited weld metal.

28)

What are dissimilar metal welds? ➢ Any weld joint (excluding weld overlays or strip lining) between ferritic steel and either austenitic stainless steel, duplex stainless steel, or nickelbased alloys, or Use of stainless steel or nickelbased filler metals on ferritic steels.

28A) Give the names of two aluminium flake weld able primers? And the maximum coating thickness? ➢ Bloxide and Deoxaluminate. ➢ The max coating thickness shall not exceed 0.050mm (0.002 inches).

29)

What is the heating and cooling rate for PWHT? ➢ The PWHT heating and cooling rates above 316°C shall not exceed 222°C/hr divided by the weld thickness in inches, but in no case shall it be more than 222°C/hr.

30) On what condition remote current controls are used in field welding? ➢ For field welding, remote Current controls shall be used if the welding is more than 30 m from the welding power source or

when the welders are working in remote locations (eg. on an elevated pipe rack). 31) Mention the drying temperatures for low hydrogen SMAW electrodes? ➢ 260-430°C for 2 hrs min (SFA A5.1) ➢ 370-430°C for 2 hrs min(SFA A5.5) ➢ 120-250°C for 2 hours minimum. (SS and NonFerrous electrodes)

32) ➢ ➢ ➢ ➢ ➢ ➢ ➢ ➢

33)

Test Positions for Groove Welds Plate Positions: 1G – Flat Position 2G – Horizontal Position 3G – Vertical Position 4G – Overhead Position Pipe Positions: 1G – Flat Position. (Pipe axis horizontal and rolled during welding so that weld metal is deposited from above) 2G – Horizontal Position. (Pipe axis vertical and weld axis in horizontal plane, pipe is fixed) 5G – Multiple Positions. (Pipe axis horizontal and weld groove in vertical plane, pipe is fixed) 6G – Multiple Position. (Pipe with its axis inclined at 45 deg to horizontal, Pipe is fixed))

Test Positions for Fillet Welds Plate Positions: 1F – Flat Position 2F – Horizontal Position 3F – Vertical Position 4F – Overhead Position Pipe Positions: ➢ 1F – Flat Position

➢ ➢ ➢ ➢

➢ 2F and 2FR – Horizontal Position ➢ 4F – Overhead Position ➢ 5F – Multiple Position 34) What are the types of Mechanical tests? ➢ Tension Tests ➢ Guided Bend Tests ➢ Fillet Weld Tests ➢ Notch Toughness Test ➢ Stud Weld Test 35) What is the equation for carbon equivalent? ➢ CE = C + (Mn)/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15 36) Equation for Heat Input? ➢ H = 60EI / 1000S Where, • H -- Heat Input (KJ/mm) • E -- Arc Voltage (volts) • I – Current (Amps) • S – Travel Speed (in/min) 37)

38)

What are the different factors that cause HIC? ➢ A sensitive microstructure ➢ A sufficient level of hydrogen ➢ A high level of stress Advantages of Argon Vs Helium as shielding gas? ➢ Argon • Good arc starting. • Good cleaning action. • Good arc stability. • Focused arc cone. • Lower arc voltage. • 10 – 30 cf/h (cubic feet per hour) flow rate. ➢ Helium • Faster travel speeds • Increased penetration.

• • • • • • •

Difficult arc starting. Less cleaning action. Less low amp stability. Flared arc cone. Higher arc voltages. Higher flow rates (2x). Higher cost than argon.

➢ Argon / Helium mix • Improved travel speed over 100% argon. • Improved penetration over 100% argon. • Cleaning properties closer to argon. • Improved arc starting over 100% helium. • Improved arc stability over 100% helium. • Arc cone shape more focused than helium. • Higher flow rate than argon. • Cost higher than argon. 39)

What are the general types of welding and joining processes? ➢ Fusion • Arc • Gas • Power beam • Resistance. ➢ Thermo-mechanical • Friction • Flash ➢ Mechanical • Fasteners ➢ Solid state • Adhesive • Soldering • Brazing

40)

Different types of electrodes? ➢ Cellulosic • Deep penetration in all positions. • Suitability for vertical down welding.

• Reasonably good mechanical properties. • High level of hydrogen generated – Risk of cracking in the HAZ. ➢ Rutile • Moderate weld metal mechanical properties. • Good bead profile produced through the viscous slag. • Easily removable slag. ➢ Basic • Low hydrogen weld metal. • Requires high welding current/speeds. • Poor bead profile (convex and coarse surface profile) • Slags remove difficult. 41)

What are the main metal transfer modes in welding? ➢ Short circuiting ➢ Droplet/spray ➢ Pulsed

42)

What is the function of shielding gas? ➢ Stabilizes the arc roots on the material surfaces. ➢ Ensures smooth transfer of the molten metal from the wire to weld pool. ➢ Forms the arc plasma.

43)

Commonly used shielding gases in GTAW? ➢ Argon ➢ Argon + 2-5% hydrogen ➢ Helium/Helium Argon mixtures ➢ What is CTOD? ➢ CTOD is Crack Tip Opening Displacement test. The test piece contains a machined notch or a genuine crack and will be loaded at a rate more representative of service conditions.

44)

SATORP INTERVIEW QUESTIONNARE (PIPING)

PART-III

WELDING & PIPING INTERVIEW REVIEW QUESTIONS

1) What are the JERES specs for hydro testing?

• JERES-A-004 – General Requirements of Pressure Testing • JERES-A-007 - Hydrostatic testing fluids and Lay up procedure • JERES-L-150 - Pressure testing of plant piping & pipelines. 2) What is a dead leg?

• Dead Legs: Piping sections that are potential for internal corrosion due to flow stagnation. • Dead legs are created mainly by flow stagnation enhanced with presence of settled water and solid deposits. • When the length of the section or branch , for 2 inch pipes and larger, is longer than three times its pipe diameter, or 1.22 m (4 ft) in length, the length of the dead leg is the distance measured from the outside diameter of the header (or run) to the near end of the branch valve. • For branch connections of 1-½ inch NPS and smaller, the length of the dead leg is the distance measured from the end of the boss to the near end of the valve.

3) What is the different ASME 31 code for pressure piping?

A. ASME B31.1 - Power piping. B. ASME B31.2 - Fuel Gas Piping. C. ASME B31.3 - Process piping. D. ASME B31.4 - Pipeline Transportation system for liquid hydrocarbon & other liquid. E. ASME B31.5 - Refrigeration Piping. F. ASME B31.8 - Gas transmission & distribution piping system. G. ASME B31.9 - Building services piping. H. ASME B31.11 - Slurry transportation piping system. 4) What are the factors in a mill test certificate?

• Chemical composition • Mechanical properties ( hardness, tensile strength, yield strength, elongation, reduction of area) • Heat number

5) Which is the rope used for lifting the external coated pipe?

• Nylon 6) What is the minimum clearance b/w a pipe and a structure?

• 50mm 7) What is the hydro test holding time for A/G piping?

• 30 min 8) What are the important activities to be checked during flange

alignment fit up? • Misalignment • Flange face • Rotation of flanges (±2.4 mm) • Tilt of the flange ( shall not exceed 1.6 mm from the square position) • Flange face thickness, gasket thickness ± 1.6 mm • Combination of vertical, horizontal and rotational offset ± 3.2 mm 9) What are the piping inspector responsibilities?

• Material receiving inspection • Ensure that approved procedure and ITP are used by construction. • Pipe fit up activities • Retention of QC reports and records. • Line checking • Hydro test activities • Reinstatement activities 10) How can you identify an ISO in a P&ID? • Line number, service, instrument, equipment, and slope. 11) What is an insulation kit? • To isolate between above ground and underground. 12) What is insulation gasket? • Isolation of dissimilar metal flanged joints ( electrical insulation)

• •

Insulating joints for cathodic protection. Eg. PIKOTEK GASKETS.

13) What are PIKOTEK Gaskets and what are their limitations?

• It is non metallic gaskets made of self energized Teflon seal supported by glass reinforced epoxy laminated to 316 stainless steel core. • The minimum required gap shall be 3.2 mm. • It shall not be used services with temp. 154’C or higher • It shall not be used in hydrocarbon gas service in which flange rating is 300 or higher. • It shall not be used in Chemical incompatibility of non metallic component with the service media. 14) What are the general points to be checked prior to hydro

test?( pre-pressure checklist) • Seal weld threaded nipples from headers to 1st block of valve (hydrocarbon service) per JERES-L-110 • Guides are in direct contact with piping horizontal run at 3 locations (6mm gap required). Relocate guides per drawing. These are welded to the pressure boundary. • Check valve is oriented in the wrong direction (flow arrow). Reverse check valve to assure correct flow direction. Reposition valve & restore internals immediately after test, COMPANY to witness. • Piping clearance to structural bracing is (50 mm spacing required). • Install permanent gaskets at flange sets 1, 4, 5, 6 on ISO dwgs per approved torque tables and install spectacle blinds oriented as per approved P&ID. • Completely remove all water and debris from low point/valve cavity for the in-line Valves with SS 400 trim, do so immediately after test. Clean with dry compressed air and relubricate sealing surfaces with approved lubricant in preparation for "ambient" lay-up specified in test package. • Indicate “No Punch items. “as applicable QA is reviewed/initialed/dated prior to package certification to verify completeness.

15) What is NCR, CAR, DR?

• NCR: (Non Conformity report): A record reporting the variation from the specified requirements. • CAR: Corrective action report: A record reporting the action taken to eliminate the effect and causes of an existing non –conformity, defect or other undesirable situation in order to prevent recurrence. • DR: Deviation report: A record of the concessions granted by client or owner to certain deviation from project specification. 16) What are specifications?

• Specifications (Specs) are guideline details for construction requirements to assure minimum quality standards are listed and met. 17) What is an SIS?

• Safety Instruction Sheet that gives full design details related to a piping system or line. 18) What is Schedule ‘Q’?

• Schedule Q stands for Owner’s minimum quality requirements for Contractor/Subcontractor quality system. 19) What are the points to be checked before pipe fit up? • Oil, moisture, rust, scale, sand, paint, metallic coatings (e.g., zinc),

• • •

•

or other foreign matter shall be removed from the weld surface and at least 25 mm (1 in) of adjacent base metal prior to welding, including any such coatings on temporary attachments or supports. Pipes and Fittings for fit-up will be placed on temporary pipe bed and will make sure that supports are secured properly. After end preparation, the alignment, fit-up and tack weld activities shall be carried out for the purpose of exact pipe spool fabrication. Line No, Component Heat No., Joint No., Fit-up inspection signature, Welder No., Visual inspection signature and date of welding will be marked near to the joint with metal paint marker. Use markers with free lead, sulfur, and water soluble chloride not more than 50ppm for SS and other alloy materials.

20) There is damage in the received material, what will you do?

• All damage material shall be placed in quarantine area with visible identification. Material Over, Short and Damage report O.S&D shall be issued. A Non-Conformance Report shall be raised for materials with severe damages. • QC inspector shall monitor all the O.S & D and NCR issued and their corrective and Preventive action taken. • Non conforming materials shall be clearly marked, segregated and controlled so that their unauthorized or inadvertent use is prevented and their final disposition formally documented and recorded. 21) How will you store the material in the storage area?

•

All materials shall be handled with care during fabrication and installation to prevent damage. ✓ End protectors on pipes, flanges, weld bevels, threads, and socket ends shall be firmly attached. ✓ Pipe shall not be rolled or dropped off trucks. ✓ End bevel protectors shall remain on pipes and fittings while in storage, protectors shall not damage internal or external coating. ✓ Flange face and threads shall be protected from rust by applying suitable rust preventives. ✓ After completion of pre-fabrication, the spool shall be cleaned and free from weld spatters, arc strikes and foreign materials on outside and inside of pipes.

•

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Lined and coated pipes and fittings shall be lifted with wide fabric or rubber-covered slings and padding shall be used to prevent damage to lining or coating. Wire rope slings shall not be used. SS materials shall be covered and protected from water splash and other contamination during storage

24) What are the ASME codes for Flanges?

•

ASME B16.5 24”)

PIPE FLANGES AND FLANGED FITTINGS (UPTO

•

ASME B16.47 LARGE DIAMETER FLANGES (ABOVE 24”)

25) What is the color code for the material?( standard)

• PFI ES 22( PIPING FABRICATION INSTITUTE) 26) What is the code for PMI (JERES)?

• JERES-A-206- POSITIVE MATERIAL INSPECTION 27) How you inspect the flush grinding?

• Any distortion resulting from the butt weld shall be removed and ground flush with the inside diameter of the pipe, PT shall be done. • The inside surface of welded joints at orifice flanges shall be ground or machined smooth. 28) What things are found in a Piping Isometric drawing?

• Line conditions, references to drawings, materials of construction(Bill Of Materials), continuations, orientation, piping and drawing details and notes, revision control and approval status. 28) What kind of inspection required during gasket installation?

• QC Piping Inspector will ensure the cleanliness of the gasket surfaces of the flanges and the condition of the gasket. Care shall be taken during this operation to prevent entering of debris in the pipe or equipment. • QC piping Inspector shall verify on site, prior to installation, each gasket has the proper material size and rating according to drawings and line class. Gaskets will have an individual painted mark, which will identify the rating number. • For gaskets 24” and less, colours code on the gaskets shall be applied on the outside surface, Mark shall be an approximately 1 inch in length circumferentially. • For Gaskets 24” and above, will be market in two locations each. • Spiral wound gaskets should have three colours, which identify the particular material spec, rating and gasket with inner ring respectively.

• During reinstatement, QC Piping Inspector shall verify that bolting is tightened according JERES-L-351. • QC Inspectors shall inspect, before hydro test and during lines reinstallation that all permanent gasket are installed accordingly. 29) What is the difference b/w torquing of CS & SS bolting? • Yield strength of CS is greater than SS.

30) Explain spectacle plate?

•

Blind flange is used to isolate equipment or other piping during the leak test, need not be leak tested.

31) How many threads can be visible after seal welding threaded

joints? • Zero

32) What is the basic difference between Pipe specification A106

Gr.A / Gr.B/ Gr.C? • Difference is due to the Carbon content.

% of carbon content in : I. ASTM A106 Gr. A – 0.25 % II. ASTM A106 Gr. B – 0.30 % II ASTM A106 Gr. C – 0.35 %. 34) What is WPS? • A document providing the required welding variables for a

specific application to assure repeatability by properly trained welders and welding operators. 35) What is PQR? • A record of welding variables used to produce an acceptable

test weldment and the results of tests conducted on the weldment to qualify a welding procedure specification. 36) What is PMI? • Verification that the nominal chemical composition of an alloy

material is as specified and ordered. 37) What are the gauges used for fit up? • Bridge cam, High Low gauge 38) What material used for drinking water service? • Galvanized steel materials 39) What are the types of bolts and spec? • A193 B7, A320 B8, JERES-L-109 40) What is color coding?

• Marking of piping bulk materials to identify the Material. 41) What are the different types of JER documents? • JEREP- Jubail Export Refinery Engineering Procedures Uniform method of assembling directions to accomplish various engineering activities. • JERES-Jubail Export Refinery Engineering Standard Minimum requirements for the selection, design, construction, test, maintenance and repair of equipment & related facilities. • JERMS-Jubail Export Refinery Material Specifications To establish minimum engineering, design, fabrication and testing requirements for the procurement of material and equipment.

• JERSD- Jubail Engineering Refinery Standard Drawing Engineering drawing that is pre approved by JER Management for through out the company. • JERITP-Jubail Export Refinery Inspection And Test Plan Minimum requirements set by the company to conduct inspection • JEREF- Jubail Export Refinery Engineering Forms JER developed forms that shall be used as a tool for Design, Construction and Pre-commissioning. 42) What are the different sections of ASME code? Where these

sections are referred? A. ASME section I : - Rules for construction of power boiler. B. ASME Section II : - Materials. Part A – Ferrous materials. Part B – Non-Ferrous materials. Part C – Specification for electrodes & filler wire. Part D – Properties. C. ASME Section IV : - Rules for construction of Heating Boiler. D. ASME Section V : - Non- destructive Examination. E. ASME Section VI : - Recommended rules for care & operation of heating boiler. F. ASME Section VII : - Recommended guidelines for care of power boiler. H. ASME Section VIII : - Rules for construction of pressure vessels. (Division I & II) I. ASME Section IX : - Welding & Brazing qualification.

43) What types of PMI machines are available? • X-Ray Fluorescence • Optical Emission Spectrography 44) For sour service and NACE which material is used? • HIC Carbon Resistant Material

45) Color coding for CS, LTCS, and Alloy? • As per PFI ES-22.

46) What type of cutting used is SS? Types of Grinding wheel and

how to identify them? • Plasma arc cutting and grinding wheel • Types for grinding wheel are: Iron oxide, zirconium, Aluminum oxide. • Identification by color coding.( blue) 47) Name the different types of Service Conditions?

• Temperature, pressure and fluid type 48) What are the acceptable branch connections and fittings? Also

mention limitations? • Branch connections on any fittings are not allowed • Branch connection is not a dead leg with any internal corrosion concerns. • Branch connections 4 inch and smaller (drain and vent valves and drip legs of all sizes excluding dummy legs) are spaced a minimum horizontal distance of 24 inches from fixed supports/obstructions.

PART-IV WELDING & PIPING INTERVIEW REVIEW QUESTIONS 1. The primary reason for PWHT is: ➢ usability characteristics 2. Hydrogen in welding may come from various sources, such as: ➢ lubricants ➢ moisture ➢ net electrodes 3. Materials with high thermal conductivity will require➢ higher heat input to weld 4. The general Brinell hardness limit for 5CR-Mo steels is: ➢ BH 241 5. A material Test Report shows the following chemistries: Carbon – 0.15%, chrome – 1.25% vanadium – 0.02% manganese – 0.20% molybdenum – 1.00% silicon – 0.53% nickel – 0.35% copper – 0.01% What is the approximate CE of this material using the formula supplied in RP 577? ➢ Calculated 0.68 6. From the above CE number, what should typically be done after welding this steel? ➢ Preheat and PWHT 7. Austenitic stainless steels typically contain chrome and nickel, and are used for:

➢ corrosion resistance ➢ resistance to high temperature degradation 8. The most common measure of weldability and hot cracking of stainless steel is➢ ferrite number 9. One of the most common types of fracture toughness tests is➢ Charpy 10. Materials with high thermal conductivity will require➢ higher heat input to weld 11. The vast majority of metallic materials used in refineries or chemical plants are➢ wrought materials 12. A welder qualifying with a groove weld in plate in the 4G position is➢ Qualified to weld groove welds in plate and Pipe over 24"O.D. in at least the Flat & overhead positions (QW-461.9). 13. A welder qualifying by making a groove weld on pipe with an O.D. of 3/4" in the 5G position is qualified to weld groove welds in: ➢ 6" O.D. Pipe in the vertical position (QW-461.9, QW-452.3) 14. Reduced-section tensile test specimens conforming to QW-462.1 (b) may be used on all thicknesses of pipe having an outside diameter greater than: ➢ 3 inches 15. A welder qualified for SMAW using an E7018 electrode is also qualified to weld with: ➢ E7015, E6011, E6010 and E7024 16. A welder is qualified to weld all thicknesses of material when:

➢ The test coupon thickness is ½ inch and over with a minimum of three layers. 17. A welder qualified to weld in the 2G position on pipe would have to be qualified in which of the additional positions to qualify for all position groove welding on pipe? ➢ 5G 18. In performance qualification of pipe welds to ASME Section IX, which positions require more than two guided bend specimens for qualification? ➢ 5G and 6G 19. What is the number of transverse guided bend tests required for Performance Qualification in a 6G position? ➢ 4 20. What positions are necessary to qualify a welder for all position pipe welding? ➢ 2G and 5G 21. What is the minimum thickness of plate that can be used in the shell or head of a pressure vessel? ➢ 1/16”

22. If 4 materials, carbon steel, 18Chr-8Ni, Monel, Aluminum are heated from 70 degrees F. to 550 degrees F., which one will expand more? ➢ Aluminum (ASME B31.3, Table 319.3.1 (a) & Appendix)

23. A carbon steel ASTM A 53 Grade B material is being impact tested. What is the minimum energy requirement for this material (average for 3 specimens-fully deoxidized steel)? ➢ 10 ft-lbs (ASME B31.3, 323.3.5, Table 323.3.5) 24. The zone for preheat shall extend: ➢ At least 1” beyond each edge of the weld (ASME B31.3,330.1.4 and 323.2.2B) 25. When components of a piping system are joined by welding, the thickness to be used in applying the heat treatment provisions of ASME B 31.3, Table 331.1.1 shall be: ➢ That of the thicker component measured at the joint, except for Certain exclusions.(ASME B31.3,331.1.3) 26. An Inspector finds incomplete penetration in a radiograph of a girth weld of normal fluid service piping. What can he accept or can he accept any incomplete penetration? ➢ If the incomplete penetration is 1/32” or less (and £ 0.2T w) deep, he may accept (ASME B31.3, Table 341.3.2A) 27. Where the design temperature of the system is the same as the hydrostatic test temperature, the hydrostatic test pressure shall be not less than: ➢ 1.5 times the design pressure (ASME B31.3, 345.4.2 -a)

PART-V WELDING & PIPING INTERVIEW REVIEW QUESTIONS

Quality Systems 1. Describe the difference between QA & QC? Answer: Quality Control is the operational techniques (Inspection, Examination & Testing) that are used to fulfill requirements for quality. Quality Assurance is the system of action and planning needed to provide confidence that a Product or Service will satisfy quality requirements 2. What do quality system audits evaluate? Answer: The degree of quality system conformance to established requirements. 3. Saudi Aramco has adopted the basic framework and definitions of the International Quality System Standards ISO-9000 Series. This has been done to provide universal understanding and improve communication between the COMPANY and prospective CONTRACTORS, whose Quality System is congruent with the ISO-9000 Series. Describe the basic elements of an ISO 9000 Series Quality Program? Answer: Quality Management & Quality Assurance Standards per ISO9000 Quality Systems per ISO-9001, 9002, 9003 Quality Plan Guidelines per ISO 10005

Mechanical/Welding 4. What is an essential variable as related to a Weld Procedure Specification (WPS)? Answer: A change in a welding condition that will affect the weld’s mechanical properties. 5. What is the relationship between a Procedure Qualification Record (PQR) and a WPS? Answer: The PQR documents what occurred during the welding and testing of the test coupon. 6. Heat input (SMAW per ASME IX) is a combination of what two electrical characteristics & travel speed? Answer: Voltage and Amperage 7. Excessive heat input is mainly attributed to what poor welding techniques during SMAW process? Answer: Excessively wide weaving and slow travel speed. 8. What are 3 potential sources of Hydrogen encountered during SMAW process? Answer: Moisture in the metal and electrode coating, oil, elemental Hydrogen in the base metal 9. What are several likely causes of porosity in carbon steel welds using the SMAW process? Answer: Poor welding technique and equipment, excessive wind, moisture & weld contaminants. 10. What dimension is measured to determine the size of a concave fillet weld? Answer: Throat

12. What dimension is measured to determine the size of a convex fillet weld? Answer: Leg 13. Where would cracking most likely occur from excessive current input in a single pass weld? Answer: Centerline of the weld 14. Using GTAW process, describe what happens to a weld without proper purging/back gassing on SS material? Answer: Oxidation at the ID (Sugaring) 15. Name 3 of the 5 mechanical tests in ASME IX employed for procedure & performance qualifications? Answer: Tension, Guided Bend, Fillet-weld, Notch-toughness & Stud-weld tests 16. How is Magnetic Particle inspection of a weld using the wet continuous test method performed? Answer: The particles (usually fluorescent) are sprayed, poured on or applied by immersion and the magnetizing current is applied while the particles are still flowing. 17. Indications with Liquid Penetrant Testing are easily seen if the surface has been prepared by grinding prior to testing? True/false? Why? Answer: False, because grinding can smear metal and mask/cover discontinuities. 18. Name an NDT method and technique that employs a reflected sound beam that can be used for the volumetric examination of welds? Answer: Ultrasonic Testing using Shear Wave Technique provides good volumetric exam coverage.

19. List 3 disadvantages of RT over other NDT Methods. Answer: Radiation Safety Precautions, Planar defects not readily detectable, heavy equipment 20. If a product is to be stress relieved, why is it important to use exactly the same RT procedure before and after stress relieving? Answer: So that a baseline evaluation is performed to ensure that borderline indications are not misinterpreted after stress relief. 21. A dark narrow area 2-3mm wide appears on a radiograph all along the edge of the area representing the weld. The joint has a 60-Degree double-vee groove. What is the indication most likely to be? Answer: External Undercut 22. A localized darker density Radiographic image with fuzzy edges in the center of the width of the weld image that may or may not be wider than the width of the root pass image is most likely what? Answer: Burn-through 23. Name 5 common film artifacts that may be cause for rejection of Radiographic Film? Answer: Film Scratches, light leaks, chemical stains, fogged film, static marks, water marks, streaks, crimp marks, finger marks, lint, dirt 24. When the radiation source is located inside piping with the film located outside, single-wall exposure and single-wall view, name this type of exposure? Answer: Panoramic

25. How do gamma rays compare with X-rays when applied to RT of welds? Answer: Gamma rays have greater penetration ability, but give poorer contrast. 26. Per ASME B31.3 (assume latest edition), name three of the four Categories of Fluid Service? Answer: Categories D, M, High Pressure & Normal 27. as per ASME B31.3, who is responsible for classification of service to a given category? Answer: The Owner 28. Per ASME B31.3 (assume latest edition), what are the RT requirements for Socket welds in severe cycle service? Answer: None 29. Relating to the above question, Give good reasons why random RT of socket welds is recommended? Answer: Both gross welding defects & poor quality welders can be identified, with repairs and corrective action taken, & Gap can be verified. 30. Briefly describe good QC practice relating to the installation & bolting of flanges? Answer: Verify Materials (type, size and rating) are acceptable, gasket verification & good bolting practices (torque value requirements met) in accordance with approved procedures. 31. What is an often-overlooked Inspection/NDT requirement on the installation of an orifice flange? Answer: Visual weld inspection of the seal weld & NDT has been missed prior to bolting of flanges

32. as per ASME Section VIII, Div. 1, can a nozzle to be attached to the exterior surface of a pressure vessel without any portion of the nozzle projecting into the shell? Answer: Yes, with many restrictions 33. Explain the difference between a 2:1 Ellipsoidal head and a hemispherical head? Answer: A hemispherical head has no flange and knuckle region and holds greater volume. 34. Which of the above two heads given equal thickness can withstand greater internal pressure? Answer: The 2:1 elliptical head can withstand much more internal pressure given equal thickness. 35. In ASME Section VIII, Division 1, Parts UW and UCS cover what scope of work? Answer: UW designates requirements for pressure vessels and vessel parts fabricated by welding, and UCS designates requirements for pressure vessels and vessel parts constructed of carbon and low alloy steels. 36. Name several Inspection items on internal component/tray installation for new columns? Answer: 1. Drawings, Calcs & Data review 2. Verification of Material Construction of Internal components (tray assemblies & systems, hardware, packing medium) 3. Location, levelness and orientation of internal components per Mfg. Drawings/tolerances. 4. Seams, holes, gaps, missing items, looseness of hardware in trays 5. Leakage Tests as needed for trays, troughs, weirs, etc. 6. Final Cleanliness of Tray Assemblies

37. What API documents apply to the replacement of an existing floor for an Aboveground Oil Storage tank? Answer: API 653 & API 650 38. What are two key items to be resolved prior to addition of new nozzles to older tanks per API 653? Answer: Tank Material identification, Material Design Considerations & selection (need for shell insert). 39. Briefly describe an area impressed Cathodic Protection System? Answer: Electrical current & use of selectively placed sacrificial anodes is employed to stop/slow the electrochemical reaction that occurs during the corrosion process. 40. Relating to Contractor Weld Shop evaluation prior to the beginning of pipe welding for a major project, what are several key items you would look for as the Inspector assigned to approve the shop for Company? Answer: 5M + E formula = Manpower, Methods, Materials, Machines, Measurement, Environment 1. Manpower=Ensure adequate Personnel that are trained, qualified, certified & approved 2. Methods=Ensure that standards are followed and that welding procedures, special processes (PMI, PWHT, etc) are acceptable and that there is a good quality system (paper trail) in place. 3. Materials=Ensure Materials are approved, certified, documented (traceable), stored correctly with area for deficient items (quarantined), and segregation of dissimilar metals. 4. Machines=Ensure Equipment is adequate for the intended work and in good working condition. 5. Measurement=Ensure Contractor QC Program & testing/calibration program is in place for equipment and work.

6. Environment=Ensure that the working environment (building) is safe, sheltered from the elements and adequate to ensure quality work. Per SAES-W-011 (show section where information is found, review with candidate) 1. What is the maximum size of low Hydrogen (E7018) permitted? 2. What are the diameter limitations (per pipe size) for different welding processes? SMAW= GTAW= GMAW= 3. a) What is the requirement (Material, location) for bridge tacks? b) In what must bridge tacks be contained to avoid the need for Surface Method NDT? 4. a) For temporary supports and attachments welded to the pipe, what are requirements related to Material? b) NDT? 5. What is the maximum amount of time that E-7018 electrodes can be kept out in the field? 6. What is the minimum drying temperature and drying time? 7. How many times can electrodes be rebaked? 8. What is the maximum internal misalignment of butt joints? 9. Piping during preparation before fit up shall be cleaned/ground internally/externally for what distance from the edge of the prepared joint? 10. Moist surfaces require moisture removal and surfaces to be preheated must be preheated to what distance from the joint edge?

PART-VI WELDING & PIPING INTERVIEW REVIEW QUESTIONS Scope: This piping questionnaire is to be referred along with piping presentation MFF.Module.1 PART I. It deals with piping, piping components including valves and pressure testing of piping.

PIPE 1. Why 1¼”, 2½”, 3½” & 5” are called non-prepared sizes in ONGC specification? ➢ These sizes are not readily available and manufacturer find difficult to manufacture. Use of the sizes should be avoided in new constructions. Hence ONGC recommends not to use this size. 2. What is the difference between Std wall / extra strong & Schedule 40 /80 thickness? ➢ From ½” to 10” STD wall & schedule 40 thicknesses will match together. Above 10”(i.e. 12 “) Std wall thickness will remains same. Whereas Sch. 40 thickness will be keep on increasing. Extra strong & sch .80 from ½” to 8” Extra strong and Sch 80 thickness will match together. Above 8” (i.e. 10” onwards) extra strong thickness will remain same where as sch 80 thicknesses will be keep on increasing.

3. What are the schedules available for Stainless Steel and Carbon Steel? ➢ (5 S, 10 S, 40 S, and 80 S) SS are suffixed by S letter along with schedule. 10,20,30,40,60,80,100,120,140,160, Std Wall, Extra strong, Double Extra Strong. 4. What are the various tolerance specified on pipe? ➢ In case of thickness it can deviate by 12.5 % of its thickness. In case of outside diameter In case of inside diameter In case of length 5. Is STD Wall, Extra Strong, Double Extra Strong? Thicknesses are available in Stainless Steel also? ➢ No. It is available on Carbon Steel only. 6. Name the Carbon Steel and Stainless Steel pipe Standards. What is the information it can furnish? ➢ ANSI B 36.10 Welded and Seamless Wrought Steel pipes up to NPS 80 sizes are available. ➢ ANSI B 36.19 Welded and Seamless Austenitic Stainless steel pipes. Both these standard gives information on sizes of pipe, tolerance, material details etc. Some time one may need to refer ASTM A 530 for general requirements of pipes.

7. Compare ANSI B 36.10, ANSI B 36.19 standards. Generally the schedule number of both the STD will match, Except the following➢ 10” sch 80/80 s, 12”sch 40/40s, 12”sch 80, /80s, 14” sch 10/10s , 16” sch 10/10s, 18” sch 10/10s, 20’ sch 10/10s, 22” sch 10/10s

ANSI B 36.10 covers pipe size up to 80”NB and ANSI B 36.19 covers pipe size up to 34” NB. 8. Name commonly used C.S, SS and non-ferrous Pipe and pipe fittings? A 53, for general service, commonly used pipe. ERW Grade A ERW Grade B Seamless Grade A Seamless Grade B Furnace butt welded (100 NB & Smaller) pipes are less expensive, but cannot be used for the same working pressure as ERW & Seamless pipe. The latter are recommended for all higher-pressure application. Under these specifications, piping up to extra strong wall thickness only can be procured. For pipes with heavier wall thick, A 106 specification to be used. A 106 for high temperature & high-pressure pipe Grade A-333 N/ mm² 48,000 Psi min. Grade B-416 N/mm² 60,000 Psi min Grade C-485 N/mm² 70,000 Psi min Although the physical & chemical properties for Grade A & B are Comparable to those for A-53 pipe and the types of testing required by both specifications are similar, the tests prescribed for A106 are more stringent and are applied to smaller lots of pipe. Therefore pipe procured to specification A 106 is preferred for exacting services. A 120.galvanized pipe This pipe are black or galvanized welded and seamless steel pipe in sizes 300NB and smaller, for ordinary uses in handling steam, water, gas or air.

This pipe is not intended for use at medium or high temperature nor close coiling and bending. No need to test the pipe for chemical and physical properties except hydro test. A 312 STAINLESS STEEL PIPE This specification covers seamless and automatic welded (without the addition of the filler material) chrome nickel pipe and is generally available in sizes 200 NB and smaller. The steel is made by electric furnace process, and the pipe is furnished in pickled and passivated condition. Fifteen grades of austenitic stainless steel (identified as grades TP 304, TP304 H, TP304 L, TP309, TP310, TP316, TP316 H, TP316 L TP317, TP 321, TP 321H, TP 347, TP 347H, TP 348 AND TP 348 H) are available. CHROME NICKEL (STAINLESS STEEL) PIPE Special consideration must be given to the ordinary 18% chrome – 8% nickel steels when they are to be welded, hot formed or used for corrosion resistance. At temperature from 425* c to 815* c, chromium carbides are formed along the grain boundaries with a consequent reduction of corrosion resistance properties. This, however, can be minimized by the addition of such as titanium and columbium. Two grades of stainless steel pipe are in common use –regular grade and L grade. Regular grade, having a maximum carbon content of 0.08% has a higher strength at elevated temperatures, but is susceptible to intergranular corrosion. Consequently the second grade, L, is developed in which the carbon content is limited to 0.03%. This serves to reduce intergranular corrosion; however, the low carbon content of the L grade decreases the tensile strength at elevated temperatures. A new grade, H, has subsequently been introduced. This grade, having a carbon content of 0.04% to 0.10%, is also susceptible to intergranular corrosion, as is the regular grade, but its higher range of carbon content assures the required high temperature

strength which would not be obtainable with the lower carbon range of the regular grade.

A-358 This specification covers electric fusion welded chromium nickel steel pipe and is sizes 200 NB and larger. The pipe is made from ASTM A-240 chromium nickel plate in seven grades. (Type 304, 309s, 310s, 316,321, 347, and 347.) A-376 Seamless austenitic steel pipe for high temperature services. LOW TEMPERATURE SERVICE PIPE. A-333 For steel pipe low temperature service three nickel grades normally available. NON-FERROUS PIPE Non-ferrous pipe is used for many extreme conditions, i.e. for low temperature, for very high temperature, for corrosive conditions beyond the abilities of ferrous materials. The most common non ferrous pipe materials are nickel, copper, aluminum and their many alloyed compositions such as Monel, inconel, hasteloy, red Brass, yellow brass, cupro-nickel. Welded fittinings The following ASTM specifications govern materials, methods of manufacture, quality controls and marking of factory made, wrought steel welding fittings. A-234 - Carbon steel and ferritic alloy steel fittings A-403 - Stainless (austenitic) steel fittings. A-420 – Carbon and alloy steel fittings for low temperature service.

All the three specifications follow the same pattern, modified only to the extent necessary for the particular material or service involved. A-234 This specification covers three grades of carbon steel, one grade of carbon molybdenum and four grades of low to medium (1% through 5%) chromium molybdenum steels. This specification requires that: A fusion-welded seam in a fitting must be welded and qualified under section IX of ASME B&PV code; A minimum of 4% of all fittings (randomly selected) in standard and extra strong wall thickness and every fitting heavier than extra strong, in any lot must be radiographically examined throughout the entire length of each weld and approved in accordance with Sec VIII of the ASME code; The fittings be normalized to refine the grain resulting in better combination of mechanical properties when the fittings are formed at temperature above 980 degree C. A-403 this specification establishes fourteen grades of austenitic steels, including the more popular grades of 304,316 and 347. These steels are used for their properties of strength at high temperature, excellent and resistance to many corrosive fluids. This specification requires that; A fusion-welded seam in a fitting must be welded and qualified under section IX of ASME B&PV code; All fittings in any lot must be radiographically examined through the entire length of weld and approved in accordance with Section VIII of the ASME code; The fittings must be subjected to a carbide solution treatment to inhibit intergranular corrosion. A-420 This specification covers four grades for low temperature service up to –100 degree. In the range between –100 degree C

and –200 degree C, the materials specified in A403 are more suitable. This specification requires that: A fusion-welded seam in a fitting must be welded and qualified under section IX of ASME code. A minimum of 4% of all fittings (randomly selected) in standard and extra strong wall thickness and every fitting heavier than extra strong, in any lot must be radiographically examined throughout the entire length of each weld and approved in accordance with Section VIII of the ASME code; The fittings are normalized to improve low temperature impact properties, regardless of forming temperatures. Forged Steel Flanges The following ASTM specifications given the manufacture of forged steel flanges. Each specification covers forged or rolled steel pipe flanges, forged fittings, and valves and parts. A-105 - Carbon steel, for high temperature service. A-181 - Carbon steel, for general service. A-182 - Alloy steel, for high temperature service. A-350 - Carbon and alloy steel, for low temperature services. A-404 - Alloy steel, specially heat treated for high temperature services. A-105 – Covers two grades of carbon steel material and is generally applied to flanges having primary pressure ratings of 400# and more. A-181 – covers two grades of carbon steel, but is intended for lower pressure with primary pressure ratings of 150# and 300#. A-182 – covers twenty-four grades of alloy steel, ten grades of ferritic steel and fourteen grades of austenitic steel flanges.

A-350 – covers four grades of carbon steel and alloy steel flanges for low temperature in addition to permitting the use of austenitic alloys covered in A-182 for low temperature installations. A-404 – contains a single grade of ferritic alloy steel, which must be specially heat-treated for high temperature use. 9. Why outside diameter is kept constant for varying schedule Number? (Why not inside diameter). (EXACT ANS. NOT KNOWN) ➢ Wall thickness varies with the schedule number but the outside diameter remains constant for the various sizes, as the thickness changes, the inside diameter changes. 10. Up to what percentage Stainless Steel & special alloys comes under ferrous group? ➢ If alloying element is within 50 % then it will be comes under ferrous group. If alloying element exceeds by more than 50 % then it will be comes under nonferrous group. And that alloy will name it. Ex. Nickel alloy. (In conal 32% nickel & 20% Cr). 11. What is the Limitation based on selection of material? ➢ C.S shall be used up to 800*f (425* c) ➢ How temperature steel shall be used below –20*f (-29*c) ➢ Alloy steel shall be used above 800*f ➢ For corrosive fluid recommendation. 12. What is the min. distance to be maintained between two welds in a pipe? ➢ The rule of thumb is that the minimum distance between adjacent butt welds is 1D. If not, it is never closer than 1-½”. This is supposedly to prevent the overlap of HAZ s. Minimum spacing of circumferential welds between centerlines shall not be less than 4 times the pipe wall thickness or 25 mm whichever is greater.

13. What is desired life cycle for piping in operation? ➢ Desired life cycle for piping in operation is 20 years (7000 cycles). The normal no. of cycles for which the displacement or thermal stresses are designed is 7000 cycles. 14. what is the allowable stress range for CS pipes? ➢ 2070 kg/cm² 15. What is the insulation materials used for piping systems. ➢ Fibrous –Rock & Glass wool Rigid- Calcium silicate, polyisocyanurate, cellular Glass ➢ 16. What is DN in pipe? ➢ DN (Nominal Diameter) is a dimensionless designator used in the SI (metric) system to describe pipe size. FITTINGS 1. Name few pipe fitting standards? ➢ ANSI B 16.5 Steel and nickel pipe flanges and flanged fittings. Size NPS ½” through 24”. ➢ Sizes NPS 26 to 60” refer B 16.47. ➢ BS 1560 for fabricated flanges. ➢ ANSI B 16.9 Steel butt weld fittings. Size NPS ½” through 48’’ ➢ ANSI B 16.11 Forged steel socket welding and threaded fittings ➢ ANSI B 16.25 Butt welding ends. ➢ ANSI B 16.28 short radius elbows and returns ➢ ANSI B 16.1 Cast iron flanged fittings tees, elbows, laterals, etc. In pressure classes 25,125,250 and 800 are used. ➢ ANSI B 16.20 Metallic gaskets ➢ ANSI B 16.21 Non metallic gaskets

2. Why screwed and socket welded fittings are expensive? ➢ These fittings are manufactured from solid forging. Hence it’s expensive. These fittings are bulky in nature. Hence it is used up to 1½” sizes. Screwed class ratings 2000,3000,6000 Socket class ratings 3000,6000,9000 Normally Butt-welded fittings schedule is matched with connecting pipes. Flange fittings are rated as ratings. O’lets are generally as per MSS-SP 3. What are the advantage of using tongue & groove or ring type joint? ➢ Because of the small gasket contact area a tight joint may be made using low bolting loads. There by resulting in lower flange stresses. These joints are widely used in high temperature and pressure. 4. What is spigot joint? ➢ Spigot /socket ends specified when lead caulked cemented joint are provided between pipes and, between pipes & fittings. These are recommended only for low pressure application. 5. Why miter bend are not used on critical service? ➢ Because of its design limitation (pressure drop, joint in the bend may cause leakage) miter bends are not subjected to high pressure and temperature. Hence it is not used on critical service. 6. How do you decide the number of flange bolt holes? ➢ The more pressure existing, the more bolts required bolts holes are always added in quantities of 4,8,12,16,20,24 etc bolting is always equally spaced on the bolt circle.

7. What is the purpose of maintaining 1/16” gap in socket weld fittings? ➢ Socket weld joints 1/16” gap is maintained to prevent weld from cracking under thermal stress. Brief about Forged steel thread and socket welded fittings as per ANSI B16.11 The std covers pressure temperature rating dimension, tolerance, marking and materials requirements for forged carbon and alloy steel fittings, although these fittings are available in sizes up to NPS 4, size limitation may be imposed by certain course acceptable material forms are forgings, bars, seamless pipe, etc which conform the chemical composition, melting processes and mechanical property requirements of ASTM A105, A182, or A 350, Limitation A maximum allowable pressure of the fitting is equal to that computed for straight seamless pipe of equivalent material, and considering manufacturing tolerance, corrosion allowances and mechanical strength allowances. Also for socket welding fittings the pressure rating must be matched to the pipe wall thickness to assure that the flat of the band can accommodate the size of fillet welded required by the applicable code. The recommended fittings pressure class for the various pipe wall thicknesses is as follows. Pipe sch threaded socket welded 80/xs or less 2000 3000 160 3000 6000 XXS 6000 9000 Brief about Forged steel thread and socket welded fittings as per ANSI B16.9 and B 16.28. Wrought fitting materials conforms ASTM A 234, A 403 or A 420, the grade of which have chemical and physical properties equivalent to that of mating pipe.

ANSI B 16.9 require that the pressure temperature ratings of the fittings equal or exceed that of the mating pipe of the same or equivalent material, same size and same nominal wall thickness, The pressure temperature rating may be established are rated at 80% of the rating calculated for seamless straight pipe of the same size and nominal thick and same or equivalent material therefore both standard require that in lieu of specifying any pressure rating, the pipe wall thickness and pipe material, type with which the fittings are intended to be used be identified. On the fitting Pressure testing of the fitting is not required. B16.9 & B 16.28 gives the dimensional and manufacturing tolerance. National standard does not govern lateral. Working pressure is rated at 40 % of the allowable working pressure established for pipe from which laterals are made. Where full allowable pipe pressure must be made, the laterals are generally made from heavier pipe. Brief about Flanged end fittings ASTM 216 Carbon steel castings ASTM B351 SS castings A 352 alloy steel castings Welded piping is usually specified for sizes 2” and above. Screwed and socket welded piping is for sizes 1½ and smaller. Piping system for refineries usually are 1”-24” screwed & socket welded fittings have 90’ ell s.45’ ells tees, caps. Etc. 8. What is Weld cap? The weld cap terminates a pipe. 9. What is Swage nipple? It is a reducer. But it is longer in sizes .it is available in eccentric or concentric and come in the welded sizes and threaded it is most commonly used in sizes 2” and smaller instead of using reducer.

10. What is Couplings? ➢ Coupling joins two pieces of pipe or male connections it also stub in a small pipe or male connections it also stub in small pipe or connection in to a larger one 11. What is Union? ➢ Union joins screwed and socket weld pipe and male connection. When they may need to be broken apart in the future, the union is a possible leak joint and should be used where the breakaway future is necessary. 12. Brief about Flange and flange facings ➢ Flange comes in all sizes and materials. The forged steel flange comes in seven basic ratings, which the ANSI set 150, 300, 400, 600, 900, 1500 & 2500. Cast iron flange come in two ratings the 125 rating has a flat face while the 250# ratings usually has a raised face Flange joint are expensive. ➢ Raised face 1/16” for 150# 300# ➢ Raised face ¼” for other series. ➢ Flat-faced flanges have no raised face and require a fully faced gasket. ➢ Groove in RT (ring type joint) flange fits a metallic ring which is compressed the groove is oval or octagonal Ring type joint could also be specified for welded neck and slip on flange. Slip-on flange may be substituted for welded neck flange in 150# & 300# ratings (cost effective and less space & less load.) The raised face, the lapped and the large male and female facing have the same dimension, which provide a relatively large contact area. Where metal gaskets are used with these facings, the gasket area should be reduced to increase the gasket compression.

7. How can flanges be classified based on facings? ➢ Flat face ➢ Raised face ➢ Tongue and groove ➢ Ring type joint 13. What do you mean by AARH (flange finish?) ➢ Arithmetic Average Roughness Height 14. Which are the different types of gasket? ➢ Full face, spiral wound, octagonal ring type, metal jacketed and inside bolt circle. 15. What should be the relative hardness between the RTJ gasket and flange groove? ➢ For a RTJ flange, the joint ring should have 30-40 Vickers hardness less than that of the mating face of flange. (Brinnel hardness for RTJ groove shall be 20-50 BHN more than the corresponding gasket hardness. 16. What do you mean cavitation in pump? ➢ A pump is designed to handle liquid, not vapour.Vapour forms if the pressure in the pump falls below the liquid’s vapour pressure. The vapour pressure occurs right at the impeller inlet where a sharp pressure drop occurs. The impeller rapidly builds up the pressure which collapses vapour bubbles causing cavitation and damage. This is avoided by maintaining sufficient NPSH. (Cavitation implies cavities or holes in the fluid we are pumping. These holes can also be described as bubbles. So cavitation is really the formation of bubbles and their collapse. Bubbles form when ever liquid boils. It can be avoided by providing sufficient NPSH.)

17. Flanges - Rating shall be based on the pressure temperature conditions. However 150 lb flanges are not permitted beyond 2000 C - Socket welding flanges may be used for all pressure ratings upto 1.5” NB size except on steam lines subjected to 1 BR regulations. - Screwed flanges shall be used for galvanized steel/cast iron piping. - Slip on flanges are used in 150 lb and 300 lb rating upto a maximum of 2000 C welding neck flanges shall be used for higher pressure ratings. - Raised face is used for flanges upto 600 lb rating. For flanges 900 lb rating and above RTJ is recommended. Tongue and groove facing shall be used selectively. - Depending on pressure and temperature gasket shall be either CAF. Spiral wound metallic for raised face flanges or to be selected based on the corrosive nature of fluid. - Use flat face flanges to mate with cast iron valves and equipments. Bellows exp. Joints 17A. Why bellows are thinner? ➢ To provide the requisite flexibility, the metal bellows is considerably thinner than the associated piping thus these exp. Joints are especially susceptible to rupture by over pressure. Exp joints are used in piping system to absorb thermal expansion where use of exp. Loops are undesirable or impractical. Exp. Joints are available in slip, ball, metal bellows and rubber bellows configurations. 18. What is purpose of Rubber expansion Joints? ➢ Are similar in design to metal bellows exp joints except that they are constructed by fabric and wire reinforced elastomers. There are most suitable for use in coldwater

service where large movements must be absorbed e.g. (condenser circulating water). 19. What is the maximum expansion in loops in normal design? ➢ 10 inches 20. What are weldolet and sockotlet? And where they are used? ➢ Weldolet and sockolet are basically self reinforced fittings. Weldolet is used for butt weld branch connection where standard tee is not available due to size restrictions and the piping is of critical/high pressure service. Sockolet is used for socket welding branch connection, which require reinforcing pad.

Valves 1. What is the purpose of valve? ➢ Valves are used to close or open or control flow. Valves are designed to perform any of the below functions. Classification of based on function ➢ Isolation (gate, ball, plug, butterfly etc.) ➢ Regulation (globe, butterfly etc.) ➢ Non return (check valves, SDNR, etc.) ➢ Special purpose (foot valves etc.) Valves can be further classified based on the end connection screwed, socket flanged, and butt weld. Pr. Temperature ratings of valvesPr temperature rating is the maximum allowable sustained non shock pressure at the corresponding tabulated temperature.

Class- Valve the specified by the pressure rating of the body of the valves. Classes are. 150 # 300 # 400 # 600 # 900 # 1500 # 2500 # class 800 # 2. What is Trim? ➢ The trim is comprised of stem seat surface and other small internal parts that normally contact the surface fluid. 3. What is Wire drawing? ➢ The term is used to indicate the premature erosion of the valves seat caused by excessive velocity between seat and seat disc Velocity at a rate of sonic 4. Brief about Globe valve ➢ It is used for throttling purpose. Ex. Wash basin Valve v named after its globular body. Higher pressure drop – 270’ turn before reaching orifice 270’ turn after reaching orifice Angle valve It is used for throttling purpose Similar to globe valve; it can replace one elbow joint. Less pr. Drop 5. Brief about Plug valve (also called cocks) ➢ Ball valves are similar to plug valve ➢ Quarter turn can open/close the valve 6. Brief about Check valve ➢ It is used admit flow in one direction. ➢ It works on the principal of pressure difference. ➢ SDNR-This valve is also one type of non return valve. 7. Brief about Gate valve (isolation valve) ➢ -Mostly used on industrial piping ➢ -Not recommend for throttling of flow. To be used for isolation (throttling means erosion at bottom of gate). ➢ -Flow is axial to piping.

➢ -Lower pr. Drop. Valve can be identified by welded shaped body line. 7a. is gate valves are used high temp also? ➢ Yes. 7b.Brief about Ball valve (isolation) ➢ It is named after ball shaped disc located within the body. Normally positive shut off valves. Positive shut off is attained because of the soft seats. (Nylon, synthetic rubber, imparts excellent sealing ability. -Lower pr. Drop. Services. -Quarter turn or handle will open /close valve. -Suitable for gas, compressed air, liquid and slurry hence used on off shore /onshore, petrochemicals, widely. -Metals seats ball valves are used for high temperature service. (With fluorinated polymer seats, can be used for temp from –450 degree Fahrenheit to 500 Fahrenheit, with graphite seats temp up to 1000 Fahrenheit. 8. Brief about Butterfly valve These are low pressure valves may be control or regulate flow. These are available with metal to metal seats and soft seats. ➢ Flanged type. ➢ Wafer lug type. ➢ Water type. ➢ Positive shut off valve ➢ Quarter shut off valve. ➢ Occupies less space. Wafer lug and wafer type body design. Is that former has provision for all the studs to pass through the body. Whereas the latter has provision for only locating bolts. Can be used for corrosion service by selecting proper disc. Material. (Nitrile. rubber. PTFE) etc. Needle valve

Generally used for instrument gauge, and meter line service. Very accurate throttling is possible and therefore extensively used in high pressure and high temperature services. 9. Difference between B16.5 and B 16.34 ➢ The pressure temperature rating of B16.34 parallels that of ANSI B 16.5 except that B 16.34 provides for an increase in pressure rating for welding –end valves that receive additional prescribed Non destructive examination. ➢ ANSI B 16.1 cast iron flange. ➢ B 16.34 steel/ nickel flange. 10. What is Relief valve? ➢ The main purpose of are relief valve is to protect an equipment or pipe line by relieving excess pressure, and is the only valve which is continuously closed position. 11. What is the difference between Safety relief valve and pressure relief valve? 1. Safety relief valve ➢ These are designed for gases; in this case the valve seat pops up to open the valve where ever set pressure is crossed. This valve reseats below the initial set pressure. There by reducing the system pressure. To a safe level prior to reseating. 2. Pressure relief valve These are designed for compressible fluids like water etc. in this case the valve seat does not pop up but gradually opens up proportionally to the over pressure margin, after the operating pressure crosses the set value.

12. What is the permissible leakage while testing the valve? (HYDRO TEST)

1. When leak test can be substituted for hydro test? ➢ As for as possible hydro test should be conducted, in case of any damage expected due hydro test then it may be substituted. (Damage to the piping linings or internal insulation, or contamination, corrosiveness or moisture present during hydro test may affect the system. Or would present the danger of brittle fracture due to low metal temperature. During the test. )

2. What is the limitation for pneumatic test? ➢ It would present an undue hazard of possible release of energy stored in the system. It would present the danger of brittle fracture due to low metal temperature during the test. 3 What should be done in case of hydro test & leak test cannot be carried out condition. ? ➢ The joints should be checked for its 100% NDT requirements (100% RT or 100% UT). 4 What is the purpose of carrying out preliminary pneumatic test? ➢ Normally pneumatic test is conducted not more then 25 psi gauge pressure prior to hydro test to locate major leaks. (May be from blanks.) 5. Can heat treatment be conducted after hydro test? ➢ No, heat treatment should be conducted before hydro test.

6 Why the visual examination is carried out at during 90% hydro test of test instead of 100% in case of higher pressure? ➢ Although job has been pressurized for 100%. Hydro test, any leakage developed during 100 %, .the traces will be available even at 90%. By doing examination at 90 %, the possible danger at 100% to human kind is avoided. 7. How much should be the pressure for hydro –test? No. Hydro test pressure should be calculated as follow except as provided against point no-D ➢ 1.5 Times of Design pressure. ➢ For a design temperature above the test temperature, minimum test pressure can be calculated as: pt=(1.5 x p x St) / S Where: Pt: Minimum Test pressure P: Internal design pressure. St: Allowable stress at test temperature S: Allowable stress as design temperature ➢ If a test pressure as per above would produce a stress in excess of the yield strength at test temperature. The test pressure may be reduced to maximum pressure that will not exceed the yield strength at test temp. ➢ If the test pressure of piping exceeds the vessel pressure and it is not considered practicable to isolate piping from vessel, The piping and vessel may be tested together at test pressure of the vessel when approved by owner and provided the test pressure for vessel is not less than 115% of piping design pressure adjusted for temperature as per point no B.

Miscellaneous 1. What are Codes and standards? A group of general rules or systematic procedures for design, fabrication, installation & inspection prepared so that if can be adopted by legal jurisdiction made in to law. 2. Standard Recommended practices –without specific recommendation or requirements. From the process licensor to be followed. 3. What is the common available software for piping? C A E S A R –II for pipe stressing. P I P E N E T For fluid flow analysis S T A A D III For stress analysis X steel, struCAD, steel CAD for steel detailing

4. What is piping class? Document indicating the dimensional and material specification of pipe fittings and valve types is called a piping class. 5. What are the allowable stresses in various codes? Allowable stress in various codes? 31.1—Uts/4---2/3 Y S 31.3---Uts/3—2/3 Y S 31.4—0.72 6. What is fluid? Fluid is a liquid but it can vapor also. 7. What is the relation between Brinell hardness No and Rockwell hardness No? 22 HRC (Rockwell Hardness)=238 BHN(Brinell Hardness No)

8. What is mean by PWHT? Why it is required? ➢ “POST WELD HEAT TREATMENT” This is done to remove residual stress left in the joint, which may cause brittle fracture. 9. What is the minimum thickness of pipe that requires stress relieving to be done as per B31.3? ➢ 19 mm thk 10. Which fluid is used in heat exchanger in side and tube side? ➢ Generally corrosive fluid is used from the tube side( as tube can be easily replaced ) and cleaner fluid is used from shell side. Sometimes hot fluid is also used from the shell side. 11. What is Reynold’s number and what is value of Reynold’s number unto which the flow is laminar? (ANS FULLY NOT COMPLETED) It’s a dimensionless number to classify the nature of flow. Re= vd/ Where: Re: Raynold’s no. ass Density of fluid. d: diameter of pipe. V: average velocity of fluid. Viscocity of fluid. Flows is laminar up to Re=2100 12. Where do you provide Anchor and slotted support of heat exchanger? Anchor support of heat exchanger is provided on the side from which tube bundle will be pulled out for the purpose of maintenance work also it is based on the growth of the connecting piping as exchanger should grow with the piping.

13. What do you mean by Hoop stresses and how do you calculate it? Stresses which are generated circumferentially due to the action of internal pressure of pipe are called as Hoop stress. It is calculated by Hoop stress (Sh)=Pdo/4t Where P = force acting from inside. Do = OD of pipe. t= pipe Thickness. 14. How does Hoop stress affect system? As per membrane theory for pressure design of cylinder, as long as hoop stress is less than yield stress of Moc. The design is safe. Hoop stress induced by thermal pressure is twice the axial stress (SL).This is widely used for pressure thickness calculation for pressure vessel. 15. Define corrosion and various type of corrosion. Corrosion is a chemical / electrochemical reaction between metal/alloy and environment that produces deterioration of the material or its properties. The Cathodic reaction is liberation of hydrogen gas or formation hydroxide and the anodic reaction is dissolution of material forming its ions. The corrosive can be classified as: Acids, alkalies and neutral solutions depending on pH, Oxidizing agents, reducing agents, Specific depolarizing ions like chloride, fluoride etc. In acids the cathodic reaction controls and in neutral solutions and alkalies the anodic reaction controls the rate. In addition the diffusion rates of ions, velocity, mixing temperature etc control the rate of corrosion. The piping materials are subject to internal and/or external corrosion, internal corrosion can usually predicted and is controlled since the nature of fluid is known.

External corrosion is the more difficult to foresee due to variety of atmosphere and soil conditions, which may exist around a single pipeline. The important types of corrosion a piping engineer should consider are: Uniform corrosion: Localized corrosion, which may again be subdivided into i) Galvanic or bi-metallic corrosion ii) Crevice corrosion iii) Pitting corrosion iv) Intergranular attack v) Stress corrosion cracking. Uniform corrosion is the most common form of corrosion and accounts for the greater proportion of metal deterioration in terms of both mass of metal converted to corrosion product and cost. It is normally characterized by a chemical or electrochemical reaction, which proceeds uniformly over the entire exposed surface. Galvanic corrosion: is enhanced corrosion of one material when the material is joined to another nobler material (at a higher potential in galvanic series which is evolved from emf series given in Table 4.1.1 and nature of corrosive.) and is exposed to corrosive, even though the normal corrosion of the material is low. Remedies for this type of corrosion are avoiding contact of dissimilar materials, providing large anode to cathode area ratio, increasing the distance between the materials, or by providing cathodic protection by impressed current or by sacrificial anode. Pitting: is a localized attack, which occurs, in passive materials. At some week locations in the material either due to mechanical factor or metallurgical factors passivity is lost and it becomes anodic and severe corrosion takes place by auto-catalytic action. It occurs in gravitational direction. It can be prevented by impressed current or by sacrificial anodes or by adding pitting inhibitors like molybdates.

Crevice corrosion: occurs in crevices or openings which are large enough to corrosive medium but not capable of communicate the changes in concentration of bulk solution. This corrosion occurs due to differential aeration or differential concentration cells formed at crevices. Remedies for crevice corrosion are the same as for pitting. Intergranular attack: occurs in stainless steel due to depletion of chromium oxide (which gives passivity) at grain boundaries in heat-affected zone of weld due to formation of carbide. The remedies are to reduce carbon content, or to add small amounts of stabilizers like Ti, Nb, or to generate ferrite islands in austenite by modifying Ni & Cr contents. Stress corrosion: cracking occurs when the combination of three factors tensile stress, corrosivity and susceptibility to crack occurs. It may be transgranular or inter granular depending on type of corroding medium. The remedy to the problem lies in modifying the nature of medium by addition of inhibitors pr avoiding tensile stress or by cathodic protection. Corrosion resistance materials like stainless steels nickel, copper, tin, lead and their alloys are usually best adapted to specific uniform conditions, which can be predicted. Protective coatings, cladding, lining plating and painting may be adapted to internal and external protection of less expensive base materials. Coatings include asphalt, tar and waxes. Lining with glass, cement, rubber, porcelain, plastic, and synthetic elastomers or plating with corrosion resisting metals offer many possible solutions to corrosion resistance. The corrosion resistance of construction materials is given in table 4.1.2. The rate of corrosion may be economically reduced by: Selection of costlier corrosion resistance material. Application of protective coatings. Deactivation of the corrosive medium by adding suitable inhibitors or by removing aggressive component. Cathodic protection of base material. Deactivation of corrosive fluid may be economically justified in many process applications like deaerating of boiler feed water.

Cathodic protection of piping has been successfully applied to underground installation and in mildly corrosive systems. WHAT IS DESIGN PRESSURE? The design pressure of each component in a piping system shall be not less than the pressure at the most severe condition of coincident internal or external pressure and temperature (Minimum or Maximum) expected during service WHAT IS DESIGN TEMPERATURE? The design temperature or each component in a piping system is the temperature at which, under the coincident pressure, the greatest thickness or highest component rating is required. WHAT IS MINIMUM TEMPERATURE? The design minimum temperature is the lowest component temperature expected in service. 16. What is the consideration generally adopted for the strength calculation by piping designer? Considerations generally adopted for the strength calculation by piping designer, based on the process parameters furnished by the process engineer are as below: a) Design pressure as 10% higher than the anticipated maximum operating pressure. b) Design temperature 25 degree C above the anticipated operating temperature c) When operating temperature is 15 degree C and below, the design temperature as the anticipated minimum operating temperature. If ASTM materials are used ASME/ANSI should be preferred. The selection of materials shall follow the norms below a) Carbon steel shall be used up to 4250 C. b) Low temperature steel shall be used below 200C c) Alloy carbon steel shall be used above 4250 C.

For corrosive fluids recommendations from the process licensors to be followed. FEW TIPS FOR THE PREPERATION PIPING SPECIFICATIONS. The approach should be minimize the number of different elements and thus simplify and rationalize stock facilities. A) Material. - Carbon steel shall be used for temperature up to 4250 C - Low temperature steel shall be used for temperature below –290 C - Alloy steel shall be used for temperature above 4260 C. - Stainless steel shall be used for corrosive fluids. Basic material of construction specified by process licensor to be referred for the type. - Galvanized steel piping shall be used for service such as drinking water, instrument air, nitrogen (LP) etc. - Selection of Non-ferrous and Non-metallic piping shall be as per the recommendation from the process licensor. B) Piping Joints. - Butt-welded connection shall be used for all alloy/carbon steel piping 2” NB and larger. - Alloy/carbon steel piping 1.5’’ NB and below shall be socket welded. - Threaded connections shall be avoided except in galvanized piping. - Flanged joints shall be minimized, as it is a point of potential leakage. It may be used to connect piping to equipment or valves. Connecting pipe lines of dissimilar materials, where spool pieces are required to permit removal or servicing of equipment and where pipes and fittings are with flanged connections. 17. What is the difference between Brazing and soldering? Ans. BRAZING: - A process where base metals do not melt. - Filler material has a temperature above 4500 C.

- Filler metal wets the base metal and drawn into joint by capillary action. - Most often used for joining of coppers and combination of metals, which cannot be welded? - Brazing procedure and personnel have to be qualified as per ASME section IX. SOLDERING: - Similar to brazing but filler metal melting point is between 2350 C to 2600 c used for aluminum. - Organic fluxes are used to prevent oxidation. - No requirements for qualification of procedure and personnel given in ASME. 18. What is the different position for pipe welding? Ans. - Pipe weld joints are identified as test positions. They are normally grove welds and are indicated by the letter ‘G’ - Test position ‘1G’ is roll welding with the axis of pipe horizontal, welding done in flat position and the pipe rotating under the arc. - Test position ‘2G’ is known as horizontal welding with pipe axis vertical, but the weld axis in horizontal position. - Test position ‘5G’ is known as horizontal fixed position. Axis of the pipe is horizontal, pipe is not to be turned or rolled during welding. - Test position ‘6G’ for pipe welding has the axis of the pipe at 450 and the pipe is not turned while welding. 19. Why preheating is required? Ans. In a weld, the problems of - Hydrogen getting dissolve in the weld metal - Stresses due to weld shrinkage. - Thermal shock from heat of welding in thick walled pipes. Preheating the base metal of the welding prior to welding process can minimize these.

- Preheating reduces the cooling rate of the weld joint and results in a more ductile structure in weld metal and heat affected zone (HAZ). 20. What is Oxy-fuel gas cutting and plasma gas cutting? Ans. Oxy-fuel gas cutting is a process where severing of the metal is effected by the chemical reaction of the base metal with oxygen at an elevated temperature. In the cutting torch, a fuel such as acetylene, propane or natural gas is used to preheat the base metal to cutting temperature. A high velocity stream of oxygen is then directed at the heated area resulting in an exothermic reaction and severing of the metal. This method is used for carbon steel and low alloy steels. Plasma Arc Cutting is a frequently used method for high alloy steels. The cutting torch generates an arc, which is forced to pass through a small diameter orifice and concentrate its energy on a small area to melt the material generating extremely high temperatures. Simultaneously a gas such as argon, hydrogen or a mixture of nitrogen and hydrogen is introduced at the orifice where it expands and accelerates through the orifice. The jet like action of the gas stream removes the melted metal. Thermal cutting methods are used for edge preparation also after the cutting operation is over.

What is Cold Spring? -Intentional stressing and elastic deformation of piping system during the erection process to permit the system to attain more favorable reactions and the stresses during the operating conditions -System dimensions are fabricated short by an amount equal to some percentage of the calculated expansion value in each direction. -System is then erected with a gap at some final closure weld, equal to the “cut shorts” in each direction

-Forces and moments are then applied at both ends as necessary to bring the final joint into alignment -Once this is done, anchors and fixtures are provided on both sides of the joint to preserve the alignment during welding, examination and PWHT -When the restraints are removed, the reactions are absorbed in to the terminal points and the piping is in stress. -During start up the piping expands as the temperature increases and levels of stress and terminal reactions resulting from the initial cold spring will decrease. -Higher stress in the piping at cold temperature is justified by the increased strength of the material at low temperatures. -It is difficult to achieve 100% cold spring, where the piping in the operating condition will have zero stress theoretically -Applied to high temperature systems such as steam lines and not reheat lines -Care should be exercised when working with cold spring lines. If the line has to be cut, it should be anchored on either side of the cut to prevent any possible accident. WHAT ARE PRESSURE PIPING CODES? B31.3 Power piping B31.3 Process piping B31.4 Pipeline transportation systems for liquid hydro carbons and other liquids B31.5 Refrigeration piping B31.8 Gas transportation and distribution piping systems B31.9 Building services piping B31.11 Slurry transportation piping systems IN B 31.3 HOW FLUID CATEGORY IS FORMED? CATEGORY D a) The fluid handled is non flammable, non toxic, and not damaging to human tissues.

b) The design gauge pressure does not exceed 150 pressure and temperature is from –29* c to 186* c CATEGORY M A fluid service in which the potential for personnel exposure is judged to be significant and in which a single exposure to a very small quantity of a toxic fluid, caused by leakages, can produce serious irreversible harm to persons on breathing or bodily contact, even when prompt restorative measures are taken. HIGHER PRESSURE FLUID SERVICE-‘K’ CATEGORY A fluid service for which the owner specifies the use of chapter ix (B.31.3 for piping design and construction). NORMAL FLUID SERVICE A fluid service pertaining to most piping covered by this code. i.e not subject to the rules for category D, category M, or high pressure fluid service.