Refrigerant explosion

mechanism

COMPANY CONFIDENTIAL

May-2016

COMPANY CONFIDENTIAL

REFRIGERANT EXPLOSION MECHANISM

•General information

•Flammability characteristics

•Ignition sources

•Consequences of explosions

Summary

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GENERAL INFORMATION

ATEX = Explosive Atmosphere

FuelCombustion

agent

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Gas, vapour, mist and dusts

Oxygen in the air or chemical products

Electric arc, electrostatic or mechanical spark, hot

surfaces or flames, etc.

GENERAL INFORMATION

Fuel: can burn

Combustion agent: facilitates

combustion

Ignition source: initiates combustion

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FLAMMABILITY CHARACTERISTICS

LEL UEL

Explosive range

0%

100% 0%

100%

FLUIDS EXPLOSIVE RANGE

R1234ze(E) 6.5% Explosive ...%

R32 13% Explosive 33%

HRD103 9.9% Explosive …%

MAINS GAS 5% Explosive 15%

Fuel

Combustion

agent

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FLAMMABILITY CHARACTERISTICS

Example: Machine containing 400kg of R1234ze(E)

fluid (LEL=6.5%) in room (400m3)

= An explosion is possible in the room if an ignition source is present

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Case of a massive leak in the room(not @safety relief valves)

=

=

Air/fuel concentration in the room:

21% of R1234ze(E)

FLAMMABILITY CHARACTERISTICS

Concept of ATEX zones

(explosive atmospheres)

Emission source

Concentration

(LEL↔UEL)

Probability

Duration

EXPLOSIVE

AREA

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FLAMMABILITY CHARACTERISTICS

Concept of ATEX zones

(explosive atmospheres)

EXPLOSIVE

AREA

A location in which an explosive atmosphere is either permanently

present, or present for long periods of time, or frequently presentZone 0

A location in which it is likely that a gaseous explosive atmosphere

will occasionally occur during normal operationZone 1

A location in which a gaseous explosive atmosphere is not likely to

occur in normal operation but which, if it does, will only persist for

a short length of time.

Zone 2

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FLAMMABILITY CHARACTERISTICS

Concept of ATEX zones

(explosive atmospheres)

Zone 2: rare

Zone 0:

Permanent

Zone 1:

occasional

EXPLOSIVE

AREA

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10

Flammable liquid

'X' tank

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Zone 0

Zone 1

Zone 2

Example of ATEX zones choice

FLAMMABILITY CHARACTERISTICS

FLAMMABILITY CHARACTERISTICS

Example of ATEX zones on the CARRIER site

EXPLOSIVE AREA:

zone 2

0.5 m

0.5 m

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IGNITION SOURCES

The ignition sources:

One-off ,ie: Sparks PERMANENT, ie:Hot surfaces

Minimum ignition

energy (MIE):

< 300 µJ 'example'

Autoignition

temperature

(368°C for R1234ze,

530°C for R32)

Example:

Static electricity

produced by the

human body > 5mJ

Example:

Brazing flame 700°C< Temp.< 1000°C

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SH

OR

T L

AS

TIN

G T

IME

LO

NG

LA

ST

ING

TIM

E

R1234ze

~ 60 mJ

IGNITION SOURCES

Example of ignition sources:

Electricity (power

equipment,

instrumentation on the

machine, in the room)

Static electricity

(insulating material,

humans, floors, etc.)

Mechanical impact

(machines and

structures, tools)

Flames and hot

surfaces (soldering

& brazing work,

etc.)

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CONSEQUENCES OF EXPLOSIONS

Impact on people: each year, the industry experiences

• about 1500 explosions

• about 500 injured, 20 fatalities

Economic and social impact: loss of equipment and facilities, loss of jobs

Environmental impact: release of toxic products into the environment

Explosion of a gas

Video

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