Dr Fiona Clarkson - Simtars

Becoming aware of the risk factors associated with your particular dusts

Dr Fiona Clarkson

Simtars

How and why dust composition varies

1. Origin of the parent product

Liquid, bulk product, grain, milled product

2. End use of the product

Powder, blended product

End use determines how a product is handled in a

process system.

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What you need to understand about your dust and its characteristics

Dust can be a combustible dust hazard as either a dust cloud, a dust layer or both

• Particle size

• Particle shape

• Moisture content

• Density

• Origin - plant, animal, mineral or man made

The limitation of relying on material data sheets

• Not all products have an SDS.

Chemicals require an SDS

Exemptions – some food products

– some pharmaceuticals

• The SDS may not list all the components

Slide 4


Review the Physical and Chemical Properties Section

Slide 5


The SDS is only as good as the information supplied by the manufacturer

Slide 6


• Key information may be spread over several sections

Slide 7

What is dust testing and how is it done ?

Series of internationally recognised tests to

evaluate the physical properties of fine powders

Explosion testing in the Siwek 20 litre sphere

Explosibility – Siwek sphere

Concentration range of 30g/m3 to 2000g/m3

Slide 9

Explosion Characteristics Max. explosion pressure: Pmax = .0 bar ± 10%

Max. rate of pressure rise: (dP/dt)max = 0 bar / s ± 30%

Product specific constant: Kmax = 0 m·bar / s ± 30%

Explosibility – Siwek sphere

Slide 10

Explosion Characteristics

Max. explosion pressure: Pmax = 8.6 bar ± 10% Max. rate of pressure rise: (dP/dt)max = 901 bar / s ± 10% Product specific constant: Kmax = 245 m·bar / s ± 10%

Explosion Indices – Siwek sphere

Slide 11



Minimum Explosive Concentration / Lower Explosive Limit

Slide 12

Minimum Ignition Energy - MIKE 3

Spark with inductance

Spark with no inductance

Energy Levels 1000 mJ

300 mJ

100 mJ

30 mJ

10 mJ

3 mJ

1 mJ

Slide 13

Minimum Ignition Energy - MIKE 3

Slide 14

Minimum Ignition Energy

Result with inductance L = 1 mH

1 mJ < MIE < 3 mJ / Es = 1.6 mJ

E2 [mJ]: 3 3 3 3 3 Es [mJ]: 2.6 2.0 2.3 1.6 1.9 E1 [mJ]: 1 1 1 1 1

tv [ms]: 60 90 120 150 180

Minimum Ignition Temperature - Cloud

Slide 15

Vertical Plate

600°C to 200°C

Flame = Ignition

3 to 5 seconds

Minimum Ignition Temperature - Layer

Slide 16

Horizontal Plate

450°C to 100°C

Embers / Ash

= Ignition

Minimum Ignition Temperature - Layer

Slide 17

Isolated Embers

Whole sample

30 to 90 minutes

per test

Potential Testing Reports – Explosion Testing

Slide 18

Simtars - Combustible Dust Laboratory

Sample: R2060033/01 CaRo2015 Customer: Simtars Reason: CaRo2015 Sphere Verification Testing Data to sample origin: Ex Kuhner Preparation of sample: As Supplied Median value: As Supplied



Potential Testing Reports –Minimum Ignition Energy Testing

Slide 19

Potential Testing Reports –Minimum Ignition Temperature Testing

Slide 20

Potential Testing Reports – Particle Size Analysis

Slide 21

Risk considerations of unknown dust particles

Particle size

• Is the median particle size in the millimetre, micron or nano particle range ?

Concentration in the atmosphere

• Can I see a dust cloud ?

• Can I see through it ?

Unknown Chemical Composition

• Could the dust be a skin sensitizer if handled or toxic if inhaled ?

Slide 22

Risk considerations of unknown dust particles

Is the material likely to have come from a plant, animal, mineral / metal refining or man made source ?

Decomposition products

• Could the off gases be toxic ?

Ignition sources

• Are there any potential ignition sources nearby eg Hot work, ovens / furnaces, motors or large electrical power sources

Slide 23

Business

Dr Fiona Clarkson - Simtars