Hazards Related Combustble Dust

7/26/2019 Hazards Related Combustble Dust

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Hazards related to Combustible

Dust in the General Industry

Pocket guide


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This material was produced under Susan Harwoodgrant number 19480-09-60--!" #ccupationalSa$et% and Health &dministration' ()S) *epartment

o$ +abor) The contents in this presentation do notnecessaril% re$lect the ,iews or policies o$ the ()S)*epartment o$ +abor' nor does the mention o$ tradenames' commercial products' or organiations impl%endorsement b% the ()S) .o,ernment)

/e grate$ull% acknowledge the *i,ision o$

ontinued ducation at the (ni,ersit% o$ Puerto

2ico 2io Piedras ampus and the team that

collaborated in the production o$ it)

3 2eser,ed rights' "010' *P'

(ni,ersit% o$ Puerto 2ico' 2o Piedras campus

5o part o$ this publication ma% be reproduced in an%

wa% without the epress permission o$ the *i,ision

o$ ontinued ducation and Pro$essional Studies at

the (ni,ersit% o$ Puerto 2ico' 2io Piedras ampus


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75T2#*(T7#5

Purpose of the Guide

This pocket guide is designed to

help industries to identi$% the presence o$ combustible

dust in their work areas

in$orm emplo%ees about the haards associated with

combustible dusts

identi$% control measures related to euipment and

electrical connections and control o$ ignition sources

establish inspection' maintenance and cleaning

schedules to reduce dust accumulation

The guide pro,ides in$ormation on important concepts and

de$initions related to combustible dust) 7t also pro,ides

checklists to guide both emplo%er and emplo%ee to identi$%

impro,ement areas within the workplace' while considering

all the elements $or the control and pre,ention o$ potentialcombustible dust eplosions

7n the $inal section %ou will $ind the re$erences used to

prepare this guide that should be consulted $or more

in$ormation about the topics herein discussed


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#:(ST7:+ *(STS

ombustible dusts are present in a great ,ariet% o$industries) 7t is estimated there are about 1; million workersin the manu$acturing industr% and o$ these' thousands ma%be at risk o$ in5orth arolina? - 6 dead and ;8

wounded) &lmost total destruction o$ the $acilit% caused b%

dust eplosion processes o$ plastics and resins

= T& &coustics >@entuck%? - ! dead and ;! in


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These $igures demonstrate the seriousness o$ a $ire or

eplosion e,ent in areas where combustible dusts are

present

7P#2T&5T #5PTS

What is a combustible dust?

There are se,eral de$initions but all agree that it is a ,er%

small particulate that when dispersed in air has the abilit% to

eplode under certain conditions) The 5P& 6A4 >"006?

de$ines it as a combustible dust particulate solid that

presents a risk o$ $ire or eplosion' regardless o$ sie or

shape' when suspended in air >or other oidant? at ,arious

concentrations) This was the de$inition adopted b% #SH& $or

its 5ational mphasis Program' launched in "008) There is

e,idence that e,en when the particulate is not spherical' but

beha,es as such' it will present an eplosion haard) The

$ollowing will be considered as solid particulate matter

= dust

= $ibers= $ragments

= $lakes

= chips' or

= mitures o$ an% o$ the abo,e mentioned)


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Which industries are at risk?

&s mentioned' an% organic solid particulate' or inorganic in

the case o$ metals' has the potential to cause an eplosion

under the right conditions) 2ecognied as common sources

o$ particulate material are industries handling' metal' plasticand B or resins' wood and wood products' $ood' also drug

manu$acturing' and manu$acturing o$ agricultural products

among others)

How small is this particulate?

/hen compared to known

materials' it can be as or

smaller than

= a grain o$ sugar or sand= $ine wood sawdust= the $lour used $or baking

bread= metal powder a$ter

grinding or cutting

How much accumulation is necessary to

become dangerous?

&s little as 1 B ;" Cinch >less than the thickness o$ the coin?

on horiontal sur$aces can cause problems

How is the solid particulate generated?


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7s generated as a result o$ mechanical processes where

solid matter is cut' sanded' polished' crushed' ground or

otherwise manipulated to generate $ine particulate solid

How is fire produced?

The $ire is the reaction that occurs when %ou ha,e a

combustible material' in this case dust' o%gen and anignition source' combined in suitable proportions to maintain

the initial combustion)

What is a Deflagration?


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7t occurs when the combustion or $ire one ad,ances rapidl%

>0)A to 1 m B sec?' generating large amounts o$ heat) The gas

epansion also creates a pressure wa,e) :oth heat and

pressure generated can cause serious damage to people

and structures)

75+(*P7T(2

ChttpDBBupload)wikimedia)orgBwikipediaBenB0B04B*rumde$lagr)


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that greatl% a$$ects the risk o$ dust eplosion is how easil%

the material can agglomerate or $orm clumps) &gglomeration

is usuall% seen in humid en,ironments)

How is the primary explosion generated?

7t is the result o$ creating a $ire in a con$ined space' where

the rapid change in temperature causes a rapid change in

pressure' resulting in a shock or pressure wa,e)

7n the case o$ combustible dusts' the eplosion' reuires the

presence o$ all these $actors to occur

1) 7gnition sources

") uel

;) Source o$ o%gen or oidiing material

4) *ispersion

A) ontainment or con$inement

What is Dispersion?

7t is the e$$ect o$ mo,ing a cloud o$ dust $rom one place to

another either b% mechanical processes >transport',entilation' ,ibration? or as the result o$ a primar% eplosion)

Secondary explosion


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The combination o$ the $ire elements within an enclosed

structure pro,ides the conditions $or the $lame to uickl%

spread' creating enough pressure to mo,e an% dust $rom

work sur$aces) This mo,ement o$ dust is enough to create

chain reactions that result in subseuent or secondar%

eplosions)

Minimum xplosi!e "oncentration

7t is the minimum dust concentration needed to sustain the

process o$ de$lagration o$ a dust sample in a laborator% test )

#uto $gnition %emperature

7t is the temperature at which dust combustion starts onl%

due to the e$$ect o$ temperature increase with no other

source o$ ignition present) &uto-ignition temperature $or the

same material' ma% be di$$erent between a cloud and a thin

la%er o$ dust

Deflagration index &' st(


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This ,alue is used to estimate the dust beha,ior o$ a

particular material during a de$lagration) The higher the

,alue o$ @ stthe more se,ere the eplosion can be)


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Here is a list o$ materials with the potential to

generate combustible dusts

Plastic

Gin%l acet%lene

Pol% ,in%l acetate

Pol% prop%lene

olded Pulp

Pol% &cr%lamide

Pol% eth%lene

o-pol%mer

Poli &cr%lonitrile

po% or phenolic resin

th%lene o-pol%mer

Pol% meth%l acr%late

Pol%mer mulsion

pol% ,in%l alcohol

elamine and its resin

Pol% ,in%l but%ral

(rea-$ormaldeh%de

Pol% ,in%l chloride >PG?

Terpene phenol resin

Chemical Industry

&dipic acid

Sul$ur

Sodium stearate

&scorbic acid

arbo%meth%lcellulose

+actose

alcium acetate

*etrin

eth%lcellulose

&nthrauinone

alcium stearate

Para$ormaldeh%de

Sodium &scorbate

+ead stearate

Metal

&luminum

7ron arbon%l

inc

:rone

agnesium


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Food

.arlic

&l$al$a

otton

2ice starch

orn starch

/heat starch

Sugar

ocoa powder

o$$ee

oconut shell

+emon peel

#nion powder

Spice powder

Potato starch

Sun$lower

.luten

+ocust bean gum

Ianthan gum

2ice $lour

#atmeal

Peanut lour

2%e $lour

ornmeal

Potato $lour

/heat $lour

+emon

alt

&pple

Peach

ied tobacco snu$$

Potato

Parsle% >dried?

2ice powder

/heat grain dust

/alnut Powder

So%bean Powder

:eet

+inseed

Seeds o$ raw cassa,a

Sun$lower Seeds

Semolina

Tomato

arrot


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#gricultural

products

2ice starch

ellulose

ilk Powder

orn Starch

ork

*r% skim milk

/heat starch

gg white

orn

Sugar

So%bean meal

/he%

:eet sugar

/heat $lour

Tapioca

:arle%+actose

"arbon Products

&cti,ated carbon

oca-cola

arbon black

:ituminous coal

Petroleum coke

Pulp

harcoal

Pine soot

#il

ellulose

+ignin

hemical *ust


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27S@ &T#2S

What elements should $ consider to pre!ent anexplosion?

Two o$ the most contributing $actors to a combustible dust

eplosion are

>1? the accumulation o$ dust in the work areas and

sur$aces and

>"? the presence o$ ignition sources)

To control these $actors we must pa% particular attention to

housekeeping programs and to the control or pre,ention o$

sparks' $lame or heat sources that can pro,ide energ% to

start the $ire that might produce the eplosion)

7t is important to identi$% whether an% o$ the materials that

%our industr% handles is classi$ied as a combustible dust)

That in$ormation could be $ound in the aterial *ata Sheets

>S*S? or technical papers pro,ided b% the manu$acturer)

5P& 61 pro,ides a list o$ organic materials that generate

combustible dust and are t%picall% present or produced in

agricultural operations) Some common eamples are sugar'

starch' $lour' grains' etc)


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mplo%ees must also know the proper handling o$ an%

combustible dust present in the $acilit%' so %ou must include

the in$ormation o$ these materials in %our Haard

ommunication Program

There should be an inspection' maintenance and regularcleaning program that controls dust accumulation to pre,ent

it $rom reaching dangerous concentrations) :oth

euipments and working sur$aces must be inspected to

a,oid dust accumulations)

uipment and procedures used $or cleaning purposes

should not introduce risks elements such as dispersing dust

while cleaning or non controlled ignition sources arising $rom

euipment or ,ehicles)

The electrical rating o$ the work area determines the

necessar% controls $or electrical euipment' machiner% and

lighting where dust is present) The ignition source controls

should consider all energ% sources' be it electrical' thermal

or static) Table 4)A)" o$ 5P& 499 indicates those chemical

materials that ha,e been identi$ied as combustible dusts and

assigns classi$ication according to the electrical

reuirements o$ the groups ' ' . o$ lass 77)


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How do you identify a combustible dust

problem?

To identi$% whether %our industr% is at risk is necessar% toanal%e the work areas that present problems in terms o$

cleanliness >maintenance' ,entilation s%stems' horiontal

sur$aces?' o$ ignition sources >electrical' mechanical'

thermal? and o$ administrati,e controls >training'

procedures?)

Here %ou will $ind a series o$ uestions that will help %ou

identi$% these risk areas) The uestions are designed to help

%ou identi$%' in general' i$ %our $acilit% ma% be at risk o$ $ire or

eplosion due to the presence o$ combustible dust) &t theend o$ each section o$ uestions are suggested standards

and B or re$erence standards that can help reduce the risk

%ouJ,e identi$ied)

2emember that these uestions are onl% guidelines and in

no wa% substitute a $ormal and detailed risk anal%sis to becarried out in the $acilities where combustible dust is present)

2emember also that %ou should consult the state plan' i$

applicable' to ,eri$% an% other pertinent rule to %our industr%

operations' especiall% with regard to electrical codes' and

$ire pre,ention and emergenc% plans)


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Housekeeping Ye

s

No

7s there an% solid particulate in the work area arising $romprocesses' or raw materialsK

/hat kind o$ dustK etallic

/ood

2esin or plastic

#rganic >$ood?

arbon *eri,ed

hemical aterials

7s there dust accumulation in the work areasK Such as

conduits B pipes

Gentilation s%stems

Hoods

:eams

/ork sur$aces

alse eilings

uipment or machiner%

#thers

7$ dust accumulated' is the thickness more than 1B16CK)

ore o$ 1B8CK

*oes the dust cloud or dust accumulation inter$eres with

,isibilit% in the areaK

&re there leaks in s%stems containing or transporting dustK

&re the cleaning methods' dr% methods >brush' brushes'

compressed air? that can disperse dust in the areaK


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7$ %ou answered)Sto an% o$ these uestions' %ou ma% be

at risk o$ $ire or eplosion due to accumulation o$ dust in

work areas) Lou must set up a cleaning program that

includes $reuent inspections in the workplace) The program

should indicate a regular schedule $or cleaning $loors and

horiontal sur$aces and should include immediate correcti,e

actions in case o$ ecessi,e accumulation o$ material) 2e$er

to standards 1910)""' 1910'1!6 #SH&' the 5P& 6A4 and

an% particular standard that applies to %our industr%)


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$gnition "ontrol Measures )es *o

*o %ou know i$ %our workspace has an% electricalclassi$icationK

7s there a program $or the control o$ staticelectricit%K

7s the machiner% that generates dust connectedand grounded to minimie accumulation o$ staticelectric chargeK

&re dust transport and handling euipmentproperl% grounded and bondedK

&re the de,ices B electrical cleaning euipmentappro,ed $or the haard classi$ication o$ lass 77locationsK

*o %ou use $orkli$ts or industrial trucks that areappro,ed $or use in lass 77 areas wherecombustible dust is presentK

The electrical euipment meets the reuirementso$ 5P& !0 and 5 $or lass 77 locationsK

7s there a hot work permit program $or areas wherecombustible dusts are presentK

The areas where smoking is prohibited are markedwith signs indicating C5o SmokingCK

*o euipments that produce heat or $lames in thework areas >i)e) boilers' $urnaces' dr%ers?' containsa$et% de,ices to control these sources o$ ignitionK

&re there methods o$ detection and B or $ire

etinction that ma% be caused b%' sparks'temperature' or $lameK

&re there methods $or the detection o$ smoke BparticlesK

7$ there are de,ices to remo,e $oreign materialssuch as magnets' are protected $rom causingignition o$ combustible dustK

&re the construction materials o$ dust collection

euipment and where dust is stored $ire resistantK

*oes the construction o$ these areasB euipment'limit the spread o$ damage in case o$ $ireBeplosionK

&re there controls to reduce the amount o$ o%genin areas where dust is storedK

&re there de,ices installed to pre,ent eplosionsuch as ,entilation' pressure containment and B orsuppressionK


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Measures to control auto+ignition+

temperature

)es *o

&re there wa%s to control the temperature inareas where combustible dust is generatedK

&re there wa%s to control the temperature where

combustible dust accumulatesK&re there moisture controls $or combustible dustK

If you answered NO to any of the questions of these two

sections, you can be at risk of fire or explosion due to the

presence of ignition sources in work areas where

combustible dust is present Lou must establish a monitoringprogram o$ ignition sources' which considers the reduction or

elimination o$ static charge' and ignition sources $rom

euipment that produce $lames' heat or sparks) !ou mustalso "erify that "ehicles, equipment or machinery that comes

into classified areas is properly appro"ed to operate in such

area #lectrical facilities and fixtures of that area must meet

the requirements of $%&' ()), $ational #lectrical Code and

$%&' *+ Check the -H' standards .).+.*/, .).+0+*,

and any particular standard that applies to your industry


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Protecti!e measures

&re dust collectors are located outside thebuildingsK

The construction o$ dust collectors or storage site

is combustible dust eplosion-proo$K*oes the ,ent B grille B duct ehaust blast isdirected into a sa$e location awa% $romemplo%eesK

&re dust collectors are designed so that the blastis released into places it does not a$$ect otherareasK

&re there isolation de,ices to pre,ent the spreado$ the con$lagration between de,ices connectedb% duct s%stemK

&re the ,entilation euipment connected b%

ductwork are designed to pre,ent an eplosion$rom spreading to other areasK

/ill dust collecting s%stems ha,e spark detections%stems and eplosion suppression s%stems BeplosionsK

*oes the $uel dust powder is diluted with $uel' toreduce their $lammabilit%K

7$ %ou answered *,to an% o$ these uestions can be at risk

o$ $ire or eplosion due to inadeuate ,entilation in work

areas where combustible dusts are present) Lou must

establish a ,entilation s%stem program that includes ,eri$%ing

the design and capacit% o$ hoods' $ans and dust collectors)

&lso ,eri$%' the materials o$ construction o$ these de,ices are

adeuate to resist $ire B eplosion) aterial handling and

transportation euipment must ha,e all sa$et% de,ices to

contain or sa$el% release the e$$ects o$ an eplosion )


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Employee Safety Ye

s

No

*o %ou in,estigate accidentsK

&re small eplosionsB $ires in,estigated anddocumentedK

&re the persons in the combustible dusteplosion risk area authoried to be thereK

7s there an action plan in case o$ emergenciesK

&re the emergenc% eit routes adeuatel%maintainedK

&re emplo%ees trained in the emergenc% planK

7s there a haard communication program at the

$acilit%K&re emplo%ees trained in the haardcommunication program >including combustibledust risks)?

&re emplo%ees trained be$ore beginning work inareas where there is danger o$ a combustibledust eplosionK

&re emplo%ees trained when the% are reassignedto another area' i$ there are changes toprocesses or changes to the Haardommunication programK

*oes the Haard ommunication Programinclude aterial Sa$et% *ata Sheets >S*S? oncombustible dustsK

&re the sa$et% data sheets o$ materials that couldbe classi$ied as combustible dust under normaloperation conditions a,ailable to emplo%eesK)

*o emplo%ees use all necessar% protecti,eeuipment $or the task including $ire retardantclothingK

7$ %ou answered *,to an% o$ these uestions emplo%eesma% be at risk o$ in


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Lou must ensure that these programs are implementedD

1? Haard ommunication

"? mergenc% &ction Plan and ire Pre,ention and

Protection Plan)

;? Personal Protecti,e uipment

4? &ccident 7n,estigation

Lou must also ,eri$% that all emplo%ees are properl%

trained in the details o$ these programs' and ha,e written

procedures associated with them)
http://www.oneinhundred.com/Upfiles/upimg1/Think-Safety-First---20--x-14--5197981.jpg


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$MP,-%#*% ",*S$D-#%$,*SThe design $or eplosion protection must incorporate at least

one o$ these methodsD

2eduction in the oidant concentration *ilution with non-combustible dust

-*e$lagration ontrol b% ,entilation' pressure

containment' suppression or de,ices $or $lame

suppression and containment

&n% part o$ the structure that is designed to relie,e

pressure during an eplosion should be located and

constructed so that it poses no accident risk while in use

The most common eplosion control mechanisms areD

o on$inement or containment'

o 7nerting

o 7solation' suppression or de$lagration release

Processing uipment that generates combustible dust

must be connected to a dust collection s%stem) This

s%stem usuall% consists o$ a structure that con,e%s the

dust through pipelines $rom the point where it isgenerated to the $inal collection point known as a dust

collector) *ust can be transported through the s%stem ,ia

mechanical energ% >con,e%or?' or pneumatic >air?) The

5P& 6A4' includes as collection and material handling

euipment' s%stems $or material trans$er' pipelines'

power machiner% euipment' separators' con,e%ors'

miers' dr%ers and more)

*ust collectors must be euipped with sa$et% de,ices that

pre,ent or minimie the risk o$ an eplosion duringnormal operation' as established b% 5P& 6A4

ilter s%stems $or dust collectors cannot be replaced b%

alternati,e t%pe s%stems unless a complete $ire risk

assessment is per$ormed and it has been properl%

documented and appro,ed b% management)


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7t is recommended that whene,er possible' locate bucket

ele,ators outside the building)

or s%stems that handle metal particulate is necessar% to

classi$% the material asDo water' compatible

o non- compatible with water' and

o water-reacti,e'

to determine the $ire protection s%stem appropriate to the

material properties)

/alls and internal partitions construction in areas where

combustible dust is present' usuall% reuire a minimum

$ire resistance protection o$ at least 1hr)

7$ the material trans$er euipment is used $or ,arious

products %ou must ,eri$% the compatibilit% betweenproducts prior to using the euipment)

7t is o$ upmost importance to alwa%s keep the horiontal

sur$aces and work area clean o$ material accumulation)

7n the e,ent that some areas are di$$icult to reach or

cannot be easil% cleaned' the recommendation is tocompletel% seal them o$$)

The initial and re$resher training to emplo%ees should

include the area haards' process description'

procedures' euipment' $ire and eplosion protection

s%stems' maintenance reuirements' cleaning and

emergenc% response plans)

-The euipment maintenance includes $reuent

inspections to detect and remo,e product accumulation

in critical areas)


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#PP*D$. # / ,SH# S%#*D#-DS

What standards or guidelines

are a!ailable?

,SH# &,ccupational Safety and

Health #dministration(

urrentl% there is under appro,al

process an #SH& standard that would

co,er industrial operations where

combustible dusts are present) &lthough

there is still no comprehensi,e standard

$or all operations that handle

combustible dusts' se,eral #SH&

standards indicate certain ke% pro,isions $or the control o$

risks associated with the handling o$ combustible dust in

industrial operations) The standards discussed in this section

are mandator% according to the t%pe o$ industr% applicable to

%our particular operation)

1910)"" - .eneral 2euirements >see Housekeeping?

!"#$$ %a& %& 'll places of employment( passage)ays(storage areas and ser*ice should +e kept clean( in order

and hygienic#

!"#$$ %a& %$& the floor of each )ork area must +e kept

clean and kept dry as much as possi+le#

Since these are general reuirements' the% appl% to all

general industr% operations co,ered b% the ode o$ ederal

2egulations >2? "9)1910


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1910);8 - mergenc% &ction Plans

1910);9 - ire Pre,ention Plans

1910)1A! - Portable ire tinguishers

1910)16A - mplo%ee alarm s%stems

These standards reuire emplo%ers to establish emergenc%

action plans' including $ireM indicate the minimum necessar%

procedures to respond to emergencies' the euipment

reuirements $or $ire pre,ention and training reuirements $or

personnel)

1910)94 N Gentilation

2elated to abrasi,e blasting s%stems' the standard indicates

that i$ $lammable or eplosi,e mitures o$ dust are present'

the work area must be constructed to pro,ide secure

mechanisms to release pressure in case o$ eplosion) 7t

incorporates b% re$erence the 5P& 68 the reuirements $or

the area construction and $or securit% mechanisms)

1910)119 - Process Sa$et% anagement >PS?

The purpose o$ this standard is to pre,ent or reduce the

catastrophic conseuences that arise $rom the handling o$

highl% haardous materials processes) The applicabilit% o$

the standard depends on the t%pe o$ material and the

amount o$ material used in the process) 2e$er to &ppendi &

$or a list o$ materials co,ered under the standard)


29/40

1910)1;" - Personal Protecti,e uipment

The $acilit% must ha,e implemented the program including a

risk anal%sis o$ each task $or the selection o$ the euipment)lothing and accessories $or use in areas where combustible

dust is present must include $ire-resistant clothing and

electricall% rated $ootwear)

1910)1!6 - aterial Handling and Storage

This standard generall% co,ers the basic reuirements $or

proper handling o$ materials) Section 1910)1!6 c? speci$ies

that storage areas be kept $ree o$ accumulation o$ materialthat ma% cause danger o$ $alling' tripping' $ire' eplosion or

pests)

1910)1!8 - 7ndustrial orkli$ts

Table 5-1 o$ the standard de$ines what kind o$ truck is

suitable $or use in handling and transportation o$ combustible

dusts $or lass 77' .roups ' ' .) The t%pe o$ $orkli$t is

identi$ied b% letters indicating which $uel or energ% is used tooperate the motor' and the euipment sa$et% de,ices)

The 11 categories o$ trucks areD= *iesel >*' *S' *L?= .asoline >.' .S?= Propane .as >+P' +PS?= lectric >' S' ' I?


30/40

or areas lass 77' .roups

and where combustible

dust is present' the onl%

trucks appro,ed are those

designated as or I) or

the .roup . the appro,ed

designation will be onl% .S'

+PS' *S' *L' S' ' or I)

&ll these designations

pro,ide mechanisms to

pre,ent that electrical or

combustion s%stems o$ the

euipment enter unwanted

ignition sources in areas where dust are present)

1910)"6; - :aker% uipment

Section 1910)"6; >k? identi$ies the electrical sa$et%

reuirements $or euipment used to pul,erie sugar and B or

spices and section 1910)"6; >l? establishes reuirements $or

euipment B mechanisms to release pressure in case o$

eplosion)

1910)"6A - Sawmills #perations

The standard applies to sawmill operations such as' logging'

handling' cutting' sanding' handling and storage o$ timber or

related products) stablishes reuirements to pre,ent $ire or

eplosion o$ dust collection euipment' electrical protection

$or certain euipment and also minimum cleaning $reuenc%

reuirements o$ the work area

1910)"!" - .rain Handling acilities

This was the $irst standard written speci$icall% to control risks

associated with grain handling' classi$ied as combustible

dust) 7t is aimed primaril% at grain handling operations $or the

$ood industr% and speci$ies the procedures' euipment


31/40

reuirements and sa$e

work practices $or that

t%pe o$ operation)

T%picall%' the silos are

considered con$ined

spaces and there$ore

must also re$er to

Standard 1910)146 -

on$ined Spaces $or

sa$et% considerations

when working in silos or

similar spaces)

1910);0! - Haardous +ocations

This standard de$ines the reuirements $or electrical

euipment and wiring to be used in electricall% classi$ied

areas based on the properties o$ $lammable liuids' solids or

gases' combustible dusts and B or $lammable $ibers present

in that area) 7t re$erences the 5P& !0 standard)

1910)1"00 - Haard ommunication

This standard reuires besides the identi$ication o$ health

haards' the ph%sical haards present in the work area

including but not limited combustible dusts) ach emplo%er is

responsible $or obtaining the in$ormation about the sa$e

handling o$ these materials and pro,iding such in$ormation to

their emplo%ees through signs' labels' notices) The emplo%er

must pro,ide training related to the handling and proper use

o$ the material as well as wa%s to protect emplo%ees$rom the

haards associated with particular material


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&P5**7I : N

5P& ST&5*&2*S

*0P# &*ational 0ire Protection

#gency(

There are se,eral standards $rom

this agenc% that pro,ide guidelines to control those $actors

that can contribute to generate a $ire or eplosion while

handling combustible dusts) cept in cases which are

incorporated b% re$erence in speci$ic #SH& standards' 5P&

standards are not mandator%) 5e,ertheless the% pro,ide

speci$ic and detailed in$ormation $or pre,enting $ires or

eplosions when handling combustible dusts

5P& 6A4 >"006? N Standard $or the Pre,ention o$ ire and

plosions $rom the anu$acturing' Processing and

Handling o$ ombustible Particulate Solid

7t is the most comprehensi,e standard $or the control o$ $ires

caused b% combustible dust) Pro,ides methods $or

identi$%ing risks and practical control measures $or work

areas' based on three principles

- Pre,enting the $ormation o$ a haardous atmosphere

- Pre,enting ignition o$ haardous atmosphere

- +imit the conseuences o$ the eplosion to anacceptable le,el >mitigation or control?

&mong the reuirements o$ 5P& 6A4 are prescripti,e

pro,isions >mandator%? $or compliance and en$orcement

options based on per$ormance)

Prescripti,e pro,isions includeD

*esign o$ s%stems and $acilities Protection o$ process euipment

ontrol o$ $ugiti,e dust and cleaning

7gnition Sources o$

Pro,isions $or $ire protection

Training and operations' maintenance and

emergencies procedures


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7nspection and maintenance

Per$ormance-based options reuire specialied and

documented engineering anal%sis that considersD

The sa$et% o$ the occupants' and

*esigns that treat $ire and eplosion speci$icscenarios

The 5P& 6A4 establishes the basic reuirements $or

protection euipment and technolog%) The design $or

eplosion protection must incorporate at least one o$ these

methodsD 2eduction in the concentration o$ oidants' which can

be o%gen' air or materials that promote combustion

b% o%gen contribution

*ilution with non-combustible dust' to limit the

burning characteristics o$ the material) 5ot

2ecommended -*e$lagration ontrol b% means o$D

o Gentilation - allows to $ocus the $orce o$ the

eplosion to a point in the $acilit% where the

pressure generated b% the eplosion causes

the least harm to people and B or structureso Pressure containment - the enclosure' tank or

structure should be able to contain at least "B;

o$ the $orce and pressure generated in the

eplosion) The degree o$ damage will be used

to determine whether to allow the container B

structure to be reused)o Suppression - uses sa$et% de,ices' $lame

detectors and other protecti,e euipment to

pre,ent the spread o$ the initial $lameo *e,ices $or $lame suppression and

containment N it is the combination o$ a $ilter

and $lame suppressing de,ice >$lame arrester?to contain the initial $lame and reduce the

e$$ects o$ the eplosion)


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#ther standard pro,isions are retroacti,e to $acilities

constructed' replaced or modi$ied be$ore 8-18-"006) The

retrospecti,e re,iew reuirements include elements $or

anagement o$ hange

Housekeeping lectrostatic ignition sources

artridge - actuated tools

#pen $lamesand sparks

Training and planning

7nspection and aintenance

There are other 5P& standards related to industries or

speci$ic operations' such asD

5P& 61 >"008? - acilities &gricultural and ood Processing

This standard is applicable to an% $acilit% which recei,es'

handles' processes' dries' mi' use' grind' pack' store or

ship dr% bulk agricultural material) 7t also applies to

structures' buildings' structures or acti,ities such as

modi$ication' reno,ation' repair' additions' and demolitions) 7t

establishes reuirements $or ,entilation' eplosion

pre,ention' pressure release' euipment >dr%ers' o,ens'

con,e%or belts' etc)?' dust control' $ire protection s%stems

and pro,ides supplementar% material on ignition controls and

administrati,e controls)

5P& 69 N>"008? plosion Pre,ention S%stem

The purpose o$ this standard is to pro,ide e$$ecti,e s%stems

to control the eplosion potential in structures to sa$eguard

li$e and propert%) 7t reuires a documented risk anal%sis to

determine the necessar% sa$et% protections) The suggestedmethods $all into two broad groups

ethods to pre,ent the combustion aimed to reduce

the concentration o$ oidant or combustible present

ethods that pre,ent or limit the damage'including


35/40

- S%stems $or the detection o$ pre-de$lagration and

ignition control

- Suppresion o$ de$lagration

- 7solation methods

- Pressure containment o$ the eplosion

5P& 484 >"009?N ombustible etals

This standard pro,ides criteria $or determining the

$lammabilit% or eplosi,eness o$ the metallic materials' which

includes alkali metals' aluminum' magnesium' titanium and

others) stablishes reuirements $or $ire pre,ention and

protection relating to euipment and dust collection

operation' and controls necessar% to control B eliminate

sources o$ static electricit%) stablishes guidelines $or

personal protecti,e euipment and sa$e rec%cling o$ these

metals)

5P& 499 >"008? - lassi$ication o$ *usts uels and

Haardous +ocations

This standard discusses the electrical classi$ication criteria

$or work areas where

$lammable or

combustible materialsare present including

,apors' dusts and

$ibers) The general

criteria $or

classi$ication areD

Class 1I, II, III2 3 defines the type of material

= lass 7 - ,apors $rom $lammable and B or combustible

liuids or gases= lass 77 - combustible dusts= lass 777 - $ibers

.roup >&.? - indicates the t%pe o$ dust or material= .roup &- - designed $or ,apors o$ $lammable and B or

combustible liuids or gases= .roup -. - designed $or dusts' speci$icall%D


36/40

-.roup - metal dust-conducts electricit%

-.roup - coal dust can conduct electricit%-.roup . - wood' $ood' agricultural products'

chemicals or manu$acturing) *o not conduct electricit%

*i,isiOn >1'"? N indicates the amount o$ material present= Di"isi4n .N there is enough dust present under

normal operating conditions as to produce an

eplosi,e or ignitable miture' or'= &n abnormal operation' mechanical or

electrical $ault causes the eplosi,e miture' or= There is enough electricall% conduct,e dust

present as to produce the eplosi,e miture

&ccording to 5P& 499 dust accumulation greater than 1B8C

under normal operating conditions the classi$ies the area as*i,ision 1

5 Di"ision 6N there is not enough amount o$ dust to create

the eplosi,e miture under normal operating conditions' but

material is suspended in air because o$ $ault% euipment or

material handling operation' and= The accumulation o$ dust on or near electrical euipment

pre,ents dissipation o$ heat generated b% the euipment' or

there are $aults in electrical euipment= There is no *i,ision " $or the dusts in .roup

7n areas where combustible dust is handled' processed' or

stored under conditions ensuring that there will be no

leakage o$ material' that ,entilation s%stems and cleaning in

the area pre,ents the accumulation o$ dust classi$ication o$

the area is not necessar%) or $urther details on this sub


37/40

used in areas classi$ied as lass 77) &rticle A04 de$ines the

reuirements $or wiring and installation o$ intrinsicall% sa$e

electrical euipment)

5P& 664 >"00!? - Processing and /oodworking

The scope o$ this standard

includes $acilities that

process or manu$acture

wood and B or wood

products' creating

$ragments' wood particles or

wood dust)

7t applies to plants with

more than A'000 suare $eet o$ ph%sical area and to $acilitieswith dust collection euipment whose $low is greater than

1A00 c$m >cubic $eet B minute?) 7$ the $acilit% $alls outside this

range the standard reuires $or speci$ic controls and a

haards anal%sis o$ the $acilit%)

The $ire pre,ention plan should consider the worst case

scenario to pre,ent the $ire $rom spreading and causing

in5?) 7t should also establish a hot work

permits program)

or more in$ormation on an% particular operation please re$er

to the $ollowing additional standards

5P& 68 >"00!? - plosion Genting

5P& 8A >"00!? - Haards o$ ombustion and :oiler

S%stems

5P& 1"0 >"010? - oal ine


38/40

5P& 49A >"010? - plosi,e aterials

5P& 6AA >"00!? - Sul$ur ires and plosions

5P& 11"4 >"006? - ireworks and ireworks


39/40

225S

#ccupational Sa$et% and Health &dministration'

www)osha)go,' "9 2 1910

5ational ire Protection &genc%' httpDBBwww)n$pa)org

(S hemical Sa$et% :oard' httpDBBwww)csb)go,

ederal 2egister *oc 9-"A0!A' 2euest $or data on

ombustible *ust

ederal 2egister !4DA4;;;-A4;4!' ombustible *ust'

&d,anced 5otice o$ Proposed 2ulemaking

H2 A""" /orker Protection &gainst ombustible *ust

plosions and ires &ct o$ "008Q

SH7: 0!-;1-"00A ombustible *ust on 7ndustr%D Pre,enting

and itigating the $$ects o$ ire and plosions

S: 2eport 5o "008-0A-7-.&' 7n,estigation 2eport on

Sugar *ust plosion and ire

olonna .)2)'5P& ombustible dust Haards odes and

Standards' $rom the %&7% Combustible Dust -ymposium

alosh 2' ' ombustible *ust ire and plosion Protection'ire Sa$et% seminar presentation

awell )&)' /hat %ou need to know about dust

eplosions' HS Toda%' *ecember "009
http://www.osha.gov/http://www.nfpa.org/http://www.csb.gov/http://www.osha.gov/http://www.nfpa.org/http://www.csb.gov/


40/40

This document was de,eloped b% The (ni,ersit% o$ Puerto 2ico

under grantR 19480-09-60 --!" and is intended to assist

emplo%ers' workers' and others as the% stri,e to impro,e

workplace health and sa$et%) /hile we attempt to thoroughl%address haards related to handling o$ combustible dusts' it is not

possible to include discussion o$ e,er%thing necessar% to ensure a

health% and sa$e working en,ironment in a document o$ this

nature) Thus' this in$ormation must be understood as a tool $or

addressing workplace haards' rather than an ehausti,e

statement o$ an emplo%erJs legal obligations' which are de$ined b%

statute' regulations' and standards) +ikewise' to the etent that

this in$ormation re$erences practices or procedures that ma%

enhance health or sa$et%' but which are not reuired b% a statute'

regulation' or standard' it cannot' and does not' create additional

legal obligations) inall%' o,er time' #SH& rules andinterpretations ma% be modi$ied in light o$ new technolog%'

in$ormation' or circumstances to keep apprised o$ such

de,elopments' or to re,iew in$ormation on a wide range o$

occupational sa$et% and health topics' %ou can ,isit #SH&Js

website at www)osha)go,)

or more information about this topic please contact the

Division of Continued Education at 764-0000, ext. 749

Documents

Hazards Related Combustble Dust