Instructor Guide 5

7/28/2019 Instructor Guide 5

1/25

PIPELINEEMERGENCIES

Chapter 5GasPipeline Operations

Michael Callan


2/25

Pipeline EmergenciesChapter 5

Facil itator Guide Notes

Page 2 of 25

Chapter 5Gas Pipeline OperationsObjectives

a) Describe The Following Physical Properties AndExplain Their Significance In The RiskAssessment Process For An Incident Involving ANatural Gas Pipeline.

i) Color And Odor

ii) Vapor Density

iii) Boiling Point

iv) Vapor Pressure

v) Solubilityb) Describe The Following Chemical Properties And

Explain Their Significance In The RiskAssessment Process For An Incident Involving ANatural Gas Pipeline.

i) Flammable (Explosive) Range

ii) Ignition Temperature

c) List The Basic Byproducts Of Complete AndIncomplete Combustion Of Natural Gas.

d) Describe The Two Primary Reasons For OdorizingNatural Gas.

e) Describe The Basic Principles Of Operation OfThe Following:

i) Natural Gas Gathering Systems

ii) Natural Gas Processing And TreatmentFacilities

iii) Natural Gas Transmission Pipelines

f) Given A Natural Gas Transmission Pipeline

System, Describe The Purpose Of The Following:

i) Compressor Stations

ii) Gate Settings / Main Line Valves

g) Describe The Following Underground AndAboveground Options For The Storage Of NaturalGas:


3/25



Page 3 of 25

i) Underground

ii) Depleted Natural Gas Reservoirs

iii) Aquifers

iv) Salt Caverns And Formations

v) LNG Storage Tanks

h) Given A Natural Gas Distribution Pipeline System,Describe The Purpose Of The Following:

i) Gas Stations Or City Gates

ii) Distribution Mains

iii) Regulator Stations

iv) Farm Taps

v) Meters

vi) Curb Valves

vii) Main Valves

i) List At Least Three Signs Or Indicators Of ALeaking Natural Gas Pipeline.

CHAPTER 5 Instructor Overview

1. Describe the following physical properties andexplain their significance in the risk assessment

process for an incident involving a natural gaspipeline.

Color and odor natural gas is colorlessand odorless in its natural state. Riskassessment must consider this hazard andunderstand the explosive potential for anatural gas pipeline. Natural gas isodorized to indicate a leak and reduces gaslosses through early detection.

Vapor density the weight of a pure vaporof gas with air. Natural gas vapor density isless than 1 which is lighter than air. Riskassessment is gas will rise rapidly anddissipate.

Boiling point low boiling point at -259deg F. Risk assessment is that more


4/25



Page 4 of 25

vapors that are produced at a giventemperature.

Vapor pressure vapor pressure for

natural gas is 120 psi at 60 deg F.Assessment is that natural gas can beunder extreme pressures when transported.

Solubility slightly soluble in water.Assessment is that water spray can beused to move or redirect natural gasvapors.

2. Describe the following chemical properties andexplain their significance in the risk assessment

process for an incident involving a natural gaspipeline.

Flammable (explosive) range for naturalgas is 4% to 15%. Significant informationfor risk assessment in that the range of thegas igniting is easy. Therefore eliminatingsources of ignition from the area andevacuation of people is top priority.

Ignition temperature of natural gas is

1,200 deg F. In assessment it is asignificant property in evaluating the easewith which it may ignite.

3. List the basic byproducts of complete andincomplete combustion of natural gas.

Complete combustion water vapor andcarbon dioxide

Incomplete combustion carbon

monoxide, excessive water vapor,aldehydes and soot

4. Describe the two primary reasons for odorizingnatural gas.

Natural gas is odorized todetect/indicate a leak and reduce gaslosses by early detection.


5/25



Page 5 of 25

5. Describe the basic principles of operation of thefollowing:

Natural gas gathering systems is asystem of smaller-diameter, low-pressurepipelines that collect natural gas duringexploration and transport the gas to gasprocessing plants.

Natural gas processing and treatmentfacilities incorporates specific treatmentprocesses to remove impurities fro thenatural gas. This process includescompression, absorption and dehydration.

Once impurities are removed the finalnatural gas product is considered pipelinequality.

Natural gas transmission pipelines arethe interstate highways of natural gastransportation system. These pipelines arehigh-strength welded steel pipelines withdiameters of up to 48 inches and pressuresranges from 300 to 1500 psi.

6. Given a natural gas transmission pipeline system,describe the purpose of the following:

Compressor stations are used tomaintain pipeline flows and pressures.Compressor stations are generally buildevery 50 to 100 miles and monitored bySCADA.

Gate settings/main line valves areinstalled along the transmission pipeline to

help isolate or control the flow of the gas.Installed approximately 10 to 20 miles alongpipeline.

7. Describe the following underground andaboveground options for the storage of natural gas:


6/25



Page 6 of 25

Underground helps to maximize the useof pipeline system capacity year round andcreates additional flexibility in operation ofthe pipeline system.

Depleted gas reservoirs most commonform of underground storage. Depletedreservoirs proven to be geologicallycapable of holding natural gas.

Aqui fers are underground porous,permeable rock formations that act asnatural water reservoirs. Located in regionswhere there are no nearby depletedreservoirs and with a single winter

withdrawal period.

Salt caverns and formations are wellsuited to natural gas storage in that saltcaverns, once formed, allow little injectednatural gas to escape from the formationunless specifically extracted.

LNG Storage tanks insulated cylindricalbulk storage tanks ranging from 50 to aslarge as 200 ft n diameter.

7. Given a natural gas distribution pipeline system,describe the purpose of the following:

Gate stations or city gates are the pointwhere natural gas from a transmissionpipeline enters the distribution system.Gate stations metering and control pipelineflow, and regulating, monitoring andreducing pipeline pressure. Natural gas isodorized at this point.

Distribution mains are the initialconnection from the transmission pipelinesystem downstream of a gate station.

Regulator stations sometimes referredto as limiting stations, control the gaspressure for major sections of the


7/25



Page 7 of 25

distribution system. These stations haveseveral valves and pressure regulators toprotect against system overpressures.

Main distribution valves normallylocated in the street and control largesections of the main gas grid.

A farm tap is a single pressure reducingstation connected to a pipeline with apressure greater than 60 psi.

Meters natural gas customers have ameter to measure the amount of gas beingused for billing purposes. Every gas meter

has a shut-off valve.

Curb valves located in a circular orsquare box in the sidewalk, near the streetor in a parking strip and is protected by asecured cover. The purpose of the curbvalve is to isolate and control flow to aspecific building or several relatedstructures.

Main valves are found in the street or

major intersections and used to isolate andcontrol larger areas of a natural area gasdistribution system.

8. List at least three signs or indicators of a leakingnatural gas pipeline.

What you see, what you hearand whatyou smell.

Discolored vegetation, vapor cloud or mist,

dirt blown in the air, bubbles in a pond orriver, fire coming out of the ground, ice ballaround pipeline, dead insects.

Hissing or roaring sound. Odor of sulfur ormercaptan.


8/25



Page 8 of 25

Slide [1]Chapter 5

Gas Pipeline Operations

P-83

[2] Objectives

a) Describe The Following Physical Properties AndExplain Their Significance In The Risk

Assessment Process For An Incident Involving ANatural Gas Pipeline.

i) Color And Odor

ii) Vapor Density

iii) Boiling Point

iv) Vapor Pressure P-84

v) Solubility

[3] Objectivesa) Describe The Following Chemical Properties And

Explain Their Significance In The RiskAssessment Process For An Incident Involving ANatural Gas Pipeline.

b) Flammable (Explosive) Range

c) Ignition Temperature

d) List The Basic Byproducts Of Complete P-84And Incomplete Combustion Of Natural Gas.

e) Describe The Two Primary Reasons For OdorizingNatural Gas.


9/25



Page 9 of 25

[4] Objectives

a) Describe The Basic Principles Of Operation OfThe Following:

b) Natural Gas Gathering Systems

c) Natural Gas Processing And Treatment Facilities

d) Natural Gas Transmission Pipelines P-84

e) Given A Natural Gas Transmission PipelineSystem, Describe The Purpose Of The Following:

f) Compressor Stations

g) Gate Settings / Main Line Valves

[5] Objectives

a) Describe The Following Underground AndAboveground Options For The Storage Of NaturalGas:

i) Underground

ii) Depleted Natural Gas Reservoirs

iii) Aquifers P-84

iv) Salt Caverns And Formations

v) LNG Storage Tanks

[6] Objectives

a) Given A Natural Gas Distribution Pipeline System,Describe The Purpose Of The Following:

i) Gas Stations Or City Gates

ii) Distribution Mains

iii) Regulator Stations

iv) Farm Taps

v) Meters P-84

vi) Curb Valves

vii) Main Valves


10/25



Page 10 of 25

b) List At Least Three Signs Or Indicators Of ALeaking Natural Gas Pipeline.

[7] Introduction

a) We Will Look At The Specifics Of Natural GasPipeline Operations And Their Facilities, With ThePrimary Emphasis Upon Natural GasTransmission And Distribution Pipeline Systems

b) Knowledge Of The Container, Its Contents, AndThe Behavior Of Both Are Critical Information In

Sizing Up The Problem, Assessing The BehaviorOf Each, Estimating Future Outcomes, AndDeveloping A Sound Incident Action Plan. P-85

[8] Natural Gas: Physical And ChemicalProperties

a) To Mount A Safe And Effective Response At APipeline Emergency, Responders MustUnderstand

i) How The Product Will Behave (I.E., ItsPhysical Properties) P-85

ii) How It Can Harm (I.E., Its ChemicalProperties)

b) Natural Gas (CH4) Is A Clean-burning Fuel ThatConsists Of Approximately 94% Methane, 4%Ethane, And The Remaining 2% Of Other Gases,Including Butane, Carbon Dioxide, Nitrogen AndIso-pentane.


11/25



Page 11 of 25

[9] Primary Characteristics Of Natural GasAre:

a) Odorless, Colorless And Tasteless In Its Natural

State

b) When Mixed With The Proper Amount Of Air, CanBurn

c) Capable Of Being Either A Liquid Or Gas.However, At Ambient Temperatures, NaturalGas Will Be In Its Gaseous Form P-85

d) With Few Exceptions, Is Transported Via PipelineIn Its Gaseous Form

[10] Primary Characteristics Of NaturalGas Are:

a) May Be Found As A Cryogenic Liquid (I.E.,Liquefied Natural Gas Or LNG) In Some StorageAnd Transportation Containers.

b) Is Non-toxic, But Can Present Inhalation Hazards.If Released Within An Enclosed Area, Natural GasCan Displace Oxygen And Act As A Simple

Asphyxiant. P-86

[11] Physical Properties

a) Physical Properties Provide Information On TheBehavior Of A Material

b) Color And Odor - In Its Natural State, Natural GasIs Colorless, Odorless And Tasteless

c) When Considering Odor As A Method ForDetecting Natural Gas Leaks, Responders ShouldRemember The Following:

d) Natural Gas Transported Via TransmissionPipelines Is Usually Transported In An P-86Unodorized State.


12/25



Page 12 of 25

e) In Certain Underground Release ScenariosInvolving Soil Conditions With A High Sand OrMoist Clay Content, The Concentration Of OdorantMay Be Reduced Or Leached


a) The Human Sense Of Smell Can Be DesensitizedTo The Odorant When Individuals Are Exposed ToLow Concentrations For An Extended Period OfTime.

b) Vapor Density the Weight Of A Pure Vapor OrGas Compared With The Weight Of An EqualVolume Of Dry Air At The Same Temperature

And Pressure. P-86

c) Natural Gas Is The Most Common Gas ThatEmergency Responders Will Encounter That IsLighter Than Air.

[13] 4H MEDIC ANNA:

4H

H = Hydrogen (VD = 0.069)

H = Helium (VD = 0.14)H = Hydrogen Cyanide (VD = 1.0)

H = Hydrogen Fluoride (VD = 0.34) P-87

[14] 4H MEDIC ANNA:

Medic

M = Methane (VD = 0.6)

E = Ethylene (VD = 0.97)

D = Diborane (VD = 0.96)

I = Illuminating Gas (10% Ethane And 90%Methane Mixture -VD = 0.6)

C = Carbon Monoxide (VD = 0.97) P-87


13/25



Page 13 of 25

[15] 4H MEDIC ANNA:

Anna

A = Anhydrous Ammonia (VD = 0.588)

N = Neon (VD = 0.7)

N = Nitrogen (VD = 0.96)

A = Acetylene (VD = 0.90) P-87


a) Boiling Point the Temperature At Which A LiquidChanges Its Phase To A Vapor Or Gas. NaturalGas Has An Extremely Low Boiling Point Of -259F (-161 C). In Comparison, Propane Has ABoiling Point Of-44 F (-42 C).

b) Vapor Pressure The Vapor Pressure Of NaturalGas At 60 F (15.5 C) Is Approximately 120 Psi.

c) Solubility Natural Gas Is Slightly SolubleIn Water. P-87

d) Simple Asphyxiant Natural Gas Is GenerallyConsidered A Non-toxic Material.

[17] Combustion Characteristics OfNatural Gas

a) Chemical Properties Are The IntrinsicCharacteristics Or Properties Of A SubstanceDescribed By Its Tendency To Undergo ChemicalChange. Chemical Properties Typically ProvideResponders With An Understanding Of How A

Material May Harm.

i) Requirements For Combustion

ii) Combustion Is A Chemical Reaction. P-88

iii)The Combustible Ingredients In Natural GasAre Hydrocarbons Consisting Of One PartCarbon And Four Parts Of Hydrogen (CH4).


14/25



Page 14 of 25

[18] Flammable (Explosive) Range

a) The Flammable Or Explosive Range Is Defined AsThe Range Of Gas Or Vapor Concentration(Percentage By Volume In Air) That Will Burn OrExplode If An Ignition Source Is Present.

b) Limiting Concentrations Are Commonly Called TheLower Flammable (Explosive) Limit And TheUpper Flammable (Explosive) Limit. P-89

[19] Flammable (Explosive) Range

a) Most Combustible Gas Indicators (CGI) AndFlammable Gas Detectors Are Set To Alarm At10% Of The LEL Of The Gas Upon Which TheSensor Is Calibrated (Approximately 4,000 Ppm).

P-89


a) Ignition Temperature

i) Even With An Ideal Natural Gas And AirMixture, There Must Still Be An Ignition SourcePresent For Combustion To Occur. TheIgnition Temperature Of Natural Gas Is1,200F (649 C) P-89


a) Heat Value

i) The Purpose In Using Any Fuel Is To DevelopAs Much Heat As Possible Per Cubic Foot OfFuel Gas. The Heat Produced By BurningNatural Gas Is Expressed In British ThermalUnits (Or Btus) Per Cubic Foot Of Gas.The Heating Value For Natural Gas Is 1,012BTU/Ft3. In Comparison, The Heating P-89


15/25



Page 15 of 25

Value Of Propane Vapor Is 2,488 BTU/Ft3.

[22] Natural Gas And Its CombustionProducts

a) When The Combustion Process Is Incomplete,Harmful Products Of Combustion Are Generated.

b) Carbon Monoxide

c) Exposure Values For Carbon MonoxideInclude The Following: P-90

i) American Society Of Heating, RefrigerationAnd Air Conditioning Engineers (ASHRAE)

Ventilation Standard 62-89 Specifies AMaximum Permissible Concentration Of 9 PpmOf CO In Residential Living Areas.

ii) The Occupational Safety And HealthAdministration (OSHA) Has Established An 8-hour Time Weighted Average / Threshold LimitValue (TLV/TWA) Of 35 Ppm.

[23] Other Gas Productsa) There Are Other Gases And Special Products

That Are Transported Through Gas Pipelines.

b) Ethane Is A Simple Hydrocarbon (C2H6).

c) Ethylene (C2H4) Is A Colorless Flammable GasWith A Faint Odor That Is Sweet And Musty.

d) Methane Gas Is A Flammable Gas OftenGenerated By The Anaerobic Bacterial P-91Decomposition Of Organic Material In Landfills

And Swamp Areas.

e) Chlorine Is A Greenish-yellow, Non-flammableGas With A Distinctive, Pungent Odor.


16/25



Page 16 of 25

[24] Natural Gas Gathering AndTransmission Pipeline Operations

a) Natural Gas Gathering Systems

b) The Natural Gas Is Collected Through A Series OfSmaller Diameter, Low Pressure PipelinesNormally Referred To As Gathering Lines

c) From The Gathering System, Natural Gas P-92May Be Injected Into A Transmission PipelineSystem Or Transported Directly To A StorageFacility Or A Gas Processing Plant.

[25] Gas Processing And TreatmentFacilities

a) Natural Gas Liquids

b) Water

c) Liquefied Petroleum Gas (LPG)

d) Ethane P-94

e) Hydrogen Sulfide (H2S)

f) Carbon Dioxide (CO2).

[26] Natural Gas Transmission Pipelines

a) Large Transmission Pipelines Are The InterstateHighways Of The Natural Gas TransportationSystem. They Are Generally The Link BetweenGathering Systems And Distribution Systems.

b) These Are High-strength Welded Steel PipelinesWith Diameters Of Up To 48-inches.

P-94


17/25



Page 17 of 25

[27] Natural Gas Transmission Pipelines

a) Operating Pressures Can Range From 300 To1,500 Psi, And Compressor Stations Are Used To

Maintain Pipeline Operating Pressures.b) Most Natural Gas Transmission Pipelines Cover

Large Geographical Areas And May Be SeveralHundred Miles Long.

P-94

[28] Compressor Stations

a) The Movement Of Natural Gas Through A PipelineSystem Is No Different Than Moving Water In AFire Department Relay Operation.

b) Similarly, As Natural Gas Flows Through APipeline, The Pipeline Pressure Will DecreaseDue To Friction Loss And Elevation Differences.


a) Pipeline Pressure Cannot Be Allowed To DropBelow The Required Delivery Pressure At TheDelivery Points Or The Flow Will Cease.

b) Compressor Stations May Be Either Attended OrUnattended

P-95


18/25



Page 18 of 25


a) Equipment At A Compressor Station Will VaryDepending Upon A Number Of Factors.

b) Engine And Compressor Units (A)

c) Positive-displacement Compressors

d) Continuous-flow Compressors

e) Piping And Piping Manifolds (B) P-96

f) Filter Separators (C)

g) Cooling Units (D)

h) Pig Manifolds

i) Generators (E)

j) Gas And Fire Detection AndSuppression Systems.

[31] Gate Settings / Main Line Valves

a) In Addition To Compressor Stations, Gate SettingsOr Main Line Valves (MLV) Are Installed AlongThe Natural Gas Transmission Pipeline System ToHelp Isolate Or Control The Flow Of The Gas.

b) Emergency Response Personnel Should NeverAttempt To Isolate Any Pipeline Valves OnTransmission Or Distribution Lines P-97

[32] Gate Settings / Main Line Valves

i) Operation Of Pipeline Valves And SystemsMust Be Under The Full Control And Direction

Of The Pipeline Operator. Failure To Do SoMay Create Additional Problems That AreWorse Than The Original Event.

P-97


19/25



Page 19 of 25

[33] Transmission Pipeline Customers

a) The Purpose Of A Natural Gas TransmissionPipeline Is To Transport Natural Gas FromProduction Locations To Customers Who Will BeUsing It.

b) Large Industrial Customers And ManufacturersMay Contract Directly With The Natural GasTransmission Pipeline Operator For Gas P-97Delivery To Their Facilities.

c) The Largest Customer Base For Natural GasTransmission Pipeline Companies Is Comprised

Primarily Of Local Distribution Companies.

[34] Natural Gas Storage

a) Storage Serves Two Major Purposes:

b) It Helps To Maximize The Use Of Pipeline SystemCapacity Year-around

c) Creates Additional Flexibility In Operation Of ThePipeline System.

d) Natural Gas May Be Stored In Either UndergroundOr Aboveground Storage Facilities.

e) Depleted Gas Reservoirs P-98

f) Aquifers

[35] Natural Gas Storage

a) Underground Salt Caverns And Formations

i) Salt Domes

ii) Salt Bedsb) Aboveground Storage. Natural Gas May Also Be

Converted To Liquefied Natural Gas (LNG), AndThen Stored As A Cryogenic Liquid InAboveground Storage Tanks. P-100


20/25



Page 20 of 25

[36] Natural Gas Distribution PipelineOperations

a) Gate Stations Or City Gates

b) Distribution Mains

c) Regulator Stations

d) Main Distribution Valves

e) A Farm Tap P-100


P-101


a) Distribution Systems

b) Bare Steel Ranges From .75 To 8-inches InDiameter, And Is Used For Pressures Up To 60Psi.

c) Wrapped Or Coated Steel Piping Ranges From .5To 30-inches In Diameter, And Is Used For

Pressures Up To Several Hundred Psi. P-102The Coating Is Usually Yellow Plastic OrBrown Paper.

d) Cast Iron Ranges From 4 To 20-inches InDiameter, And Is Usually Used For Low PressureGas (.25 Psi).


21/25



Page 21 of 25


i) Wrought Iron Ranges From 2 To 8-inches In

Diameter, And Is Used For Pressures Up To60 Psi.

ii) Polyethylene (PE) Plastic Piping Ranges From.5 To 8-inches In Diameter, And May Be UsedFor Pressures Up To 100 Psi. PE PipingIs Also Susceptible To The Buildup Of P-102Static Electricity And May Possibly CauseThe Ignition.


a) A Pressure Relief Valve (PRV) Venting To TheAtmosphere Is Normally Performing Properly.

i) A PRV Should Never Be Shut-off, Isolated OrRestricted By Emergency ResponsePersonnel.

P-102

[41] Natural Gas Service Meters

a) Natural Gas Customers Have AMeter To Measure The AmountOf Gas Being Used For Billing Purposes.

b) Every Gas Meter Will Have A Shut-off ValveLocated On The Supply Side (I.E., Upstream) OfThe Meter.

c) Meters May Be Classified By Pressure Or Use

d) Intermediate Pressure (2 60 Psi) And P-103High Pressure (60 300 Psi) Meters WillHave A Regulator Between The Supply Side AndThe Meter To Reduce The Pressure.


22/25



Page 22 of 25


P-104


P-103


a) Multiple Meters

b) Industrial Meters

c) Earthquake Shut-off Valves

d) Curb Valvese) Main Valves

P-105


23/25



Page 23 of 25

[45] Clues Of A Natural Gas PipelineIncident

a) What You See

b) Browning Or Discolored Vegetation That IsOtherwise Green Along A Pipeline Right-of-way.

c) Presence Of A Vapor Cloud Or Mist Around ThePipeline Right-of-way.

d) Dirt Being Blown Into The Air. P-105

e) Bubbles Coming From A Pond Or River.

[46] Clues Of A Natural Gas PipelineIncident

a) Fire Coming Out Of The Ground.

b) Presence Of Construction Or ExcavationEquipment In The Area, Such As Backhoes,

Drilling Rigs, Telecommunications Vehicles, Etc.c) Ice Ball Around The Pipeline.

d) Collection Of Dead Insects. P-105

e) Odor Of Mercaptan Or Sulfur. Remember ThatTransmission Pipeline Systems Typically HandleUnodorized Natural Gas.

f) What You Hear

i) Unusual Hissing Or Roaring Sound Along APipeline Right-of-way.


24/25



Page 24 of 25

[47] Street Smart Tips

a) Natural Gas Is Lighter Than Air And Will Rise.b) Natural Gas Can Be Trapped Under Asphalt,

Concrete Or Frozen Ground, And Move LaterallyFrom Its Source In Underground Conduit, CasingsAnd Right-of-ways.

c) Underground Leaks Of Natural Gas Will P-106Follow The Path Of Least Resistance. SoilThat Has Been Disturbed By Excavation Will AllowFor The Easier Passage Of Natural Gas. InAddition, Certain Soils May Cause The MercaptanOdorants To Be Scrubbed From The NaturalGas.


a) A Combustible Gas Indicator (CGI) Or FlammableGas Detector Will Be Required To Determine TheConcentration Of Natural Gas Vapors Present. IfYour Detector Is Not Calibrated On Methane, ACalibration Curve Or Factor Will Be Required ToDetermine The Actual Reading Of Natural

Gas Present. P-106

b) Eliminate All Ignition Sources. Do Not OperateVehicles Or Equipment That Can Produce ASpark, Including Door Bells, Telephones And LightSwitches When A Natural Gas Leak Is Suspected.


a) If Ventilating An Enclosed Space, Remember TheExplosive Limits Are 4-15% Gas In Air. Ventilation

May Momentarily Increase The Hazard As YouPass Though This Range.

b) Natural Gas That Is Trapped In Enclosed Areas OrConfined Spaces Will Cause A SignificantExplosion If Ignited. P-106

c) Natural Gas Vapors Will Quickly Flash Back ToTheir Source When Ignited.


25/25



d) Natural Gas Fires Will Give Off TremendousAmounts Of Radiant Heat And Provide SignificantExposure Concerns.

[50] Summary

a) Natural Gas (CH4) Is The Predominant ProductTransported In Gas Pipelines.

b) Natural Gas (CH4) Is A Clean-burning Fuel ThatConsists Of Approximately 94% Methane, 4%Ethane, And The Remaining 2% Of Other Gases,Including Butane, Carbon Dioxide, NitrogenAnd Iso-pentane. P-106

c) An Odorant That Smells Like Sulfur Or RottenEggs is Added To Natural Gas So That It Can BeDetected By Human Smell At Concentrations

[51] Summary

a) Natural Gas Will Burn In The Presence Of AnIgnition Source When It Is Within Its FlammableRange Of Approximately 4 To 15%.

b) Natural Gas Is Initially Collected FromUnderground Wells Into A Series Of Small, LowPressure Pipelines Normally Referred To AsGathering Lines.

P-106

Documents

Instructor Guide 5