Prepare for your interview with our expertly curated list of Interview Preparation Topics. Explore critical areas like HSE plans, hydro-jetting, and confined space safety. Gain the knowledge and confidence you need to excel in your next career opportunity.
A scheduled and periodic shutdown (total or partial) of a plant. They stop daily plant operations completely during the duration of turnaround maintenance work and instead the focus shifts to maintenance-related activities, cleaning, inspection, repair, and replace
Shutdown Names
Turn Around (TRA)
Annual Maintenance
General Maintenance
Shutdown
Shutdown Phase (Activities)
Pre-Shutdown
Shutdown
Post-Shutdown
HSE Plan
It is a plan document that a contractor prepares and gives to the client
A way to control and distribute up-to-date documents
Safety Inspection Checklist
Risk Assessments
Emergency Response Plan
Training Programme & Documentation System
Internal Audit Policy & Schedule
List of Laws & Health and Safety Regulations for Compliance
Measurable Performance Metrics
Regular Meetings & Communications Strategy
Regular Management Review
Hydro Jetting (High Water Pressure)
Hydro jetting is a widely-used method or process to remove corrosion, erosion, scaling, fouling, and sludge by high water pressure through a Hydro-Jetting Pump (also used for cold cutting material)
It is a Loss Prevention Technique
Pressure depends upon:
MOC (Material of Construction)
Thickness
Diameter
Length
Impurities
Hydro-jetting Technique also use for cutting Trees
Cold Cutting Material
Turtle Cover All (Waterproof): Used to protect equipment or personnel during cutting.
Hydro-jetting Gun (1200-1300 Bar): Operates at 20,000 PSI (equivalent to 1300 bar) for high-pressure cutting or cleaning.
Hydro-jetting Screen: Provides safety or containment during hydro-jetting.
Yard (Opposite Side): Positioned on the opposite side to prevent failure or damage during operations.
N2S Pressure Testing
Purpose: Applied when only part of a pipeline is affected by corrosion or erosion.
Example: For a 100-meter pipeline, if 40 meters are corroded/eroded and 60 meters are in good condition, only the 40-meter section is replaced, followed by N2S pressure testing.
ITP (Inspection, Temperature, Pressure): Ensures the integrity of the tested section.
ITP of New Equipment (Inspection Testing Plan): Validates new equipment before use.
N2 Pressure Guidelines:
Minimum: 1.5 times the operating pressure.
Maximum: 4 times the operating pressure.
Example: If operating pressure is 100 bar, N2 pressure ranges from 150 bar (min) to 400 bar (max), no higher.
Testing Factors:
MoC (Material of Construction)
Thickness
Length
Diameter
Stay Time (refer to chart)
Gas Testing: Use N2 gas (inert) or fresh air.
Liquid Testing: Use water (known as hydro-testing).
Hydro-Testing (Hydrostatic Testing)
Definition: A method to check the integrity of pressure vessels (e.g., natural gas pipelines, gas cylinders, boilers, storage tanks, fuel tanks).
Objectives:
Verify pressure tightness.
Test structural strength.
Detect leakages.
Procedure: Similar to N2S testing but uses water for liquid-based systems.
Purging
Definition: Process to remove gas from a system, typically before a shutdown.
Purpose: To gas-free a plant.
Key Details:
Kick Line: First inlet to the plant.
Process Time: 1 to 1.5 days.
Responsibility: Handled by the client.
Shutdown Duration: Approximately 35 days.
Hot Bolting
Definition: The practice of removing, replacing, or re-tightening bolts on live piping/equipment.
Timing: Pre-shutdown activity to ensure bolts can be easily opened during shutdown.
Procedure:
Open bolts in a diagonal, star, or hexa pattern.
Remove one bolt at a time.
Clean bolts with WD40 or Molicote.
Mark jammed/rounded bolts for cold cutting.
Use a pneumatic saw for cutting jammed bolts.
Ensure new bolts are available during the process.
Variants:
Hydro Hot Bolting: Specific to hydro systems.
Spanner & Hammering Hot Bolting: Manual method.
Restrictions:
Not allowed if there are 4 bolts or fewer.
Contamination Prevention:
Liquid Lines: Open bolts from the top side.
Gas Lines: Depends on gas density (heavier or lighter than air).
Spading / De-Spading
Definition: Mechanical isolation using a blind plate to block two pipeline flanges.
Procedure: After inserting the blind plate, apply LOTTO (Lock Out Tag Out) for safety and isolation.
Sand Grit Blasting
Definition: A process to remove rust, dust, dirt, scales, and old paint from surfaces using compressed air.
Purpose: Loss prevention technique.
Application: Used for external cleaning.
Materials:
Chemically treated sand is called “grit.”
Limitation: Only used for open vessels.
Painting
Definition: The process applied after sand blasting.
Purpose:
Loss prevention technique.
Enhances equipment quality.
Mechanism: Utilizes electrostatic adhesion for coating.
PWHT (Post Weld Heat Treatment)
Purpose: Enhances weld quality after weld testing.
Context: Typically follows Non-Destructive Testing (NDT) to improve material integrity.
NDT (Non-Destructive Testing) Techniques
Definition: Methods to test material integrity without causing damage.
Examples:
Di-Penetration Test: Qualitative test to detect surface defects.
Radiography: Quantitative test for internal structure analysis.
Scope: Utilizes 38 different techniques for material testing.
Fuel Bowser
Definition: A process or equipment deployed to distribute fresh water in emergencies.
Use Case: Applied when the normal piped water distribution system fails or is insufficient.
Types of Waste Management
Municipal/General Waste (Green):
Examples: Paper, Wood
Hazardous Waste (Yellow):
Examples: Chemical, Pyrophoric materials
Non-Hazardous Waste (Red):
Examples: Metal, Glass
Waste Management Methods
Reduce: Minimize waste generation.
Reuse: Repurpose materials for extended use.
Recycle: Process materials for new use.
Disposal: Safely discard waste that cannot be reduced, reused, or recycled.
Behavioral Audit
Definition: Walking around the workplace or facility to assess the working environment and safety practices.
Purpose: Provides a general appraisal of safety compliance and conditions.
Traffic Management System
Vehicle Rules:
Diesel vehicles: Allowed in the plant.
Petrol vehicles: Not allowed in the plant.
Defensive Driving Training
Speed Limits:
In plant area: 30 km/hour.
In office area: 20 km/hour.
Safe Distance Techniques:
3-Word Gap Technique: Count “1001-1002-1003” to maintain distance from other vehicles.
Distance Rule: Safe distance always depends on speed.
World’s Dangerous Gases
CO (Carbon Monoxide): Misnoted as CO2 in your input; assuming CO based on context (colorless, odorless, toxic gas).
H2S (Hydrogen Sulfide): Highly toxic and flammable gas with a rotten egg smell.
NH3 (Ammonia): Corrosive and toxic gas with a pungent odor.
Detector Types
Heat Detector: Detects increases in temperature indicative of fire or overheating.
Smoke Detector: Identifies smoke as an indicator of fire.
Dust Detector: Monitors dust levels for safety or environmental control.
Infrared Detector: Uses infrared technology to detect heat, motion, or specific gases.
Types of Hazards
Mechanical Hazards: Related to machinery or moving parts.
Physical Hazards: Environmental factors like noise, heat, or vibration.
Biological Hazards: Risks from living organisms (e.g., bacteria, viruses).
Electrical Hazards: Dangers from electrical systems or equipment.
Ergonomic Hazards: Issues from poor posture or repetitive strain.
Radiation Hazards: Exposure to ionizing or non-ionizing radiation.
Pollution Hazards: Risks from environmental contaminants.
Types of Incidents
Near-Miss: An event that could have caused harm but didn’t.
Incident: An unplanned event that may or may not result in injury or damage.
Accident: An incident resulting in injury, damage, or loss.
Accident
Causes of Accident:
Direct Cause:
Unsafe Act: Human actions that compromise safety.
Unsafe Condition: Hazardous physical environments or equipment.
Indirect Cause:
Lack of Knowledge/Skill: Insufficient training or expertise.
Improper Attitude: Negligence or disregard for safety protocols.
Physical or Mental Deficiency: Health-related limitations affecting performance.
Types of Injury
Lost Time Injury (LTI): Injury causing absence from work beyond the day of the incident.
Restricted Work Injury/Case (RWI/C): Injury limiting normal work duties without full absence.
Medical Treatment Injury/Case (MTI/C): Injury requiring medical attention beyond first aid.
Types of Safety Signs
Prohibition: Circle with a red color, indicating actions that are not allowed.
Warning: Triangle with a dark yellow background, alerting to potential hazards.
Mandatory: Blue background, specifying required actions or behaviors.
Safe Condition: Green background, indicating safe areas or conditions.
Fire-Fighting Equipment: Red background, marking locations of fire safety tools.
Forms of Safety Communication
Alarm: Audible or visual alert for immediate attention.
Barrier: Physical obstruction to restrict access or highlight hazards.
Color Coding: Use of colors to convey safety information.
Hand Signal: Gestures for non-verbal communication in noisy environments.
Memos: Written notes for internal safety updates.
Notice: Formal announcements or instructions.
Poster: Visual displays for safety awareness.
Permit to Work: Authorization for specific hazardous tasks.
Safety Sign: Standardized symbols for safety instructions.
Warning Lights: Illuminated signals to indicate danger or status.
Types of Radiation
Ionizing Radiation:
Characteristics: High-energy particles, more harmful to the environment.
Examples: Alpha, Gamma, Beta, X-Rays, Neutron.
Non-Ionizing Radiation:
Characteristics: Low-energy particles, less harmful to the environment.
Examples: Ultraviolet (UV), Infrared, Radio waves, Laser.
H2S (Hydrogen Sulphide)
Two Types of Oil and Gas Industries
Explore: Activities related to discovering oil and gas reserves.
Refining: Processing crude oil and gas into usable products.
H2S (Hydrogen Sulfide) Names
Flammable Gas: Capable of igniting under certain conditions.
Toxic Gas: Harmful to human health upon inhalation.
Killer Gas: Lethal at high concentrations.
Silent Killer: Odorless at dangerous levels, making it hard to detect.
Swab Gas: Associated with oil and gas extraction processes.
H2S Concentration Effects
0.13 PPM: Smells like rotten eggs.
Around 100 PPM: Kills the sense of smell as concentration increases.
100 PPM: Classified as IDLH (Immediately Dangerous to Life and Health).
500-700 PPM: Causes unconsciousness.
1000 PPM: Results in death on the spot.
Properties of H2S
Kills Sense of Smell: Becomes undetectable by odor at high concentrations.
Heavier than Air: Tends to settle in low-lying areas.
Density:
H2S: 34 gm/mole.
Air: 29.32 gm/mole.
H2S is 19% heavier than air (Density = 1.18 gm/cm³).
Solubility: H2S + H2O → H2SO4 (forms sulfuric acid; avoid using water with H2S).
Flammability: Forms a flammable mixture with oxygen, producing sulfur dioxide (SO2).
Blue Flame: Indicates H2S combustion; an unsmooth system shows a blue flame from the chimney.
Areas Prone to H2S Accumulation
Low-lying areas such as basements, pits, shallows, culverts, confined spaces, vessels, pipelines, tunnels, and columns due to its heavier-than-air nature.
Flammability Limits of H2S
LEL (Lower Explosive Limit) / LFL (Lower Flammable Limit): 4.3 PPM (mixture too lean to burn below this).
UEL (Upper Explosive Limit) / UFL (Upper Flammable Limit): 44-46 PPM (mixture too enriched to burn above this).
Flammability Zone:
Zone 0: Continuously flammable.
Zone 1: May or may not be flammable.
Zone 2: Continuously safe.
Exposure Limits
Definition: Maximum concentration of an airborne substance an employee can be exposed to by inhalation over a period of time.
Types of Exposure Limit Names:
OEL: Occupational Exposure Limit.
WEL: Workplace Exposure Limit.
WEEL: Workplace Environment Exposure Limit.
REL: Recommended Exposure Limit.
TLV: Threshold Limit Value.
ILV: Indicative Limit Value.
LTEL: Long-Term Exposure Limit.
PEL: Permissible Exposure Limit.
STEL: Short-Term Exposure Limit.
STEL Details:
Ceiling limit for maintenance workers: 15 PPM for 15 minutes.
If exceeded, workers must leave the area.
Emergency Procedures for H2S Exposure
Rescue: Emergency rescue team or BA (Breathing Apparatus) personnel intervene.
Emergency Escape Hood:
Pressure: 315 bar (prevents toxic gas entry).
Duration: 15 minutes of breathable air (fiber gas).
Evacuation: Move perpendicular to wind direction toward the nearest assembly point.
H2S Detection Systems
1. Plant Fixed Gas Monitor:
Features: Equipped with flashing lights and alarms.
Purpose: Continuous monitoring within the plant.
2. Portable Gas Monitor:
Location: Placed at the center of the workplace.
Range: Detects H2S within a 15-meter radius.
3. H2S Personal Toxic Clip:
Features: Beeps, flashes lights, and vibrates to alert the wearer.
Bump Test: Press the blue button for auto-calibration before use.
Certification: All detectors must be certified by a third party.
Types of Emergency
Plant Emergency: Affects the entire facility.
Personal Emergency: Affects an individual worker.
Emergency Procedure
Applies to Both Types of Emergency:
Stop the Work: Cease all activities immediately.
Manage Your Equipment: Secure tools and materials.
Check Wind Direction (Using Wind Sock):
Upwind: Direction from which the air is coming.
Downwind: Direction the air is moving toward.
Use Emergency Escape Hood:
Pressure: 315 bar (prevents toxic gas entry).
Duration: 15 minutes of breathable air (fiber gas).
Evacuate: Move perpendicular to the wind direction toward the nearest assembly point.
Assembly Point Names
Assembly Point: General gathering location.
Safe Point: Designated safe area.
Master Point: Central coordination point.
Marching Point: Staging area for further movement.
Head Count: Conducted to account for all personnel, followed by waiting for further instructions.
H2S Zone Classification
Green Zone: Less than 50 PPM (low risk).
Yellow Zone: Less than 100 PPM (moderate risk).
Amber Zone: Less than 1000 PPM (high risk; hood must always be carried).
Red Zone: 1000 PPM and above (extreme risk; hood must always be carried).
Zone Management:
Marking: Clearly indicates the zone.
Hard Barricade: Physical barriers to restrict access.
Attendant: Present to monitor and check every entrant in the zone.
