Risk Engineering Energy Forum
Crude Oil Tank Fires:
The Fundamentals
January 12, 2018
Ken Donaghey
Introduction to Tank Fire Protection
Objective:
Provide basic knowledge of:
• Fire Protection Concepts
• Passive & Active
• Risk Reduction Through Design
• Types of Tank Fires
• Tank Fire Protection Systems
• Response Options to Major Incident
NFPA 550 Fire Safety Concept Tree
Managing Fire Risks
Risk Reduction Measures
• Eliminate or Reduce Known Hazards (Design & Practice)
• Choose Inherently Safer Design (Floater vs Cone Roof)
• Process Safety & Control Systems (Detection & Isolation)
• Solid Operations & Maintenance Programs
• Pre-Emergency Planning
• Fire Protection Features
Introduction to Tank Fire Protection
• Tank Design – Cone, Floater, Weather Dome, etc
• Tank Monitoring – Level Gauging to avoid overfills
• Tank Spacing and Concentration
• Intermediate Tank Diking
• Equipment Location, Pumps and Manifolds located outside
primary dike area.
• Isolation and Emergency Shutdown
• Grounding & Bonding (Lightening Protection)
• Pre Fire/Emergency Plans
• Allowance for Fire Fighting Access
Passive Protection for Tank Farms
Active Fire Protection includes the following concepts or
systems:
Fire Detection
• Thermal – Primarily Property Protection intent
• Linear Detection – Thermistor or Optical (Rim Seal)
• Spectrum – UV IR or combination detection (IR CCTV)
• Fusible Plugs or Sprinklers
• Early Detection – Life Safety/High Value Electrical
• Smoke Detection Ionization/Photoelectric
• High Sensitivity Smoke Detection
• Open Path/Liner Optical (Laser/IR)
Active Tank Fire Protection
Gas Detection
• Provides early warning
• Not Common in tank farms with the exception around
pumps
Suppression Systems – Water based
• Deluge systems ( Pumps & Exposure Protection)
• Foam system
• Fix Monitors
• Hydrants
Active Tank Fire Protection
The group or class of water based suppression systems rely on
several key fundamentals, these are:
• Water Hydraulics – Head & Friction Loss Calculations
• Agents – Additives (Foam Concentrates) – Dry Chem
• Density – Delivery of water in gpm (lpm) per sq ft (m2)
• Design area
• Rim Seal
• Full Surface (Not Common for large tanks)
• Dike Area/Equipment
The factors above influence system capacity or volume delivery
Suppression Options
Tank Fires – Causes & Sources
(A study of storage tank accidents, Journal of Loss Prevention in the Process Industries 19 (2006) 51–59)
Tank Design / Types
Types of tanks commonly used to store liquids include:
1. Fixed-roof tanks
2. External floating rood tanks
3. Internal floating roof tanks
4. Domed external floating roof tanks
5. Horizontal tanks
6. Pressure tanks
7. Variable vapor space tanks
8. LNG (Liquefied Natural Gas) tanks
External Floater
Floating Roof Tanks
Internal Floater
Floating Roof Tanks
Geodesic Domes
Floating Roof Tanks
Typical Floating Roof Fire Scenarios
Floating Roof Fires
Tank Fires Escalation Paths
Fire Initiator
Rim Seal
Fire
Roof Spill
Fire
Sunken
Roof
Dike
Fire
Full Surface Fire (single tank)
Boilover Full Surface Fire (multi tank)
Escalation
Escalation
Crude tank potential fire event types:
Risks of Full Surface Fires
Escalation of a Full Surface Fire
Escalation of a Full Surface Fire
Escalation of a Full Surface Fire
Tank Boilover
Nicaragua, 2016
Boilover Fire Escalation
California, 1924
Nonintervention:
• High Risk – Low Value – Ensure Safety of Public and
Personnel and let fire burn out
Defensive:
• May except loss of a tank or product, but take actions to
prevent or limit escalation or addition loss, i.e. Pump out
product, Protect Exposures, etc.
Offensive:
• Aggressive intervention to control and extinguish fire
Fire Protection / Fire Fighting Strategies
Depending on tank type, there are typically several options
for providing tank fire protection. This presentation will focus
on Floating Roof Tanks as they are the most common and
recommended tank type for Crude Storage.
Options:
• No Protection (rely solely on passive – not generally recommended)
• Type II Systems
• Semi-Fixed (requires support of Foam Apparatus)
• Fixed – Manual or Automatic (automatic is not common)
• Combination Rim Seal – Full Surface System (not common)
Tank Fire Protection - Options
Introduction to Tank Fire Protection
Foam Engine Supported Pump Solution via Hose Connection
Semi-Fixed
Rim Seal Systems - Fixed
Foam Tests of Rim Seal Systems
Rim Seal Systems - Fixed
System design must:
• Have Sufficient Volume & Pressure
• Be capable of Rim and Full Surface
Application
• Must Consider Foam “spread” limits
Rim Seal & Full Surface (External Floaters)
Monitors Fix Spray Systems
Exposure Protection
Over the Top – Full Surface Fires
Big Guns
Large Capacity – Foam Pumpers
Water Supply
• 300 ft tank = 11,300 GPM (0.16 GPM/ft2)
• Often Requires 1,000’s of feet of Large
Diameter Hose 5” or Larger (12” is
becoming common)
• Supplemental Fire Pumps
Full Surface Fires - Logistics
Foam Supply
• Over the Foam Application Rate 0.16 x 65 minutes
• 113 GPM of 1% = ~8,000 gallons of concentrate
• 340 gpm of 3% = ~22,000 gallons of concentrate
Proportioning
• Foam Pumpers
• Jet Ratio Controllers
• Self Educting Nozzles
Full Surface Fires - Logistics
Drainage / Runoff
• Can prevent access to fire
• Can carry hydrocarbon liquids into
undesirable locations
Full Surface Fires - Logistics
Buncefield UK - 12/11/2005 - Product Terminal
Large Tank Losses
Nicaragua 2016
• Fire Started in a Crude Oil
Tank
• Escalated from Rim Seal to
Full Surface Fire
• Tank Suffered Multiple
Boilovers
• Exposed Naptha Tank
failed on day two
Recent Large Tank Losses
1. Design Options
• Greenfield vs Brownfield Options
• Water Supply Options
• Select Safer Technologies /Design
2. Protection Options
• Passive Only
• Fixed – Semi Fixed
• Rim Seal, Full Surface – Combination
3. Emergency Planning
• Strategies & Tactics
• Available Equipment
• Mutual Aid or Specialist Contractor - Services
Summary – Crude Oil Tank Fires
NFPA 11,20,600
API 650, 653, 2030, 2350, 2510
Lastfire
Journal of Loss Prevention in the Process Industries
Energy Institute – Code Of Safe Practice 19
Williams Hazard Control
References & Sources
Historical Note – Early Tank Protection
BONUS QUESTION
What piece of motorized Fire Apparatus cannot
proceed down a one way street the wrong way???
Fire Protection 101