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SOG 31-33 Emergency Response Guidelines for LPG and NG Handling

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63 Questions

What is the primary hazard associated with natural gas?


What is the flammable range of natural gas in air?

5% - 15%

What is the typical ignition temperature of natural gas?

1100°F - 1200°F

What is the recommended firefighting practice for an uncontrolled natural gas leak that cannot be shut off?

Allow the gas to burn in a controlled manner

When responding to a natural gas leak inside a building, what is the first action that should be taken?

Shut off the gas at the meter from the outside

What is the recommended approach when dealing with an outdoor natural gas leak?

Approach the leak from uphill, upwind

What is the primary purpose of the guidance provided in SOG 32 SAR?

To provide guidance for search and rescue operations at a structural collapse

What is the primary difference between an unframed and a framed building?

The presence or absence of load-bearing walls

What is the role of the Incident Commander at a structural collapse incident?

To ensure the safety of all personnel and civilians at the scene

What is the recommended action if there are signs of potential building collapse?

Call for the special operations team to assess the situation

Which type of wall collapse is indicated by large bows in the middle or leaning/separated from the floor?

Walls out of plumb

Which of these is NOT a form but rather a sign of collapse?

Beams pulling away

Which type of collapse is the result of the total bearing wall or column failure of an upper floor causing the upper floors to pancake down on the floors below?

Pancake collapse

What is the primary purpose of the reconnaissance phase during a building collapse incident?

All of the above

What is the first priority during the immediate rescue phase of a building collapse incident?

All of the above

What is the purpose of establishing a unified command during a building collapse incident?

All of the above

Which type of collapse is characterized by the floor collapsing at the center, leaving two void spaces?

V-shape void

What is the purpose of the rapid intervention team (R.I.T.) during a building collapse incident?

To be prepared for deployment to assist rescue personnel

What is the primary purpose of the scene organization and management during a building collapse incident?

All of the above

What type of collapse is characterized by one end of the floor or roof section still being attached to the wall, while the other end hangs unsupported?


What should the caller be instructed to do if they can detect a strong odor of gas or hear gas escaping?

Leave the building immediately by walking, not running

How many engines should enter the area in response to a LPG/NG emergency?

Only 1 engine should enter the area

What should be done if the response is to a ruptured natural gas line or LPG tank over 20 lbs?

Evacuate the surrounding area and notify Fire Rescue Communications to have Special Operations (HazMat) response initiated

Which of the following is NOT a possible leak indication mentioned in the text?

A strong odor of gas

What is the main purpose of the guidelines outlined in the text?

To establish procedures for the response, operations, and safety of personnel in handling LPG and NG emergencies

What is the scope of the guidelines outlined in the text?

Only Fire Rescue personnel who respond to LPG and NG emergencies

What is the expansion ratio of liquid to gas for ethyl mercaptan?


What is the ignition temperature range for Propane Vapor?

920°F - 1120°F

Why should small tanks be placed upright during a leak?

To allow vapor release instead of liquid release

What does LP Gas do when it comes in contact with oxygen?

Displaces oxygen and acts as an asphyxiant

What is the Flammable Range of LP Gas?

2.1% - 9.5%

In case of a leak, what should be used to determine the concentration of gas in the atmosphere?

Combustible gas meter

What does the 'Two In - Two Out' rule require?

Having at least two rescuers outside and two inside the hazardous area

What is the primary concern when responding to a nuclear/biological/chemical (NBC) event?


Which of the following is NOT one of the guidelines for general decontamination during NBC incidents?

Transporting victims in rescue apparatus before decontamination

According to the guidelines, what should be used for decontamination if the substance is known to be water-reactive?

No decontamination should be performed

Which of the following observations may indicate that the scene is too risky to enter?

All of the above

How long after exposure may it take for acts of biological contamination to become evident?

72 hours

Which of the following is NOT mentioned as a way that biological agents can contaminate?


What should be done with the clothing and jewelry of victims who have been contaminated?

Contained (bagged) with victims' ID

Which of the following is NOT mentioned as a form that biological bacteria, viruses, and toxins can exist in?


What should be done if there is an unusual number of dying people and/or animals observed at the scene?

Immediately retreat from the scene

Which of the following is NOT mentioned as one of the supporting policies or guidelines referenced in the text?

Radiation Safety

What are common signs and symptoms of exposure to biological agents?

Fever, weakness, headache, nausea, vomiting

Which chemical agent may be in the form of a solid, liquid, or gas?


What are the categories of chemical weapons mentioned in the text?

Nerve agents, Blister agents, Blood agents

What could indicate the detonation of a chemical/biological weapon?

Unusually colored vapor clouds, strong acrid odors

Why is the possibility of a terrorist faction producing a nuclear bomb considered very remote?

Lack of technological capability

Which equipment category is NOT mentioned as part of the deployed radiation equipment?

Chemical detectors

What action is recommended to be taken upon the detection of any reading equal to or greater than 1 R/Hr?

Establish exclusion zones and alert responders to avoid

What is crucial for all responders entering the hot zone to have?

Survey meters and personal dosimeters

Which symptom is NOT mentioned as a common sign of exposure to biological agents?

Excessive sweating

Which chemical weapon is likened to organophosphates?


What should be the approach direction when dealing with L.P.G. emergencies?

Approach from an uphill direction

What is the main reason for keeping all bystanders at least 2000 feet away from the hazardous area?

To minimize the risk of injury or death in case of an explosion

What is the primary reason radios are prohibited in a possible explosive atmosphere?

Risk of setting off an explosion due to radio signals

What is the primary purpose of establishing HOT, WARM, and COLD zones?

To facilitate coordination and safety measures based on proximity to the hazardous area

What is the correct procedure if pressure relief valve whistling becomes louder during L.P.G. fires?

Evacuate the area immediately

What must personnel do if they must operate in a precarious position during an emergency?

Be protected with another fire stream

What action must be taken if an L.P.G. tank has rolled over due to a vehicle accident?

Be cautious as the relief valve may be inoperable

What is the purpose of comparing available resources against the required level when handling an emergency?

To determine if additional resources need to be called in

What is one critical consideration for an Incident Commander when deciding on Offensive, Defensive, or Non-intervention Operations?

The nature and severity of the emergency situation

What should be done when personnel identify a gas leak and can safely identify the gas company?

Notify the gas company as soon as possible

Study Notes

Propane/Natural Gas Emergencies

  • Full protective clothing and SCBA is required for all propane/natural gas firefighting and leak control operations
  • Apparatus placement should stop short of the area, preferably uphill and upwind
  • Determine the hazardous area, considering that LPG is heavier than air and settles in low-lying areas

Incident Command

  • Establish HOT, WARM, and COLD zones
  • Formulate a plan of action based on the initial size-up
  • Secure and shut off NG and LPG to the building or residence
  • Compare resources available versus the level required to effectively and safely handle the problem

Safety Precautions

  • Avoid a full commitment of personnel and apparatus until a complete size-up has been made
  • Keep all bystanders at least 2000 feet away from the hazardous area
  • Remove all ignition sources in the hazardous area
  • Keep clear of tank ends if fire is impinging on the tank

LPG Fires

  • If whistling from the pressure relief valve becomes progressively louder, evacuate the area, as an explosion is imminent
  • Imminent explosion evacuation will be signaled by continuous blasts of airhorns and/or high-low electronic siren

LP Gas Properties

  • Belongs to the family of chemical compounds known as Hydrocarbons
  • LP Gas is highly flammable
  • Tasteless, colorless, odorless

Natural Gas Properties

  • Combustible mixture of hydrocarbon gases that is highly flammable
  • Non-toxic, but has inhalation hazard; will displace oxygen and act as an asphyxiant
  • Tasteless, colorless, odorless; odorant added - similar to heavy skunk odor
  • Lighter than air; if natural gas escapes into the atmosphere, it dissipates rapidly unless trapped

Leak Control and Mitigation

  • Establish adequate water supply
  • Secure ignition sources
  • Approach leak from upwind
  • Use fog streams to protect exposures

Building Collapse

  • Initial response: consider safety hazards prior to arrival on scene based on dispatch information
  • Park apparatus in a safe location and perform a thorough scene size-up and identification of possible hazards

Void Detection

  • Voids may be formed for various reasons and in various forms
  • During the search phase, survivors are most likely to be found inside voids

Search and Rescue

  • A systematic approach to dealing with building collapse will enable the Incident Commander to increase efficiency and reduce injury to both rescue personnel and civilians
  • The initial stages can be broken down into two basic functions: Reconnaissance and Immediate Rescue

Scene Organization and Management

  • Working within the incident command system is essential to a successful operation
  • A unified command should be established
  • The following checklist may assist: shutting down utilities, ensuring structural integrity, and establishing a contingency plan

Nuclear, Biological, and Chemical (NBC) Emergencies

  • Personal safety is a high priority when responding to a NBC event
  • Decontamination is a primary concern for NBC terrorism
  • Patients are not to be placed in rescue apparatus for transport prior to completing decontamination measures

Biological Emergencies

  • Acts of biological contamination are not likely to be immediately detectable, and may not be evident until 72 hours post-exposure
  • Common signs and symptoms that may occur from three hours to six days after exposure include flu-like symptoms, fever, weakness, headache, nausea, vomiting, cough, diarrhea, and chills

Chemical Emergencies

  • The use of chemical weapons, unlike biologic agents, will have immediate effects ranging from seconds after exposure until the first few hours

  • Chemical agents may be in the form of a solid, liquid, or gas### Properties of LP Gas

  • Ethyl mercaptan is added to LP gas to give it an odor.

  • LP gas can be a liquid or gas, and it will be a gas at ambient temperature.

  • It is usually stored and transported as a liquid under pressure.

Handling and Safety

  • When LP gas is stored or transported, it can expand from liquid to gas in a 270:1 ratio.
  • Heat can cause the product to expand and increase container pressure, leading to a boiling liquid expanding vapor explosion (BLEVE) if left un-cooled.
  • LP gas is non-toxic, but it can displace oxygen and act as an asphyxiant, making it an inhalation hazard.

Physical Characteristics

  • Propane vapor is 1.5 times heavier than air and will settle in low areas, becoming concentrated.
  • The ignition temperature of LP gas is between 920°F and 1120°F.
  • The flammable range of LP gas is between 2.1% and 9.5%.

Emergency Response

  • The Immediately Dangerous to Life or Health (IDLH) concentration of LP gas is 2000 PPM.
  • When responding to an LP gas leak, establish an adequate water supply, secure ignition sources, and approach the leak from uphill and upwind.
  • Use fog streams to protect exposures and direct the vapor cloud.
  • If possible, use heavy fog streams to dissipate the vapors without disturbing the liquid.

Mitigation and Control

  • Consult with the driver of the vehicle or plant personnel to locate the valve and shut off the fuel supply if possible.
  • Close the valve if deemed safe to do so, but follow the "Two In - Two Out" rule and wear full structural firefighting gear with SCBA.
  • Use hose lines with a fog pattern to create a safe zone and protect responders while working in the hot zone.
  • Do not use tools that may spark, and note that if the leak cannot be stopped by turning the valve to the off position, responders will immediately return to the cold zone.

Fire Response

  • Special Operations response is required for LP gas fires.
  • Establish a sufficient and reliable water supply, and use hose streams to protect the container from overheating and protect exposures from radiant and convected heat.
  • Approach from uphill and upwind, and direct streams to the area above the liquid level.
  • If the tank is burning, fire streams must be used to cool the vapor area of the tank.
  • Consult with the driver of the vehicle or plant personnel to locate the valve and shut off the fuel supply if possible.
  • Do not extinguish tank or cylinder fires unless the shut off can be effected.

Learn about the guidelines for responding to Liquefied Petroleum Gas (LPG) and Natural Gas (NG) emergencies to ensure the safety of personnel and citizens. Understand the procedures for handling gas leaks and protecting individuals in such situations.

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