QC Notes Lecture_8 Aramco Standard Electrical and Instrument Question Answers Part_4

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Aramco Standard Electrical and Instrument Question Answers Part_4

1.           What should be done, when union cannot be avoided in underground conduit installation?
Ans: Unions shall be protected with heat-shrinkable sleeves.
2.            What shall be provided on each duct where it terminates?
Ans: Bell end fitting or protective bushings.
3.            How many spare ducts in duct banks?
Ans:   Duct bank shall have 20% spare ducts (minimum one), unless this number is decreased bythe facility proponent.
4.            What is the minimum conduit size excepted for instrumentation wiring inside building?
Ans: ¾ Inch.
5.            What is the minimum conduit size excepted for prefabricated skids and in-industrialarea?
Ans: ½ Inch.
6.            What the meaning of (EMT) and for what used?
Ans: Electrical Metal Conduit (EMT), you can use only indoor.
7.            What are the conduit fittings for outdoor rigid steel conduit and liquid tight flexible metal (LFMC)?
Ans:   Shall be cast or forged steel, cast iron or malleable iron either hot-dip galvanized (preferably) electroplated.
8.            Can be use the aluminum fitting in outdoor?
Ans:   No aluminum fitting or fitting accessories such as covers, sealing fitting plugs shall be used outdoor only malleable iron sealing fitting shall be used.
9.            What is the minimum distance from main door to marshaling panel?
Ans: Minimum shall be 3 meter from main door to marshaling panel.
10.         What shall be the slope for impulse line?
Ans: A minimum of a 1mm, for every 12mm towards tapping point.
11.         What shall be having extra length for unistrut support?
Ans: 40mm should be extra.
12.         What shall be the test pressure of instrument impulse line?
Ans: 1.5 times of the working pressure.
13.         What shall be minimum acceptable insulation resistance of instrument cable during Megger Test?
Ans: 100 Mega ohms
14.         Name some testing equipments used for instrument calibration?
Ans:   Deadweight tester, Digital multimetter, Megger, Digital pressure calibrator, Temperature calibrator, Temperature bath,
Field communicator, Vibration meter.
15.         What shall be the maximum acceptable attention value of fiber during OTDR test?
Ans:   0.5Db/Km or less for wave length of 1310 nm and 0.3Db/Km or less .for wave length of 1550nm.
16.         What shall be the maximum pulling tension of FOC?
Ans:   600 Pounds.
17.         What is name of fieldbus communicator?
Ans: FBT6 (Fieldbus Transducer 6)
18.         What is the Principle of Bimetal Thermometer?
Ans: Different Metal of Different Coefficient.
19.         What is the color coding for accepted instrument or rejected instruments?
Ans:      Blue     –           Pre-installation Test (Calibrated)
White   –           Test Fail (written message may be added giving reason failure)
Red      –           Pre-commissioned
Green   –           Cable Test (Megger)
Yellow  –           Pressure Test
20.       How do you calculate new factor from new range using old factor and old range?

21.         Definition of Instrument Range and Span?


Instrument Range and Span
22.         Calculation of Resistance or Pt100?
Ans:   Ro= 100 Ω X for platinum = 0.00385 / C
To calculate resistance at 100 oC
R100 = 100 [1 + (.385 x 100)]=100 + (100 x 0.385)
R100 = 138.5
Resistance at 100 oC = 138.5 Ω
23.         Calculation of oC to oF?
24.         Calculation of oF to oC?
25.         What is the effect of weep hole on calculation of orifice bore?
Ans:   D = dm {1 + 0.55 (dm) 2 / dh}
Where: dm = Measured diameter of orifice
dh = Drain hole diameter
d = Corrected diameter orifice size


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2 Responses

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