cng training

Copyright 2004 AFV Institute with limited permission to U.S. DOE.

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Compressed Compressed Natural Gas Natural Gas

as a as a Vehicle FuelVehicle Fuel


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Copyright 2004 AFVICopyright 2004 AFVI

This material is intended to be used for in-house trainers of NGV fleet operators to train drivers and other interested parties on how to safely fuel natural gas vehicles. The material may not be used to develop or deliver commercial training programs or for any purpose other than stated above.


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Drivers Need to KnowDrivers Need to Know

Introduction to natural gas

Why CNG as a vehicle fuel

Properties and characteristics of CNG

CNG fueling station safety practices

Fueling station safety equipment

Emergency procedures

Safe vehicle fueling procedures


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Module 1Module 1

Introduction Introduction toto

Compressed Compressed Natural GasNatural Gas


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Module 1Module 1Learning ObjectivesLearning Objectives

Understand why natural gas as a vehicle fuel

Understand where natural gas comes from

How natural gas is delivered to a CNG fueling station

Environmental benefits


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Why CNG?Why CNG?

Domestically produced

Large existing underground distribution network in place

Large installed base of vehicles in U.S.


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Why CNG? - 2Why CNG? - 2

Clean air benefits

– 66% less carbon monoxide (CO)

– 68% less non-methane hydrocarbons (NMOG)

– 87% less oxides of nitrogen (NOx)

– 40% less particulate matter (PM10)


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Why CNG? - 3Why CNG? - 3

Does not contaminate ground water or soil

Is an EPAct alternative fuel


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Module 2Module 2

Properties Properties and and

Characteristics Characteristics of CNGof CNG


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Understand natural gas and how it compares to other fuels

Be familiar with the characteristics of natural gas

Understand potential health and safety hazards


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Physical PropertiesPhysical Properties

Natural gas occurs underground and may be mixed with petroleum.

Chemical composition

– Mixture of methane, ethane, propane and butane

– Natural gas is mostly (85% to 96%) methane


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Compared to Other FuelsCompared to Other Fuels

Natural Gas CH4

Propane C3H8

Gasoline C8H30

Diesel C14H30

Biodiesel (Palmitic) C15H31CO2CH3

Methanol CH3OH

Ethanol CH3CH2OH


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Specific GravitySpecific Gravity

.55 - .65 (air = 1) Since natural gas is lighter than

air it rises when released into the atmosphere

Both the fuel and vapors of Biodiesel, E85, and Propane are heaver than air


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Appearance & SmellAppearance & Smell

Colorless and tasteless

Odorless (but odorants are added for safety)


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Health &Health &Safety HazardsSafety Hazards

Non-toxic

Simple asphyxiant

– Inhalation is primary route of exposure

– Overexposure symptoms: shortness of breath, unconsciousness

CPR recommended to overcome over exposure


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Physical StatePhysical State

Compressed to allow maximum fuel storage

– 3000 or 3600 psi

Measured for sale in mass weight– 5.66 pounds = 1 gasoline gallon

equivalent (GGE)

CNG is 117 octane fuel


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Flammability Flammability

Burns with a pale, faintly luminous blue flame at 1100° F

– Gasoline 630o F

– Diesel 125o F

Fuel-to-air ratio is 4% (LFL) to 16% (UFL)

– Gasoline 1.3% (LFL) to 7.6% (UFL)

– Diesel .3% (LFL) to 10% (UFL)


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Fire ExtinguishingFire Extinguishing

Fire extinguisher(s) located at or near the dispenser

If flame is extinguished without stopping gas flow, air/fuel mixture may reignite

Use a fire extinguisher only if properly trained to do so by qualified person


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Module 3Module 3

CNG Fueling CNG Fueling Station EquipmentStation Equipment


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Understand different types of fueling stations

Be familiar with various components of a CNG fueling station


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Types of Fueling StationsTypes of Fueling Stations

Time - Fill– Time - fill dispenser

• Example: school bus


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Types of Fueling Stations Types of Fueling Stations - 2- 2

Time - Fill– Refueling appliance

• FuelMaker: Individual vehicle or small fleets


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Types of Fueling Stations Types of Fueling Stations - 3- 3

Cascade Fast - Fill– Cyclical fueling

patterns

– Public fueling


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Fueling Station Fueling Station ComponentsComponents

Gas dryer

Compressor(s)

CNG storage

Dispenser(s)


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Fueling Station Fueling Station Components - 2Components - 2

Card reader

Emergency shutdown system

Fire extinguisher


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Module 4Module 4

Emergency Emergency Action PlanAction Plan


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Know purpose and content of Emergency Action Plan

Be familiar with emergency equipment Understand emergency actions


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Purpose of Purpose of Emergency Action PlanEmergency Action Plan

Identification of emergencies

Action items

Notification procedures

Evacuation procedures

Safety systems

Emergency event action items


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Facility LayoutFacility Layout

Compressor

CNG storage tanks

Emergency Shutdown Devices (ESDs)

Fire extinguishers


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Facility Layout - 2Facility Layout - 2

Pre-planned evacuation route

Designated assembly area(s)

Street address of facility


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Safety PracticesSafety Practices

Emergency telephone numbers– Fire department

– Emergency medical help

– Police

–Maintenance

–Adjoining facilities

Safety Signs


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Safety Practices – 2Safety Practices – 2

Equipment Inspection:

– Defective equipment• Dispenser hoses• Fueling nozzle and receptacle

– Report unsafe conditions to maintenance technician or station attendant


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Safety Practices – 3Safety Practices – 3

Cell phones and static discharge danger– CNG/air mixture is flammable like gasoline vapors

– CNG Fueling system is sealed, so there is no air in the fuel system at the station or on the vehicle

– Nevertheless, it is advisable to turn off/do not use cell phone during vehicle fueling

Do not re-enter vehicle during fueling


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Fire Safety RulesFire Safety Rules

Keep ignition sources away from fuel

Do not light matches or smoke cigarettes

Do not use cell phones while fueling vehicle


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Gas Release at Gas Release at DispenserDispenser

Close nozzle valve

Turn dispenser quarter turn shut-off valve to the off position

Disconnect fueling nozzle from vehicle and re-attach to mounting bracket on dispenser

Report situation to facility maintenance and/or station attendant


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Fire Involving CNGFire Involving CNG

Evacuate immediate area of fire

Press ESD button

Prevent other people from entering the danger zone

Do not attempt to extinguish CNG fire without training


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Fire During Fire During Vehicle FuelingVehicle Fueling

Do not attempt to disconnect fueling nozzle from vehicle

Direct others to evacuate immediate area

Press ESD button Call fire department


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Combustible Combustible Debris FireDebris Fire

Press ESD button

Extinguish only if trained and it is safe to do so

Near equipment, extinguishing should be attempted only by qualified fire fighters


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Module 5Module 5

Correct Use of Correct Use of Safety EquipmentSafety Equipment


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Understand how to correctly operate safety equipment

– Fire extinguisher

– Emergency shut-down device


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Correct Use of Correct Use of Safety EquipmentSafety Equipment

Fire Extinguisher

– Located on or adjacent to fueling island

–Used to eliminate air (oxygen) from fire

–Driver must be properly trained to fight (extinguish) a natural gas fire


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Correct Use of Correct Use of Safety Equipment - 2Safety Equipment - 2

Emergency shut-down device (ESD)

– Located on or adjacent to fueling island

–Activation will close at least two isolation valves, causing the compressor and gas flow from storage to the dispenser to stop


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Module 6Module 6

NGV Technology NGV Technology and and

Safety Features Safety Features


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Understand how natural gas vehicles (NGVs) work

Understand how NGVs differ from gasoline and diesel powered vehicles

Be knowledgeable about the four types of on-board fuel storage cylinders


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CNG Fuel SystemCNG Fuel System

Fuel receptacle: Flow fuel from dispenser nozzle into fuel storage cylinders

High-pressure fuel lines: flow CNG from fuel storage cylinders to pressure regulator

Manual quarter turn shut-off valve: can stop the flow of CNG from the fuel storage cylinders to the pressure regulator


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CNG Fuel System - 2CNG Fuel System - 2

Pressure regulator: Provides fuel pressure regulation to the fuel injectors

Fuel injectors: Flow CNG into the engine cylinder for combustion


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NGVs vs. Gasoline & Diesel NGVs vs. Gasoline & Diesel VehiclesVehicles

NGVs have sealed fuel systems

– No air or oxygen in fuel system

Vehicle fuel is in a gaseous form

– If fuel leaks, vapors will float upward

Vehicle fuel requires 1100o F to ignite

– High temperature not usually available


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On-Board Fuel Storage On-Board Fuel Storage System System

Fuel storage cylinder types:– Type 1: All metal (steel or aluminum)

– Type 2: Hoop-wrapped steel or aluminum

– Type 3: Fully-wrapped steel or aluminum

– Type 4: All composite (non-metallic)


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On-Board Fuel Storage On-Board Fuel Storage System - 2System - 2

CNG fuel storage cylinder useful life is 15 years from date of manufacture

Visual inspection required by NHTSA at 36,000 miles or 36 months

Fuel storage cylinders hold CNG at 3,000 or 3,600 psi @ 70o F


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Module 7Module 7

How to Fuel How to Fuel a a

CNG Vehicle CNG Vehicle


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Be familiar with fueling instructions

Understand fueling nozzle/receptacle operation


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Fueling InstructionsFueling Instructions

Open the fuel door and remove the protective cap on the vehicle fuel receptacle

Remove the fueling nozzle from the dispenser

Inspect the fueling hose and nozzle for damage

Place the nozzle on the receptacle and pull back to insure it is secure


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Fueling Instructions - 2Fueling Instructions - 2

Turn fueling valve handle on the nozzle to open position

Swipe fueling card through card reader

Turn dispenser fueling handle to the on position

After fuel stops flowing, turn dispenser fueling handle to the off position


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Fueling Instructions - 3Fueling Instructions - 3

Turn fueling valve handle on the nozzle to the vent position

Remove the nozzle from the receptacle and place it back on the dispenser

Replace the protective cap on the vehicle fuel receptacle


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FuelingFueling

Nozzle operation

Receptacle characteristics


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Fueling - 2Fueling - 2

NGV 1 nozzle

– Type 1

– Typical public fueling nozzle


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Fueling - 3Fueling - 3

NGV 1 nozzle– Type 2

– Typical fleet fueling nozzle

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