1. LNG Hazards

2. LNG Hazards – Introduction
Liquefied Natural Gas
Facilitates transportation and storage of natural gas
600:1 vapor to liquid ratio
Natural gas is refrigerated to cryogenic temperatures to liquefy it
Liquefaction and vaporization facilities
Natural gas in it’s vaporous form requires large volumes for storage. Liquefying it reduces the volume by a factor of approximately 600 to 1 making it much easier to store and transport over long distances. The liquefaction process involves refrigerating natural gas using natural materials such as ethane and propane as refrigerants. At atmospheric pressure natural gas must be chilled to approximately -260 degrees F to convert it to a liquid form. Once liquefied it is typically stored in low pressure (less than 15 PSI) storage tanks. LNG facilities may consist of a liquefaction plant, a vaporization and distribution plant, or a combination of the two.

3. LNG Hazards – LNG Properties
Mostly methane with small amounts of propane, ethane and other materials
Very flammable
Flammability range of 5% to 15%
Cryogenic at ~ -260 ºF
Near atmospheric pressure in most cases
Heavier than air below ~ 170 ºF

4. LNG Hazards – Types of Facilities
Liquefaction
At source of fuel
Converts natural gas to LNG
Base Load
Main receiving point for large shipments of LNG
Vaporization facility
Peak Shaving
Liquefies natural gas during off season, stores it and vaporizes it during high demand periods
Liquefaction and vaporization processes

5. LNG Hazards – Types of Facilities
Distribution
Relatively small operation
Receives shipments of LNG
Normally by tanker truck
May supply remote town or specific facility
Vehicle Fueling
Similar to Distribution facility but for refueling vehicles only

6. LNG Hazards – Typical Hazards
Storage Tank Diked Areas
Typically earthen banks
Containment in case of tank leak or rupture
Very large areas
Storage Tank Relief Valves
Located on top of storage tanks
Fire hazard due to lightning strikes
Manual fire fighting not practical
Need LNG storage tank diked area picture

7. LNG Hazards – Typical Hazards
Pump Skids and/or Areas
May be inside storage tank dike
May be in pit outside of dike
Potential for large fire due to LNG flow rates
Vaporizers
Many different type
Direct fired
Remote heat source
Ambient air
Water bath

8. LNG Hazards – Typical Hazards
Loading / Unloading Hazards
Truck loading/unloading
Loading arms for transfer from ship at marine terminals
General Plant Areas
Process piping
Pipe racks
Typical plant hazards
Need LNG truck loading rack area picture

9. LNG Hazards – Typical Hazards
Enclosed Areas
Computer rooms
Control rooms
Buildings enclosing equipment

10. LNG Hazards – Protection Objectives
Dikes to Control LNG Flow
Collection Pits in Safe Location
Natural Gas Vapor Control
Flame Extinguishment
Heat Flux Control
Separation
Between Hazards
Between Hazards and Facilities

11. LNG Hazards – Detection Methods
Flammable Gas
Flame
Heat
Spot detectors
Linear detectors
Video
Need Gas Detector Slide

12. LNG Hazards – Agents Sprinkler Building sprinkler systems
Equipment / piping heat protection
Cooling of equipment/piping
Will not extinguish natural gas fires
Vapor control
Prevent downwind drift
Warm vapors

13. LNG Hazards – Agents Water Fog / Spray Vapor control Heat control
Warms vapors to prevent downwind travel
Heat control
Used to control heat flux
Protect fire fighters and/or exposures to a fire

14. LNG Hazards – Agents High Expansion Foam
Typically used for diked areas
Required containment
Vapor control
Natural gas vapor forms chimneys that warms vapor
Fire control
Natural gas vapor forms chimneys that reduces flame size

15. LNG Hazards – Agents Dry Chemical Extinguishes natural gas fires
Portables & hose-lines
General plant protection
High capacity monitors
Specific hazards
Fixed nozzle systems
Automatic actuation

16. LNG Hazards – Agents Clean Agents Indoor total flood systems only
Computer rooms
Control rooms
Hazardous enclosures
Normally occupied areas