Response to Natural Gas Fires and Emergencies Fire Engineer Scott Sanders

1. Response to Natural Gas Fires and Emergencies Fire Engineer Scott Sanders

2. Natural Gas Fires and Emergencies • Most common gas fuel in US • More than half American homes use natural gas for heating and cooking • Installed in 60% of new homes • Installed in CNG Hybrid Vehicles • Natural Gas • Methane 70-90% • Ethane • Propane • Butane • Carbon Dioxide and Nitrogen

3. Natural Gas Fires and Emergencies • Natural Gas • Primary Hazard is “Flammability” • Non-Toxic • Asphyxiant • Carbon Monoxide: Toxic Product of In-Complete Combustion • Odorization • Mercaptan • 1/10th of 1% air • Identifies gas leak long before dangerous (LEL) • Prolonged exposure may desensitize individuals

4. Natural Gas Fires and Emergencies Characteristics of Common Gas Fuels Gas Vapor Density Ignition Point LEL Natural Gas .55-.65 1,000-1,200F 4% Propane 1.6 842F 2.1% Butane 2.0 550F 1.6% ALL should be considered…. Although NG is most prevalent.

5. Natural Gas Fires and Emergencies • Distribution Systems • May be pressurized as high as 1,000 psi • Williams Pipeline • Atlanta Gas Light / Scana • Similar to municipal water systems • Consist of street mains that branch to service lines that bring gas to individual occupancies • Regulator reduces pressure to ¼ psi

6. Natural Gas Hazards • Air in a Gas Line • Usually occurs after work has been done and air hasn’t been properly bled from line. • Can also enter a gas line as a result of meter tampering. • Results in “Air Slug”

7. Natural Gas Hazards • Combustion Explosion • Gas leak confined to an area • Flammable range • Ignition results in: • Rapid combustion or explosion • Air doubles in volume for every 459F of increase • Air increases pressure inside building 60-110 psi • Most buildings can’t withstand increase of more than 1 psi without failing

8. Natural Gas Hazards • Loss of Odor • Sand/Dirt can “Scrub” odorant out of gas • Results in virtually undetectable gas • Some companies use “Odorless” gas in manufacturing process • Sensitization can result from prolonged exposure to gas and can result in miss-identification by firefighters. • Use Combustible Gas Indicator for NG emergencies

9. Natural Gas Hazards • Regulator Failure • Strong smell of gas • Hissing sound • May lead to over-pressurization of appliances • High Pressure Systems • Vent pipe: Atmospheric Dump • FD Response • Control utilities • Notify Gas Supplier

10. Flammable Gas Fires • Tactics • Protect Exposures • # 1 Consideration after LIFE SAFETY • May compound situation due to lack of resources • Shut off gas before extinguishment • May re-ignite after extinguishment in presence of ignition source • If gas is confined nay result in explosion. • Dissipate Leaking Gases • Ventilate Inside and Disperse Outside • Secure Ignition Sources • Allow Gas to “Vent & Burn” • Safest practice if gas cannot be secured prior to extinguishment

11. Indoor Gas Leaks • Understand your enemy and where he lives!!! • Tactics for Indoor Gas Leaks • Life Safety (Search) • Position Apparatus Safely • Collapse potential • Water Supply? • Determine whether the report of the leak is accurate • When was the leak noticed? • What is involved?

12. Indoor Gas Leaks • Search the Area for Trapped Occupants • Effects of Gas on Occupants • Normal Oxygen Concentration = 21% • Loss of motor coordination = 17% • Faulty judgment and fatigue = 10%-14% • Unconsciousness and death = 6%-10% • Consider SUICIDE in some cases! • Usually from Carbon Monoxide not Natural Gas.

13. Indoor Gas Leaks • Prevent Ignition • Ignition Sources • Hand Light? • Radio? • SCBA Electronics? • Static Electricity? • Building Utilities? • If it is OFF, Leave it OFF! • Ventilate • Natural Ventilation

14. Indoor Gas Leaks • Locating the leak • Use Combustible Gas Indicator; NOT your NOSE!! • 10% LEL (Methane 5%, Propane 2.1%, Butane 1.6%) • Call Gas Company • Always report even if you stopped the leak • Required to re-light pilot lights and repair system

15. Indoor Gas Leaks • Shut-Off Gas • Order of priority: • Appliance Quarter-Turn Shutoff • Meter Quarter-Turn Wingcock • NEVER TURN ON A GAS VALVE, SERVICE OR APPLIANCE AFTER IT HAS BEEN SHUT OFF!!!! NOTIFY GAS COMPANY!!!!

16. Indoor Gas Leaks • Shut Off and Meter

17. Outdoor Gas Leaks • Tactics and Considerations • Determine whether a Gas Leak Exists • Use Meters • Consider Sewer Gas (Hydrogen Sulfide) • Call the Utility Company • Low Pressure – FD can sometimes handle • Beware of Static Hazard of Plastic Pipe • High Pressure – Requires Special Equipment

18. Outdoor Gas Leaks • Determine Scope of Incident • Size of Line • Pressure • Gas Escaping into atmosphere • Gas Escaping into Storm Drains (Buildings) • Other utilities affected • Define Hazard Area and Protect Public • Evacuation or Protection in Place?

19. Summary • The single most important piece of knowledge that ANY First Responder can possess is an understanding of what/where they are responding to. This will allow him/her to act in the safest most prudent manner possible to ensure the safety of his/her crew and the public. The Hazardous Materials Team is always available for consultation and should be used accordingly whenever a crew has questions or concerns, The #1 priority is “Everyone Goes Home!”