IS 107 SAFETY IN CHEMICAL AND PETROCHEMICAL INDUSTRY SBTET AP IS

7.1 FUNDAMENTALS OF CHEMICAL SAFETY

7.1.1 UN Classification of Hazardous Materials

UN system of classification for transport and handling of dangerous goods
Hazard classes based on physical, chemical, and toxic properties
Labels, placards, and identification numbers for hazard communication
Global harmonization and compatibility with GHS (Globally Harmonized System)

7.1.2 Safety in Chemical Industry

Common causes of chemical accidents and preventive strategies
Hazard identification (HAZID) and risk assessment (HAZOP) techniques
Importance of standard operating procedures (SOPs) and permits to work
Handling, storage, and segregation of hazardous chemicals
Chemical compatibility charts and spill management techniques

7.1.3 Criteria for Siting and Layout of Chemical and Petrochemical Plants

Selection of plant location: environmental, safety, and community factors
Minimum safety distances between process units, storage areas, and public zones
Layout principles to minimize accident impact and ensure safe evacuation
Fire and explosion risk zoning, wind direction, and access control
Provision for emergency response centers, assembly points, and firefighting systems

7.1.4 Plant Area Classification

Division of plant into hazardous and non-hazardous zones
Classification based on presence of flammable vapors or gases (Zone 0, 1, 2)
Area classification in accordance with IS/IEC standards
Control of ignition sources, electrical equipment selection, and earthing practices

7.1.5 Instrumentation for Safe Plant Operations

Process control systems for safety: alarms, trips, and interlocks
Pressure relief and shutdown systems
Gas detection, leak detection, and fire alarm systems
Emergency shutdown (ESD) and Safety Integrity Level (SIL) concepts
Instrument calibration and preventive maintenance for reliability

7.2 PROCESS SAFETY AND HAZARD CONTROL

7.2.1 Hazards in Unit Processes and Unit Operations

Chemical reaction hazards: exothermic reactions, runaway reactions, polymerization
Unit operation hazards: distillation, drying, filtration, mixing, storage, and transfer
Equipment failure modes and effects (FMEA)
Thermal and mechanical hazards in reactors, heat exchangers, and compressors

7.2.2 Control, Precautions and Prevention in Specific Chemical Industries

Fertilizer plants: ammonia leaks, fire hazards, toxic gas exposure
Insecticide & pesticide plants: carcinogenic and toxic exposure control
Chlor-alkali industry: chlorine handling, hydrogen explosion prevention
Explosives industry: static electricity control, controlled environment, PPE use
Polymer plants: monomer storage hazards, reaction control
Engineering and administrative controls for minimizing risks

7.2.3 Sampling Techniques for Toxic and Flammable Substances

Safe sampling procedures for liquids, gases, and solids
Use of closed-loop and purged sampling systems
Personal protective equipment and gas monitoring during sampling
Special precautions for toxic, corrosive, or flammable chemicals
Sampling in pharmaceutical and petrochemical plants — contamination prevention

7.3 HANDLING OF EXPLOSIVE AND TOXIC MATERIALS

7.3.1 Precautions in Processes and Operations Involving:

Explosives: control of initiation sources, safe mixing, and storage practices
Flammables: control of vapor release, grounding, and inert gas blanketing
Toxic substances: leak detection, neutralization, and emergency isolation
Dusts and gases: prevention of dust explosions, use of dust collectors and vents
Vapor cloud formations: dispersion modeling and mitigation measures
Combating measures: firefighting techniques for chemical fires, use of foam and dry powder, emergency shutdowns, and evacuation procedures

Here’s the complete section for Unit 7.4 to 7.6 – “Safety in Chemical and Petrochemical Industry”, formatted clearly and professionally in continuation with the previous part:

7.4 STORAGE AND HANDLING OF CHEMICALS

7.4.1 Receiving, Storing and Handling of Chemicals

Procedures for safe receiving and inspection of chemical consignments
Verification of labeling, documentation, and Material Safety Data Sheets (MSDS)
Segregation of incompatible materials during unloading and storage
Storage design: ventilation, temperature control, spill containment, and fire protection
Handling techniques for solids, liquids, and gases (manual and mechanical methods)
Safe storage of flammable, corrosive, oxidizing, and toxic substances
Periodic inspection and maintenance of containers, drums, and storage tanks
Emergency measures for spills, leaks, and accidental releases
Housekeeping, signage, and use of personal protective equipment (PPE) in storage areas

7.4.2 Chemical Compatibility Considerations

Importance of chemical compatibility in storage and transfer
Use of compatibility charts to prevent violent reactions, fires, or explosions
Segregation of acids, bases, oxidizers, reducers, and organic materials
Safe use of storage containers and pipelines made of compatible materials
Monitoring of temperature, pressure, and humidity for reactive substances
Proper labeling and color coding of chemical storage areas
Use of secondary containment and neutralization systems for incompatible leaks

7.5 TRANSPORTATION OF HAZARDOUS MATERIALS

7.5.1 Transportation of Hazardous Material

Legal framework and regulatory requirements (Motor Vehicle Act, IMDG Code, etc.)
Classification, packaging, labeling, and documentation as per UN Recommendations
Responsibilities of consignor, transporter, and consignee
Vehicle design, route planning, and driver training for hazardous transport
Inspection and maintenance of transport containers, valves, and fittings
Emergency response plans and communication systems during transit

7.5.2 Safety Precautions for Transporting Hazardous / Toxic / Flammable / Explosive / Radioactive Substances by All Modes

Road transport: segregation of loads, vehicle placards, driver rest and emergency drills
Rail transport: wagon design, labeling, securement, and loading procedures
Air transport: IATA regulations for dangerous goods, pressure and temperature safety
Sea transport: IMDG Code compliance, segregation, and spill response equipment
Pipeline transport: integrity monitoring, leak detection, and automatic shutoff valves
Radiation shielding, monitoring, and dosimetry for radioactive material transport
Use of GPS tracking, communication protocols, and escort vehicles for high-risk cargo
Emergency preparedness: firefighting appliances, first-aid, and spill containment kits

7.6 TRANSFER OF CHEMICALS BY PIPELINES

7.6.1 Transfer of Chemicals by Pipelines within and Outside Installations (Aboveground, Underground, and Submarine)

Design standards and materials selection for chemical pipelines
Classification of pipelines based on pressure, contents, and location
Layout design — routing, segregation, and accessibility for maintenance
Safety measures for above ground pipelines: supports, identification, leak detection
Precautions for under ground pipelines: corrosion protection, cathodic protection, pressure testing
Submarine pipelines: marine environmental protection, buoyancy control, and coating
Inspection, testing, and preventive maintenance schedules
Monitoring systems — pressure gauges, flow sensors, and alarm systems
Emergency isolation valves and remote shutdown systems
Procedures for safe transfer, draining, purging, and maintenance
Documentation and record keeping as per statutory regulations

7.7 PIPELINE SAFETY AND SAFE WORK PRACTICES

7.7.1 Colour Coding and Identification of Contents

Colour coding ensures quick identification of pipeline contents to prevent accidents.
Follow IS 2379:1990 – Colour Code for Identification of Contents in Pipelines.
Example colour codes:
- Water – Green
- Steam – Silver Grey
- Air – Light Blue
- Acids – Violet
- Alkalis – Dark Green
- Flammable liquids – Brown
- Toxic/Corrosive – Orange
Arrows indicating direction of flow must be marked on pipelines.
Regular inspection and repainting to maintain visibility and accuracy.
Colour coding must also appear on valves, manifolds, and terminal points.

7.7.2 Safety Precautions for Working on Pipelines

Obtain work permit before any maintenance, alteration, or cutting work.
Isolate the section using blinds, spades, or double block and bleed method.
Depressurize, drain, and purge the line before starting work.
Test atmosphere for oxygen and toxic gases prior to hot work or confined space entry.
Use non-sparking tools, flame arresters, and grounding to prevent static discharge.
Continuous monitoring during welding, cutting, or mechanical work.
Clearly display “Men at Work” or “Pipeline Under Maintenance” signage.

7.7.3 Safe Entry Procedures to Confined Spaces Including Reaction Vessels

Confined space examples: reactors, tanks, pits, towers, and large pipelines.
Follow a Confined Space Entry Permit system.
Steps before entry:
- Isolate and clean the vessel thoroughly.
- Test for oxygen (19.5–23.5%), flammable gas (<10% LEL), and toxic vapours (below TLV).
- Provide forced ventilation to remove residual gases.
- Workers must wear full-body harness, lifeline, and breathing apparatus.
- Maintain standby personnel outside for communication and rescue.
- Continuous monitoring and emergency rescue equipment must be available.

7.7.4 Safe Procedure of Startup and Shutdown

Startup:
- Check readiness of equipment, valves, and control systems.
- Gradual pressurization and temperature increase to avoid thermal shock.
- Ensure all safety devices (relief valves, alarms, interlocks) are functional.
- Strict supervision during chemical charging or line pressurization.
Shutdown:
- Stop feed gradually, maintain cooling and venting.
- Depressurize and purge systems with inert gas (e.g., nitrogen).
- Isolate and drain process fluids before maintenance.
Preventive and Emergency Maintenance Safety:
- Use proper tools and PPE.
- Follow lockout–tagout (LOTO) procedures.
- Keep fire-fighting and first-aid equipment ready.
- Never bypass interlocks or safety valves during maintenance.

7.8 USE OF MATERIAL SAFETY DATA SHEETS (MSDS)

7.8.1 Importance and Use

MSDS provides complete hazard information for each chemical used.
It contains 16 standard sections as per GHS (Globally Harmonized System).
Key information includes:
- Chemical identity and manufacturer details
- Hazard classification (flammable, toxic, corrosive, reactive)
- Safe handling and storage instructions
- Exposure limits and PPE requirements
- First aid, firefighting, and spill control measures
- Reactivity and stability data
- Waste disposal and transport information
Workers must be trained to interpret and apply MSDS information before using chemicals.
MSDS must be readily accessible in all work areas where chemicals are used or stored.

7.9 WORK PERMIT SYSTEM AND SPECIAL OPERATIONS

7.9.1 Work Permit System

A Work Permit System (WPS) ensures control over hazardous maintenance or non-routine jobs.
Types of permits include:
- Hot Work Permit – for welding, gas cutting, grinding, etc.
- Cold Work Permit – for mechanical or non-sparking operations.
- Confined Space Entry Permit – for entry into tanks, pits, or reactors.
- Electrical Work Permit – for energized or de-energized systems.
- Height Work Permit – for scaffolding, roofing, or elevated jobs.
Key elements:
- Job description, hazards, and control measures
- Isolation and LOTO verification
- PPE and gas test requirements
- Permit validity time and authorized signatories
- Supervision and closure after job completion

Confined Space

Entry only after gas testing and ventilation.
Lifeline, breathing apparatus, and rescue standby required.
Continuous monitoring of oxygen, flammable and toxic gases.

Hot Work

Area must be cleared of combustibles and gas-free certified.
Use fire watch, fire blankets, and extinguishers nearby.
Grounding to prevent static discharge.

Working at Height

Use full body harness, lifeline, and fall arrest systems.
Proper scaffolding, guardrails, and safe access ladders.
Weather conditions (rain, wind) must be considered.
Tools to be secured with tool lanyards to prevent falling.

7.10 – FIRE AND EXPLOSION SAFETY

7.10.1 Fire and Explosion

Fire and explosion are among the most serious hazards in chemical and petrochemical industries.
These incidents cause major loss of life, property, production, and environment.
Explosion is a sudden release of energy, resulting in a rapid rise in pressure and temperature.

7.10.2 Chemistry of Fire and Classification

Chemistry of Fire:

Fire is a chemical reaction (oxidation) between fuel, oxygen, and heat producing flame, light, and heat.
Represented by the Fire Triangle (Fuel + Heat + Oxygen).
The reaction becomes self-sustaining when enough heat is produced to continue vaporization of the fuel.

Factors Contributing to Fire:

Presence of flammable substances (liquids, gases, vapours, dusts).
Leakage, poor maintenance, static charge, or open flame.
Poor ventilation or confined areas.
Improper electrical connections and overloading.

Classification of Fires (as per IS 2190:2010):

Class	Type of Fire	Examples	Suitable Extinguishing Agent
Class A	Ordinary combustibles	Wood, paper, cloth	Water, foam
Class B	Flammable liquids	Petrol, diesel, oil	Foam, CO₂, DCP
Class C	Flammable gases	LPG, methane	CO₂, DCP
Class D	Metal fires	Sodium, magnesium	Dry powder (special)
Class E	Electrical fires	Cables, motors	CO₂, DCP (non-conductive)
Class F	Cooking oils/fats	Kitchen fires	Wet chemical extinguishers

Common Causes of Industrial Fires:

Electrical faults, short circuits, overloading
Static electricity or friction sparks
Hot work (welding, cutting) near flammable materials
Poor housekeeping and spillages
Leakage from pipelines or storage vessels
Smoking or use of open flames in restricted areas

7.10.3 Fire Load and Building Design for Fire Safety

Determination of Fire Load:

Fire load = Total heat energy (in kcal or MJ) released if all combustibles burn per unit floor area.
Formula:
[
\text{Fire Load (MJ/m²)} = \frac{\text{Weight of combustibles (kg)} × \text{Calorific value (MJ/kg)}}{\text{Floor area (m²)}}
]
Helps determine fire resistance, classification, and required fire-fighting system.

Design for Fire Safety:

Adequate number and width of exits as per National Building Code (NBC Part IV).
Use of fire-resistant materials for walls, doors, and partitions.
Fire escape routes clearly marked and illuminated.
Proper spacing between process areas and storage areas.
Installation of fire walls, fire doors, and emergency lighting systems.

7.10.4 Fire Prevention and Extinguishing Systems

Fire Prevention:

Eliminate ignition sources (spark, heat, flame).
Control flammable vapor concentration below LEL (Lower Explosive Limit).
Maintain equipment and ensure leak-proof systems.
Strict control of smoking, hot work, and static charge.

Types of Fire Extinguishing Systems:

Portable Extinguishers:
- Water, Foam, CO₂, DCP, Wet Chemical types.
- Used for initial fire control (first aid firefighting).
Hydrant System:
- Network of pipes supplying pressurized water through hydrant valves.
- Fire pumps (main, jockey, diesel) maintain pressure.
Sprinkler System:
- Automatic water discharge when temperature rises.
- Used in warehouses, production halls.
CO₂ System:
- For electrical and flammable liquid fires.
- Non-conductive and leaves no residue.
Foam System:
- For oil and chemical fires; smothers the surface preventing oxygen contact.
Dry Chemical Powder (DCP) System:
- Suitable for Class A, B, and C fires.
- Breaks the chemical chain reaction.
Halon Replacement Agents:
- Halon phased out due to ozone depletion.
- Replaced by FM-200, FE-36, Novec 1230 gases.

7.10.5 Fire Detection and Alarm System

Early detection minimizes damage and allows timely evacuation.
Types of detectors:
- Smoke Detectors: Ionization or optical type.
- Heat Detectors: Fixed temperature or rate-of-rise type.
- Flame Detectors: Infrared or ultraviolet sensing.
Alarm systems:
- Audible (sirens, bells), visual (flashing lights).
- Linked to central fire control room.
Automatic fire alarm system integrated with sprinklers and emergency shutdowns (ESD).

7.10.6 Safety Precautions for Handling Flammable Materials

Use inert gas blanketing (nitrogen) for flammable liquids.
Grounding and bonding to prevent static ignition.
Ventilation to prevent accumulation of vapours.
Avoid welding or hot work near flammable storage.
Dust Explosion: Prevent dust accumulation, use explosion vents.
BLEVE (Boiling Liquid Expanding Vapour Explosion):
- Caused by rupture of pressurized vessel containing superheated liquid.
- Prevent by pressure relief valves and proper cooling.
Vapour Cloud Explosion (VCE):
- Occurs when flammable vapour cloud ignites after spreading over a large area.

7.10.7 Fire Emergency Action Plan

Alarm and Communication: Activate fire alarm, inform control room.
Evacuation: Follow emergency escape routes; assembly points pre-identified.
Firefighting: Trained teams with PPE and extinguishers.
Medical Aid: Provide first aid to affected persons.
Deflagration: Slow combustion (subsonic flame speed).
Detonation: Fast combustion with supersonic flame propagation and high pressure wave.

7.11 – FIRE AND EXPLOSION INDEX, PRESSURE VESSEL SAFETY

7.11.1 Fire, Explosion and Toxicity Index

DOW Fire and Explosion Index (F&EI):

Developed by Dow Chemical Company to estimate potential fire/explosion risk.
Based on process materials, operating conditions, and equipment layout.
Steps:
1. Determine Material Factor (MF) (based on chemical flammability/reactivity).
2. Apply Penalty Factors for process hazards.
3. Calculate F&EI = MF × (Penalty Factors).
4. Evaluate Damage Potential and Area of Exposure.
Used for insurance, plant layout design, and risk prioritization.

Toxicity Index:

Indicates potential hazard of chemicals due to toxicity or exposure risk.
Based on IDLH, TLV, and LD₅₀ values.

Dispersion and Probability Analysis:

Models used to predict the spread of toxic or flammable vapours (e.g., ALOHA, PHAST).
Probability analysis helps estimate likelihood of accidents and risk ranking.
Modeling supports emergency planning and zoning decisions.

7.11.2 Pressure Vessels (Fired and Unfired)

Fired vessels: Boilers, heaters – use direct flame for heating.
Unfired vessels: Reactors, separators, air receivers – not exposed to direct flame.
Governed by Static and Mobile Pressure Vessel Rules, 1981 (amended 2000) and ASME Section VIII.
Safety aspects:
- Design pressure ≥ operating pressure + safety margin.
- Fitted with safety valves, pressure gauges, temperature indicators.
- Periodic inspection and hydrotesting as per statutory norms.
- Relief valves tested and calibrated regularly.
- Proper earthing to prevent static discharge.

7.12 – RELIABILITY AND TESTING OF PRESSURE VESSELS

7.12.1 Assessment of Reliability of Vessels

Reliability means the probability that a vessel will perform its function safely during its service life.
Factors influencing reliability:
- Design quality and material selection.
- Fabrication methods and welding quality.
- Corrosion, fatigue, creep, and thermal stresses.
- Inspection frequency and maintenance practices.

Test Checks and Inspections:

Visual Inspection: For cracks, leaks, corrosion, or deformation.
Non-Destructive Testing (NDT):
- Ultrasonic testing (UT) – thickness, defects.
- Radiography (RT) – weld integrity.
- Magnetic particle (MPT) and Dye penetrant (DPT) tests.
- Hydrostatic test – pressure test using water.
- Pneumatic test – for leak detection using air/nitrogen.
Periodic Re validation: As per statutory requirements (Factories Act and SMPV Rules).

7.13 INSPECTION AND MAINTENANCE IN CHEMICAL INDUSTRIES

7.13.1 Inspection Techniques for Plants and Reaction Vessels

Purpose of Inspection:

To ensure safety, reliability, and efficiency of equipment.
To detect corrosion, cracks, wear, leaks, or other deterioration.
To prevent accidents, breakdowns, and environmental releases.

Types of Inspection:

Visual Inspection:
- External and internal examination for corrosion, leakage, or deformation.
- Carried out regularly during maintenance shutdowns.
Non-Destructive Testing (NDT):
- Ultrasonic Testing: Detects internal flaws and thickness of vessels/pipes.
- Radiographic Testing (X-ray/Gamma ray): Checks weld quality and hidden cracks.
- Magnetic Particle Testing: Detects surface/sub-surface cracks in ferrous materials.
- Dye Penetrant Test: Used for detecting surface cracks in non-porous materials.
- Eddy Current Testing: Detects flaws in conductive materials.
Pressure Testing (Hydrostatic/Pneumatic):
- To ensure vessel integrity and leak tightness.
Vibration and Thermography Monitoring:
- For rotating machinery and electrical equipment health assessment.
Corrosion Monitoring:
- By corrosion coupons, probes, and thickness measurement.

Checklist for Routine Inspection

Equipment	Inspection Points
Storage Tanks	Leakage, corrosion, venting, pressure relief valves, earthing connections
Reactors & Vessels	Lining condition, temperature/pressure gauges, agitators, relief devices
Pipelines	Color coding, identification tags, joints, supports, insulation, leakage
Valves & Flanges	Tightness, packing, operation ease, lubrication
Pumps & Compressors	Alignment, vibration, seals, noise, lubrication, motor condition
Instrumentation	Calibration, alarms, interlocks, emergency shutdown systems
Safety Devices	Fire extinguishers, hydrants, safety showers, eyewash stations

Checklist for Specific Maintenance and Breakdown

Isolation and lockout of affected equipment (LOTO procedure).
Purging, cleaning, and gas-free certification before entry.
Confined space entry permit with continuous gas monitoring.
Verification of replacement spares’ quality and compatibility.
Reassembly inspection before recommissioning.
Post-maintenance testing — pressure, leak, vibration, and function tests.
Documentation of maintenance activity and inspection records.
Root cause analysis for repeated failures.

Importance:
Proper inspection and preventive maintenance minimize unplanned shutdowns, improve safety, and ensure compliance with statutory regulations.

7.14 CORROSION AND ITS PREVENTION

7.14.1 Corrosion: Definition and Types

Definition:
Corrosion is the gradual destruction of a material (usually metal) due to chemical or electrochemical reactions with its environment.

Types of Corrosion:

Uniform Corrosion: Even metal loss over entire surface.
Galvanic Corrosion: Occurs between two dissimilar metals in contact with an electrolyte.
Pitting Corrosion: Localized attack forming pits or holes.
Crevice Corrosion: Occurs in confined spaces where stagnant solution is present.
Intergranular Corrosion: Along grain boundaries due to impurities.
Stress Corrosion Cracking (SCC): Cracks caused by tensile stress and corrosive environment.
Erosion Corrosion: Accelerated corrosion due to high fluid velocity.
Microbial Corrosion (MIC): Caused by bacteria or microorganisms.

Corrosion Locations in Chemical Plants

Storage Tanks: At bottom due to water/chemical accumulation.
Pipelines: At bends, joints, and underground sections.
Heat Exchangers: On tube surfaces due to scaling and pitting.
Reaction Vessels: Internal walls due to aggressive media.
Cooling Towers: Due to humid and oxygen-rich environment.

Causes of Corrosion

Presence of moisture, oxygen, and corrosive chemicals (acids, alkalis).
Poor material selection.
Inadequate protective coating or insulation.
Galvanic coupling between dissimilar metals.
Improper design leading to stagnant zones or crevices.
High temperature or pressure accelerating reaction rate.

Inspection Methods for Corrosion

Visual Inspection for rust, pitting, scaling.
Ultrasonic Thickness Measurement.
Radiographic Test for internal corrosion.
Corrosion Coupons/Probes for rate monitoring.
Electrochemical Measurement (Potential readings).

Prevention of Corrosion

Material Selection:
- Use of stainless steel, non-ferrous alloys, or corrosion-resistant materials.
Protective Coatings:
- Painting, galvanizing, epoxy, or rubber lining.
Cathodic Protection:
- Sacrificial anode or impressed current system for buried pipelines and tanks.
Corrosion Inhibitors:
- Chemical additives that slow down corrosion rate.
Design Improvement:
- Avoid crevices, ensure drainage, and allow easy cleaning.
Environmental Control:
- Reduce humidity, temperature, or chemical concentration.
Regular Inspection and Maintenance:
- Early detection and timely repairs prevent major failures.

✅ Summary:

Regular inspection and preventive maintenance ensure equipment safety.
Corrosion is a major cause of plant failure—must be monitored and controlled.
Proper material selection, coatings, and cathodic protection increase equipment life and reduce risk of leaks or explosions.