OIL & GAS CAREER GUIDANCE : INTERVIEW QUESTIONS & ANSWERS - PART 4
101. What is the need for a glandless piston valves?
These valves are maintenance free valves and they are used in the steam service
102. What is a stress intensity factor?
It is the ratio of the maximum stress intensity to normal stress
103. Why is it important to clean pipes before installation?
Cleaning eliminates pollutants including dust, debris, rust, and oil residues that can have built up during production, storage, or handling. This guarantees unimpeded flow, safeguards delicate components like valves and sensors from harm, and promotes long-term system performance and dependability.
104. What is pigging, and why is it used in piping systems?
Pigging is the technique of putting a "pig" into the pipeline to dean, check, or clear obstructions. It preserves ideal flow conditions, avoids product contamination, and prolongs the service life of the pipeline.
105. How does a pressure relief valve operate?
System pressure exceeding a predetermined level causes a pressure relief valve to open automatically. By means of this regulated fluid discharge, overpressure situations are avoided, hence safeguarding the pipeline and its devices from possible damage or catastrophic collapse.
106. What are the consequences of corrosion in pipelines?
Corrosion slowly destroys pipe material, hence weakening mechanical strength, causing leaks, and causing system failure. It reduces efficiency, raises maintenance expenses, and endangers safety of plant operations.
107. How can proper pipe alignment be ensured during installation?
Correct alignment means precisely locating and fastening pipes to avoid joint stress. This covers employing appropriate tools or supports during assembly to prevent future leaks or mechanical wear, as well as aligning flanges and correctly seating gaskets.
108. What is a hydrostatic test, and what is its purpose?
A hydrostatic test evaluates structural integrity and detects any leaks by filling the pipe system with a liquid usually water and applying pressure. It is a major commissioning verification phase.
109. What is pipe bending, and what are its benefits?
Shaping pipes to particular angles or curves eliminates the need for extra fittings, therefore pipe bending is the result. Fewer possible leak locations, more even flow routes, and better space use follow from this.
110. What factors influence pipe routing decisions in a facility?
Pipe routing takes into account safety and legal requirements, conflict with current structures or equipment, maintenance access, and length minimization for cost and efficiency.
111. How are vibration problems in piping systems managed?
Using appropriate supports, hangers, and vibration dampeners controls vibration. Routing should prevent resonance with operational machinery frequencies; flexibility should be incorporated where required to absorb dynamic forces.
112. What role do gaskets play in a piping system?
Gaskets seal flanged connections, hence stopping fluid leakage. Choosing the appropriate gasket calls for knowledge of the fluid type, pressure, temperature, and chemical compatibility of the gasket material.
113. What factors determine pipe sizing in new system designs?
Required flow rate, fluid velocity, permissible pressure drop, and fluid characteristics all determine pipe sizing. Often, engineers utilize simulation software or size guides to find the best pipe diameter.
114. What are common reasons for pipe failure?
Corrosion, too much mechanical stress, bad installation techniques, material flaws, or operating mistakes can all cause pipe failures. Regular inspections and proactive maintenance help to reduce these hazards.
115. What responsibilities does a piping engineer have during construction projects?
Designing the piping plan, specifying materials, making sure relevant rules and standards are followed, working with other disciplines, and supervising installation and testing operations including hydrostatic tests are all duties of a piping engineer.
116. How do piping codes differ from piping standards?
Pipe codes offer legally enforceable guidelines for the safe design, manufacture, and testing of pipe systems. On the other hand, plumbing standards specify technical specifications for materials, parts, or processes to guarantee uniformity and quality throughout the sector.
117. How is piping system efficiency assessed?
Efficiency is defined as how well a piping system moves fluid with least energy loss and pressure drop. Important signs are hydraulic performance, thermal insulation, flow capacity, and the general running cost of the system.
118. What is the purpose of piping engineering?
Piping engineering involves designing and implementing piping systems to safely and efficiently transport fluids or gases within a facility. It ensures the integrity, reliability, and cost-effectiveness of these systems.
119. What are the common materials used in piping systems?
Common materials include carbon steel, stainless steel, copper, PVC, and HDPE. The choice depends on factors like fluid type, pressure, temperature, and environmental conditions.
120. Explain the difference between a pipe and a tube.
A pipe is measured by its nominal inside diameter and wall thickness (schedule), while a tube is measured by its actual outside diameter and wall thickness.
121. What is a P&ID?
A Piping and Instrumentation Diagram (P&ID) is a detailed graphical representation of a piping system, showing all piping, equipment, valves, and instrumentation.
122. What is a piping isometric drawing?
An isometric drawing represents a three-dimensional view of the piping system on a two-dimensional plane, showing the exact lengths and orientation of pipes and fittings.
123. Describe the function of a pressure relief valve.
A pressure relief valve protects the piping system from overpressure by releasing excess pressure when it reaches a preset limit.
124. What factors influence the selection of pipe size?
Factors include the flow rate, fluid properties, pressure drop, velocity, and economic considerations.
125. What is a flange?
A flange is a method of connecting pipes, valves, pumps, and other equipment to form a piping system. It provides easy assembly and disassembly.
126. What is the significance of pipe schedule?
Pipe schedule indicates the wall thickness of the pipe. Higher schedules mean thicker walls, which can handle higher pressures.
127. Explain the term “corrosion allowance.”
Corrosion allowance is the extra thickness added to the pipe wall to compensate for the expected material loss due to corrosion over the pipe’s service life.
128. What is the purpose of a gasket in a piping system?
A gasket creates a seal between flanges to prevent leaks in the piping system.
129. What are the different types of pipe fittings?
Common fittings include elbows, tees, reducers, couplings, and flanges. Each type serves a specific purpose in directing and connecting pipes.
130. What is a valve’s Cv value?
Cv (flow coefficient) indicates the flow rate through a valve for a given pressure drop, reflecting the valve’s capacity to pass fluid.
131. Explain the difference between a ball valve and a gate valve.
A ball valve uses a spherical ball to control flow, providing quick on/off control, while a gate valve uses a gate to start or stop flow, offering a tighter seal.
132. What is NPSH in pump terminology?
NPSH (Net Positive Suction Head) is the difference between the pump suction pressure and the vapor pressure of the fluid, ensuring proper pump operation without cavitation.
133. Describe the term “water hammer.”
Water hammer is a pressure surge caused by the sudden change in flow velocity, often due to rapid valve closure or pump shutdown.
134. What is a pigging operation in pipelines?
Pigging involves sending a device (pig) through the pipeline to clean, inspect, or maintain the interior surface.
135. Explain the importance of stress analysis in piping design.
Stress analysis ensures that the piping system can withstand thermal expansion, pressure, and external loads without failure.