PIPING INTERVIEW QUESTIONS: 1) What Is the ASME code for designing the piping systems in process piping( Refining & Chemical)? Ans )
ASME B 31.3
2) Which American institute does does piping engineer refres refres in general? API- American Petroleum Insititute. AISI-American iron and steel insitutute ASTM-Amercian society for testing materials ANSI-American national standard institute. ASME-American Society for Mechanical Engineers. AWS-American Welding Society. 3) What are the different pressure piping codes for ASME B31? ASME B 31.1 Power Piping. ASME B 31.2 Fuel Gas Piping. ASME B 31.3 Process Piping. ASME B 31.4 Pipeline Transportation system for liquid Hydrocarbon & other Liquid. ASME B 31.5 Refrigeration Piping. ASME B 31.8 Gas Transmission and distributing piping system. ASME B 31.9 Building services piping. ASME B 31.11 Slurry Transportation piping system. 4) What are the differenct sections of ASME code? Where these sections are referred? ASME SECTION 1- Rules for Construction of Power boiler. ASME Section 2- Materials. Part A- Ferrous materials. Part B- Non-ferrous Materials. Part C-Specification fro electrodes & filler wire. Part D-Properties. ASME Section 4- Rules for construction of heating boiler. ASME Section 5- Non Destructive examination. ASME section 6- Recommended rules for care and operation of Heatingg boiler. 5) Which American Standard is referred fro selection of the following elements? A.Flanges, B. Butt Welded Fittings. C.Gasket. D.Socket & Threaded Fittings. E.Valves F.Pipes. A.Flanges: 1) ASME B 16.1: Cast Iron Pipe flanges & Flanged fittings. 2) ASME B 16.5: Steel flanges (upto 24”) 3)ASME B 16.47: Steel Flanges Above 24” 4)ASME B 16.9 Butt Welded Fittings. 5)ASME B 16.28 Butt welded Short radius elbows & returns bends. 6)ASME B 16.20/API 601: Metallic Meta llic Gaskets for pipe Flanges-spiral wound, octagonal ring joint & jacketed flanges. 7)ASME B 16.21: Non metallic gasket. 8)ASME B 16.11: Socket welded and threaded fittings. 9)ASME 16.10: Face to Face, End to end dimension of Vavles.
10)ASME B 16.34: Flanged & Butt Welded ends steel valves.(Pressure and temperature ratings) 11)ASME B 36.10: Carbon Steel and Wrought steel pipe. 12) ASME B 36.19: Stainless stell pipes. 6) What are the commonly used ASTM Carbon steel pipes? Carbon Steel: ASTM A53 Gr. A/B, ASTM A106 Gr. A/B/C 7) What are the commonly used ASTM Stainless steel pipes? Stainless Steel: ASTM A312 TP304/TP304L/TP 304H/TP 308/TP 310/TP 316/ TP316H/TP 317/TP 321/ TP 321H/TP 347/ TP 347H/TP 348/TP 348H. 8) What are the Commonly used ASTM Alloy Steel Pipes? Alloy Steel: ASTM A335 Gr.P1/P2/P5/P7/P9/P11/P12/P22. 9) What are the commonly used ASTM wrought iron fittings? 1) Wrought Iron fittings :I. Carbon Steel :- ASTM A234Gr.WPA/B, ASTM A420 Gr.WPL6. 2)
Alloy Steel :- ASTM A234 WP1/WP5/WP7/WP9/WP11/WP12/WP22.
3) Stainless Steel :- ASTM A403 WP304/WP304L/WP304H/WP309/WP310/WP316/ WP316L/WP316H/ WP317/WP321/WP321H/WP347/WP347H/ WP348. 10) What are the commonly used ASTM forged Fitttings? 1) Carbon Steel :- ASTM A181. ASTM A105, ASTM A350 LF1/2. 2) Alloy Steel :- ASTM A182F1/F2/F5/F7/F9/F11/F12/F22. 3) Stainless Steel :- ASTM A182F6/F304/F304L/F304H/F310/F316/F316L/F316H/F321/ F321H/F347/F347H/F348. 11) What are the commonly used ASTm Cast fittings? 1)
Carbon Steel :- ASTM A216, ASTM A352 LCB/C.
2) Alloy Steel :- ASTM A217 WC1/WC6/WC9/C5/C12. 3) Stainless Steel :- ASTM A217 CA15, ASTM A296 CA15, ASTM A351 CF8/CF3/CH20/ CK20/CF 8M/CF 3M/CF 8C/HK40 12) What are the commonly used ASTM plate materials? 1) Carbon Steel :- ASTM A285, ASTM A515, ASTM A516. 2) Alloy Steel :- ASTM A387 Gr.2/Gr.5/Gr.7/Gr.9/Gr.11/Gr. 12/Gr.22. 3) Stainless Steel :- ASTM A240 TP410/TP405/TP430/TP304/TP304L/TP309/TP310S/ TP316/TP316L/TP317/TP321/TP347/TP348
13) What is the basic difference between pipe specification A106 Gr A, GrB, & GrC? Difference is due to the carbon content. Percentage of Carbon Content in : 1) ASTM A 106 Gr A- 0.25% 2) ASTM A 106 GrB-0.30% 3) ASTM A106 GrC-0.35% 14) What is the difference between pipe Specification ASTM A312 TP 304 & ASTM A312 TP 304L, ASTM A312 TP 316 & ASTM A 312 TP 316L? Difference is due to the carbon content. The letter L denotes Lower percentage of carbon. For ASTM A312 TP304- 0.08%, ASTM A312 TP304L-0.035%, ASTM A312 TP316-0.08%, ASTM A312 TP316L-0.035% 15) How can flanges be classified based on pressure-temperature ratings? Flanges are classified based on pressure temperature ratings as 150#,300#,400#,600#,900#,1500#,2500#
Pressure Temperature rating charts in the standard ASME 16.5 specify the non-shock working guage pressure to which the flange can be subjected to at a particular temperature. In General, Ratings 150,300 are Low Pressure ratings. Ratings 400,600,900 are Intermediate Pressure ratings, Ratings 1500,2500 are termed as High Pressure ratings 16) How can Flanges be classified based on facing? Flat Face, Raised face, Tongue & groove, Male & female,Ring type joint 17) How can Flanges be classified based on Face fininsh? Smooth finish, Serrated Finish 18) Where the smooth finish flange & Serrated Finish flange finds its use? The smooth finish flange is provided when metallic gasket is provided and serrated finish flange is provided when non-metallic gasket is provided. 19) What are the types of serrated finish provided on flange face? Concentric, Spiral(Phonographic) 20) How the serration on Flanges specified? Serration on flanges is specified by the number, which is Arthematic Average rough height(AARH) 21) Where the concentric serration is insisted for face finish? Concentric serration are insisted for face finish where the fluid being carried has very low density and can find leakage path through cavity. 22) How the gaskets are classified based on the type of contruction? Based of type of construction, Gaskets are classified as Full face, spiral wound metallic, ring type, metal jacketed, inside boltcircle 23) Most Commonly used material for gasket? Compressed asbestos fibre 24) Which type of gasket is recommended for high temperature and high pressure applications? Spiral wound metallic gasket 25) What are the criteria for selection of material of construction of Spiral wound metallic gasket winding material? The selection of material of construction of gasket winding depends upon. 1) The corrosive nature and concentration of fluid being carried. 2) The operating temperature of the fluid 3) The relative cost of alternate winding material 26) What are the most common materials used for spiral wound metallic gasket winding? 1) Austenitic stainless steel 304 with asbestos filler, 2) Austenitic stainless steel 316 with asbestos filler. 3) Austenitic stainless steel 321 with asbestos filler 27) Which material is used for filler material for spiral wound gasket incase of high temperature services? Graphite filter is used. 28) What is centrering ring in connection to spiral wound gasket? Spiral wound gaskets are provided with carbon steel external ring called centrering ring to assist in centering the gasket while installation. 29) What will be the AARH finish on flange face for using spiral Wound Gasket?
125-250 AARH finish. 30) On Which type of flanges the use of spiral wound gasket are restricted? ASME B 16.5 does not recommended the use of 150# rating spiral wound gasket on flanges other than welding neck and lapped joint type. 31) Upto what temperature limits the low strength c arbon steel bolts should not be used for flanged joints? 200 deg C or below -28 deg C 32) How the pipe fittings are classified based on end connections? Socket Weld fittings, Screwed end fittings, bevelled end or butwelded, spigot socket 33) Upto what temperature the carbon steel materials shall be used in general? 425 Deg C 34) Which material is used for temp 426 deg C? Alloy steel materials for above 426 deg C 35) Which type of material is used for corrosive fluid? Stainless steel material is used for corrosive fluid 36) Which type of piping material is used for drinking water, instrument air etc? Galvanized steel materials shall be used for drinking water, utility instrument air and nitrogen lines(low pressure) 37) What is the difference between Pipe & Tube? Pipe is identified by nominal bore and thickness is defined by schedule whereas tube is identified by OD and thicknesss as BWG(Birmingham wire guage or 1/100 i nch) Pipe is used for mass transfer, tube is used for heat and mass transfer Pipe is round in shape, tube may be round or rectangular or any odd shape 38) From which size onwards Nominal bore of pipe is equal to OD of pipe? 14” onwards NB=OD of pipe. 39) What should be the radius of long radius elbow? 1.5D (diameter of pipe) 40) What should be the radius of short radius elbow? 1D 41) What is the basis of using short radius and long radius elbow? Long radius elbow are used for small pressure drop whereas short radius elbow are used for high pressure drops. For Catalyst flows vary long radius elbows are used, Short radius elbow are used in jacketed piping, usually in small bore. 42) Normally, Where do we use the Eccentric Reducer & Concentric reducers? Eccentric reducers:pump suction to avoid cavitation, to maintain bop or elevation in rack Concentric reducers:Pump discharge, vertical pipeline etc. 43) Concentric reducer is used in pump suction ( yes/ no) explain? No. Air pockets may form if concentric reducer is used at pump suction, which results in cavitaion and c ause damage to pump. To avoid this problem Eccentric reducer with FSU is used in pump suction. 44) Where The ERW and Seamless pipes are used? ERW-18” pipes, Below 18”, Seamless pipes are used, seamless can sustain high press & temp. 45) What is the main use of ASTM A53 & A106 GrB pipes?
ASTM A53 pipes are mainly used for utility services whereas A106 GrB pipes are used for high pressure and high temperature services. 46) From which side of pipe will you take a branch connection? When Fluid is Gas, Air or Steam and Cryogenic Service- Top side, When Fluid is liquid- Bottom side Steam is also sometimes taken from side to avoid dual phase flow of moist steam and dry steam. 47) Why don’t we take a branch for cryogenic service from bottom side though the fluid is i n liquid state? There is the chance of ice formation during normal operation and since ice flows from the bottom of the pipe it will block the branch pipe connection. 48) Why do we provide High Point Vent(HPV) and Low Point Drain(LPD) in piping? HPV-for removing air during hydro test LPD-for draining water after conducting hydro test. 49) What do you mean by jacketed piping? Piping where the most uniform application of heat/temperature is required to the process, where steam tracing is not capable of maintaining the temperature of fluid constantly. Usually used for molten sulphur, polymers service etc. 50) What is the minimum distance to be maintained between two welds in a pipe? The thumb rules is that the minimum distance between adjacent butt wleds is 1D or 1-1/2 inch, this is due to prevent the overlap of HAZs. . 51) What are Sockolet and Weldolet and where they are used? Weldolet and sockolet are basically self-reinforced fittings. Weldolet is used for butt weld branch coneection where standard tee is not available due to size restrictions and the piping is of critical/high pressure service. 2” & above. Sockolet is used for socket welding branch connections, which require reinforcing pad. Below 2” 52) What is the normal upstream and downstream staigh lengh of orifice flow meter? Upstream-20D, Downstream-5D 53) What are the main function of valves? Isolation, Regulation, Non-return,special Purpose. 54) What are the main types of isolation valves used in the industry? Gate valve, Ball Valve, Butterfly Valve, Plug Valve 55) What are the main types of regulation valves used in the industry? Globe Valve, Needle vavle, Diaphram 56) Whate are the main types of non return vavles used in the industry? Check Valve 57) Special Valves Single block and bleed, Double block and bleed and breather valve. 58) What is the purpose of the spiral wound gasket colour coding? To identify the material( Based upton the gasket colour coding we can easily identify wheter the correct gasket has installed or not during final walk down and before commissioning the line) 59) Commonly used Destructive Tests? Tension Test, Bend Test, Impact Test, Hardness Test.
60) Commonly used Non Destructive tests? Radiography testing, ultrasonic testing, magnetic particle testing, penetrant testing, eddy current testing, visual testing.
