TRAINING BULLETIN EMERGENCIES 2 December 18, 2008 NATURAL GAS EMERGENCIES AND FIRES

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1 TRAINING BULLETIN EMERGENCIES 2 December 18, 2008 Gas emergencies can pose a great risk to FDNY members and the civilians we protect. This bulletin addresses major and minor, indoor and outdoor natural gas incidents. Con Edison and National Grid both deliver gas, above ground electric and below ground electric to customers in the City of New York. Con Edison also delivers steam. Although this training bulletin deals exclusively with gas emergencies, all utilities, along with water and sewer, are intertwined underground and a serious underground incident may involve multiple utilities. 1. GAS UTILITY COMPANIES WITHIN NYC Con Ed provides gas service to all of Manhattan, the Bronx and the following sections of Queens: Astoria, Long Island City, College Point, Whitestone, Malba, Flushing, Fresh Meadows, Glen Oaks, Douglaston, parts of Sunnyside and Woodside, Little Neck, Bellerose, Floral Park, and also Roosevelt Island and Governors Island. National Grid provides gas services to Brooklyn, Staten Island and the parts of Queens not covered by Con Ed. 2. PROPERTIES OF NATURAL GAS Natural gas is comprised mainly of methane but also contains ethane, propane and nitrogen. Colorless Odorless o Mercaptan is added to natural gas giving it a distinctive rotten egg odor Lighter Than Air Explosive Range 5% - 15% Ignition Temperature Degrees Fahrenheit Non-Toxic Asphyxiant 1

2 3. USES OF NATURAL GAS Furnaces and Boilers Hot water heaters Stoves Ovens Dryers Barbecues Vehicles (Compressed Natural Gas) Fireplaces Outside Decorative Lighting Refrigeration Air Conditioners - large commercial units Wall mounted gas heaters (Pictures 1, 1a) Picture 1 Window mounted gas heater Picture 1a Wall mounted gas heater 4. GAS DELIVERY SYSTEM Natural gas is delivered via pipeline to New York City at approximately 700 to 1400 psi. It is regulated down to 300 psi for transmission gas mains and regulated to lower pressures for distribution mains. Distribution gas mains are run under the streets and deliver either high pressure (60 psi), medium pressure (3-15 psi) or low pressure gas (¼ psi). Gas service pipes branch off of these mains to deliver gas from the main to individual customers. High and medium pressure gas is regulated down to ¼ psi before it passes through the customer s meter. 5. GAS PIPE COMPOSITION Transmission mains: Steel High Pressure Mains: Steel, Plastic Medium Pressure Mains: Steel, Plastic or Cast Iron Low Pressure Mains: Steel, Plastic or Cast Iron Gas Service Piping: Steel, Plastic or Copper (plastic and copper gas pipes are not allowed inside structures) 2

3 6. GAS METERS Gas meters can supply individual occupancies or entire buildings. Gas meters supply gas to most customers at ¼ psi. Exception: A few commercial customers receive gas at 1 to 3 psi. Regulators are usually located before the gas meter on high and medium pressure systems to reduce incoming gas pressure to ¼ psi or higher as in the exception above. (Picture 2) Peck Vent - found on high pressure services. If the regulator fails, this safety valve vents excess gas to the exterior of the building. (Pictures 22, 22a) Picture 2 High Pressure Gas Regulator Single master meter - Some multi-occupancy buildings have only a single meter supplying gas to all occupancies. Shutting it down will shut the gas to the entire building. (Picture 7) Some older apartment buildings may have the individual gas meters located in each apartment served, and in some buildings the meters may be found in the public hallway. 7. NATURAL GAS SHUT OFF VALVES Most gas shutoffs are of the ¼ turn variety and can easily be shut off using the fork end of a Halligan tool, (Picture 3) vice grips or pliers to turn the wing cock valve ¼ turn counter clockwise. When the key operating nut is parallel to the piping, it is in the open position. (Picture 4) When it is perpendicular to the piping it is in the closed position. (Picture 5) Picture 3 Halligan tool, vice grips or pliers can be used to shut the ¼ turn gas valve. Picture 4 Gas Valve Open Picture 5 Gas Valve Closed 3

4 Picture 6 Picture 7 Wheel Handle Main Low Pressure Residential Master Meter - Note interior Gas Shutoff Valve riser valves on gas piping above the meter. Do not force the valve, it could break causing a new gas leak at the valve location. When it is necessary to shut a gas valve, if possible shut the valve closest to the leak. In older installations where large amounts of gas are used by a consumer and the piping from the supply main in the street into the consumer s building is 3 or larger, a simple wheel-handled gate valve may be found as the main shutoff valve. (Picture 6) This would be located just inside the building walls where the service enters the building. Depending on the size of the supply pipe and manufacturer, the wheel handle can vary from approximately 3 in diameter to approximately 10 in diameter. o Caution: Members should be aware that these older multiple turn wheel-handle valves resemble water valves, or open stem and yoke valves, in the closed position. Care should be exercised that one is not mistaken for the other. The priority order of valve shutdown is: 1) Appliance Valve - Shut this first when possible. It is usually located behind or alongside the gas appliance and connected by hard piping or flexible metal tubing. You may have to move the appliance to access it. If the valve is damaged, missing, stuck or inaccessible, shut the meter valve. It is a ¼ turn valve. 2) Meter - A building can have multiple meters or a single master meter. A. Meter Valve - There will be a meter valve for each meter. The meter valve will be located just before the meter. It is a ¼ turn valve. Do not force it. If it is not accessible, or is stuck, shut the head of service valve. B. Master Meter - A large building may have many meters, one for each occupancy, or a single master meter for the entire building. (Picture 7) Shutting down a master meter will shut the gas to the entire building. It is a ¼ turn valve. Note: Often there are gas riser valves coming off the master meter. These can be used to isolate a section of the building instead of shutting service to the entire building. These valves are typically found in the basement ceiling. 4

5 When possible, avoid shutting the master meter. It is preferable to shut the gas supply at the appliance valve or at an interior gas riser valve as close to the leak as possible. Before restoring service to a large building or complex, once the gas is shut off, the utility company must access each apartment, shut the gas appliances, pressure test the piping and then relight the pilot lights in each occupancy. If the building is large, it may take several weeks to restore service to the building. This process is not only time consuming and a great inconvenience to occupants, but it is also expensive. If possible, notify the utility company of your intention prior to shutting a master meter and inquire as to possible alternatives. A single master meter may have a second master meter next to it. This second meter is used in case there is a malfunction in the meter in use. The utility company can switch service over to the second meter without disrupting service to the building. Make sure the correct meter is being shut down. If the meter is inaccessible or damaged as a result of a fire, you may have to shut the gas supply to the building at the head of service valve. 3) Head of Service Valve (Building Service Valve) (Picture 8) - It is found just inside the building where the gas service enters. Most of these are ¼ turn valves. If the meter or meters are located outside, it will be before the meter(s). If the service valve is inoperable or inaccessible, then look for the curb valve. Picture 8 Picture 9 Head of Service (Building Service) Valve Old High Pressure Shutoff Note: In some older high pressure gas services (Con Ed System), the main shut-off valve will require approximately 4½ to 5 turns of the operating nut, in a clockwise direction to shut off the gas flow. (Picture 9) 5

6 4. Exterior Gas Riser Valve - Gas riser valves are located on the gas riser outside of the building before any exterior meters. It is a ¼ turn valve. All external meter installations will have a riser valve installed prior to the meter. If a curb valve is found, look for the exterior riser valve. This valve may be present outside, even when meters are installed inside the building. (Picture 10) Exterior Gas Riser Valve Picture 10 Exterior gas riser valve is located on riser before bank of outside meters. Each meter also has its own shut off valve. 5. Gas Shut-off Key - The gas shut-off key consists of a long shaft with a uniquely shaped wrench socket on either side of the shaft. (Pictures 11, 12, 13) The socket is placed onto the curb valve s operating nut. Before using the key, determine which end is suitable for the curb valve operating nut being shut down. Picture 11 Picture 12 6

7 Picture 13 Firefighters close a curb valve using gas shutoff key and a Halligan tool for leverage. 6. Curb Valve - (Picture 14) The curb valve is usually found on the sidewalk side of the curb. It shuts the gas supply to the building. It is usually recessed in from the curb and is covered with a 4 by 4 square or round brittle concrete or steel cover which may be sitting on top of a plastic or wooden plate. It is shut using the gas key found on Department apparatus. To shut the valve, remove or break the cover and plate, insert either the U shape or the square end of the gas key, whichever fits, onto the valve and in most cases, turn the key ¼ turn clockwise. Before shutting the valve, look into the valve box and if the valve is white, close it gently. A white valve means that it is a plastic valve and plastic valve stops are easily broken by excess force. National Grid supplies a white plastic insert for shutting down plastic valves. Con Ed uses the gas key as is to shut plastic valves. A white operating nut indicates a plastic curb valve. Long Service - On the National Grid system, the curb valve is sometimes located across the street from the building it supplies. It may be found in the street. These curb valves are identifiable by an arrow cast into the cover pointing to the building it supplies. These also require a ¼ turn clockwise to close. (Picture 15) Picture 14 Picture 15 Curb Valve National Grid Long Service Curb Valve 7

8 The curb valve may not be visible as it may have been cemented over or covered with grass by contractors or the building owner. Some older curb valves are gated and will require multiple turns to close. If ¼ turn does not shut the gas off, continue to turn the valve until resistance is met. This may occur at between 7½ to 15 full turns. Do not turn the valve more than 15 times. Note: Before turning the key, place chalk or some other mark near the valve to indicate your start point. This will enable you to note when ¼ turn is completed. 7. Street Valve (a.k.a. Line, Main or Isolation valves) - These valves are located on the street side of the curb. They can look like curb valves but they control main gas lines running under the street. These valves are used to isolate large sections of the gas main. On the National Grid system, these valve covers are identified by an ID number stamped on the North side of the cover but these numbers may be obscured. The cover may be round or square and come in a variety of sizes (9 or larger). These valves are usually not present on low pressure gas systems and stopping the flow of gas in a low pressure main will require that street mains be excavated and stoppers installed. This may take several hours. Shutting a single street valve may not stop the flow of gas as distribution piping can be fed from more than one direction. It may be necessary to shut several street valves in order to isolate a section of piping. The utility company must refer to maps to determine which valves to shut. These valves may be located remote from the building to be shut down or from the leak area. Shutting a street valve may disrupt gas service to a large area and to critical locations. Gas service may not be restored to the area for several weeks. Have the utility company shut all valves beyond the curb valve. High pressure mains have isolation valves located in the street that can be shut by the utility company to stop gas flow and isolate sections of piping. CAUTION: Do not operate street valves except under extreme circumstances and only upon direction of the Fire Department Incident Commander after consultation with the utility representative supervisor. 8. NATURAL GAS HAZARDS Flammable o Explosive when confined: (4 walls, ceiling and floor) If natural gas in the explosive range ignites in a confined location, it will explode with destructive force. o Flammable when unconfined (outdoors): natural gas will ignite, not explode. Asphyxiant o While non-toxic, natural gas in sufficient quantity can displace the oxygen in an enclosed space and cause asphyxiation. 8

9 Static Spark (Polyethylene Plastic Pipe) Gas flowing out of a broken plastic pipe generates static electricity which builds up on the outside and inside surface of the pipe. Coming near to or touching a leaking plastic gas pipe could result in a spark that ignites the escaping gas. (Picture 16) Plastic pipe is not allowed to be used as gas pipe inside of a structure. Picture 16 Although easily folded, firefighters should not approach or attempt to fold leaking plastic gas pipe. Odor Loss o Natural gas leaking up through soil can have the mercaptan odorant scrubbed out of it. This can leave the gas odorless and undetectable without a combustible gas indicator. o Be aware that you can become desensitized to the odorant in natural gas over time and may no longer smell it even if it is still present. Always test for the presence of natural gas with a combustible gas indicator. 9. GENERAL PRECAUTIONS Ignition sources o Door bell - Knock on the door, do not ring the bell. o Static electricity - - Walking on a carpeted floor can generate a static charge and result in a spark when a metal object is touched. - Do not touch or come near a leaking plastic gas pipe. The resulting spark can ignite the escaping gas. o Building light switches - Do NOT turn lights on or off until the area is properly vented, tested and found safe. o Telephones - desk top and cellular can generate a static spark. o Heating / Air-conditioning unit - A furnace or boiler can provide an ignition source. 9

10 o Apparatus, overhead and underground trains and other vehicles are potential sources of ignition. o Traffic control boxes on light poles are a source of ignition. o Fire Department issued flashlights are intrinsically safe. Non-FDNY issued flashlights and FDNY thermal imaging cameras are not. - As a precaution, turn flashlight on before entering a building or an explosive atmosphere and do not shut it off while in a gas atmosphere. Once you turn a gas valve off, never turn it back on. o Turning a gas valve back on will result in gas leaks at the stove, boiler and other pilot lights in the building as well as at the location of any damaged piping. Note: Notify the gas utility company of any gas valves that you shut off. 10. CONSIDERATIONS A burst water main can undermine and cause a break in underground gas piping. Notify the gas utility of water main breaks. o Cast iron pipe is brittle. A ruptured water main or excavation can undermine cast iron pipe causing the pipe to crack from its own weight and leak. o Steel and plastic gas lines can also be damaged by undermining. A burning or arcing electrical manhole can burn through a nearby metal or plastic gas line, causing and igniting a gas leak. o If you smell gas or suspect its involvement in a manhole fire, request the response of the gas utility in addition to the electric utility. Always consider the possibility that leaking gas is migrating into buildings and other structures. The arc from fallen high voltage electric wires can burn through asphalt or concrete down to buried gas lines. The damage this causes to the metal or plastic gas lines can result in a leak which can be ignited by the arcing wire. o If you smell gas or suspect its involvement, request the response of the gas utility in addition to the electric utility. Star Valve - This old type gas valve may be found between the head of service valve and the gas meter. It is rarely found today, is unreliable and should not be used. Gas can migrate underground through the soil, electric conduit and sewer pipes. If you can t find the source of an indoor leak, take readings at sewers and manholes. Also check sewers and manholes at outdoor leaks to determine where and how the gas is migrating, and to determine the danger area. The utility company can track gas movement through the ground by inserting probes through the concrete and pavement. Pulling an electric meter or opening a breaker can generate a spark. Have the power to a gas filled building removed at the pole or manhole by the utility company. Before removing power from a building, ascertain if emergency power or a generator exists. If a building has emergency power or an emergency generator, it will kick in when power is cut, possibly providing an ignition source. Have it disabled, if safety permits, before cutting power to building. 10

11 11. GAS LEAKS MINOR INDOOR GAS LEAK: Most interior gas leaks are minor and can be mitigated by shutting off the gas valve at an appliance or boiler. Units must be aware that minor gas odors/leaks can escalate quickly. Some precautions should be taken and observations made so a basic gas emergency is mitigated without incident. Be aware of sources of ignition as you attempt to locate and control leak. Size up: Odor of Gas Is there an odor of gas? Be aware gas may be entering the building from an outside leak. o Is there an odor outside? Are any utility trucks/workers, construction sites or recently patched sections of pavement in the area? They may indicate recent or ongoing work and may be the source of a gas leak. Does the combustible or digital gas indicator carried by Battalions and Ladder companies indicate the presence of gas? Determine if the gas is leaking from a high or low pressure gas system. o Look for peck vent and/or regulator. Obtain information from the occupant. o Was anyone doing plumbing, excavation or construction on the premises? o How long has the odor been present? Tactics Wear full PPE when operating at these incidents and wear SCBA facepiece when operating in a gas atmosphere. Do not position apparatus in what is or might become a hazardous area. o All units should stay out of the potential collapse or ignition zone. o Ladder companies should take a preliminary safe position that will allow them access to the building. o Engine companies should take hydrants in safe locations and prepare to stretch lines as needed. Locate gas leak. Ventilate as necessary. Shut gas supply as close as possible to the leak. 11

12 If the leaking gas is burning, allow it to burn until the gas supply is shut off. o Extinguishing the burning gas before the gas supply is shut off will allow the gas to continue to discharge after extinguishment. An explosion may occur or the leaking gas may suddenly ignite if it comes in contact with a source of ignition. Combustible material near the burning gas should be wet down while waiting for the gas supply to be shut off. Shutting the gas supply is the safe way to extinguish a gas fire. If gas is leaking indoors and not burning, the gas supply should be shut off and the area ventilated. A fog nozzle may be used for venting if necessary. o Department fans are not intrinsically safe and should not be used to vent the gas. A leak or break in low pressure gas piping may be stopped or greatly diminished by taping, stuffing rags, paper, etc., into break. This tactic will not work on high pressure piping. (Remember, do not touch or approach leaking plastic gas pipe.) Notify the utility company of all gas valves shut. Consider the possibility that gas is leaking in from an adjoining apartment or may be coming from the outside or from more than one location in the building. Do not operate any of the buildings electrical switches or devices. Operate with a minimum of personnel in the gas atmosphere. If the Incident Commander deems it necessary, have Haz-Mat Company 1 respond. Considerations: Mercaptan can be scrubbed out of the gas resulting in only a slight or no gas odor even if it is a significant leak. Old gas lines were used for illumination. These lines were sealed with wax and over time this wax deteriorates resulting in a gas leak. These types of leaks can be difficult to locate. (Picture 17) Picture 17 Old gas lighting pipes are visible on this ceiling. Direct vent boilers and hot water heaters have become prevalent throughout the city. They may be located anywhere within a structure and are vented by a short length of pipe through an exterior wall. At fires, the presence of window or wall mounted gas heating units must be communicated to the Incident Commander and their gas supply shut down. (Pictures 1, 1a) 12

13 MAJOR INDOOR GAS LEAK: Indicators Heavy odor of gas unless the mercaptan has been scrubbed out of the gas. High readings on digital combustible gas indicator. Tactics Transmit the appropriate signals. Take gas readings with all available gas meters (Altair, Digital and Tiff). Special call a unit with an Altair digital gas meter if none is available at the scene. All special units including SOC support ladder companies carry sophisticated digital combustible gas indicators. If the Incident Commander deems necessary they should be special called. Notify dispatcher of conditions and have the utility company respond. Request an ETA. Evacuate as necessary. Locate the source of the leak if safe to do so. Shut the gas valve as close to source as possible. Ventilate if it is safe to do so. If gas levels are above the flammable limits, they will drop into the flammable range as you ventilate. Start venting at the upper levels of the building when possible and work your way down to the first floor and then out of the building. Check at least three exposures on both sides of the occupancies with positive gas readings for the presence of a gas odor or leak including above and below the suspected leak. Evacuate and ventilate as necessary. Consider closing windows and shutting ventilation systems in nearby buildings. Exclude vehicles and pedestrians from the potential danger area. Position apparatus safely. o Engines companies should take a position at a hydrant that will be safe should the leaking gas ignite or explode. o If ignition or explosion is a possibility, Engine Companies should stretch precautionary lines to safe areas. o Ladder companies should be positioned out of the danger area in a location where they can be utilized if necessary. Heavy odors of gas inside of a structure may be coming in from the outdoors. Take notice of any construction being done in the vicinity of the building. Do not operate any of the building s electrical switches or devices and make sure the occupants do not operate switches or telephones. Do not pull the electric meter or open a circuit breaker. If power must be cut to the building, have it cut by the utility company at the pole or manhole. o Find out if the building has emergency power before having the power cut. 13

14 OUTDOOR GAS LEAK: Indicators A heavy gas odor in the area. It may be intermittent especially on a windy day. There may be an opaque cloud rising from the ground at the site of the leak. Dirt and debris may be seen blowing into the air from an excavation. This would indicate a high pressure leak. A loud roaring sound indicates a high pressure leak. Tactics Transmit the appropriate signals. Take gas readings with all available gas meters (Altair, Digital and Tiff). Special call a unit with a digital gas meter if none is available at the scene. All special units including SOC support ladder companies carry sophisticated digital combustible gas indicators. If the Incident Commander deems necessary they should be special called. Notify Dispatcher of the location and extent of the leak and whether it is low pressure or high pressure. Have the utility respond and request an ETA. The apparatus is a source of ignition. When approaching an alarm location, if a strong gas odor is detected, stop the apparatus and take readings with a digital combustible gas indicator. Position apparatus in a safe area, upwind and out of the gas cloud, and approach the leak from upwind. Do not position apparatus in what is or what might become a hazardous position. Ladder companies should take a safe position out of the gas cloud that will allow them to reposition as needed. Engine companies should be positioned at a safe hydrant and precautionary lines should be stretched to a safe location, out of the gas cloud, to protect exposures. Do not park over manholes or sewer gratings as gas may be venting from these locations. Notify incoming units of the need to approach from upwind and designate a safe staging area. Search the area for victims and locate the leak. Assist any injured civilians and evacuate anyone in the danger area. Secure the area by excluding vehicular and pedestrian traffic. Always monitor surrounding structures, sewers and manholes for gas infiltration. If gas readings are obtained in ELECTRIC, SEWER or any other utility MANHOLE(S), the surrounding structures must be checked. When arriving on the scene of a serious gas incident prior to the arrival of gas utility personnel and finding gas readings in an ELECTRIC MANHOLE, the following information shall be requested from the utility company via the FDNY dispatcher: o The identity of the buildings(s) being supplied electricity by the involved manhole(s). 14 Rev. 04/12/11

15 o If you detect gas readings inside buildings where the electricity enters the building (Electric Point of Entry or POE) request the location of the manhole that supplies electricity to the building and any other building(s) it supplies. o Utilize this information to prioritize the checking of buildings for the presence of gas. Removal of MANHOLE COVERS by FDNY personnel may reduce the infiltration of gas into surrounding properties and shall be done only in compliance with the following guidelines: SEWER MANHOLE COVERS o Removal of SEWER MANHOLE covers can be performed by FDNY personnel with the approval of an on-scene Chief Officer. ELECTRIC MANHOLE COVERS o Removal of ELECTRIC MANHOLE covers by FDNY personnel may be performed only when requested by a utility company gas representative on the scene and approved by an on-scene Chief Officer. o Prior to requesting FDNY personnel to remove a manhole cover, the utility company gas representative must test the cover for stray voltage. If the cover is found to be free of the stray voltage, FDNY personnel may remove the cover upon the orders of an on scene Chief Officer in conjunction with the utility company gas representative. o Round Manhole covers should be removed by two firefighters utilizing manhole hooks. Battalion vehicles carry two manhole hooks for use in removing electric manhole covers. o DO NOT pull rectangular or square electric manhole covers. o DO NOT pull any electric manhole covers if there is a manhole fire in the area or if a smoking or arcing is observed in an electric manhole or transformer vault. o If in doubt as to which type of manhole is affected or if there is obvious smoke under pressure or electric arcing DO NOT remove the manhole cover. o Any time the decision is made to remove a manhole cover(s) the Chief Officer ordering such removal shall ensure the area around the manhole(s) is properly cordoned off to identify the hazard. Note: This policy relates to operations with both Con Edison and National Grid Gas Personnel. Gas from a leaking pipe may travel some distance before finding a place to surface because pavement, snow or frozen ground can trap it underground. Search and evacuate structures as needed. Remove all sources of ignition if safety permits. Do not pull the electric meter or open a circuit breaker if gas is found in a building. Natural gas can infiltrate the meter and pulling it can generate a spark capable of igniting the leaking gas. If power to the building must be cut, have it cut by the utility company at the pole or manhole. 15 Rev. 04/12/11

16 Find out if the building has emergency power before having the power cut. Cutting power may result in activation of an emergency power source which can be a source of ignition. Look for sources of ignition such as: decorative gas street lamps, barbecues, overhead trains, sparks from fireplaces, construction equipment, and remove them if it is safe to do so. Shutting down construction equipment and vehicles can cause a spark and be a source of ignition. If gas is burning, do not attempt to extinguish it. Protect exposures with fog streams and wait for the utility company to stop the gas flow. If the escaping gas is not burning, fog streams can be used to dissipate the escaping gas or to direct it away from threatened exposures. If the leaking pipe is in an excavation, avoid filling the excavation with water. Doing so will only hamper the repair process. Considerations Exterior gas leaks can occur at construction sites, during electrical emergencies, at steam leaks, and as the result of a flood or water main break. Gas piping is placed alongside water, steam and electrical lines. When operating at any of these type emergencies, be aware that they may affect each other. Damage to a gas pipe at a construction site may result in additional damage to the gas pipe at other locations. For example, when a backhoe pulls and/or breaks a gas service line, it may also have dislodged the service line from the building, separated a coupling and/or pulled the pipe from the gas main in the street. The result would be a gas leak where the backhoe was operating, another leak at the building line or in the building and still another one at a coupling or where the service line connects to the street main. NOTIFICATIONS: Notify your Officer whenever you shut a gas valve. Notify the Incident Commander whenever a gas valve is shut. Notify the gas utility company whenever a gas valve is shut by FDNY. 16 Rev. 04/12/11

17 12. GAS EMERGENCIES TACTICAL CHART Type Incident Hazards Indicators Tactics Minor Indoor Gas Leak Major Indoor Gas Leak Outdoor Gas Leak If leaking for prolonged time: Ignition / Explosion Ignition / Explosion Asphyxiation Ignition of gas cloud Radiant heat Infiltration Into Buildings, Sewers, Manholes and Other structures Explosion Ignition Slight odor of gas Low readings on combustible gas indicator Heavy gas odor High readings on combustible gas indicator Ruptured main Opaque cloud Dirt blowing into air Strong gas odor Construction equipment or excavation in area Loud noise (high pressure only) Take gas readings* Evacuate if necessary Locate source of leak Shut gas valve as close to source as possible Ventilate Notify utility of valves shut Stretch hose line as needed Safely stage apparatus Take gas readings* Call utility Evacuate Locate external meter or curb valve & shut down Eliminate ignition sources Ventilate Stretch hose line as needed Call utility Search area Assist injured Secure area Evacuate area Check and monitor surrounding structures* Evacuate structures as needed Eliminate sources of ignition Stretch hose line as needed Use fog to dissipate gas cloud or protect exposures Underground Gas Leak Infiltration into buildings, sewers, manholes and other structures Ignition Combustion Explosion Inability to locate source of gas odor in building Inability to locate source of outdoor gas odor Gas odor coming from sewer or manhole Safely stage apparatus Call utility Take gas readings in buildings, sewers and manholes* Secure hazard area Evacuate as needed Stretch hose line as needed *Take readings in attached and nearby structures if warranted and evacuate as necessary. 17 Rev. 04/12/11

18 13. METERS A. Combustible Gas Indicator (CGI)- Tiff Meter Combustible gas indicators (CGI) are carried by all Battalions and Ladder companies. It is usually the first meter available on the scene. It is able to pinpoint leaks even in small amounts. It should be used in conjunction with a digital gas meter. When turned on in fresh air, it should be set to click slowly. If a flammable gas is present, it will click faster. It does not indicate how hazardous the atmosphere is. If the meter is clicking quickly, call for a unit with a digital combustible gas indicator. B. MSA Altair Digital Gas Meter Carried by all non SOC Support Ladder Companies. It will give a digital readout of LEL (Lower Explosive Limit) for combustible gas and also is an oxygen sensor. It is to be used in conjunction with the Tiff meter if available. C. Digital Combustible Gas Indicator (DCGI) Digital combustible gas indicators are carried by all SOC companies, SOC Support Ladders and Haz-Mat Technician Units. It is calibrated to display the percentage of the lower explosive limit (LEL) of any flammable gas present. The DCGIs and Altair currently in use by the Department sound an alarm at 10% LEL, the indoor action level, and a different alarm at 20% LEL, the outdoor action level. The FDNY in compliance with OSHA standards will begin evacuation at 10% LEL level if we are unable to reduce the LEL level immediately (ventilation. shutting of valves). It is important to keep in mind that the reading on the meter represents the level of flammable vapors at the specific location of the meter only! The environment closer to the source of the leak (or in other areas where the gas may have accumulated) could contain a higher level of flammable vapors, including at some point 100%. LEL. Note: The utility company s meters are not calibrated the same as FDNY meters. The utility company s meters display percent of gas in air. When given a reading from any meter, be sure you know if it is given in LEL or in % in air. (Diagram 1) Table 1 is used to convert the DCGI readout from % LEL to % in air for natural gas. TABLE 1 Utility Meter %GAS in air %LEL Fire Department Meter Indoor Action Level Lower Explosive Limit 18 Rev. 04/12/11

19 Diagram 1 is a graphical comparison of LEL to % gas in air. Percentage of Natural Gas in Air Measured by Utility Company 0% 5% 10% 15% 0.50% 2.5% Explosive range 10% 50% 0% 100 % 100% LEL equals 5% gas in air. Percentage of Lower Explosive Limit Note: 10% LEL Is FDNY Action Level Diagram PECK/RELIEF VENT The location of the curb valve may be indicated on the peck/relief vents which are located on the exterior of the building in high pressure systems. The vent is a device that will allow excess gas to be vented to the outside air if a malfunction of the pressure regulator valve in the high pressure system occurs. There should normally be no odor of gas at a peck vent. If an odor is detected, you must investigate to determine the source. (Pictures 22, 22a) The diagrams and methods contained in this bulletin concerning the code letters and numerals found on the gas vents, and used in determining the approximate location of "Curb Valves" are of the conventional type most commonly encountered. It is to be noted however that some factors such as unusual construction of buildings, odd layout or locations of some buildings, technical problems that may be encountered by the utility company when installing the service piping, etc., may cause variations from the basic method described herein. A series of code letters and numbers will be found on or attached to these vents indicating the location of the curb valve. Picture 22 Peck Vent Picture 22a Peck Vent Peck Type Vent (Showing Con Ed coding and measuring directions) 19 Rev. 04/12/11

20 The Con Edison System codes their peck vents as follows: If the code reads 5-R-25, the following procedure should take place to locate the curb valve; starting at the left hand front corner of the house, as it is faced from the street, 5 feet would be measured off to the right. At that point 25 feet would be measured off at right angles toward the sidewalk. The curb valve should be located at this point. (Picture 23) Picture 23 Con Edison Peck Vent Location System 20 Rev. 04/12/11

21 National Grid Peck Vent Location Coding System The National Grid Peck Vent location coding system differs from Con Edison s system. National Grid uses two different systems. One method is used in the Rockaways and another in the rest of Queens, Brooklyn and Staten Island. In the Rockaways, you will find the numerals and letters on the peck vent, or on a tag (Picture 24) hanging on the piping in the immediate area of the gas meter. If it reads L-30, R-25, M-10, then, starting at the left corner of house (facing it from street) an arc is inscribed with a radius of 30'. The same would be done from the right corner with a radius of 25'. Where these two arcs intersect, would be the location of the curb valve. Then, 10 feet at right angles from this curb valve, in the direction of the street, would be the location of the gas main pipe running in the street parallel to the curb. (Picture 25) Picture 24 National Grid Peck Vent Coding on Metal Tag If the letters EFV are inscribed on the tag then there is no curb valve and where the lines meet denotes the location of an Excess Flow Valve which will automatically shut down the flow of gas when it senses an excess flow of gas. The Letters NC on the tag also indicate that there is no curb valve present. Picture 25 National Grid curb valve location system for the Rockaways. 21 Rev. 04/12/11

22 In the rest of the areas served by National Grid excluding the Rockaways, there is a different coding system. It will read as follows: 15RLBW and 10FFW. 15 RLBW indicates 15 feet right of the left building wall, 10FFW indicates 10 feet from the buildings front wall. (Picture 26) Starting at the left building wall, measure off 15 feet to the right. From this point, measure 10 feet at right angles toward the street. This is approximate location of the curb valve. National Grid Picture 26 National Grid curb valve location system excluding the Rockaways. 22 Rev. 04/12/11

23 FORMERLY SAFETY MESSAGE # 66 UNUSUAL GAS EXPLOSION Last October, an alarm was transmitted for a gas explosion in a two story 100' x 100' cellarless commercial occupancy. The explosion blew three overhead garage doors off the building. On arrival of our members, blue flames were issuing from the seams of the concrete floor and all pipe openings adjacent to and below the gas meter. Units shut off the gas at the meter and requested the response of Con Edison. The flaming continued and it was determined that the leak was from a two inch, high pressure gas line located between the meter and the curb valve. Con Edison shut off the curb valve and units evacuated the building to stand-by positions. Suddenly, a violent second explosion occurred below the floor slab, blowing the gas meter off the wall and dislodging a twenty by thirty foot section of the reinforced concrete floor. This second explosion sent fire, dust and debris through the open doors injuring fifteen members. An investigation of the incident disclosed that there was an accumulation of unburned gas (too rich to burn) trapped in a two to three foot void between the soil and the reinforced concrete slab floor. The second explosion occurred as this rich atmosphere was being reduced and passing through the explosive limits. Units operating at premises with a gas leak that occurs before the main gas meter shall evacuate the building occupants where necessary and withdraw members to a safe location, preferably shielded by an object, in anticipation of a second explosion. Since this incident, all battalions have been issued combustible gas detectors. Proper use of these instruments will add a measure of safety to these and related type incidents. 23 Rev. 04/12/11