ver2-0 part 01 ignition properties

8/8/2019 Ver2-0 Part 01 Ignition Properties

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Part 1 Hazardous Areas

GENERAL PRINCIPLES

SOURCES OF IGNITION

Ver: 2.0


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Fire Triangle

FUEL

(GAS, VAPOUR, MISTS) OR DUSTS

AIR21% OXYGEN

79% NitrogenSOURCE OF IGNITION


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Flammable (Explosive) Limits

UPPERUPPER

EXPLOSIVEEXPLOSIVE

LIMIT (LIMIT (UELUEL) %) %

Too Rich

Insufficient

Oxygen

LOWERLOWER

EXPLOSIVEEXPLOSIVE

LIMIT (LIMIT (LELLEL) %) %

Too Weak

Insufficient

Fuel

MATERIALSMATERIALS LEL%LEL% UEL%UEL%

Propane 1.7 10.9

Ethylene 2.3 36

Hydrogen 4.0 77

Kerosene 0.7 5.0

Acetylene 2.3 100

FLAMMABLE

RANGE

(Explosive Range)

Play Video


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Sources Of Ignition

EXTERNAL- Flames, Welding, Electrical Equipment

CHEMICAL REACTION

- Exothermic Runaway

PLANT OPERATIONS

- Static Electricity, Mechanical Friction, Friction Sparks

SUBJECT TO PROCEDURES AND REGULATIONS- Welding, Lightning, Electrical Equipment, Hot

Surfaces

SUBJECT TO GENERAL CONTROL IN PLANT AREA

- Mobile Phones Etc, Cigarettes, Lighters & Matches


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Ignition Sources Arising

Within Plant1. Electrostatic Sparks

2. Thermite Sparks

3. Mechanical Friction

4. Hot Surfaces

5. Smouldering Deposits

6. Ignition Temperature (Previously

Autoignition)


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Flash Point

DEFINITION:

The lowest temperature at which

sufficient vapour is given offaliquid, to form a flammablemixture withair, that can be

ignited byan arc, spark or nakedflame.


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Flash Point

Material Deg CPropane -104

Ethylene -120 (Approx)

Hydrogen -256 (Approx)

Kerosene 38

Acetylene -82 (Approx)

Amount of vapour releaseddependant on temperature

VAPOUR

Liquid1. DEPENDS ON PRESSURE

Increase with increasing pressure

Decrease with decreasing pressure

2. PRESENCE OF SOLIDS

Can raise flash point

3. PRESENCE OF VOLATILES

Can effect significant reduction

Effects to Flashpoint


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Flash Point

Ignition Source

Paraffin -

Flash Point 38 Deg C

At 0 Deg C

At 33 Deg C

At 38 Deg C


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Minimum Ignition Energy (MIE)

LIQUIDSData obtained from literature -

benzene (Approx) 200 J

hexane (Approx) 240 J

acetone (Approx) 1.15 mJ (Milli Joules)

DUSTSData normally obtained by in house measurement -

anthraquinone (Approx) 2.5 - 4 mJ

phenothiazine (Approx) 25 - 50 mJ

sulphur (Approx) < 1 mJ

GASESHydrogen (Approx) 20 J (Micro Joules)

Ethylene (Approx) 95 J

Propane (Approx) 260 J

Methane (Firedamp) (Approx ) 280 J


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Ignition Temperature

DEFINITION:

The lowest temperature at which a

material can ignite and sustain

combustion, when mixed with air at

normal pressure, without the ignition

initiated by any spark or flame. i.e.

when making contact with a hotsurface.


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Ignition Temperature

Hot Surface

MATERIAL TEMP

Propane 470 C

Ethylene 425 C

Hydrogen 560 C

Acetylene 305 C

Kerosene (Paraffin) 210 CMethane (Fire damp) 537 C

Oxygen Enrichment can occur at compressed air factories or

where there is oxygen burning equipment. It lowers the Ignition

Temperature and Widens the Flammable range


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T Rating Of Apparatus In Relation

To Ignition Temperature

Material Ignition Temp T Rating

Methane (Firedamp)

Hydrogen

Propane

595C

560C

470C

T1 450C

Ethylene

Acetylene

425C

305CT2 300C

Cyclohexane

Kerosene

259 C

210CT3 200C

Diethyl Ether 160 C T4 135C

T5 100C

Carbon Disulphide 95 C T6 85 C


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Temperature Classification

Relating To Equipment

TEMPERATURE

CLASSIFICATION

MAXIMUM SURFACE

TEMPERATURE C

T1 450

T2 300

T3 200

T4 135

T5 100

T6 85

A potential ignition surface will not exceed the temperature

related to the T rating in normal or specified fault conditions.


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Ambient Temperature Range

T6 (85C) Temperature Classification

Ta in Europe the value is:

-20 +40C

0 Deg.C

20 Deg.C

40 Deg.C

100 Deg.C

-20 Deg.C

60 Deg.C

80 Deg.C

35 Deg C

Temp rise

Correctly

Installed

Not Correctly

Installed


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Vapour Density

COMPARISON OF A GAS/VAPOUR WITH AIRPLACEMENT OF GAS DETECTORS & VENTILATION

MATERIAL VAPOUR DENSITYAIR 1.0

PROPANE 1.56

ETHYLENE 0.97

HYDROGEN 0.07

ACETYLENE 0.9KEROSENE 4.5 (Approx)

= Gas Detector


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Area Classification

ZONE 0 In This Zone, A Flammable Atmosphere IsContinuously Present, Or Present ForLong Periods.

ZONE 1 In This Zone, A Flammable Atmosphere IsLikely To OccurDuring Normal Operation.

ZONE 2 In This Zone, A Flammable Atmosphere IsNot Likely To OccurDuring Normal Operation But If It Does,Its Duration Will Be For A Short Time Only.

1000 8760 hrs per year

10 1000 hrs per year

0 10 hours per year


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Area Classification

Zones Diagrammatic Representation

Zone 0 Zone 1

Zone 2 Non Hazardous Zone

Small Circles 45 Cross Hatching

45 Slanting Lines


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Area ClassificationFixed Roof Storage Tank


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Area Classification1 2

3


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Sources of Release

Welded pipe Non-hazardous

Flanged Joint - Zone 2

300mm Diameter min standard

Pump Gland - Zone 1

Generically, a movement of a pump may

change the zone or manufacture may choose

the zone

Space above liquid in a closed tank - Zone 0

Area Classification


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Grouping

Gas or Dust

Sub Division

Representative

Material Description

IMethane

(Firedamp)Mining

II IIA Propane SurfaceIndustries

Gas

II IIB Ethylene

II IIC Hydrogen/Ace

III IIIACombustible

Flyings Surface

Industries

DustIII IIIB

Non-Conductive

dust

III IIIC Conductive Dust


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1st Figure Protection against Solids

IP Test Comment

0 No protection

1

Protected against solid bodiesgreater than 50mm diameter.(e.g. accidental contact with thehand)

2

Protected against solid bodiesgreater than 12.5mm diameter.(e.g. finger)

3Protected against solid bodies

greater than 2.5mm diameter(e.g. tools, wires)

1st Figure Protection against Solids

IP Test Comment

4

Protected against solid bodiesgreater than 1.0mm diameter(e.g. thin tools and fine wire).

5Protected against dust (noharmful deposit)

Dust Proof

6

Completely protected againstdusts

Dust Tight

INGRESS PROTECTION

IP 1st 2nd (Additional Letters)Solids

Where there is no requirement for a protection rating with

regard to one criteria the digit is replaced with an X.


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2nd Figure Protection against Liquids

IP Test Comment

0 No protection

1

Protected against vertically fallingdrops of water (condensation)

2

Protected against drops of waterfalling up to 15 from the vertical

3

Protected against water sprayed upto 60 from the vertical

4

Protected against splashing waterfrom all directions

2nd Figure Protection against Liquids

IP Test Comment

5

Protected against jets of water from alldirections

6

Protected against powerful jets ofwater from all directions

7

Protected against the effects oftemporary immersion in water

8

Protected against the continuouseffects of immersion in water havingregard to specific conditions

INGRESS PROTECTIONIP 1st 2nd (Additional Letters)

Liquids

Additionalletters that can be appended to classifyonlythe level of

protectionagainstaccesstohazardousparts bypersons:

Level Protection against access to hazardous parts with

A Back of hand

B Finger

C Tool

D Wire

Further letters can be appendedtoprovide additional information

relatedtothe protectionofthe device:

Letter Protection against access to hazardous parts with

H High voltage device

M Device moving driving water test

S Device standing still during water test

W Weather conditions

ver2-0 part 01 ignition properties

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