pipe Fitter question and answer
What Is Preferred Location For Drain?
Answer : Must be located at the bottom section of line.
What Are Functions Of Valves?
Answer : Isolation, regulation, non-return and special purposes.
What Are Isolating Valves?
Answer : Gate, ball, plug, piston, diaphragm, butterfly, pinch.
What Are Regulating Valves?
Answer : Globe, needle, butterfly, diaphragm, piston, punch.
What are non-return Valve?
Answer : check valve.
What Are Special Valves?
Answer : Multi-port, flush bottom, float, foot, pressure relief, breather.
What Materials Are Used For making Of Valves?
Answer : Cast iron, bronze, gun metal, carbon steel, stainless steel, alloy carbon steel, polypropylene and other plastics, special alloys.
Which Standard Specifies Trim Numbers For Valve?
Answer : API 600.
What Are Wetted Parts Of Valve?
Answer : All parts that come in contact with surface fluid are called wetted parts.
What Pressure Tests Are Carried Out On Valves?
Answer : Shell-hydrostatic, seat-hydrostatic, seat-pneumatic
What Are Available Valve Operators?
Answer : Hand-lever, hand-wheel, chain operator, gear operator etc.pneumatic operator, electric operator
Full Form Of ASME?
Answer : American Society for Mechanical Engineers.
Which Piping Code Is Used For Power Piping And Which Code Is Used For Process Piping Design?
Answer : Power Piping: ASME B 31.1
Process Piping: ASME B 31.3
What Are The Main Differences Between Asme B 31.1 And Asme B 31.3?
Answer : The main differences are listed below:..
Material allowable stresses are different in both codes.
Stress increases due to occasional loads are different in each code.
B 31.3 neglects torsion while calculating sustained stresses, but B 31.1 includes it.
Sustained stress calculation is specific in B 31.1 but undefined for B 31.3.
B 31.1 intensifies torsion but B31.3 does not intensify it.
How To Calculate The Basic Allowable Stress For A Material?
Answer :The basic allowable stress is defined in respective code. For example as per B 31.3 the basic allowable stress for a material is the minimum of the following:
1/3rd of tensile strength at design temperature.
2/3rd of yield strength at design temperature.
100% of average stress for a creep rate of 0.01% per 1000 hours.
67% of average stress for rupture at the end of 100000 hours.
80% of minimum stress for ruptures at the end of 100000 hours.
For austenitic stainless steel or nickel alloys the lower of yield strength and 90% of yield strength at temperature.
For structural grade materials 0.92 times of the lowest value of point (a) to (f)
pipe Fitter question and answer
pipe Fitter question and answer
What Is The Main Difference Between Constant And Variable Spring Hanger? When To Use These Hangers?
Answer : In Constant Spring hanger the load remains constant throughout its travel range. But In variable spring hanger the load varies with displacement.
Spring hangers are used when thermal displacements are upwards and piping system is lifted off from the support position. Variable spring hanger is preferable as this is less costly.
pipe Fitter question and answer
Constant springs are used:
When thermal displacement exceeds 50 mm
pipe Fitter question and answer
When variability exceeds 25%
Sometimes when piping is connected to strain sensitive equipment like steam turbines, centrifugal compressors etc and it becomes very difficult to qualify nozzle loads by variable spring hangers, constant spring hangers can be used.
pipe Fitter question and answer
What Do You Mean By Variability? What Is The Industry Approved Limit For Variability?
Answer : Variability= (Hot Load-Cold load)/Hot load = (Spring Constant × displacement)/Hot load.
Limit for variability for variable spring hangers is 25%.
pipe Fitter question and answer
What Is The Software Available For Performing Piping Stress Analysis?
Answer :Caesar II, Auto Pipe etc.
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