Evaluation of fire and explosion hazard of nanoparticles

© 2019 Fire Protection Research Foundation

1 Batterymarch Park, Quincy, MA 02169-7417, USA Email: [email protected] | Web: nfpa.org/foundation

Evaluation of fire and explosion hazard of nanoparticles

FINAL REPORT BY:

Nabila Nazneen Qingsheng Wang, Ph.D., PE, CSP Mary Kay O’Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA. August 2019

TECHNICAL NOTES

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FOREWORD The NFPA Dust standards need a common definition for a nanoparticle, an understanding of how

their combustion properties differ from larger particles, and an awareness of the effect on the

selection and application of fire and explosion prevention, detection, and suppression methods.

Are there significant differences in the combustion characteristics between nanoparticles and

larger particles that would significantly affect fire and explosion prevention, detection, and

suppression methods and are these differences present for all commodity dusts? What numerical

size criterion should be used to distinguish a nanoparticle from larger particles from the standpoint

of fire and explosion safety principles?

The goal of this project is to determine the particle size at which the combustion properties

significantly change from that of larger particles through a literature review. More specifically to

identify the combustion properties, fire and explosion hazard posed by the nanoparticles.

The Fire Protection Research Foundation expresses gratitude to the report authors Nabila

Nazneen and Dr. Qingsheng Wang, who are with the Mary Kay O’Connor Process Safety Center,

Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station,

Texas, USA. The Research Foundation appreciates the guidance provided by the Project

Technical Panelists, and all others that contributed to this research effort. Thanks are also

expressed to the National Fire Protection Association (NFPA) for providing the project funding.

The content, opinions and conclusions contained in this report are solely those of the authors and

do not necessarily represent the views of the Fire Protection Research Foundation, NFPA,

Technical Panel or Sponsors. The Foundation makes no guaranty or warranty as to the accuracy

or completeness of any information published herein.

About the Fire Protection Research Foundation

The Fire Protection Research Foundation plans,

manages, and communicates research on a broad

range of fire safety issues in collaboration with

scientists and laboratories around the world. The Foundation is an affiliate of NFPA.

About the National Fire Protection Association (NFPA)

Founded in 1896, NFPA is a global, nonprofit organization devoted to eliminating death, injury, property and economic loss due to fire, electrical and related hazards. The association delivers information and knowledge through more than 300 consensus codes and standards, research, training, education, outreach and advocacy; and by partnering with others who share an interest in furthering the NFPA mission. All NFPA codes and standards can be viewed online for free. NFPA's membership totals more than 65,000 individuals around the world.

http://www.nfpa.org/foundation

http://www.nfpa.org/codes-and-standards/free-access

http://www.nfpa.org/member-access

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Keywords: nanoparticle, dust, dust explosions, hazard, particle, particulates, deflagration.

Report number: FPRF-2019-10

Project manager: Sreenivasan Ranganathan

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PROJECT TECHNICAL PANEL

Paul F. Hart, American International Group, Inc. & NFPA 652 Chair

James F. Koch, The Dow Chemical Company

Jack E. Osborn, Airdusco, Inc.

Laura Moreno, NFPA

PROJECT SPONSORS

National Fire Protection Association (NFPA)

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EXECUTIVE SUMMARY

Nanoparticles are a wonder of the modern age. It brings tremendous change in the field

of science, from biological to physical sciences. However, like many other blessings,

nanoparticles have their disadvantages too. Being so small makes them create dusts in

the atmosphere, which poses serious fire and explosion threat. The main motivation of

this work is to find the correlation of explosion parameters against the size of the

nanoparticles. Some inflection points were identified, below or above which the explosion

severity decreases. Additionally, the review found that concentration plays a huge role in

determining the explosion severity of nanoparticles. The report also covers the prevention

and suppression nature of nanoparticle explosion and how the size range of nanoparticles

impacts the prevention and suppression nature. The research suggests that the

prevention and suppression largely depend on the normalized rate of pressure rise which

is dependent on particle size.

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1

Evaluation of Fire and Explosion Hazard of

Nanoparticles

Nabila Nazneen, Graduate Student

Dr. Qingsheng Wang, Associate Professor

Mary Kay O’Connor Process Safety Center

Artie McFerrin Department of Chemical Engineering

Texas A&M University

Date: August 2019

2

Table of Contents List of Figures ................................................................................................................................................ 2

Introduction .................................................................................................................................................. 3

Experimental Apparatuses ............................................................................................................................ 3

Results ........................................................................................................................................................... 4

Aluminum .................................................................................................................................................. 4

Magnesium ............................................................................................................................................... 5

Carbon Nanotube ...................................................................................................................................... 7

Discussion ..................................................................................................................................................... 8

Effect of Aggregation ................................................................................................................................ 8

Effect of Concentration ............................................................................................................................. 8

Effect of Turbulence and Dispersion ......................................................................................................... 9

Prevention and Suppression ......................................................................................................................... 9

Conclusions ................................................................................................................................................. 12

References .................................................................................................................................................. 12

Appendix A .................................................................................................................................................. 14

Reference List for the table......................................................................................................................... 27

List of Figures Figure 1: (a) Maximum explosion overpressure vs. particle size for Aluminum (b) Normalized rate of

pressure rise vs. particle size for Aluminum ................................................................................................. 4

Figure 2: Minimum explosible concentration vs. particle size for Aluminum ............................................. 5

Figure 3: (a) Maximum explosion overpressure vs. particle size for Magnesium (b) Normalized rate of

pressure rise vs. particle size for Magnesium ............................................................................................... 6

Figure 4: (a) MEC vs. particle size for Magnesium (b) MIE vs. particle Size for Magnesium .................... 6

Figure 5: (a) Maximum explosion overpressure vs. particle size for Aluminum and Magnesium (b)

Normalized rate of pressure rise vs. particle size for Aluminum and Magnesium ....................................... 7

Figure 6: (a) Maximum explosion overpressure vs. BET surface area for Carbon Nanotube (b)

Normalized rate of pressure rise vs. BET surface area for Carbon Nanotube .............................................. 7

Figure 7: 1 m3 suppression test for 500 g/m3 of Aluminum dust (Taveau, Vingerhoets, Snoeys, Going, &

Farrell, 2015)............................................................................................................................................... 10

Figure 8: 1 m3 suppression test for 1750 g/m3 of Aluminum dust (Taveau et al., 2015) ............................ 10

Figure 9: 1 m3 and 4.4 m3 suppression tests for 500 g/m3 of Aluminum dust (Taveau et al., 2015) .......... 11

3

Introduction The study on dust explosion has become crucial as this kind of incidents has been happening more

frequently than ever. According to the data provided by US Chemical Safety Board (CSB),

between 1980 and 2005, there had been 281 dust explosions which killed 119 workers and injured

718. These explosions brought in severe damage to the industrial facilities in 44 states.

Occupational Safety and Health Administration (OSHA) and National Fire Protection Association

(NFPA) have guidelines and standards to prevent and suppress dust explosions. Dust explosions

are affected by a few important factors such as particle size, moisture content, dust concentration,

presence of inert gas, etc.

This report focuses particularly on the effect of particle size to determine the size below or above

which the explosion behavior changes.

Experimental Apparatuses The apparatuses below were mainly used to run the experiments to determine the explosion

parameters:

• Spherical chamber (20 L) by Kühner AG

• Dust explosion apparatus (36 L)

• Hartman tube (1.2 L) by Kühner AG

• Spraytec

• Tristar II 3020

20 L and 36 L apparatuses focus on determining Maximum Explosion Overpressure (Pmax),

Maximum Rate of Pressure Rise (dP/dTmax) and Minimum Explosible Concentration (MEC). 1.2

L Hartman tube was used to find MEC and MIE (Minimum Ignition Energy). The problem with

smaller scale chamber is that it has a possibility to have wall quenching effect, i.e., the sphere has

a possibility to disturb the flame propagation and thermal mechanisms by absorbing radiation. It

has been experimented that 20 L and 1m3 vessel give out comparable results but higher ignition

energy may show different behavior.

Particle sizes were measured by using Spraytec, which is based on the idea of using light

diffraction against the size. Tristar II 3020 was used for carbon particles to determine the BET

(Brunauer–Emmett–Teller) specific surface area with N2 adsorption. The greater surface area

indicates smaller particle size.

4

Dust particles are seldom mono-dispersed. Different sized particles are generally distributed in a

dust cloud. However, while determining the explosion parameters, an effective diameter is used,

which influences the overall nature of the explosion. A good estimate is the Sauter Mean Diameter,

d32, which can be defined as the diameter of a sphere having the same volume to surface area ratio

as the particle of interest (Dufaud, Traoré, Perrin, Chazelet, & Thomas, 2010).

Results The data for all the materials were tabulated in one spreadsheet. The explosion parameters were

then plotted against their particle size. There were significant data available for Aluminum,

Magnesium and Carbon Nanotubes. For other particles, there weren’t enough data to make a

correlation, see Appendix A. Thus we only focused on the discussion of Aluminum, Magnesium

and Carbon Nanotubes in this report.

Aluminum

The data from Aluminum were collected from different labs which may have resulted in some

inconsistencies in the graph. The Aluminum plots suggest a particle size ranging from 100 to 200

nm is the most explosive zone. The 100 nm particles show the largest maximum explosion

overpressure (Pmax) and the 200 nm particles show the largest normalized rate of pressure rise.

(a) (b)

Figure 1: (a) Maximum explosion overpressure vs. particle size for Aluminum (b) Normalized rate of

pressure rise vs. particle size for Aluminum

4

5

6

7

8

9

10

11

10 100 1000 10000 100000

Pm

ax(b

ar)

Particle Size (nm)

0

100

200

300

400

500

600

700

800

10 100 1000 10000 100000

Kst

(ba.

ms-

1)

Particle size (nm)

5

When minimum explosible concentrations (MEC) were plotted against the particle size for

Aluminum, it was found that the MEC initially increases with the increase of particle size. At about

1,000 nm, a plateau starts which continues till 10,000 nm and then the MEC starts to decrease. It

is to be noted that the explosion parameters drop at smaller diameter zone. The reason for this is

the particles below a certain size (for Aluminum it is 100 nm) tend to agglomerate which

essentially increases the effective size of the diameter and decreases the explosion intensity.

Figure 2: Minimum explosible concentration vs. particle size for Aluminum

Magnesium

The inflection point for Magnesium falls perfectly on 400 nm. The particles sized below or above

this size have less explosion severity.

0

20

40

60

80

100

10 100 1000 10000 100000

ME

C (

g/m

3)

Particle Size (nm)

6

(a) (b)

Figure 3: (a) Maximum explosion overpressure vs. particle size for Magnesium (b) Normalized rate of

pressure rise vs. particle size for Magnesium

MEC vs. particle size for Magnesium shows an exponential increase in MEC with the increase of

particle size.

(b) (b)

Figure 4: (a) MEC vs. particle size for Magnesium (b) MIE vs. particle Size for Magnesium

Minimum Ignition Energy (MIE) was plotted against the particle size of Magnesium and it was

found that MIE increases with the increase of particle size. When the MEC and MIE of Aluminum

and Magnesium were plotted in a single graph, respectively, it shows that the most severe

explosion range is around 300 to 600 nm.

6

8

10

12

14

16

10 100 1000 10000 1000001000000

Pm

ax(b

ar)

Particle Size (nm)

0

100

200

300

400

500

600

10 100 1000 10000 1000001000000

Kst

(bar

.m.s

-1)

Particle Size (nm)

0

20

40

60

80

100

120

140

160

180

10 1000 100000

ME

C (

g/m

3)

Particle Size (nm)

0

10

20

30

40

50

60

10 100 1000 10000 100000

MIE

(m

J)

Particle size (nm)

7

(a) (b)

Figure 5: (a) Maximum explosion overpressure vs. particle size for Aluminum and Magnesium (b)

Normalized rate of pressure rise vs. particle size for Aluminum and Magnesium

Carbon Nanotube

The review work included lots of data regarding Carbon Nanotube. The explosion parameters were

found against their BET specific surface area. The report focused on Carbon Nanotubes as these

were the data for Carbon that were mostly available. The Pmax and Kst data suggest that when the

particle size decreases, the explosion parameters increase. It should be noted that when increasing

BET surface area, the particle size decreases.

(a) (b)

Figure 6: (a) Maximum explosion overpressure vs. BET surface area for Carbon Nanotube (b)

Normalized rate of pressure rise vs. BET surface area for Carbon Nanotube

0

2

4

6

8

10

12

14

16

10 100 1000 10000 100000 1000000

Pm

ax (

bar

)

Particle Size (nm)

0

100

200

300

400

500

600

700

800

10 100 1000 10000 100000 1000000

Kst

(bar

.ms-1

)

Particle Size (nm)

0

1

2

3

4

5

6

7

8

9

10 100 1000

Pm

ax(b

ar)

BET (m2/g)

0

20

40

60

80

100

120

10 100 1000

Kst

(bar

.m/s

)

BET (m2/g)

8

Discussion MIE has a very strong correlation with particle size. Dobashi showed that Aluminum and

Polyethylene both have their MIE increased when particle size increased (Dobashi, 2009). The

metallic nanoparticles have a very low MIE (less than 1 mJ), which makes them very prone to

explosion.

Effect of Aggregation

According to Worsfold et al., agglomeration plays an important role in influencing explosion

severity (Worsfold, Amyotte, Khan, Dastidar, & Eckhoff, 2012). The nano-sized particles tend to

aggregate, which increases their effective size; these particles thus show different behaviors from

their original size. Contrary to this, Turkevich et al. thought differently. According to their

argument, the aggregate behavior should be based on the same allotropes rather than considering

the nanomaterials only (Turkevich, Fernback, Dastidar, & Osterberg, 2016). Their experiments

on carbonaceous materials show very weak correlation of aggregated particle size with Pmax and

Kst. Different sizes of aggregates from the same allotropes have not been tested yet. So we cannot

reach a conclusion here. Additionally, as we know, Aluminum does not have any allotropes; thus

this leads us to put more faith on Worsfold et al.’s conclusion.

Worsfold et al. showed that while considering the particle size, the diameter of the particle was

considered rather than the length. Although length does not impact much while considering the

parameters of the particles, it does have some impact when the melting point of the material is

lower than the ignition temperature. Then the particle is melted, and it becomes more spherical in

shape with the diameter of the particle being increased. This generally happens with the flocculent

micron sized particles like nylon.

Nanopowders have very low bulk density, which means that their thermal conductivity is low.

This puts them in much higher ignition risk as they tend to self-heat themselves when put in storage

containers (Bouillard, Vignes, Dufaud, Perrin, & Thomas, 2010).

Effect of Concentration

Concentration plays a significant role in the explosion severity. The maximum explosion

overpressure changes with concentration when the particle diameter is kept constant. However,

the particle size decides how the dust will behave. For example, in case of Aluminum, with smaller

particles, the maximum rate of pressure rise increases significantly with increasing concentration.

The larger particles, however, show very little increase of dp/dtmax with increasing concentration.

(Dufaud et al., 2010)

9

Effect of Turbulence and Dispersion Nanopowders are cohesive type. They have greater interparticle forces that hold them together

than the fluid characteristic that would help them in dispersion. For Aluminum, turbulence plays

a major role at low nominal concentrations. At the initial stage of injection, the kinetic energy rises

abruptly, which results in a variable dust dispersion. Uniformity restores when turbulence

decreases. At higher concentrations, uniformity is prevalent, which significantly impacts the

explosion. Turbulence affects dust explosion in both ways. On one hand, the increased flame

surface increases the explosion intensity. On the other hand, the impact on the dust uniformity

decreases the intensity. However, turbulent kinetic energy decays with time after the dust is

injected into the chamber. (Zhang, Liu, & Shen, 2018)

After the feeding, the difference of concentration at different parts of the vessel gets smaller with

time. The following figure depicts the scenario properly. The part closest to nozzle experiences

the most concentration changes. As the distance increases, the concentration change decreases.

After a certain time, when turbulence decreases, the concentrations from all part of the vessel tends

to be the same. Therefore, we can conclude that the high level of turbulence creates a non-

homogeneous dispersion of dust, which impacts the concentration and thus the explosion severity.

Prevention and Suppression As the nanoparticle explosion tends to be quite drastic, the need of effective prevention and

suppression is crucial. The prevention and suppression both depend on the fact that how severe an

explosion can get. Suppression fairly depends on the particle sizes. However, it depends on dust

concentration even more. For nanoparticle explosions, different suppressants are used, among

which SBC (Sodium Bicarbonate) is the most popular one. The rate of pressure rise helps to

understand how soon a suppressant can extinguish the fire. The density of the suppressant matters,

as well as the concentration of the nanodust. A low-concentration dust can be extinguished

abruptly, but a high-concentration dust requires more time and a larger amount of suppressants.

Suppressants work best if it can immediately be effective when the incipient explosion is detected.

There is a protected zone for the vessel safety, suppressing the explosion in this zone ensures full

extinguishment of the explosion. If the suppressant is not effective enough, the explosion crosses

the safety barrier and vessel fails.

There is almost no pressure generation due to combustion at a low dust concentration of 250 g/m3.

As the concentration increases, so does the explosion pressure. When the dust concentration

reaches 1000 g/m3 and beyond, the substantial pressure gets really large before the suppressant

comes into play. If we look at the pressure vs. time curves for dust explosion tests carried out in a

1 m3 vessel with concentration of 500 g/m3 and 1750 g/m3, respectively, we can see that more

pressure is generated per unit time with increasing concentration, which is evident by the steep

10

latter curve. The suppression time also depends on the concentration. For 500 g/m3, the time is less

than 20 ms whereas for 1750 g/m3, it is more than 30 ms. (Taveau, Vingerhoets, Snoeys, Going, &

Farrell, 2015)

Figure 7: 1 m3 suppression test for 500 g/m3 of Aluminum dust (Taveau, Vingerhoets, Snoeys, Going, &

Farrell, 2015)

Reprinted from Journal of Loss Prevention in the Process Industries, 36, Jerome Taveau, Jim Vingerhoets, Jef Snoeys, John

Going, and Thomas Farrell, Suppression of metal dust deflagrations, p. 250, Copyright (2015), with permission from Elsevier.

Figure 8: 1 m3 suppression test for 1750 g/m3 of Aluminum dust (Taveau et al., 2015)


Going, and Thomas Farrell, Suppression of metal dust deflagrations, p. 250, Copyright (2015), with permission from Elsevier.

11

The suppression behavior of Aluminum dust in 1 m3 and 4.4 m3 vessels suggests a fairly good

scalability of suppression. The total suppression pressure (TSP) for 4.4 m3 vessel is a bit higher

because the suppressant concentration is lower in the 4.4 m3 vessel (9.5 kg/m3 vs. 12.5 kg/m3).

The suppressant discharge device is larger for 4.4 m3 vessel (10 L vs. 5 L), which took more time

to release. Smaller multiple suppressant discharge devices may eliminate this problem.

Figure 9: 1 m3 and 4.4 m3 suppression tests for 500 g/m3 of Aluminum dust (Taveau et al., 2015)


Going, and Thomas Farrell, Suppression of metal dust deflagrations, p. 250, Copyright (2015), with permission from Elsevier

The recent experiments suggest that for Aluminum dust with up to 500 g/m3 concentration and a

Kst below 200 bar·m/s, the explosion can be suppressed with fairly good suppressant concentration.

As the industrial dust collectors do not usually reach more than 500 g/m3 concentration, it is

believed that the dust filter in the Aluminum processing plants can be protected by a suppression

system. However, in the event of a higher dust concentration, the technique of using multiple small

suppressant discharge containers can help lower the pressure. (Taveau et al., 2015) Recent research

by Wang’s lab at Texas A&M University show that wet dust removal systems could be an effective

design for preventing aluminum dust explosion while adding a small amount of special chemicals

(i.e., L-phenylalanine and CeCl3) in the solution to inhibit hydrogen production in the systems.

(Xu et al., 2018; Zheng et al., 2018)

12

Conclusions This review found that there is an essentially significant correlation between particle size and

explosion parameters. However, it is also evident that depending solely on particle size to

understand the explosion severity will not give the actual picture. Other factors like concentration,

turbulence, dispersion etc. also have to be considered. It was found while tabulating the data that

some explosion parameters are rarer than the others. For example, for Minimum Ignition

Temperature (MIT), Minimum Auto Ignition Temperature (MAIT), not enough data are available

to develop correlations. There have been outliers in different experimental results, mainly because

the experiments were conducted at different concentrations. This again proves the dependence of

explosion parameters on concentration.

For Pmax and Kst, Aluminum and Magnesium follow a somewhat similar trend, i.e., they have

smaller values at smaller particle size due to agglomeration. The values increase up to a certain

point and then again decreases due to increase in actual particle size. However, the MEC values

show different behavior. While the Aluminum produces a plateau, the Magnesium has its value

slowly increased to a certain point, with increasing particle size, and then opts for a sudden

increase. This happens because larger Magnesium particles needs larger amount of dust, i.e., larger

concentration to reach the same effective surface area as of nano-sized low concentration particles.

The plot trend of MEC vs. particle size for Aluminum may be explained through further

experiments as consolidated different lab data may have not shown the actual picture.

The correlation of explosion parameters with particle size indicates that effective collection of the

dangerous sized particles can help reduce severe incidents. Thus focus should be given to an

effective dust capture method. Also, nanoparticles have very low bulk density, which means their

thermal conductivity is low. They tend to self-heat themselves when put in storage containers.

(Bouillard et al., 2010) Therefore, proper identification of MAIT and design of a safe storage

system should be considered.

References Bouillard, J., et al., Ignition and explosion risks of nanopowders, Journal of Hazardous Materials,

181 (2010) 873-880.

Cashdollar, K., et al., Explosion temperatures and pressures of metals and other elemental dust

clouds, Journal of Loss Prevention in the Process Industries, 20 (2007) 337-348.

Dobashi, R., Risk of dust explosions of combustible nanomaterials, Journal of Physics:

Conference Series, 170 (2009) 012029.

Dufaud, O., et al., Experimental investigation and modelling of aluminum dusts explosions in the

20 L sphere, Journal of Loss Prevention in the Process Industries, 23(2) (2010) 226-236.

13

Krietsch, A., et al., Explosion behaviour of metallic nano powders, Journal of Loss Prevention in

the Process Industries, 36 (2015) 237-243.

Taveau, J., et al., Suppression of metal dust deflagrations, Journal of Loss Prevention in the

Process Industries, 36 (2015) 244-251.

Turkevich, L. A., et al., Potential explosion hazard of carbonaceous nanoparticles: screening of

allotropes, Combustion and Flame, 167 (2016) 218-227.

Worsfold, S. M., et al., Review of the explosibility of nontraditional dusts, Industrial &

Engineering Chemistry Research, 51(22) (2012) 7651-7655.

Xu, K., et al., Inhibition of hydrogen production reactions in the wet dust removal system using

CeCl3 solutions, International Journal of Hydrogen Energy, 43 (31) (2018) 14859-14865.

Zhang, Q., et al., Effect of turbulence on explosion of aluminum dust at various concentrations in

air, Powder Technology, 325 (2018) 467-475.

Zheng, X., et al., Study of hydrogen explosion control measures by using l-phenylalanine for

aluminum wet dust removal systems, RSC Advances, 8 (2018) 41308-41316.

14

Appendix A Data Collection on Nanoparticle Explosions

Material Type Particle Size (nm)

Size Distribution

Equipment Size

Concentration (g/m3)

Turbulent Velocity (m/s)

Ignition Energy (kJ)

Time From Ignition to pressure Peak (ms)

d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)

MIE (mJ) MEC (g/m3) LOC (%vol)

MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

Al Metal 100

20L Spherical ASTM E1226, modified Hartmann tube kuhner 8.2 1340 364 St3 <1 30 3 1,2,5

Al Metal 200 9.5 2420 656 St3 7 30 1,5

Al Metal 200 9.5 3480 673 St3 2

Al Metal 21000 7.5 400 106 St1 1

Al Metal 27000 7.2 360 98 St1 1

Al Metal 27000 7.5 400 106 St1 5

Al Metal 3000 9.8 2090 567 St3 14 1,5

Al Metal 42000 900 7.2 360 98 St1 440 5

Al Metal 7000 9.1 1460 396 St3 5

Al Metal 9000 9.1 1460 396 St3 1

Al Metal 40000 10000-50000

20L Spherical kuhner, 1.2 L Hartmann 1250 5 5.9 282 77 60 35

9,10,12

Al Metal 100 20-120

20L Spherical kuhner, 1.2 L Hartmann 1500-2000 5 12.5 1090 296 <1 50

9,10.12

Al Metal 35 10-50

20L Spherical kuhner, 1.2 L Hartmann 1300-1800 5 7.3 1286 349 <1 40

9,10,12

Al Metal 50-70 4.51 15.2 8.8 1551 421 30 16

Al Metal 90-110

20L spherical Siwek Chamber 4.45 12.25 9.1 1360 369 30 16

Al Metal 1000 330 9.4 85 19

Al Metal 7000 330 9 90 19

Al Metal 15000

330 7.5

90

19

Al Metal 40000 330 6.6 120 19

Boron Metal 3000 130 7 110 19

Chromium Metal 10000 610 3 F 19

Cu Metal 50-70 6.7 7.11 0.3 18 5 250 16

Cu Metal 30000 ∼2200 1 NF 19

15


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

Fe Metal 150000 4

Fe Metal 15 <1 4

Fe Metal 35 <1 4

Fe Metal 65 <1 4

Fe Metal 50-70 N/A 1.27 6.11 60 16

Fe Metal 90-110 N/A 1.29 6.42 60 16

Fe Metal 4000 400 3.5 12 19

Fe Metal 4000 600 4.2 18 19

Fe Metal 4000 800 4.3 23 19

Fe Metal 4000 1000 4.5 27 19

Fe Metal 45000 400 1.3 2 19

Fe Metal 45000 600 2.4 3 19

Fe Metal 45000 800 3 3.5 19

Fe Metal 45000 1000 2.9 3.5 19

Fe Metal 4000 1000 4.5 220 19

Fe Metal

45000 1000

3.1

500 19

Hafnium Metal 8000 1600 5.2 180 19

Lead Metal 40000 3600 1.1 NF 19

Mg Metal <74000 6.21 621 620 40 17

Mg Metal 28000 17.5 508 30 17

Mg Metal 240000 7 12 760 17

Mg Metal 240000 17.5 508 17

Mg Metal 241000 7 12 760 17

Mg Metal 400000 17

Mg Metal 30000 10.8 400 17

Mg Metal 16000 8.5 17

Mg Metal 0-20000 513 4 <8 17

Mg Metal 20000-37000 530 5 <8 17

Mg Metal 37000-45000 550 12 17

Mg Metal 45000-74000 563 44 17

16


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

Mg Metal 74000-105000 575 82 17

Mg Metal 105000-125000 578 102 17

Mg Metal 125000-149000 585 194 17

Mg Metal 149000-177000 625 242 17

Mg Metal 6000 480 >2 17

Mg Metal 47000 8 150 520 46-54 6.8 17

Mg Metal 104000 620 250-300 17

Mg Metal 75000 560 17

Mg Metal 20000-60000 53 17

Mg Metal 7500 7.8 430 17

Mg Metal 22400 6.6 380 17

Mg Metal 54500 5.8 250 17

Mg Metal 28000 17.5 508 17

Mg Metal 240000 7 12 760 17

Mg Metal <44000 620 40 17

Mg Metal <44000 600 240 17

Mg Metal 16000 7.5 17

Mg Metal 125000 1500

7

98

600 120 160 5

17

Mg Metal 74000 1500

8.8

202

570 50 90 5

17

Mg Metal 38000 1250

10.8

362

530 10 60 5

17

Mg Metal 22000 1250

12.4

450

510 4 50 4

17

Mg Metal 10000 1000

13.2

482

480 3 40 4

17

Mg Metal 1000 1000 14 510 450 2 30 4 17

Mg Metal 400 750 14.6 528 400 1 30 3 17

Mg Metal 200 750 12.4 460 380 1 30 4 17

17


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

Mg Metal 150 750 11 400 350 1 20 4 17

Mg Metal 100 750 10.6 360 350 <1 20 4 17

Mg Metal 50 750 10 332 350 <1 20 5 17

Mg Metal 30 750 9.4 262 350 <1 20 5 17

Mg Metal 16000 530 8.5 55 19 Molybdenum Metal

5000 600

1

NF 19

Nickel Metal 6000 900 1 NF 19

Niobium Metal 20000 800 4.6 F 19

Niobium Metal 30000 3.7 420 19

Tantalum Metal 10000 1300 4 400 19

Ti Metal 60-80 1.24 30 16

Ti Metal <150000

5.5 84

23

>590 1-3

60 18

Ti Metal <45000 7.7 436 118 460 1-3 60 18

Ti Metal <=20000

6.9 420

114

460 <1

50 18

Ti Metal 150 250 630 250 <1 40-50 18

Ti Metal 60-80 250 640 240 <1 18

Ti Metal 40-60 250 <1 18

Ti Metal 25000 400 5 22 19

Ti Metal 25000 600 5.4 34 19

Ti Metal 25000 800 5.4 34 19

Ti Metal 25000 520 5.7 70 19

Ti Metal 100 <1 4

Ti Metal 20000 18.73 4

Ti Metal 3000 <1 4

Ti Metal 35 <1 4

Ti Metal 45000 21.91 4

Ti Metal 75 <1 4

Ti Metal 8000 21.91 4

Tin Metal 8000 1100 4.3 450 19

Tungsten Metal ⩽1000 1100 3.3 700 19

Tungsten Metal 10000 1100 1 NF 19

Zn Metal 120 3.9 223 61 St1 19 5

Zn Metal 40000 3.7 71 19 St1 >1000 5

Zn Metal 90-150 12.6

8 3.2 4.3 652 177 125 16

18


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

Zn Metal 4000 1300 4.4 300 19

Zn Metal 45000 ⩽2 NF 19

Brown Coal Organic 32 11 152 41 60 7

Carbon Organic ⩽1000 120 5.5 90 19

Carbon

Organic

1000

120

5

F

F=Flammable but MEC could not be determined 19

Carbon

Organic

4000

120

1.1

NF

NF= Nonflammable or Nonignitable 19

Carbon (Stoichiometric Conc.) Organic

36L customized vessel 111 6

Carbon black Organic 7.2 112 250000-500000 53 >600 8

Carbon Black - Carbex 330 Organic 33 70 6.4 103 29 71 683 360 Active N330 7

Carbon Black - Carbex 330 (P) Organic 32 81.2 6.3 96 27 75 683 410 Active N330 7

Carbon Black - Carbex 330a Organic 30 85 6.3 182 51 66 667 350 Active N330 7

Carbon Black - Corax N115 Organic 7.7 326 88 St1 780 >1000 60 1

Carbon Black - Corax N115 Organic 150 7.5 503 136 >1 60 7

Carbon Black - Corax N550 Organic 7.5 503 136 St1

>900 >1000 60 1

Carbon Black - Corax N550 Organic 50 6.7 240 65 >1 60 7

Carbon Black - Printex 90 Organic 306.3 4.9 103 28

Carbon Black (DeGussa-Huels)

Tested in Conc. 500g/m3 7

Carbon Black - Printex XE2 Organic 40 7.2 343 93 St1 810 >1000 60 1

Carbon Black - Printex XE2 Organic 40 200 6.6 227 62 >1 60 7

Carbon Black - Regal 330R Organic 83 5.9 180 49

Carbon Black (Cabot)

Tested in Conc. 7

19


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

500g/m3

Carbon Black - Sapex 20 Organic 89 27 6 79 22 150 885 395 Semiactive 7

Carbon Black - Sapex 20 (P) Organic 89 26.5 6.1 63 18 144 882 435 Semiactive 7

Carbon Black - Sapex 35 Organic 78 36.9 6.8 66 19 126 359 Semiactive 7

Carbon Black - Sapex 35 (P) Organic 78 39.5 6.1 50 14 103 896 415 Semiactive 7

Carbon Black - Sterling V Organic 36.8 5.6 142 39

Carbon Black (Cabot)


Carbon Black - Thermal Black N990 Organic 6.7 240 65 St1

>900 >1000 60 1

Carbon Black - Thermal Black N990 Organic 20 7.2 343 93 >1 60 7

Carbon Black - Vulcan (Furnace) Organic 8.5 24 7 60

Furnace Carbon Black 7

Carbon Black - Vulcan (P) (Furnace) Organic 9.1 62 17 60

Furnace Carbon Black 7

Carbon Black - Vulcan 3 Organic 30 81 6.3 169 47 73 656 450 Active N330 7

Carbon Black - Vulcan 6 Organic 24 122 6.9 246 69 61 645 470 Active N200 7

Carbon Nanotube (MWCNT) (Arkema) Organic 950 7.7 326 88 >1 60 7

CNF Organic 7.1 96

10^6-2.5*10^6 51 >600 8

CNF-PR-19-XT-HHT Organic 18.9 4 16 4

CNF (Pyrograph)


CNF-PR-19-XT-LHT Organic 22.2 4.8 33 9

CNF (Pyrograph)

Tested in Conc. 7

20


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

500g/m3

CNF-PR-19-XT-PS Organic 28.2 5 47 13

CNF (Pyrograph)


CNF-PR-24-XT-HHT Organic 33.3 0.4 0 0

CNF (Pyrograph)


CNF-PR-24-XT-LHT Organic 36.8 5.4 56 15

CNF (Pyrograph)


CNF-PR-24-XT-PS Organic 57.3 5.1 53 14

CNF (Pyrograph)


Corax N550 Organic >100000

Corn Starch Organic 58000-74000 500 1.5 4.54 26.78 13


Corn Starch Organic 58000-74000 875 1.5 4.4 14 13




Crystalline (300 mesh) Organic 11.6 4.7 72 19

Graphite (Alfa Aesar)


Diamond Organic 1000 7.5 6.3 320 87


Diamond Organic 10 268.9 5.8 430 117


21


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

fibrous wood Organic <500000 7.8 80 9

fibrous wood Organic <75000 8.2 149 9

fibrous wood (bulk) Organic 7.2 41 9

Flake (7-10µm) Organic

7000-10000 8.4 5 87 23



Fullerene Organic 8 199 <250000 17 550 8

Fullerene (C60) Organic 0.4 6.6 373 101


Furnace Carbon Black (Unspecified) Organic 9.4 122 33 60 7

Furnace Carbon Black (Unspecified) Organic 10 65 17 50 7

Grain Sorghum Organic 19100 200 0.095 0.016 0.0604 585 70

Secondary Explosion data 14













22


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

















Graphene Organic 6.6 70 500000-10^6 73 >600 8

Graphite Organic 6.3 64

10^6-2.5*10^6 92 >600 8

Graphite - Natural Crystal (2-15 µm) Organic 6.5 4.6 98 27



Graphite (Coarse-1) Organic

25-32 6 90 24 100

2 × 10^6 –10^7 7

Graphite (Coarse-2) Organic

40-45 6 75 20 100

2 × 10^6 –10^7 7

Graphite (Fine) Organic 4 6.5 260 73 70

10^6 –10^7 7

graphite dust Organic 25000-32000

36L customized vessel 100 10kJ igniter 6

23


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref


36L customized vessel >250 2kJ igniter 6




36L customized vessel >250 2kJ igniter 6

graphite dust (4μm) (10kJ igniter) Organic 4000


graphite dust (4μm) (2kJ igniter) Organic 4000

36L customized vessel

125<MEC<500 2kJ igniter 6

High volatile coal Organic 5500 133 11




Lignite Organic <74000 600 0.091 19.2083 735 290


Low Volatile coal Organic 5100 150 11



Lycopodium Organic 446.1 3

Monarch 120 Organic 29.9 5.9 144 39 Carbon Black (Cabot)




24


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref



MWCNT Organic 6.7 104 250000-500000 48 >600 8

MWCNT (BayTubes C150HP) Organic 191.9 6 120 33


MWCNT (BayTubes C150P) Organic 200.2 5.8 155 42


MWCNT (CheapTubes A) Organic 111.1 5.9 210 57


MWCNT (CheapTubes B) Organic 68.7 5.6 156 42


MWCNT (Mitsui 7) Organic 23 4.3 19 5


MWNTs Organic 6.6 227 62 St1 2

N008-100N Organic 11.6 5.5 168 46 Graphene (Angstron)


Nanotubes Organic 6.6 227 62 St1 >1000 45 1

Peat Organic 38 500 46 8.4 513 15

Peat Organic 54 500 35 8.4 610 15

Peat Organic 72 500 60 7.2 248 15

Peat Organic 96 500 47 7.8 413 15

Peat Organic 100 1000 59 7.8 350 15

Peat Organic 165 500 45 7.7 395 15

Pittsburgh high volatile coal Organic

36L customized vessel 60 6

25


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

SAB-1 Organic 6 73 20 68 Channel & Special Blacks 7

SAB-1 (P) Organic 5.2 69 19 43 Channel & Special Blacks 7

SAGAL-3 (P) Organic 6 83 23 50 Channel & Special Blacks 7

SAKAP-6 Organic 6.1 82 22 62 Channel & Special Blacks 7

SAO Organic 5.6 68 19 86 Channel & Special Blacks 7

Sulfur Organic 35000 280 5 100 19

SWCNT Organic 7.3 123 250000-500000 64 570 8

SWCNT (Cheap Tube) Organic 372 6.8 290 79


SWCNT (SWeNT SG-65) Organic 617.2 6.5 198 54


SWCNT (Unidym HiPCO) Organic 559.9 6.4 382 104


Synth. Cond. (325 mesh) Organic 3.3 4.6 57 16



Wheat Organic 21100 200 0.062

5 0.022 0.0647 645 110


Wheat Organic 21100 300 0.145 0.04 0.0647 645 110


Wheat Organic 21100 400 0.18 0.062 0.0647 645 110


Wheat Organic 21100 500 0.12 0.022 0.0647 645 110


26


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref

Wheat Organic 21100 600 0.085 0.022 0.0647 645 110


Wheat Organic 24400 200 0.09 0.032 0.0951 690 120


Wheat Organic 24400 300 0.11 0.042 0.0951 690 120


Wheat Organic 24400 400 0.17 0.086 0.0951 690 120


Wheat Organic 24400 500 0.08 0.02 0.0951 690 120


Wheat Organic 24400 600 0.19 0.06 0.0951 690 120


Wheat Organic 28000 200 0.062

5 0.018 0.0226 670 150


Wheat Organic 28000 300 0.08 0.039 0.0226 670 150


Wheat Organic 28000 400 0.065 0.01 0.0226 670 150


Wheat Organic 28000 500 0.105 0.03 0.0226 670 150


Wheat Organic 28000 600 0.09 0.02 0.0226 670 150


Wood Char Organic 542.4

3 3

fibrous polyethylene (bulk) Plastic 5.8 22 9

fibrous polyethylene <75μm Plastic <75000 7.2 75 9

Polyethylene Plastic 5460 46 11

27


Size Distribution

Equipment Size





d agg (μm)

d-BET (nm)

BET (m2/g)

Pmax (bar)

(dP/dT)max (bar/s)

Kst (bar.m.s1)

Explosive Class

MIT (oC)


MAIT (oC)

MIT cloud (oC)

MIT layer (oC)

Note 1 Note 2 Ref





Silicon 4000 300 7.7 200 19

Reference List for the table 1. Vignes, A. Évaluation de l’inflammabilité et de l’explosivité des nanopoudres : une demarche essentielle pour la maîtrise des risques. Autre. Institut National Polytechnique de Lorraine, (2008)

2. Bouillard, J., et al., Ignition and explosion risks of nanopowders, Journal of Hazardous Materials, 181 (2010) 873-880

3. Danzi, E., et al., A statistical approach to determine the autoignition temperature of dust clouds, Journal of Loss Prevention in the Process Industries, 56 (2018) 181–190

4. Wu, H., et. Al., Research of minimum ignition energy for nano Titanium powder and nano Iron powder, Journal of Loss Prevention in the Process Industries, 22 (2009) 21–24

5. Dufaud, O., et al., Ignition and explosion of nanopowders: something new under the dust, Journal of Physics: Conference Series, 304 (2011) 012076

6. Zhang, J. et. Al., Dust Explosion of Carbon Nanofibers Promoted by Iron Nanoparticles, Industrial & Engineering Chemistry Research, 54 (2015) 3989−3995

7. Turkevich, L. A., et al., Potential explosion hazard of carbonaceous nanoparticles: screening of allotropes, Combustion and Flame, 167 (2016) 218-227

8. Turkevich, L. A., et al., Potential explosion hazard of carbonaceous nanoparticles: Explosion parameters of selected materials, Journal of Hazardous Materials, 295 (2015) 97–103

9. Worsfold, S. M., et al., Review of the explosibility of nontraditional dusts, Industrial & Engineering Chemistry Research, 51(22) (2012) 7651-7655

10. Kadir, N., et al., Investigation of the Explosion Behaviour Affected by the Changes of Particle Size, Procedia Engineering, 148 (2016) 1156 – 1161

11. Lemkowitz, S., et al., Investigation of the Explosion Behaviour Affected by the Changes of Particle Size, KONA Powder and Particle Journal, 31 (2014) 53-81

12. Wu et al., Explosion Characteristics of Aluminum Nanopowders, Aerosol and Air Quality Research, 10 (2010) 38–42

13. Kauffman, C., et al., Turbulent and Accelerating Dust Flames, Twentieth Symposium (International) on Combustion, (1984) 1701-1708

14. Lesikar, B., et al., Determination of Grain Dust Explosibility Parameters, American Society of Agricultural Engineers, 34(2) (1991) 3402-0571

15. Eckhoff, R., Dust Explosion in the Process Industries, Gulf Professional Publishing is an imprint of Elsevier Science, 3 (2003) 394

16. Krietsch A., et al. Explosion behaviour of metallic nano powders, Journal of Loss Prevention in the Process Industries, 36 (2015) 237-243

17. Mittal, M., Explosion characteristics of micron- and nano-size magnesium powders, Journal of Loss Prevention in the Process Industries, 27 (2014) 55-64

18. Boilard, S., et al., Explosibility of micron- and nano-size titanium powders, Journal of Loss Prevention in the Process Industries, 26 (2013) 1646-1654

19. Cashdollar, K., Zlochower, I., Explosion temperatures and pressures of metals and other elemental dust clouds, Journal of Loss Prevention in the Process Industries, 20 (2007) 337–348

Documents

Evaluation of fire and explosion hazard of nanoparticles