IOCL Non Executive 2026 Exam Important Questions

FIRE & SAFETY – QUESTION ANSWERS

Fire & Safety Basics

Q1. What is a siren?
A siren is an emergency indicating system used to alert people during abnormal or dangerous situations.

Q2. What is the siren duration for a major fire?
The siren duration for a major fire is 5 minutes.

Q3. What is the siren pattern for a big disaster?
A big disaster siren lasts for 8 minutes with a one-minute gap.

Q4. What is a clear or normal siren?
A clear siren is a continuous straight siren of 2 minutes duration.

Emergency Numbers

Q5. What is the emergency number for fire?
101 or 4377

Q6. What is the emergency number for first aid?
102 or 2222

Q7. What is the emergency number for police?
100 or 3333

Q8. What is the emergency number for ambulance?
108

Chemical Hazards

Q9. What are hazardous chemicals?
Hazardous chemicals include HCl, H₂SO₄, Acetic Acid, Ammonia, and Caustic Soda.

Q10. What are hazardous gases?
Hazardous gases include H₂S, CO, CO₂, SO₂, and NH₃.

Fire Basics

Q11. What is fire?
Fire is a continuous chemical reaction that produces heat and light.

Q12. Fire is which type of reaction?
Fire is an oxidation reaction.

Q13. What is the fire triangle?
Fire triangle consists of three elements: Oxygen, Fuel, and Heat.

Classification of Fire

Q14. What is Class A fire?
Class A fire involves solid materials such as wood, paper, cloth, and building materials.

Q15. What is Class B fire?
Class B fire involves flammable liquids such as oil and petrol.

Q16. What is Class C fire?
Class C fire involves flammable gases and energized electrical equipment.

Q17. What is Class D fire?
Class D fire involves combustible metals.

Q18. What is Class E fire?
Class E fire involves electrical equipment.

Q19. What is Class K fire?
Class K fire involves cooking oil and kitchen fires.

Fire Extinguishing Methods

Q20. How is Class A fire extinguished?
Class A fire is extinguished using water or sand.

Q21. How is Class B fire extinguished?
Class B fire is extinguished using foam, CO₂, or Dry Chemical Powder (DCP).

Q22. How is Class C fire extinguished?
Class C fire is extinguished using CO₂ or DCP.

Q23. How is Class D fire extinguished?
Class D fire is extinguished using special dry chemical powder.

Foam Fire Fighting

Q24. How much water does foam contain?
Foam contains approximately 97% water.

Q25. What are the types of foam?
AFFF (Aqueous Film Forming Foam) and AR-AFFF (Alcohol Resistant AFFF).

Fire Extinguishers

Q26. What are the types of fire extinguishers?
DCP extinguisher, CO₂ extinguisher, and water type extinguisher.

Q27. What is the PASS technique?
PASS technique means Pull the pin, Aim at the base of fire, Squeeze the lever, and Sweep side to side.

Explosion

Q28. What causes an explosion?
Explosion occurs due to high pressure and temperature.

Q29. What is an unconfined explosion?
An explosion occurring in open space is called unconfined explosion.

Q30. What is a confined explosion?
An explosion occurring in a closed space is called confined explosion.

Q31. What is UVCE?
UVCE stands for Unconfined Vapour Cloud Explosion.

Q32. What is BLEVE?
BLEVE stands for Boiling Liquid Expanding Vapour Explosion.

Fire Fighting Equipment

Q33. What is a fire tender?
Fire tender is a mobile fire fighting vehicle.

Q34. Which pump is used in fire fighting?
Centrifugal pump is used in fire fighting.

Q35. How much does 1 litre of water expand into steam?
1 litre of water expands into 1600 litres of steam.

Q36. How much does 1 litre of CO₂ expand into gas?
1 litre of CO₂ expands into 450 litres of gas.

Personal Protective Equipment (PPE)

Q37. What PPE should be worn?
Helmet, safety shoes, and goggles.

Q38. What PPE should be carried?
Ear muff or ear plug, gloves, and nose mask.

Breathing Apparatus

Q39. What is a breathing apparatus?
Breathing apparatus is used in fire fighting to protect against smoke and toxic gases.

Q40. Which PPE protects which body part?
Helmet – Head
Goggles – Eyes
Gloves – Hands
Shoes – Legs
Ear muff – Ears
Respirator – Respiratory tract
Safety harness – Height work

Area Classification

Q41. What is Zone 0?
Zone 0 is an area with continuous presence of flammable gas.

Q42. What is Zone 1?
Zone 1 is an area where flammable gas is present sometimes.

Q43. What is Zone 2?
Zone 2 is a safe zone.

OISD

Q44. What is OISD?
OISD stands for Oil Industry Safety Directorate.

Q45. What is OISD-STD-105?
OISD-STD-105 relates to work permit.

Q46. What is OISD-STD-116?
OISD-STD-116 relates to fire protection facilities.

Q47. What is OISD-STD-118?
OISD-STD-118 relates to layout for oil and gas installations.

MSDS

Q48. What is MSDS?
MSDS is a Material Safety Data Sheet that contains hazard, health, fire, and environmental information.

Q49. What information does MSDS contain?
Hazard identification, composition, physical and chemical properties, handling and storage, disposal method, PPE details, accidental release measures, and supplier details.

Q50. What does MSDS colour coding indicate?
Red – Fire hazard
Blue – Health hazard
Yellow – Reactivity
White – Special hazard

VALVES – QUESTION ANSWERS

Q51. What is a valve?
A valve is a piping component used to control fluid flow.

Q52. What is the function of a gate valve?
Used for on/off service with low pressure drop.

Q53. What is the use of a globe valve?
Used for throttling service.

Q54. What is the function of a check valve?
Allows flow in one direction only.

Q55. What is the function of a safety valve?
Provides overpressure protection.

COMPRESSOR – QUESTION ANSWERS

Q56. What is a compressor?
A compressor is a mechanical device used to compress gas.

Q57. What are the types of compressors?
Positive displacement (reciprocating, rotary) and dynamic (centrifugal, axial).

Q58. Where is centrifugal compressor used?
Centrifugal compressors are used in refineries.

Q59. What is the function of an after cooler?
It reduces discharge temperature and removes moisture and oil vapour.

CHEMICAL ENGINEERING – QUESTION ANSWERS

Centrifugal Pump

Q60. What is a centrifugal pump?
A centrifugal pump is a device that moves liquid by increasing its energy through centrifugal action.

Q61. What are the types of centrifugal pumps?
Single-stage and multi-stage centrifugal pumps.

Q62. What is cavitation?
Cavitation is the formation of vapor or air bubbles in liquid.

Q63. What is priming?
Priming is the process of removing air from the pump casing by filling it completely with liquid.

Q64. Why is impeller called the heart of a pump?
Because it transfers energy to the liquid and enables pumping.

Heat Exchanger

Q65. What is a heat exchanger?
A heat exchanger transfers heat between a hot fluid and a cold fluid.

Q66. What are the types of heat exchangers?
Shell and tube, plate, spiral, and air-cooled heat exchangers.

Fan

Q67. What is a fan?
A fan is a rotating equipment used to move gas.

Q68. What is the function of an ID fan?
It creates negative pressure and draws flue gases from the furnace.

Q69. What is the function of an FD fan?
It forces air into the furnace for combustion.

Distillation Column

Q70. What is distillation?
Distillation is a separation process based on difference in boiling points.

Q71. What are the main components of a distillation column?
Column, reboiler, condenser, and reflux drum.

Q72. What is reflux?
Reflux is the portion of condensed liquid returned to the column.