FOG & HAZEFOG & HAZELooking into understanding Looking into understanding

fog and its various fog and its various applications.applications.

Presenter: Thierry PouliotPresenter: Thierry Pouliot

What is Fog?What is Fog? Meteorological phenomenonMeteorological phenomenon

Water dropletsWater droplets Fine ice crystalsFine ice crystals

Near-freezing air temperatureNear-freezing air temperature Water saturationWater saturation

How does it happen?How does it happen?

3 common types of fog3 common types of fog

Advection fogAdvection fog

Radiation fogRadiation fog

Evaporation fogEvaporation fog

Advection FogAdvection Fog

Vapor condensation Vapor condensation around dust particlesaround dust particles

Warm air blown Warm air blown across a cool across a cool surface, like wind surface, like wind from the oceanfrom the ocean

Creates fogCreates fog

Radiation FogRadiation Fog

Cool GroundCool Ground Warm airWarm air Vapor condensation Vapor condensation

around dust particlesaround dust particles

Creates fogCreates fog

Evaporation FogEvaporation Fog

Additional water vapor Additional water vapor enters an already enters an already saturated air near saturated air near maximum vapor maximum vapor pressure (Kpa) pressure (Kpa)

The air is cooled down to The air is cooled down to dew pointdew point

Creates fogCreates fog

Natural fog vs Artificial fogNatural fog vs Artificial fog

Comes mostly from Comes mostly from water water evaporation and evaporation and stagnant particlesstagnant particles

Is affected by air Is affected by air temperature, temperature, barometric pressure, barometric pressure, wind speed and water wind speed and water saturation.saturation.

May come from May come from pollution!pollution!

Comes from various Comes from various chemicals and chemicals and processesprocesses

Is affected by air Is affected by air temperature, temperature, barometric pressure, barometric pressure, wind speed and water wind speed and water saturation.saturation.

May cause pollution!May cause pollution!

Creating artificial fogCreating artificial fog

Creating fog requires 3 key elements:Creating fog requires 3 key elements:

A Method of productionA Method of production

Some form of chemical compoundSome form of chemical compound

Ambiant air supportAmbiant air support

Methods of productionMethods of production

Fog / Haze GeneratorFog / Haze Generator

Fog / Haze MachineFog / Haze Machine

« Cracker »« Cracker »

OthersOthers

Fog Generators vs Fog MachinesFog Generators vs Fog Machines

Quiet!Quiet! Constant outputConstant output 100% duty cycle100% duty cycle Gas Gas used as:used as:

– Non-flammable Non-flammable propellantpropellant

– PurgePurge– Fog Fog dispersiondispersion

LouderLouder Pressure Pressure variationvariation Sometimes needs a Sometimes needs a

pause to reheatpause to reheat.. No gas requiredNo gas required

« Crackers »« Crackers » Thermal cracking: petrochemical industry…Thermal cracking: petrochemical industry…

… … or the nuclearor the nuclear

So, « Crackers »?So, « Crackers »?

Cracking modifies chemicals at the Cracking modifies chemicals at the molecularmolecular level level

Cracking requires Cracking requires very highvery high operating operating temperature and / or pressuretemperature and / or pressure

Artificial fog chemical compoundsArtificial fog chemical compounds

MINERAL OIL BASEMINERAL OIL BASE

- Inert chemical - Inert chemical compoundcompound

- Byproduct of - Byproduct of petroleum distillationpetroleum distillation

- Can be broken into - Can be broken into microscopic particlesmicroscopic particles

- Light weight- Light weight

- Long lasting- Long lasting

GLYCOL BASEGLYCOL BASE

- Disperses heat - Disperses heat rapidlyrapidly

- Hygroscopic - Hygroscopic chemical compoundchemical compound

-Heavier than oilHeavier than oil

-Larger particlesLarger particles

-Short life as fogShort life as fog

OTHERSOTHERS

GlycerolGlycerol

(GLYCERIN)(GLYCERIN)

Potassium Nitrate Potassium Nitrate (SALTPETRE)(SALTPETRE)

Mineral oil-based fluidMineral oil-based fluid

MDG Neutral (suitable MDG Neutral (suitable for standard MAXfor standard MAX™ ™ and ATM™ series).and ATM™ series).

Odourless and insipid.Odourless and insipid. Produces fine particles (0.5 ~ Produces fine particles (0.5 ~

0.7µm)0.7µm) Long hang time (Brownian Long hang time (Brownian

Motion) – low gravitational Motion) – low gravitational pullpull

Low coalescence, high Low coalescence, high dispersion.dispersion.

Mineral oil?Mineral oil?

Inert, non-reactive, non-irritant Inert, non-reactive, non-irritant Used as a medically-supervised laxativeUsed as a medically-supervised laxative Main ingredient in Baby oil / lotionsMain ingredient in Baby oil / lotions Cosmetic cold creams, make-up removerCosmetic cold creams, make-up remover Used as a machanical lubricant / coolantUsed as a machanical lubricant / coolant Used as a preservative (lithium) and Used as a preservative (lithium) and

oxydation inhibitor (nihontoxydation inhibitor (nihontō)ō) Aka - Paraffin, Petrol gellyAka - Paraffin, Petrol gelly

Glycol-Based fluidGlycol-Based fluid

MDG LOW FOG fluid MDG LOW FOG fluid (suitable for standard Ice-(suitable for standard Ice-FogFog™ series) and MDG ™ series) and MDG DENSE or WB2 fluid DENSE or WB2 fluid (suitable for standard (suitable for standard MM™ series).MM™ series).

Distinctive smell, acrid tasteDistinctive smell, acrid taste Produces larger particles (2.5 ~ Produces larger particles (2.5 ~

20 µm)20 µm) Variable hang time Variable hang time Higher coalescence, high Higher coalescence, high

dispersion.dispersion.

Glycol?Glycol?

2 main types used in fog: Diethylene and 2 main types used in fog: Diethylene and Propylene Glygols Propylene Glygols

Hygroscopic compoundHygroscopic compound Fast heat dissipationFast heat dissipation

Other uses of GlycolsOther uses of Glycols

Industrial coolantIndustrial coolant Automotive coolantAutomotive coolant Anti-perspirantAnti-perspirant Componant in the manufacturing of resins, Componant in the manufacturing of resins,

polyesters, explosives, and vaccinespolyesters, explosives, and vaccines Used as a preservative to replace Used as a preservative to replace

formaldehyde. formaldehyde.

Safety StandardsSafety Standards

Using your fog machine / cracker / generatorUsing your fog machine / cracker / generator

NEVER NEAR PEOPLENEVER NEAR PEOPLE– Most fog machines operate either under pressure Most fog machines operate either under pressure

or at high temperatures. or at high temperatures. – Most fogs are still in a liquid state (Wet Fog)Most fogs are still in a liquid state (Wet Fog)– Most fogs are hot near nozzle / exit portMost fogs are hot near nozzle / exit port– ALL FOGS LEAVE RESIDUESALL FOGS LEAVE RESIDUES

INERT GASESINERT GASES

Unlike Noble gases, Inert gases are not Unlike Noble gases, Inert gases are not necessarily elemental.necessarily elemental.

Most are compoundsMost are compounds Complete valence electron (last orbit full)Complete valence electron (last orbit full)

Inert gases: Helium and Neon (elemental) Inert gases: Helium and Neon (elemental) Carbon Dioxide (COCarbon Dioxide (CO22)and Nitrogen (N)and Nitrogen (N22))

Inert gases usageInert gases usage

Non-flammableNon-flammable Readily available everywhereReadily available everywhere Relatively cheapRelatively cheap Standard safety code throughout the EUStandard safety code throughout the EU

Fog applications:Fog applications:

•First Response TrainingFirst Response Training

Final tip of the dayFinal tip of the day

LESS IS MORELESS IS MORE