Bernalillo County Fire & Rescue Natural Gas Emergencies PDF

**Brian Rose, Deputy Chief Greg Perez, Fire Chief** Purpose: This procedure identifies operational tactics for safe handling of natural gas pipeline emergencies. Scope: The scope of this guideline will be to describe best practice tactics and situational awareness issues for consideration for na...

**Brian Rose, Deputy Chief Greg Perez, Fire Chief** Purpose: This procedure identifies operational tactics for safe handling of natural gas pipeline emergencies. Scope: The scope of this guideline will be to describe best practice tactics and situational awareness issues for consideration for natural gas emergencies, including gas leak, ruptured gas line without fire, ruptured gas line with fire, and post explosion gas leak. Definitions: General Information: **Natural Gas -- Fire Diamond** - Health -- 2 - Flammability -- 4 - Instability -- 0 - Special - None **Natural Gas Physical Properties:** - Colorless, tasteless, odorless gas (unless an odor causing agent has been added) - Natural gas is predominately methane - Natural gas is a Class 2 Flammable gas - Ignition Temperature - 1163º F - Flash point - minus180 Celsius - Molecular weight 16.04 (air is 28.97) - Natural gas is much lighter than air and will dissipate rapidly outside - Inside of buildings and any other contained vessels, natural gas tends to pocket, particularly in attics, under stairs, and in dead air spaces - The flammable limits are 5 percent to 15 percent in air (remember that your meter is reading the percentage of the lower explosive limit not the actual percentage of the product in air) **Natural gas physical and health effect on humans** - - **Emergency Response Guidebook 2020** - The material is listed as "natural gas, compressed" in the blue pages - Directs the user to guide \#115 page 166-167 - Chemical ID number: 1971 Specific procedures: Calls for \"odor of gas,\" \"gas leaks,\" \"broken gas lines,\" and similar situations may range from minor to potentially disastrous incidents. Due to possible extreme consequences, these types of incidents must be approached with the upmost caution. **Reported Gas Leak** Use the ERG as a basic guide for natural gas leaks. When responding to a reported gas leak with no fire or explosion, the first arriving unit should: - First arriving unit will stop at least two houses away or 333 ft. (100 meters) from the dispatched address, upwind whenever possible - All later arriving units shall maintain Level-1 staging a minimum of 800 feet away from the address/area of the leak, upwind whenever possible - Only a minimum number of personnel shall be allowed to size-up the situation - All personnel must be in full PPE and crew must be equipped with a 4-gas monitor capable of detecting NG LEL - Personnel are metering for the percentage of LEL and the possible displacement of Oxygen in confined areas and dead spaces within and around the structure - In the Cold Zone, start monitoring the environment when approaching the leak area - Shut off all vehicles (ignition sources) in the Warm Zone - Personnel in the Warm Zone must be in full PPE with SCBA on with their face piece ready to don. When metering for natural gas, any positive LEL readings indicate that NG is present. Units shall: - Immediately go from the Offensive strategy (investigating) to the Defensive strategy - Ensure the local NG provider is responding - Evacuate any civilian and firefighting personnel from the structure a minimum of at least 2 houses away or 333 ft. -- 100 meters from the last LEL reading - Upon evacuation, if easily accessible, isolate and shut-off the gas meter to the occupancy - Single family home; evacuate at least the 2 homes around all sides of house (or 333 ft. -- 100 meters) - Multi family, mixed use and commercial occupancies; the entire building should be evacuated initially with consideration for additional evacuation of the exposures depending on their distance and arrangement around the source (using the 100-meter evacuation guideline) - The larger the occupancy, the larger the potential energy there is to release - Await the local utility company for control/mitigation Ruptured gas lines that are exposed to open air =============================================== - Immediately assume the Defensive strategy - Ensure the local NG provider is responding - Evacuate any civilian and firefighting personnel from the structure a minimum of at least 333 ft away -- 100 meters - NG providers are the AHJ for NG incidents. They have all the necessary personnel and equipment to mitigate these types of events. FD personnel at no time should try to mitigate/control the leak - Fire department members will remain outside of the Hot Zone and will only provide warm and Cold Zone support to the NG provide Fire department shall not provide "protection lines" for NG workers. The greatest threat of NG is an explosion. A hand line will not put out an explosion and only exposes more people to the threat Underground, migrating NG leaks =============================== - The foundation - Around pipes - Storm drains and sumps - Other void spaces - Ensure the local NG provider is responding - Evacuation distances for these types of incidents could be much further than the standard 333 ft. (100 meters) - While evacuating, continue to meter the exterior of structures to determine the overall scope of the incident (size of the Hot Zone) - Do not rely on gas odor, the odorant in the gas may be scrubbed out by passage through the ground - Continued metering will be performed by the NG provider to determine the proper evacuation distances and what control measures will be taken to stabilize. **General considerations** - - - Anytime a gas meter is secured (turned off) the local NG provider must be notified, dispatched to the scene, and command transferred over to them. - - Natural gas leaks with ignition (free burning) ============================================== - Evacuate any occupants to minimum safe distances - Protect exposures - Continue to monitor the area for any natural gas reading/concentrations to define the Hot Zone - Await the local utility company for final control/mitigation NG Explosion has occurred ========================= - Notify the gas and electric companies and request an immediate response - The number of exposed personnel shall be kept to an absolute minimum. All apparatus must spot at least two houses away or 333 ft. away (100 meters) from the explosion area, in the Cold Zone. A SAFETY PERIMETER SHALL BE ESTABLISHED AND MAINTAINED AROUND ANY SUSPECTED GAS LEAK, FIRE, OR EXPLOSION - Conduct a recon and search for possible victims outside of the explosion zone. Interview neighbors or witnesses to try to determine if the building(s) was occupied. Victims can be found a long distance from the origin of the explosion - Observe for signs of gas leaks, i.e., flames coming through cracks in the ground or around foundations, or bubbling through puddles - Do not extinguish flames coming up through the ground - Check systematically using combustible gas meters, following the "Reported gas Leak - NO visible ignition" metering guidelines - Any metering readings of LEL - all personnel must be evacuated a minimum of 333 ft. -- 100 meters from the last zero reading on the meter - Evacuate all exposed structures. Do not enter the structure after it has been evacuated. The NG provider will meter the interior all the exposures during their size-up - Always beware of the possibility of additional explosions - Shut off the gas in other exposed buildings if easily accessible and it's safe to do so (you're out of the Hot Zone) **Decontamination** Decontamination is not required for natural gas only issues. References: B Shifter Blue Card Hazardous Materials Natural Gas SOG.