LINE BREAKING & PIPELINE OPENING PERMIT: COMPLETE SAFETY GUIDE
Why This Guide Matters
Line breaking is one of the most hazardous maintenance activities in the chemical, pharmaceutical, and petrochemical industries. Workers face critical risks: chemical burns, toxic gas exposure, explosions, pressurized releases, and environmental contamination.
This guide covers: Permit systems, hazard identification, isolation procedures, gas testing, PPE selection, emergency response, regulations, and real accident case studies.
📋 QUICK TABLE OF CONTENTS
- Introduction to Line Breaking
- Hazards Associated with Line Breaking
- Types of Pipelines & Systems
- Permit to Work (PTW) System
- Pre-Line Breaking Planning
- Isolation Procedures
- Draining, Depressurizing & Purging
- Gas Testing & Monitoring
- Personal Protective Equipment (PPE)
- Barricading & Area Control
- Line Breaking Execution Procedure
- Special Conditions & High-Risk Scenarios
- Emergency Preparedness
- Environmental Protection
- Post Line Breaking Activities
- Documentation & Records
- Roles & Responsibilities
- Training & Competency
- Common Mistakes in Line Breaking
- Accident Case Studies & Learning
✅ PRE-LINE BREAKING SAFETY CHECKLIST
- ☐ Correct line identified (P&ID + physical verification)
- ☐ Chemical MSDS reviewed by all workers
- ☐ Hazard assessment (JSA/JHA) completed
- ☐ Line Breaking Permit approved
- ☐ All isolations installed (mechanical, electrical, pneumatic)
- ☐ Line drained completely
- ☐ Line depressurized and vented
- ☐ Gas testing completed (O₂, LEL, Toxic gas)
- ☐ Continuous gas monitoring ready
- ☐ All PPE available and inspected
- ☐ Barricades installed and signs posted
- ☐ Emergency equipment ready
- ☐ Emergency procedures briefed
- ☐ All workers acknowledged understanding
⚠️ DO NOT START IF ANY ITEM UNCHECKED
1. Introduction to Line Breaking
What is Line Breaking?
Line breaking is the activity of opening, cutting, disconnecting, or removing any pipeline, hose, flange, valve, or equipment that previously contained hazardous material such as chemicals, solvents, acids, alkalis, hydrocarbons, steam, or gases.
Definition & Scope
It includes maintenance, modification, tie-ins, decommissioning, leak repair, and equipment replacement where stored energy, pressure, temperature, or toxic material may be released. It applies to process lines, utility lines, reactors, storage tanks, and transfer systems.
Why Line Breaking is High Risk
Sudden release of toxic, flammable, or corrosive substances
Trapped pressure or vacuum inside lines
Residual chemicals even after draining
Fire, explosion, and flashback risk
Chemical burns, inhalation hazards, and suffocation
Environmental contamination
Industries Where Line Breaking is Common
Chemical manufacturing plants
Pharmaceutical formulation and API plants
Petrochemical refineries and polymer units
Bulk drug, solvent recovery, and distillation units
Oil & gas processing facilities
Legal & Statutory Requirements (India – General)
Factories Act, 1948 & State Factory Rules
Manufacture, Storage and Import of Hazardous Chemicals (MSIHC) Rules
Petroleum Rules and Gas Cylinder Rules (where applicable)
OISD guidelines (for petroleum sector)
OSHA-type safe work practices (globally followed)
Mandatory Permit to Work (PTW) system
Compliance with HAZOP, HIRA, and SOPs
- Worker exposed to acid vapor due to unflushed line
- Fire caused by opening a solvent line with trapped flammable residue
- Toxic gas release from improperly isolated reactor outlet
- Hot steam line opened without depressurizing
- Explosion due to static discharge during hydrocarbon line opening
These incidents usually occur due to poor isolation, lack of purging, no gas testing, absence of PPE, and failure to follow permit systems.
2. Hazards Associated with Line Breaking
Chemical Hazards
Residual chemicals may remain inside pipelines even after draining. These can be toxic, flammable, reactive, or corrosive, causing serious injury on contact or inhalation.
Toxic Gas Release
Sudden release of gases like ammonia, chlorine, H₂S, solvent vapors, or process fumes can cause suffocation, lung damage, unconsciousness, or death.
Flammable Vapors
Hydrocarbon vapors, solvents, and alcohols can form explosive mixtures with air. A small spark can cause fire or explosion.
Corrosive Liquids
Acids, alkalis, and strong oxidizers can cause severe skin burns, eye damage, and permanent tissue injury.
High Temperature Fluids
Steam, hot oil, or heated chemicals can cause thermal burns, scalding, and heat stress.
High Pressure Release
Trapped pressure can eject fluid, gas, or metal parts at high speed, causing serious impact injuries and loss of control.
Stored Energy Hazards
Energy stored in pressurized lines, springs, thermal expansion, or vacuum conditions can suddenly release and cause violent movement of parts.
Mechanical Hazards
Falling flanges, swinging pipes, sharp edges, and tool slippage can cause cuts, fractures, crush injuries, and amputations.
Environmental Hazards
Spillage of chemicals can contaminate soil, drains, and water bodies, leading to regulatory violations and long-term damage.
Health Hazards
Long-term exposure can cause respiratory illness, skin diseases, nerve damage, organ toxicity, and occupational cancers depending on the chemical involved.
3. Types of Pipelines & Systems
Process Pipelines
Carry raw materials, intermediates, and finished products between reactors, columns, and storage. They may contain hazardous, hot, pressurized, or reactive chemicals.
Utility Lines (Steam, Air, Nitrogen, Water)
Support plant operations. Steam can cause burns, compressed air can cause impact injuries, nitrogen can cause oxygen deficiency, and water lines may be hot, chilled, or chemically contaminated.
Chemical Transfer Lines
Used for loading, unloading, and transferring acids, solvents, fuels, and toxic liquids. High risk of spills, splashes, and vapor release during line breaking.
Gas Lines
Carry flammable, toxic, or inert gases like hydrogen, LPG, chlorine, or nitrogen. Main risks are fire, explosion, poisoning, and suffocation.
Slurry Lines
Transport solid-liquid mixtures such as catalysts, pigments, or waste sludge. Can cause blockages, sudden pressure release, and abrasive injuries.
Cryogenic Lines
Carry extremely cold liquids like liquid nitrogen or liquid oxygen. Contact can cause frostbite, brittle pipe failure, and oxygen-rich fire risks.
Vacuum Lines
Operate under negative pressure. Opening them suddenly can cause air inrush, dust release, implosion risk, and contamination.
Drain & Vent Lines
Used to remove residual chemicals and gases. Often assumed safe but may still contain toxic, flammable, or corrosive residues, making them high-risk during opening.
4. Permit to Work (PTW) System for Line Breaking
What is a Permit to Work?
A Permit to Work is a formal written authorization that ensures all hazards are identified, risks are controlled, and safety conditions are met before starting line breaking.
Why Special Permit is Required
Line breaking involves direct exposure to hazardous chemicals, pressure, temperature, and stored energy. A normal permit is not enough because this job has higher risk of leaks, fire, toxic release, and injury.
Line Breaking Permit vs Hot Work Permit
Line Breaking Permit: Focuses on chemical isolation, draining, purging, gas testing, and residual hazards.
Hot Work Permit: Focuses on ignition sources like welding, cutting, or grinding.
Line breaking may need both permits if cutting or heating is involved.
Authorization Levels
Multiple approvals are required to ensure technical, operational, and safety checks are complete before work starts.
Roles & Responsibilities
Initiator
Raises the permit request. Provides job details, location, material in line, and required precautions.
Area Owner
Confirms line identity, process status, isolation points, and ensures the area is safe for maintenance.
Maintenance Team
Executes the job. Ensures tools, PPE, blinds, gaskets, and procedures are followed properly.
Safety Officer
Checks hazard controls, PPE, gas test results, MSDS, emergency readiness, and compliance with rules.
Approver
Gives final permission after verifying all safety and technical conditions are met.
Executor
Performs the actual line breaking. Must follow permit conditions, use PPE, and stop work if unsafe conditions arise.
5. Pre-Line Breaking Planning
Job Scope Definition
Clearly define what line will be opened, why it is required, what work will be done, and expected duration. Avoid confusion and wrong-line opening.
Pipeline Identification
Physically verify the correct line using tags, color codes, flow direction, and line numbers to prevent wrong isolation.
P&ID Review
Study piping and instrumentation diagrams to understand flow paths, isolation valves, vents, drains, and connected equipment.
MSDS Review
Check chemical hazards, toxicity, flammability, reactivity, PPE needs, and first-aid measures of the material inside the line.
Chemical Compatibility Check
Ensure gaskets, blinds, hoses, containers, and PPE are compatible with the chemical to avoid corrosion, melting, or reaction.
Risk Assessment (JSA / JHA)
Identify all possible hazards and define control measures such as isolation, purging, gas testing, barricading, and PPE.
Method Statement Preparation
Prepare a step-by-step safe procedure including isolation, draining, flushing, venting, breaking, and restoration.
Tool & Equipment Selection
Use non-sparking tools, proper spanners, blind flanges, drip trays, absorbents, gas detectors, and emergency kits.
Emergency Preparedness Plan
Ensure eyewash, safety shower, spill kits, fire extinguishers, escape routes, emergency contacts, and trained responders are available.
6. Isolation Procedures
Mechanical Isolation
Physical separation of the line from the source by closing valves and disconnecting equipment to stop material flow.
Positive Isolation
A fail-safe method where a solid barrier (blind, spade, or removed spool) is placed to fully block chemical flow. It is the safest form of isolation.
Blinding / Spading
Insertion of a metal blind or spade between flanges to prevent any leakage. Used for high-risk toxic or flammable services.
Double Block & Bleed (DBB)
Two isolation valves are closed and the space between them is vented or drained. This confirms no pressure or material is trapped.
Lockout Tagout (LOTO)
Valves, switches, and energy sources are locked and tagged to prevent accidental opening or energizing during work.
Electrical Isolation
Power supply to pumps, heaters, and motors connected to the line is disconnected to avoid accidental startup.
Instrument Air Isolation
Instrument air is isolated to prevent automatic valve movement or control actions during line breaking.
Steam Isolation
Steam lines are isolated, depressurized, and cooled to avoid burns, scalding, and sudden expansion.
Hydraulic Isolation
Hydraulic pressure is released and isolated to prevent sudden movement of actuators or mechanical parts.
7. Draining, Depressurizing & Purging
Draining Techniques
Remove all liquid contents using low-point drains, sampling points, or temporary hoses. Collect in approved containers to avoid spills and exposure.
Depressurization Methods
Release trapped pressure slowly through vents or bleed valves. Sudden pressure release can cause spray, pipe movement, or injury.
Venting Procedures
Open vent points to allow trapped gases or vapors to escape safely. Vent to a safe location or scrubber system when dealing with toxic or flammable gases.
Purging with Nitrogen / Air
Nitrogen is used to remove oxygen and flammable vapors. Air purging is used only when safe. Proper flow direction and duration must be followed.
Water Flushing
Flush the line with water to remove chemical residues, sediments, or deposits. Required especially for corrosive and toxic services.
Chemical Neutralization
Use suitable neutralizing agents for acids, alkalis, or reactive chemicals before opening the line to reduce hazard.
Verification of Zero Energy
Confirm no pressure, no vacuum, no flow, and no chemical presence using gauges, gas detectors, pH paper, and visual checks before breaking the line.
8. Gas Testing & Monitoring
Importance of Gas Testing
Gas testing ensures the area is safe before and during line breaking. It detects hidden toxic, flammable, or oxygen-deficient atmospheres that cannot be seen or smelled.
Types of Gas Detectors
Portable multi-gas detectors
Single-gas detectors
Fixed gas monitoring systems
Tube-type or manual detectors
Explosive Gas Testing (LEL)
Checks the presence of flammable vapors. Work is allowed only when readings are well below the Lower Explosive Limit (LEL) to prevent fire or explosion.
Toxic Gas Testing
Detects harmful gases like ammonia, chlorine, H₂S, solvent vapors, or other process-specific toxins to prevent poisoning and long-term health damage.
Oxygen Level Testing
Confirms oxygen is within safe range (normally 20.9%). Low oxygen can cause suffocation; high oxygen increases fire risk.
Continuous Gas Monitoring
Required for high-risk jobs. It tracks gas levels in real time and gives alarms if conditions become unsafe during work.
Calibration of Gas Detectors
Detectors must be regularly calibrated using standard gases to ensure accurate readings. Wrong calibration can give false safety assurance.
9. Personal Protective Equipment (PPE)
Basic PPE
Safety helmet, safety shoes, cotton coverall, and industrial gloves. Protects from minor mechanical and impact hazards.
Chemical Resistant PPE
Includes aprons, suits, boots, and gloves made of PVC, neoprene, nitrile, or butyl. Prevents skin contact with hazardous liquids.
Flame Resistant Clothing (FRC)
Protects against flash fires and heat. Used where flammable vapors or hot work is involved.
Respiratory Protection
Half-face or full-face respirators with suitable cartridges to protect from vapors, dust, and fumes. Cartridge must match the chemical type.
SCBA (Self-Contained Breathing Apparatus)
Used in toxic, oxygen-deficient, or unknown atmospheres. Supplies clean air independent of surroundings.
Splash Goggles & Face Shields
Protect eyes and face from chemical splashes, high-pressure sprays, and flying particles.
Chemical Suits
Full-body suits for highly toxic, corrosive, or reactive chemicals. Prevents skin absorption and contamination.
Gloves Selection Guide
Nitrile: solvents, oils
Neoprene: acids, alkalis
Butyl: ketones, esters
PVC: general chemicals
Latex: light-duty only
Wrong glove selection can cause chemical penetration and burns.
10. Barricading & Area Control
Danger Zone Identification
Mark the area where chemical release, splashing, pressure discharge, or toxic vapors may spread. Include downwind and low-lying zones.
Barricading Methods
Use hard barricades, chains, caution tapes, cones, or temporary fencing to physically block unauthorized entry.
Warning Signage
Display clear signs like “Line Breaking in Progress”, “Toxic Hazard”, “No Entry”, and “PPE Mandatory” in local language and English.
Access Control
Allow entry only to authorized persons with valid permits and proper PPE. Keep a log if required.
Permit Display
The approved permit must be displayed at the job site for easy reference and verification.
Communication to Nearby Units
Inform nearby operators and control room about the activity to prevent accidental startup, valve operation, or ignition sources.
11. Line Breaking Execution Procedure
Tool Inspection
Check spanners, torque wrenches, non-sparking tools, and cutting tools for defects. Damaged tools can slip and cause injuries or sparks.
Bolt Loosening Sequence
Loosen bolts diagonally and gradually. First open bolts in which prevents sudden release of trapped pressure or liquid splash to working person.
Controlled Opening Technique
Open the flange or joint slowly. Create a small gap first to check for any pressure, vapor, or liquid before fully opening.
Splash Prevention
Stand to the side, not in front of the joint. Use splash guards, plastic sheets, or shields to protect workers.
Use of Drip Trays
Place drip trays below the joint to collect residual liquid and avoid floor contamination and slip hazards.
Temporary Blind Installation
Install blinds or spades immediately after opening to prevent backflow or accidental release.
Leak Control Measures
Keep absorbents, neutralizing agents, clamps, and emergency kits ready to control any unexpected leaks.
Safe Dismantling
Support heavy pipes, valves, and flanges properly. Use lifting tools if needed to prevent falling and crush injuries.
12. Special Conditions & High-Risk Scenarios
Line Breaking on Live Lines
Opening lines that still contain product, pressure, or energy is extremely dangerous. It can cause sudden release, fire, poisoning, or explosion. This must be avoided unless specially approved with full controls.
Acid Lines
Risk of severe chemical burns, toxic fumes, and corrosion. Even small splashes can cause permanent injury. Proper neutralization, flushing, and acid-resistant PPE are mandatory.
Alkali Lines
Strong alkalis can cause deep skin damage and eye blindness. Residual material can remain stuck to pipe walls. Thorough flushing and compatible PPE are required.
Flammable Hydrocarbon Lines
Release of vapors can form explosive clouds. Static, sparks, or hot surfaces can ignite them. Gas testing, grounding, and ignition control are critical.
Toxic Gas Lines
Gases like chlorine, ammonia, or H₂S can cause rapid unconsciousness or death. SCBA, continuous gas monitoring, and emergency rescue plans are essential.
Cryogenic Lines
Extremely low temperatures can cause frostbite and brittle pipe failure. Sudden expansion can crack metal. Special insulated gloves and face protection are required.
High Pressure Lines
Sudden release can cause jetting, flying debris, and impact injuries. Pressure must be fully released and verified before opening.
Vacuum Lines
Sudden air entry can cause implosion, dust release, or inward collapse of components. Controlled venting is necessary before breaking.
13. Emergency Preparedness
Emergency Scenarios
Possible emergencies include chemical splashes, toxic gas release, fire, explosion, sudden pressure discharge, and worker collapse.
Chemical Splash Response
Immediately flush the affected area with clean water for at least 15 minutes. Remove contaminated clothing and seek medical help.
Gas Leak Response
Stop work instantly, move upwind, activate alarm, evacuate the area, and inform control room. Use SCBA for any rescue attempt.
Fire Emergency
Raise alarm, isolate ignition sources if safe, use suitable fire extinguisher, and evacuate. Do not attempt firefighting without training.
Medical Emergency
Provide first aid, call emergency response team, and shift the victim to medical center without delay.
Evacuation Procedure
Follow marked escape routes, assemble at the muster point, and do headcount. Do not re-enter until clearance is given.
Emergency Equipment
Spill kits, fire extinguishers, absorbents, neutralizing agents, SCBA, stretchers, and first-aid boxes must be readily available.
Eye Wash & Safety Shower
Must be located near the job site. Used immediately after chemical exposure to prevent serious eye and skin damage.
14. Environmental Protection
Spill Control
Use drip trays, absorbent pads, spill kits, and bunding to contain leaks. Clean spills immediately to prevent spreading.
Drain Protection
Cover nearby drains with drain covers or mats to stop chemicals from entering the sewer or stormwater system.
Effluent Handling
Collect flushed water and residues in designated tanks or containers. Send only to approved effluent treatment systems.
Waste Disposal
Dispose chemical residues, sludge, and contaminated materials as per hazardous waste rules through authorized agencies.
Contaminated PPE Disposal
Used gloves, suits, wipes, and absorbents must be treated as hazardous waste and disposed in labeled containers.
Soil & Water Protection
Prevent any chemical contact with open ground or water bodies. Use secondary containment and immediate cleanup to avoid long-term contamination.
15. Post Line Breaking Activities
Line Blanking Confirmation
Verify that blinds, spades, or isolation devices are correctly installed and secured to prevent any backflow or accidental release.
Cleaning & Housekeeping
Remove all chemical residues, spills, and waste from the area. A clean site reduces slip, exposure, and fire risks.
Tool Removal
Collect and inspect all tools, temporary hoses, trays, and equipment to ensure nothing is left behind.
Area Restoration
Restore barricades, insulation, cladding, and safety covers. Ensure the area is safe for normal operations.
Permit Closure
Close the permit only after confirming the job is complete, the area is safe, and all controls are in place.
Handover Procedure
Formally hand over the system to operations with clear communication on line status, blanks installed, and any limitations.
Documentation
Record job details, safety observations, incidents, and changes made. These records help in audits, learning, and future planning.
16. Documentation & Records
Line Breaking Permit Format
Standard permit format that includes line details, chemical name, hazards, isolation points, PPE, gas test values, approvals, and validity time.
Isolation Certificate
Confirms that all required isolations (mechanical, electrical, pneumatic, hydraulic) are done correctly and verified before work starts.
Gas Test Records
Documents pre-job and continuous gas monitoring results for oxygen, toxic gases, and flammable vapors. Ensures safe atmospheric conditions.
JSA Forms
Job Safety Analysis records identified hazards, risk levels, and control measures. Acts as a reference for safe execution.
LOTO Register
Tracks all locked and tagged energy sources. Prevents accidental energizing during the job.
Shift Handover Log
Ensures continuity of safety between shifts. Records job status, hazards, isolations, and pending actions.
Incident Reporting
Records any leak, exposure, near miss, or injury. Helps in root cause analysis and prevention of future incidents.
17. Roles & Responsibilities
Operator Responsibilities
Identify the correct line, stop the process, drain and depressurize, apply isolations, provide line history, and support safe handover.
Maintenance Team Responsibilities
Follow approved method, use correct tools and PPE, execute line breaking safely, install blinds, control leaks, and report unsafe conditions.
Safety Officer Role
Verify hazard controls, PPE, gas testing, barricading, and emergency readiness. Stop work if unsafe conditions exist.
Supervisor Role
Coordinate between teams, ensure permit compliance, monitor work progress, and enforce safety rules at site.
Contractor Responsibilities
Follow site rules, permit conditions, PPE requirements, and method statement. Do not deviate without approval.
Permit Issuer Role
Review hazards, confirm isolations, ensure all safety measures are in place, and authorize the job only when conditions are safe.