Saudi Aramco Instrument Questions/Answers

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Saudi Aramco Instrument Questions & Answers 

1. What are the parts of coaxial cables?

Center Core

Dielectric Insulator

Metallic Shield

Plastic Jacket

2. What is Junction Box?

An earthed enclosure within which wires or cables can be safely connected

3. What are the Kinds of Metering Instrument?

Conventional electronic and pneumatic transmitter



Pressure Gage


Resistance Temperature detectors

Level Transmitter

Instruments air line pressure gage

Turbine positive displacement and magnetic flow meters

Pilot Tube annular flow meters

Temperature gage

4. What are the task in performing instrument loop checking?

Conducted as per cable package and markings, Tagging and Wire color coding. Testing to be conducted or using test equipment or hand tools continuity test and referenced loop package documents

Considering to identify the Instruments loop (either Closed Loop or Open Loop)

Obtain Documents pertaining to the process loop in order to understand All devices and their intended functions

Inspect the loop components through visual observation in order to ensure that the components are correctly installed

The prepared approved Instrument loop package or folder shall be always implemented

5. What is instrumentation?

It is a branch of science which deals with measurement and control of process variables such as pressure, flow, temperature, level and etc.

6. What are the kinds of pressure measurement?

Pressure Gauges

Draft Gauges

Pressure Switches

Pressure Transmitters

Deferential Pressure Instruments

7. What are the Kinds of Smoke Detector?

Air Sampling type detector

Automatic fire detector

Automatic Fire Extinguishing or suppression system operation detector

Combination detector

Electrical conductivity heat detector

Fire-Gas Detector

Fixed temperature detector

Flame detector

Heat detector

Line-type detector

Other Fire detectors

Pneumatic rate-ofrise tubing heat detector

Projected beam-type detector

Radiant sensing fire detector

Rate compensation detector

Rate offrise detector

Smoke detector

Spark/Ember Detector

8. What are the Types of Switches?

Lever actuator limit switch

Proximity Switch

Speed switch

Pressure switch

Temperature switch

Liquid level switch

Liquid level flow switch

Nuclear level switch

Toggle switch

9. What are the Kinds of Alarm Control Unit?

Fire Alarm Control Unit (Panel)

Intermediate Fire Alarm Fire Supervisory control Unit

Master Control Unit (MCU Panel)

Protected Premises (Local Control Unit Panel)

10. What is the Saudi Aramco Instrument Signal Pair wire color coding?

P – Black

N – White

11. What is the Saudi Aramco Instrument Signal Triad wire color coding?

P1 – Black

P2 – Red

N – White

12. What are Instrument Loop-package Documents Contents?

Applicable design documents

Procurement documents

Manufacturer’s documentation needed to test and verify loop operation

Completed quality control RFI checklists and test reports from receiving, installation, and calibration

13. What Items we should to check for Instrument Stand / Supports?

Fabrication of Stand as per drawing

Deburred , Primed and Painted

Instrument location as per IPL Drawing

Access is unobstructed and clear for maintenance

Stand Grounded

Stand and Support Secure

14. What Items we should to check for Instrument Device Installation?

Instrument Calibrated prior to installation and documentation checked

Instrument mounted in accordance with hook up drawing

Check instrument is correct in accordance with ISS / P & ID

Instrument securely installed on stand

Elevation correct relative to process tapping

Sunshade installed

Stand and Support Secure

15. What Items we should to check for Instrument Impulse Tubing?

Material used according to specification

Steam tracing and insulation as per hook up

Seal fitting installed and Filled

Isolation and equalization valves / manifold installed

Vent and drain / manifold installed

Tubing slope Checked

Verify Tubing connection to HP & LP sides

Leak Test done

Pressure Test of impulse tubing

16. What Items we should to check for Instrument Cabling / Signal / Conduit?

Check electrical installation with respect to conduits, glands, seals, are correct

Core and cable tagging are meggered and checked

Check connection terminations with instrument for tightness

Instrument installation pressure tested as required

17. What kinds of materials being used for impulse tubing pressure leak testing?



18. What are the test procedures of Pressure Transmitter?

The process connection shall be connected to a dead weight tester Budenberg (Range 1-1200 bar g) or equivalent

The output signal shall be connected to an electronic test meter or precision manometer as applicable

Align equipment at zero

Apply actuating pressure to full range and lock-in signal pressure- check system for leaks

Reset to zero

Apply actuating pressure of 25,50,75 and 100% of range-record readings

Reduce actuating pressure of 75,50,25 and 0 % of range-record readings

When necessary, adjustments according to the manufacturer’s instructions shall be made until the quoted accuracy is obtained

Apply 110% signal as check for hysteresis

Transmitters with indicating scales shall have the indicator calibrated during the above tests and the transmitters color coded

19. What are the specific contents of Material Requisition (MR) in Saudi Aramco?









20. In Area Classification what are the difference between Class 1 Zone 0, Class 1 Zone 1 & Class 1 Zone 2 Location?

Class 1 Zone 0

In which ignitable concentrations of flammable gases or vapors are present Continuously and in which ignitable concentrations of flammable gases or vapors are present for long periods of time.

Class 1 Zone 1

In which ignitable concentrations of flammable gases or vapors are likely to exist under normal operating conditions or vapors may exist frequently because of repair or maintenance operations or because of leakage and in which equipment is operated or processes are carried on, of such a nature that equipment breakdown or faulty operations could result in the release of ignitable concentrations of flammable gases or vapors and also cause simultaneous failure of electrical equipment in a mode to cause the electrical equipment to become a source of ignition.

Class 1 Zone 2

in which ignitable concentrations of flammable gases or vapors are not likely to occur in normal operation and if they do occur they will exist only for a short period or in which volatile flammable liquids, flammable gases, or flammable vapors are handled, processed, or used, but in which the liquids, gases, or vapors normally are confined within closed containers of closed systems from which they can escape, only as a result of accidental rupture or breakdown of the container system and in which ignitable concentrations of flammable gases or vapors normally are prevented by positive mechanical ventilation, but which may become hazardous as a result of failure or abnormal operation of the ventilation equipment.

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