Piping QC Aramco CBT Exam Questions and Answers

This article is about Piping QC Aramco CBT Exam Questions and Answers and useful for those who want to become Piping QC Engineers, Supervisors and managers in oil and gas refinery projects.

Piping QC Aramco CBT Exam Questions and Answers

1. What is dead leg and explain?

A dead leg refers to a section of piping that is susceptible to internal corrosion due to flow stagnation. It occurs when there is a lack of fluid movement or circulation in a particular area of the piping system. Dead legs are typically formed when water or solid deposits settle in the stagnant area.

In general, a dead leg is considered significant when its length is greater than three times the pipe diameter or exceeds 1.22 meters (4 feet) for pipes with a diameter of 2 inches or larger. The length of the dead leg is measured from the outside diameter of the header (or run) to the nearest end of the branch valve.

For smaller branch connections, such as those with a size of 1-½ inch NPS and below, the length of the dead leg is measured from the end of the boss (protrusion) to the nearest end of the valve.

Dead legs are a concern because stagnant fluids can lead to localized corrosion, increased microbial growth, and accumulation of sediment or debris. Therefore, it is important to identify and address dead legs in piping systems to prevent potential damage and maintain the integrity of the system. Measures such as regular flushing, proper system design, and the use of appropriate corrosion inhibitors can help mitigate the risks associated with dead legs.

2. Write any 4 types of piping supports?

Here are four types of piping supports:

1. Pipe Shoe: A pipe shoe is a type of rigid support that cradles the pipe and prevents it from moving vertically or horizontally. It provides support at specific points along the pipeline and helps distribute the weight and loads effectively.
2. Spring Loaded Support: A spring-loaded support, also known as a variable spring hanger, is designed to accommodate thermal expansion and contraction of the piping system. It uses a spring mechanism to provide vertical movement and absorb the changes in pipe length caused by temperature variations.
3. Resting Support: Resting supports, also called pipe rests or pipe racks, are used to provide continuous support for long stretches of horizontal or sloping pipes. They are usually designed as structures or frames that hold the pipes in place and prevent excessive sagging or movement.
4. Wear Pad: A wear pad, also known as a guide or slide plate, is a support used to reduce friction and wear between the pipe and its supporting structure. It is typically made of a low-friction material such as PTFE (polytetrafluoroethylene) and is placed between the pipe and the support to allow smooth movement and prevent damage to the pipe surface.

3. Line class 103CS3C is listed on the Isometric Drawing. Explain each________

1 Raised face 03 Flange rating 300 CS Carbon steel 3 C.A-4.5mm C Caustic
As per SAES-L­-105

4. What type of connection is acceptable for a 24” header, 12” branch?

For a 24″ header and 12″ branch connection, the acceptable type of connection, as per SAES-L-110 Appendix A, would be a Weldolet or a welded branch with a reinforcement pad.

A Weldolet is a type of branch connection that is welded onto the header pipe, providing a smooth transition from the header to the branch. It is a commonly used fitting for making branch connections in piping systems.

Alternatively, a welded branch with a reinforcement pad can also be used. In this case, the branch pipe is welded directly to the header pipe using a welding process, and a reinforcement pad is added to enhance the strength and integrity of the connection.

Both options, Weldolet and welded branch with reinforcement pad, are acceptable for creating a 24″ header and 12″ branch connection according to SAES-L-110 Appendix A. The specific choice between these two options may depend on factors such as the design requirements, operating conditions, and project specifications.

5. How many minimum Pressure gauges to be installed during hydro test?

According to SAES-A-004, paragraph 7.1.5, a minimum of two pressure gauges should be installed during a hydro test. This requirement ensures redundancy and accuracy in measuring the pressure during the test. Having two pressure gauges allows for comparison and verification of the pressure readings, enhancing the reliability of the test results.

6. Relief valve calibration period would be

According to SAES-A-004, paragraph 5.5.1, the relief valve calibration period is one week. This means that the relief valves should be calibrated at least once every week to ensure their proper functioning and accurate relief pressure. Regular calibration helps maintain the reliability and effectiveness of the relief valves, ensuring they operate within the specified tolerances and provide the required overpressure protection.

7. What is a PIP?

PIP stands for “Process Industry Practices.” PIP is a collection of standardized practices and guidelines developed by a consortium of engineering, construction, and operating companies in the process industry. These practices cover various aspects of design, engineering, construction, and operation of facilities in industries such as oil and gas, petrochemical, chemical, pharmaceutical, and power generation.

8. Name the different types of Service Conditions?

The different types of service conditions in the context of ASME B31.3 (Process Piping) are as follows:

1. Normal Fluid Service (NFS): This refers to regular operating conditions where the fluid being transported is not corrosive or hazardous, and the temperature and pressure are within normal design limits.
2. Category M: This refers to fluid services involving highly hazardous materials, such as toxic or highly reactive substances. Special precautions and additional design considerations are required for these services.
3. Category D: This refers to fluid services involving substances that can cause damage to equipment or systems due to their corrosive nature. Special attention is given to material selection, corrosion allowances, and protection measures.
4. High-Pressure Fluid Service: This refers to services where the operating pressure exceeds certain thresholds defined by ASME B31.3. Additional design considerations and safety measures are necessary to handle the higher pressures safely.

9. How do you verify (name several items to check) that the correct piping material is used?

To verify that the correct piping material is used, several items can be checked:

1. Material Specification: Ensure that the material specified for the piping system matches the required material for the specific service conditions.
2. Pipe Size and Schedule: Verify that the pipe size and schedule mentioned on the piping components match the design requirements.
3. Length: Check that the actual length of the pipes corresponds to the required dimensions specified in the design.
4. Flange Face Rating: Confirm that the flange face rating, such as raised face or flat face, matches the design specifications.
5. Olet Size Rating: For branch connections like weldolets or sockolets, ensure that the olet size rating matches the design requirements.
6. Threaded/Socket Weld Type: Check whether the piping components require threaded or socket weld connections and verify that the appropriate type is used.
7. Material Test Certificates (MTC): Inspect the MTCs provided by the supplier or manufacturer to verify the material grade, chemical composition, mechanical properties, and compliance with applicable standards.
8. Positive Material Identification (PMI) Report: If PMI testing is conducted, review the PMI report to ensure that the material composition matches the required specifications.

Read Also: Best Resources of Piping QC Notes CBT Aramco.

Piping QC Interview Questions and Answers