🏗️ PROJECT & SITE MANAGEMENT
2️⃣6️⃣ How do you manage contractors at site?
Answer:
Clear scope definition, daily monitoring, safety enforcement, quality checks, and regular communication ensure effective contractor management.
2️⃣7️⃣ What is RA bill certification?
Answer:
Running Account bills are verified based on actual work completed. Engineers certify quantity, quality, and compliance before payment approval.
2️⃣8️⃣ What is material reconciliation?
Answer:
Material reconciliation ensures issued materials match consumed quantities. It helps control cost, avoid wastage, and maintain inventory accuracy.
2️⃣9️⃣ What is constructability?
Answer:
Constructability focuses on ease of construction during design. It reduces rework, improves safety, and saves time and cost.
3️⃣0️⃣ How do you handle site delays?
Answer:
Identify root causes, replan activities, optimize resources, and coordinate with stakeholders to minimize impact and recover schedule.
🔍 COMMISSIONING & TROUBLESHOOTING
3️⃣1️⃣ What is pre-commissioning?
Answer:
Pre-commissioning includes cleaning, flushing, alignment, testing, and checks before equipment startup. It ensures readiness and safe commissioning.
3️⃣2️⃣ What is commissioning?
Answer:
Commissioning is the process of starting equipment and systems to confirm they operate as designed under actual conditions.
3️⃣3️⃣ What is root cause analysis?
Answer:
RCA identifies underlying causes of failures rather than symptoms. It prevents recurrence and improves system reliability.
3️⃣4️⃣ What is predictive maintenance?
Answer:
Predictive maintenance uses condition monitoring tools like vibration and thermography to predict failures before they occur.
3️⃣5️⃣ Why documentation is important?
Answer:
Documentation supports maintenance history, audits, troubleshooting, and future modifications. It ensures continuity and compliance.
🎯 FINAL INTERVIEW QUESTIONS
3️⃣6️⃣ How do you ensure safety during shutdown?
Answer:
Proper planning, permits, isolation, supervision, and communication ensure safe shutdown execution.
3️⃣7️⃣ What is mechanical clearance?
Answer:
Mechanical clearance certifies that equipment is ready for operation after installation or maintenance.
3️⃣8️⃣ What is free issue material?
Answer:
Free Issue Material is supplied by the client to contractors for execution. Proper control prevents misuse.
3️⃣9️⃣ What is lifting plan?
Answer:
A lifting plan defines crane selection, load weight, rigging method, and safety measures for heavy lifts.
4️⃣0️⃣ What causes mechanical failures?
Answer:
Poor design, improper installation, overload, lack of maintenance, and human error are common causes.
4️⃣1️⃣ What is torque tightening?
Answer:
Torque tightening ensures bolts are tightened to specified torque to avoid leakage or failure.
4️⃣2️⃣ What is alignment tolerance?
Answer:
Alignment tolerance defines acceptable deviation limits. Staying within limits ensures smooth operation.
4️⃣3️⃣ What is flange management?
Answer:
Flange management ensures correct gasket, bolt tightening, and leak-free joints.
4️⃣4️⃣ What is hot alignment?
Answer:
Hot alignment accounts for thermal expansion during operation to maintain proper alignment.
4️⃣5️⃣ What is shutdown modification?
Answer:
Shutdown modification includes design changes executed during shutdown to improve performance or safety.
4️⃣6️⃣ How do you handle emergency breakdowns?
Answer:
Ensure safety first, isolate equipment, diagnose quickly, and restore operation with proper documentation.
4️⃣7️⃣ What is spare management?
Answer:
Spare management ensures critical spares are available to avoid long downtime.
4️⃣8️⃣ What is maintenance KPI?
Answer:
KPIs measure maintenance performance like downtime, MTBF, and schedule adherence.
4️⃣9️⃣ What motivates you as a mechanical engineer?
Answer:
Solving real problems, improving reliability, and contributing to safe operations motivate continuous learning.
5️⃣0️⃣ Why should we hire you?
Answer:
I bring hands-on plant experience, strong safety focus, teamwork, and problem-solving skills aligned with industrial requirements.
🔧 MECHANICAL ENGINEERING – INTERVIEW Q&A (50–80)
5️⃣0️⃣ What is shaft alignment and why is it important?
Answer:
Shaft alignment ensures that the centerlines of connected rotating machines like motor and pump are aligned within permissible limits. Proper alignment reduces vibration, bearing failure, seal leakage, and power loss. Poor alignment increases maintenance cost and shortens equipment life.
5️⃣1️⃣ What is dynamic balancing?
Answer:
Dynamic balancing corrects unbalanced rotating components while they are rotating. It prevents excessive vibration, noise, and mechanical stress. Proper balancing improves equipment reliability and smooth operation, especially for high-speed machinery.
5️⃣2️⃣ What is NDT and why is it used?
Answer:
Non-Destructive Testing (NDT) checks material or weld quality without damaging components. Methods include UT, RT, MPI, and DPI. NDT ensures structural integrity, safety, and compliance with codes in construction and maintenance.
5️⃣3️⃣ Difference between UT and RT?
Answer:
Ultrasonic Testing (UT) uses sound waves to detect internal defects, while Radiographic Testing (RT) uses X-rays or gamma rays. UT is safer and faster, while RT provides permanent records but requires radiation safety controls.
5️⃣4️⃣ What is cold cutting and where is it used?
Answer:
Cold cutting is pipe or metal cutting without sparks or heat. It is used in hazardous areas to avoid fire or explosion risks. It improves safety during modification and maintenance work.
5️⃣5️⃣ What is flange leak and common causes?
Answer:
Flange leaks occur due to improper gasket selection, uneven bolt tightening, wrong torque, misalignment, or damaged gasket faces. Proper flange management prevents leakage and safety incidents.
5️⃣6️⃣ What is gasket and its function?
Answer:
A gasket is a sealing material placed between flanges to prevent leakage of fluids or gases. Selection depends on pressure, temperature, and fluid type. Correct installation ensures leak-free joints.
5️⃣7️⃣ What is torque wrench and why is it used?
Answer:
A torque wrench applies specific torque to bolts as per design requirement. It ensures uniform tightening, prevents over-tightening or under-tightening, and avoids flange leakage or bolt failure.
5️⃣8️⃣ What is pipe flushing?
Answer:
Pipe flushing removes debris, rust, and foreign particles from piping before commissioning. It protects equipment like pumps and valves from damage and ensures clean operation.
5️⃣9️⃣ What is pickling and passivation?
Answer:
Pickling removes oxides and contaminants from stainless steel, while passivation forms a protective oxide layer. These processes improve corrosion resistance and material life.
6️⃣0️⃣ What is expansion joint?
Answer:
An expansion joint absorbs thermal expansion, vibration, and movement in piping systems. It prevents stress buildup and damage to piping and connected equipment.
6️⃣1️⃣ What is mechanical seal?
Answer:
A mechanical seal prevents leakage in rotating equipment like pumps. It consists of rotating and stationary faces. Proper installation and cooling ensure long seal life.
6️⃣2️⃣ Difference between mechanical seal and gland packing?
Answer:
Mechanical seals provide leak-free operation and low maintenance, while gland packing allows controlled leakage and requires frequent adjustment. Mechanical seals are preferred in modern plants.
6️⃣3️⃣ What is bearing failure and its causes?
Answer:
Bearing failure occurs due to poor lubrication, misalignment, overload, contamination, or vibration. Proper lubrication and monitoring prevent premature failure.
6️⃣4️⃣ What is preventive shutdown maintenance?
Answer:
Preventive shutdown maintenance is planned work during shutdown to replace worn parts and inspect equipment. It improves reliability and reduces unexpected breakdowns.
6️⃣5️⃣ What is turnaround maintenance?
Answer:
Turnaround is a major planned shutdown involving inspection, overhaul, and modification of plant equipment. It requires extensive planning, manpower, and safety control.
6️⃣6️⃣ What is scaffolding and why is it required?
Answer:
Scaffolding provides safe access to elevated work areas. Proper design, inspection, and tagging ensure worker safety during construction and maintenance.
6️⃣7️⃣ What is rigging?
Answer:
Rigging involves lifting and moving heavy equipment using cranes, slings, and shackles. Proper rigging plans and trained personnel prevent accidents.
6️⃣8️⃣ What is lifting capacity and SWL?
Answer:
SWL (Safe Working Load) is the maximum load equipment can handle safely. Exceeding SWL can cause failure and accidents. Always verify load calculations.
6️⃣9️⃣ What is mechanical integrity?
Answer:
Mechanical integrity ensures equipment is designed, installed, and maintained to operate safely. It includes inspections, testing, and documentation.
7️⃣0️⃣ What is preventive vs predictive maintenance?
Answer:
Preventive maintenance is time-based, while predictive maintenance uses condition monitoring tools to predict failures. Predictive maintenance reduces downtime and cost.
7️⃣1️⃣ What is critical equipment?
Answer:
Critical equipment directly affects plant safety or production. Failure leads to major downtime or hazards. Such equipment needs special monitoring and spare planning.
7️⃣2️⃣ What is spare part criticality?
Answer:
Spare criticality identifies essential spares required to minimize downtime. Proper classification ensures availability during emergencies.
7️⃣3️⃣ What is hot bolting?
Answer:
Hot bolting replaces flange bolts while the system is pressurized. It requires special procedures and safety controls to prevent leakage.
7️⃣4️⃣ What is equipment derating?
Answer:
Derating reduces equipment operating limits due to aging or design limitations. It ensures safe operation but may reduce capacity.
7️⃣5️⃣ What is punch list?
Answer:
A punch list contains incomplete or defective items identified during inspection. All items must be cleared before final handover.
7️⃣6️⃣ What is mechanical completion?
Answer:
Mechanical completion certifies that installation work is completed as per drawings and ready for commissioning.
7️⃣7️⃣ What is line clearance?
Answer:
Line clearance confirms piping is cleaned, tested, and safe for operation before introducing process fluid.
7️⃣8️⃣ What is job close-out?
Answer:
Job close-out includes documentation, lessons learned, and final approval. It ensures proper handover and future reference.
7️⃣9️⃣ What is equipment nameplate data?
Answer:
Nameplate data provides design limits like pressure, temperature, speed, and power. Operating beyond limits can cause failure.
8️⃣0️⃣ How do you handle emergency maintenance?
Answer:
Ensure safety first, isolate equipment, assess risk, execute repair with proper permits, and document actions for future prevention.