SNFO 07 Natural Gas Emergencies.pdf

Southern Nevada Fire Operations STANDARD OPERATING PROCEDURES EMERGENCY OPERATIONS Effective date: Supersedes: 9/29/2010 N/A NATURAL GAS EMERGENCIES SOP# SNFO-07 Page 1 of 4 PURPOSE The purpose of this operating procedure is to establish a standard approach and response to emergencies involving Natu...

Southern Nevada Fire Operations STANDARD OPERATING PROCEDURES EMERGENCY OPERATIONS Effective date: Supersedes: 9/29/2010 N/A NATURAL GAS EMERGENCIES SOP# SNFO-07 Page 1 of 4 PURPOSE The purpose of this operating procedure is to establish a standard approach and response to emergencies involving Natural Gas and to enhance the safety of the public and Fire Department personnel. PROCEDURE Fire Department units may encounter natural gas in a variety of situations and incident types, each presenting a different set of hazards and problems. The following guidelines present an approach which will be applicable in the majority of situations. Use good judgment and experience in dealing with any particular incident. Properties of Natural Gas: Composed primarily of methane: CH4 Lighter than Air (Vapor Density =.60 / Air = 1.0) (Molecular Weight = 18 / Air = 29) Colorless Highly Flammable: Flashpoint = 1200°F Flammable Range (4 - 14%) Can travel great distances to an ignition source Natural gas is much lighter than air and will usually dissipate rapidly in the outside environment. Inside buildings, however, it tends to pocket, particularly in attics and dead air spaces. Natural gas itself is non-toxic; however, it displaces oxygen and can result in asphyxiation if in a confined space. Burning natural gas should not normally be extinguished, since this would change the situation from a known to an unknown hazard with explosive potential. Fires should be controlled by stopping the flow of gas. Southern Nevada Fire Operations STANDARD OPERATING PROCEDURES EMERGENCY OPERATIONS Effective date: Supersedes: A. 9/29/2010 N/A NATURAL GAS EMERGENCIES SOP# SNFO-07 Page 2 of 4 PERSONNEL SAFETY 1. Full PPE will be required for all responses to potential gas leaks. 2. A ‘Hot Zone’ shall be established and maintained around any suspected gas leak and fire line tape should be used to identify the ‘Hot Zone’ when necessary. 3. All non-essential personnel should be outside of this zone. B. INCIDENTS INVOLVING A REPORTED GAS LEAK - NO FIRE OR EXPLOSION Calls for "odor of gas," "gas leak," "broken gas line" and similar situations may range from minor to potentially major incidents. All of these should be approached as potentially dangerous situations. Apparatus placement should be upwind of any potential vapor cloud. Company Officers should call for a Gas company representative early in the emergency. Fire Companies shall determine whether a leak exists (as much as it can be done safely). Gas company personnel shall be responsible for locating and eliminating leak sources. **At no time should FD personnel attempt to control a leak from a broken or ruptured line. Fire Department units shall take whatever actions are necessary to provide for life safety, (including their own safety). 1. Evacuate any civilians in the area of escaping gas, (based upon the size of the leak, and weather conditions). The 2008 NAERG general guideline is 330’ in all directions. 2. Secure all known Gas shutoff valves before attempting to locate the source of the gas and any other shutoff devices. If you can safely access a shutoff valve, use it to stop the flow of gas. 3. Gas leak situations within a building where the source of the leak is unknown or uncontrolled, the gas supply shall be shut off at the meter. (Possible leak could be indicated by a spinning dial on the meter.) Command shall ensure the meter is redtagged and locked off until repairs are completed. This is most easily accomplished with the cooperation of the gas company representative. 4. If there is any indication of gas accumulating within a building, control ignition sources. Do not shut off electrical power from an outside breaker until cleared to do so by the Gas Company. Ventilate from the exterior using PPV. Personnel shall ensure that blowers/fans are not placed in an explosive environment. Southern Nevada Fire Operations STANDARD OPERATING PROCEDURES EMERGENCY OPERATIONS Effective date: Supersedes: 9/29/2010 N/A NATURAL GAS EMERGENCIES SOP# SNFO-07 Page 3 of 4 5. If gas company personnel must excavate to shut off a leak, provide stand-by protection with a charged 1-3/4 inch line and two firefighters in full protective equipment and SCBA. Occasionally Gas company personnel may want you to wet down the area to control static sparks. Again, communication and cooperation are key to the successful mitigation of these events. 6. In the event that there is equipment, (tractors, compressors, or other spark generating equipment) operating in the immediate area, leave it running. C. INCIDENTS AT WHICH AN EXPLOSION HAS OCCURRED Units arriving at the scene of a structural explosion must consider natural gas as a possible cause. Underground leaks may travel considerable distance and can enter a structure around pipes or through void spaces. In these circumstances, the cause of the explosion may be difficult to determine. 1. Initial efforts should be directed at isolating the area and determining the cause of the explosion. (Don’t discount the possibility of intentionally placed explosive devices, and be wary of secondary devices). Until it can be determined that the area is safe from the danger of further explosions, evacuate all civilians and keep the number of Fire Department and/or other emergency personnel (i.e., Gas company personnel) in the area, to the minimum number necessary to stabilize the situation. Take a pessimistic point of view. 2. Do not rely on gas odor. Use combustible gas indicators to check all suspected areas. Both gas company personnel and the Technical Rescue Team (T.R.T.) have combustible gas indicators for this purpose.(LEL Readings) 3. Check areas systematically using combustible gas indicators. Start outside of the area of the explosion, and move into the area until readings indicate detectable concentration. Map the readings for the affected area. 4. If a gas concentration is encountered inside, adjacent to, or underneath any building, secure all possible sources of ignition in the affected area. The power company can be requested to secure the electricity from a remote location outside the affected area to avoid arcing. The LEL must be eliminated before shutting off any electrical breakers to the individual home. 5. Where gas is found inside buildings, ventilate from the exterior using PPV. Personnel shall ensure that blowers/fans are not placed in an explosive environment. Southern Nevada Fire Operations STANDARD OPERATING PROCEDURES EMERGENCY OPERATIONS Effective date: Supersedes: 9/29/2010 N/A NATURAL GAS EMERGENCIES SOP# SNFO-07 Page 4 of 4 6. Under Fire Conditions, the breaker to the individual home should only be shut off (prior to Gas Company arrival) when personnel entering the structure could be endanger by not securing the power. 7. Command shall provide for effective interaction between gas company personnel and the Fire Department. Gas company personnel are responsible for locating and eliminating leaks in the gas system. As industry specialists, they can provide Command with valuable assistance in the effective handling of these incidents. In most cases, a Company Officer with a portable radio will be required to liaison and otherwise supervise during on-site operations. 8. Command must ensure the safety and stability of the structure. If entry is required and further collapse is possible, a Technical Rescue Team should be called to provide shoring, cribbing or other means of stabilizing the structure after the natural gas hazard has been eliminated.