Chemical safety measures in storage

Chemical safety measures in storage | Safety blog

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Safety aspects

1. Safe Design & maintenance

Safe design and maintenance ensure process safety, industrial safety, plant reliability, chemical handling safety, hazardous area protection, and compliance with global standards, reducing risks of fire, explosion, leakage, and environmental damage while improving plant efficiency and profitability.

1. Design Considerations
Plant design must prioritize process safety, equipment reliability, and regulatory compliance (OSHA, GMP, API standards). Proper layout reduces risk of leaks, fire, explosion, and contamination while improving maintenance access and operational efficiency.

2. MOC (Material of Construction)
Selection of material depends on chemical compatibility, corrosion resistance, temperature, and pressure conditions.

Common MOC: SS316/SS304, Carbon Steel, Alloy Steel, Rubber/Glass-lined reactors
Wrong MOC leads to corrosion, contamination, failure, and safety hazards

3. Thickness (Equipment & Piping)
Thickness must withstand internal pressure, vacuum, corrosion allowance, and mechanical stress.

Designed as per ASME / API codes
Regular thickness monitoring prevents leakage and rupture

4. Piping, Connections, Nozzles, Valves, Coating

Piping & Connections: Leak-proof design, proper routing, avoid dead legs
Nozzles: Correct orientation for safe flow and cleaning
Valves: Isolation, control, non-return valves for process safety
Coating: Anti-corrosion and chemical resistance protection
Improper design causes leaks, pressure loss, and contamination

5. Jacket, Insulation, Cladding, Colour Coding

Jacket: Heating/cooling control for reactions
Insulation: Prevent heat loss/gain, energy saving, personnel protection
Cladding: Protect insulation from weather damage
Colour Coding: Easy identification of pipelines (as per standards like IS/OSHA)
Ensures process control, safety, and easy maintenance

6. Dyke / Bund Requirement

Secondary containment for storage tanks (chemicals, solvents, fuels)
Prevents spread of leaks or spills
Capacity generally 110% of largest tank volume
Critical for fire safety and environmental protection

7. Level, Pressure & Temperature Measuring Devices

Instruments like level transmitters, pressure gauges, RTD/thermocouples
Enable real-time monitoring and control
Essential for process safety, automation, and avoiding overpressure/overheating

8. Safety Systems (Relief & Emergency Handling)

Safety Valves (PSV): Release excess pressure
Rupture Disc: Instant pressure relief in emergencies
Vent Line: Safe discharge of gases
Scrubber: Removes toxic gases before release
Flare System: Burns hazardous gases safely
Prevents explosion, toxic release, and major industrial accidents

9. Type of Pump Requirement
Selection based on fluid properties (viscosity, corrosiveness, flow rate)

Centrifugal Pumps: Low viscosity fluids
Positive Displacement Pumps: High viscosity / precise dosing
Magnetic Drive Pumps: Leak-proof for hazardous chemicals
Wrong selection leads to leakage, failure, and unsafe operation

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2. Identification notice

Purpose of Identification Notice:
Each storage tank or chemical area must have a clear notice board for hazard communication, safety awareness, and regulatory compliance (GHS, OSHA, NFPA). It helps operators and emergency teams understand risks quickly.
Chemical Name & Language:
Display chemical name, common name, and UN number in simple language (English + local language if required). Use GHS symbols for easy hazard identification.
Tank Capacity & Pressure Details:
Mention maximum storage capacity, operating pressure, and design pressure to avoid overfilling and overpressure situations.
Physical & Chemical Properties:
Include key data for safe handling:

Specific Gravity (SpGr): Density vs water
Vapour Density: Behavior of vapours in air
Boiling Point: Liquid to vapor temperature
Flash Point: Ignition temperature
LEL–UEL: Explosive range
TLV: Safe exposure limit

Incompatibility of Materials:
Clearly mention substances that must not mix (e.g., acid vs alkali, oxidizer vs solvent) to prevent dangerous reactions.
Emergency Control Measures:
Provide actions like spill control, fire fighting method, PPE requirement, first aid steps, and emergency contacts for quick response.
NFPA Code & Hazard Rating:
Display NFPA diamond (Health, Flammability, Reactivity, Special hazards) for instant understanding of risk levels.
Safety & Compliance Importance:
Proper identification ensures safe handling, accident prevention, and effective emergency response while meeting global safety standards.

Identification notice

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3. Dyke Or Bund

Purpose of Dyke / Bund: A dyke (bund wall) is a secondary containment system built around storage tanks to confine leaks, spills, or tank rupture, preventing spread of hazardous chemicals and reducing fire and environmental risk.
Capacity Requirement:
Bund capacity should be 100–110% of the largest tank or as per plant standard (many sites use higher safety margins). Ensures full containment during worst-case leakage.
Wall Height & Design:

Typical height: 1–2 meters (optimum ~1 meter for safety access)
Constructed with concrete/earthen walls with chemical-resistant lining
Must be strong enough to withstand liquid pressure and weather conditions

Individual Tank Dyke Concept:
Prefer separate bund for each tank or compatible group of tanks to avoid cross-contamination and fire escalation.
Slope & Collection Pit:
Bund floor should have proper slope towards a collection pit (sump).

Pit collects spilled liquid
Equipped with controlled discharge valve for safe removal

Drainage & Valve Control:

Drain valve must remain normally closed and locked
Open only after checking contamination to avoid environmental pollution

Access & Safety Features:

Provide steps with handrails for safe entry/exit
Non-slip surface for maintenance activities
Ensure easy access for emergency response teams

Fencing & Restricted Entry:

Required for highly flammable/volatile chemicals (petroleum, solvents, fuels)
Prevents unauthorized entry and reduces ignition risk

Safety & Compliance Importance:
Dyke system is critical for spill containment, fire prevention, hazardous area safety, and environmental protection, ensuring compliance with API, OISD, and industrial safety standards.

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4. Separation distance

1. Incompatible Chemicals Separation

Acids vs Alkalis: 3–5 meters or separate rooms
Oxidizers vs Flammable liquids: 5–8 meters
Toxic vs Reactive chemicals: isolated storage
→ Prevents dangerous reactions and toxic gas release

2. Tank to Boundary Wall (Plot Limit)

Small tanks: 15–30 meters
Large hazardous tanks: 30–60 meters
→ Protects outside areas and public safety

3. Tank to Tank (Same Farm)

Minimum: 0.5 × tank diameter (or 10–15 meters typical)
→ Avoids fire spread and allows emergency access

4. Dyke Wall to Tank Distance

Minimum: 1.5–3 meters
→ Provides spill containment and inspection space

5. Chemical Warehouse Storage

Between stacks: 1–2 meters aisle
From wall: 0.5–1 meter
→ Ensures ventilation and safe handling

6. LPG / Gas Cylinder Storage

From buildings: 15–30 meters
Between groups: 3–5 meters
→ Reduces fire and blast impact

7. Road / Access Distance

Tanks from roads: 6–15 meters
→ Keeps safe movement for vehicles and emergency teams

8. Electrical Equipment Distance

Non-flameproof equipment: outside hazardous area
Switchgear rooms: 15–30 meters away
→ Avoids ignition sources

9. Pump House / Transfer Area

From storage: 15–30 meters
→ Controls risk during transfer operations

10. Loading / Unloading Area

From storage: 15–30 meters
→ Minimizes risk during tanker handling

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5. Vent valve/pipe

Importance

Prevents tank rupture, fire, and explosion
Controls hazardous emissions and environmental impact
Ensures safe storage and handling of flammable and volatile chemicals

Function (Why Vent is Required)

Allows air entry during liquid pumping to prevent vacuum and tank collapse
Releases air during tanker filling to avoid pressure build-up
Provides safe outlet for vapours/gases to control internal pressure

Design Aspects (Safe Design Requirements)

Mesh / Demister Pad: Stops dust, insects, and liquid droplets from entering/exiting
Free Air Flow: Ensures smooth venting to avoid pressure or vacuum damage
Proper Diameter: Sized based on chemical properties, tank capacity, and flow rate

Safety Systems (Critical Controls)

Flame Arrester: Required when flash point < 23°C to stop flame entry into tank
Breather Valve (PVRV): Controls pressure and vacuum for flammable liquid storage
Nitrogen Blanketing: Maintains inert atmosphere to reduce fire and oxidation risk

Loss & Emission Control

Vent Cooler / Condenser: Reduces evaporation loss of costly chemicals
Scrubber System: Treats toxic or corrosive fumes before release to atmosphere

Monitoring & Protection

Pressure Indicator: Prevents overpressure or vacuum failure
Temperature Indicator: Detects abnormal heat conditions
Level Indicator: Prevents overfilling and sudden vapour release

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6. Overflow line design

Importance

Prevents tank overflow, fire, and environmental damage
Controls hazardous chemical release
Ensures safe and reliable plant operation

Overflow line safely removes excess chemical from tank to prevent overfilling, spill, pressure rise, and accident.

Design Requirements

Larger Size than Inlet: Ensures rapid discharge without restriction
Proper Slope: Continuous downward slope to avoid stagnation
Dedicated Line: No mixing with other chemicals
Outlet Clearance: 2–3 inches above ground for free flow
Corrosion Resistant Material: Selected as per chemical compatibility
Minimum Bends: Reduces blockage and pressure drop
Proper Supports: Avoids vibration and line failure

Safety & Protection

Scrubber / Neutralizing System: For toxic, corrosive, fuming chemicals
Flame Arrestor (if flammable): Prevents fire travel through line
Non-return Valve (NRV): Stops backflow into tank
Isolation Valve: For maintenance and emergency shutdown
Earthing / Bonding: Prevents static charge in flammable service

Routing & Disposal

Safe Discharge Point: Slop tank / collection pit / neutralization tank
No Direct Open Drain: Avoids environmental contamination
Away from Ignition Sources: Safe routing in plant layout

Instrumentation & Control

Level Indicator & High Level Alarm: Prevents overflow condition
Interlock System: Stops filling when high level reached
Pressure Monitoring (if closed system): Avoids line overpressure

Operational Aspects

Regular Inspection & Cleaning: Prevents choking and corrosion
Leak Proof Joints: Avoids loss and exposure
Clear Identification & Labeling: Easy operation and safety

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7. Tank filling ratio

It is a ratio of weight of material to weight of water that tank can hold.

Tank should not be filled above its filling ratio

Where C = Cubical expansion of liquid

D15 = Density of liquid at 15'CDr = Density of liquid at TmTm = maximum bulk temperatureTf = Filling temperature

8. Flameproof electrical fitting should be used in flammable zone flash point below 23'C

9. Earthing & Bonding

Tank and piping which is containing flammable fluid must have continuous double earthing with earthing monitoring system.

Earthing pit must be recharged periodically
Earthing jumpers must be installed on each flange joint.
When ever tankers loading / unloading in process double earthing must be provided.

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10. Protective media

Chemicals must be protected against non compatible chemicals and conditions

Low boiling point tanks should be underground
Polymerization chemicals must be stored in water spray
Chemicals with high melting point should be stored in hot storage vessels
Sodium metal must store in kerosene
Flammable fluids are stored in nitrogen blanketing

11. Labeling

Labelling is the practice of clearly marking every chemical container, drum, tank, and storage area with correct safety and identity information so that users can identify.

Labelling importance

Prevents wrong chemical use
Avoids mixing of incompatible materials
Reduces fire, explosion, and exposure risks
Supports quick emergency response
Ensures legal and regulatory compliance
Helps in inventory and expiry control

Chemical Label Must Contain

1. Chemical Name: Full name (no short forms or local names), Trade name + scientific name if applicable

2. Hazard Classification: Flammable, Toxic, Corrosive, Oxidizer, Explosive, etc.

3. GHS Pictograms: Standard hazard symbols for quick visual warning

4. Signal Word: Danger (high risk), Warning (moderate risk)

5. Hazard Statements: Short description of risk

Example: Causes skin burns, Highly flammable liquid

6. Precautionary Statements: Basic safe handling and storage instructions

7. Batch Number: Required for traceability (especially in pharma)

8. Manufacturing Date & Expiry Date: Mandatory for stability and safety control

9. Storage Conditions: Temperature, light protection, moisture sensitivity, etc.

10. Handling Instructions: Use in fume hood, avoid sparks, keep container closed, etc.

11. Emergency Information: First-aid summary, Spill or fire response type

12. Supplier Details: Name, address, and emergency contact

Storage Area Labelling

Storage rooms must be labeled by hazard type

Flammable Store
Acid Store
Toxic Material Store
Oxidizer Store

Tanks and pipelines must show:

Chemical name
Flow direction
Hazard color code

Color Coding (Common Practice)

Red → Flammable

Yellow → Reactive / Oxidizer

Blue → Health hazard

White → Corrosive

Green → Non-hazard / Safe material

(Plant-specific codes must be displayed)

Labelling Rules

Labels must be clear, readable, and permanent
No handwritten labels for hazardous chemicals
Damaged or faded labels must be replaced immediately
Secondary containers must also be labeled
No container should remain unlabeled

Emergency Value of Proper Labelling

Helps firefighters choose correct extinguisher
Guides medical team in treatment
Prevents wrong spill response
Saves time during accidents

Segregation of Chemicals in Storage Safety

Segregation of chemicals means storing incompatible chemicals separately so they do not react with each other if leaked, mixed, or exposed accidentally. This prevents fires, explosions, toxic gas release, and product contamination.

Why Segregation is Necessary

Prevents dangerous chemical reactions
Reduces fire and explosion risks
Avoids toxic gas formation
Protects workers and equipment
Supports safe emergency response

Common Dangerous Combinations

Acids + Bases
Oxidizers + Flammables
Water-reactive + Moisture
Cyanides + Acids
Peroxides + Metals
Ammonia + Chlorine

12. Miscellaneous

PPEs and Fire fighting equipments must be used near storage
Safe loading /unloading processes & checklists
Chemical detection system Fire detection system and sprinkler system should be installed in fire prone area
Tanker loading MOC compatibility must be checked