Kirk Richardson

8/13/2019 Kirk Richardson

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LNGLNG Vapor and Fire ControlVapor and Fire Control

Using High Expansion FoamUsing High Expansion Foam

Kirk RichardsonKirk RichardsonEmergency Services Training InstituteEmergency Services Training Institute

Texas Engineering Extension ServiceTexas Engineering Extension ServiceTexas A&M University SystemTexas A&M University System



Vapor Control



Fire Control

Ignition of an unconfined LNG vapor cloudIgnition of an unconfined LNG vapor cloud

Storage TemperatureStorage Temperature --260260F/F/ --162162CC

A cryogenic l iquidA cryogenic l iquid

Boiling PointBoiling Point --258F/258F/ --161161CC


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ExpansionExpansion

CoefficientCoefficient

ButaneButane 222222

PropanePropane 290290

LNGLNG 620620

NitrogenNitrogen 642642

HydrogenHydrogen 788788

Expansion RatioExpansion Ratio 620 to 1620 to 1 Burn RateBurn Rate 12.5 mm/minute12.5 mm/minute

(Steady State)(Steady State) (Gasol ine(Gasoline 4 mm/minu te)4 mm/minute)

Initial vaporization rate on waterInitial vaporization rate on water

5050 cfmcfm vapor/sq. ft.vapor/sq. ft.

Initial vaporization rate on landInitial vaporization rate on land

vaporization ratesvaporization rates


Steady state vaporization rateSteady state vaporization rate


Vapor Control

Confined spill on landConfined spill on landConfined spill on landConfined spill on land

Vapor Control


Vapor Control

1 cfm / sq ft



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Vapor Control


Vapor Control


Vapor Control

The Value of

Confinement

Vapor Cloud (down wind plume) CharacteristicsVapor Cloud (down wind plume) Characteristics

before concentrations fall below LFL

(5%).

Positive buoyancy

LNGLNGvaporsvaporsLNGLNGvaporsvapors

Specific gravity (gas).5539

Vapor Cloud (down wind plume) CharacteristicsVapor Cloud (down wind plume) Characteristics

Neutral buoyancy -160F/ -107C

Negative Buoyancy

LPG vaporsvapors

Always hug the ground.

LPG vaporsvapors

Always hug the ground.

-2600F

Specific gravity (gas)1.5 2.0

Foam ClassificationFoam Classification

NFPA Gaz de France

High Expansion 200:1 to 1000:1 400:1 to 1000:1

Medium Expansion 20:1 to 200:1 75:1 to 400:1

Low expansion < 20:1 < 75:1

photograph courtesy of Angus Fire / a UTC Fire & Security Company


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Foam ApplicationFoam Application

High Expansionfoam is a toolused to gaincontrol of an LNGincident

High Expansionfoam is a toolused to gaincontrol of an LNGincident

Used to controlLNG vapors

Used to controlLNG fires

Used to controlLNG vapors

Used to controlLNG fires

Sonatrach- Arziew

High expansion foam works in conjunction with passivemethods for maintaining control of an incident.High expansion foam works in conjunction with passivemethods for maintaining control of an incident.

photograph courtesy of Angus Fire / a UTC Fire & Security Company


High expansion foam works in conjunction with passivemethods for maintaining control of an incidentHigh expansion foam works in conjunction with passivemethods for maintaining control of an incident

photographs courtesy of Angus Fire / a UTC Fire & Security Company





Vapor Control Techniques

Spill ConfinementSpill Confinement

Water CurtainsWater Curtains

Hi Ex FoamHi Ex Foam

Vapor Control Techniques

Spill ConfinementSpill Confinement

Water CurtainsWater Curtains

Hi Ex FoamHi Ex Foam


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How Foam Works - Vapor Dispersion Allows for controlledAllows for controlled

vaporisationvaporisation

WarmsWarms vaporsvapors so they riseso they rise

Minimizes down windMinimizes down windplumeplume

Ice layer & ice tubes formIce layer & ice tubes form

Insulates LNGInsulates LNG

Regular foam topRegular foam top--upuprequiredrequired

Dynamic situation requiringDynamic situation requiringconstant monitoringconstant monitoring

graphic courtesy of Angus Fire / a UTC Fire & Security Company

Using High Expansion Foam for Vapor Control Vapor Control Techniques

LNG Pool FiresLNG Pool Fires Flame height is typicallytwo to three times thepool diameter.

Flame height is typicallytwo to three times thepool diameter.

60 ft60 ft

Pool FiresPool Fires

30 ft30 ft


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Water Application onWater Application on

a Burning Pool of LNGa Burning Pool of LNG

How Foam Works - Fire Control Foam allows controlled

LNG burn-off

Foam insulates & reducesradiation feedback to LNG

Fire intensity decreases

Ice layer & ice tubes form

Regular foam top-uprequired to maintain steadystate

Dynamic situation requiringconstant monitoring

graphic courtesy of Angus Fire / a UTC Fire & Security Company

The Use of High Expansion Foam for

Fire Control


Fire Contro l


Fire ControlFire ControlFire Control

...on a 200 m...on a 200 m22 LNG fire,LNG fire,

the foam causes thethe foam causes the

flame height to dropflame height to drop

from about 30 meters tofrom about 30 meters toabout 2 meters.about 2 meters.

-- GazGaz de Francede France


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Fire ControlFire Control

...the amount of...the amount of

radiation from a burningradiation from a burningLNG spill can beLNG spill can be

reduced by as much asreduced by as much as

95 % with some high95 % with some high

expansion foams.expansion foams.

-- American Gas AssociationAmerican Gas Association

Fire ControlFire Control

Expansion ratios and drain timesExpansion ratios and drain times

affect performance:affect performance:

Low expansion ratios will produce foamLow expansion ratios will produce foamthat is too wet (contains too much water)that is too wet (contains too much water)

this excess water will increasethis excess water will increasevaporization, hence the size of the firevaporization, hence the size of the fire

Rapid drain times will have the sameRapid drain times will have the same

effecteffect

Fire ControlFire ControlExpansion ratios and drain times affectExpansion ratios and drain times affect

performance:performance:

Higher expansion ratios will be:Higher expansion ratios will be:

drier and thus have less resistance todrier and thus have less resistance to

thermal effects (they will break down fasterthermal effects (they will break down fasterii i . i .

Expansion ratios and drain times affectExpansion ratios and drain times affect

performance:performance:

Higher expansion ratios will be moreHigher expansion ratios will be more

adversely affected by wind and thermaladversely affected by wind and thermal

updraftsupdrafts

Expansion ratios and drain times affectExpansion ratios and drain times affect

performance:performance:Just tell them you

thought it wasdisconnected.

Higher expansion ratios will be moreHigher expansion ratios will be more

adversely affected by wind and thermaladversely affected by wind and thermal

updrafts.updrafts.

Foam Expansion & Application Rates

Tests show 500:1 is optimum expansionTests show 500:1 is optimum expansion

ratio for vapour dispersion and fire controlratio for vapour dispersion and fire control

Most operators use 500:1 systemsMost operators use 500:1 systems

Practical application rates need to bePractical application rates need to be

higher than test, typicallyhigher than test, typically

higher rates give faster controlhigher rates give faster control

less risk of escalationless risk of escalation

less radiant heat damageless radiant heat damage


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Fire SuppressionUse of dry chemical:

Appl ication technique

is everything

but a higher flow rate

never hurt anything.

but a higher flow rate

never hurt anything.



Kirk RichardsonKirk Richardson

Emergency Services Training InstituteEmergency Services Training InstituteTexas Engineering Extension ServiceTexas Engineering Extension Service

Texas A&M University SystemTexas A&M University System

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