fire performance of fr polymers bundy f&m 2005

8/11/2019 Fire Performance of FR Polymers Bundy F&M 2005

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FIRE PERFORMANCE OF FLAME RETARDEDPOLYMERS USED IN CONSUMER ELECTRONICS

Matthew Bundy* & Thomas OhlemillerNational Institute of Standards and Technology, Gaithersburg, M, !S"

ABSTRACT

"n e#$erimental study was $erformed to com$are the bench%scale and full%scale fire$erformance of commercial $olymeric materials used in electronic eui$ment' The ignition resistance,self%e#tinguishing beha(ior, heat release rate )++, and combustion $roduct yields of -. differentmaterials at two thic/nesses were characteri0ed using three standard bench%scale fire tests' 1i(e of the-. materials were molded into -23 com$uter monitors for full%scale fire testing )using real andsimulated internal com$onents' The results of this study were used to assess the $redicti(e (alue of the

bench%scale tests in determining full%scale fire $erformance and to describe the fire ha0ard of the full%scale s$ecimens when e#$osed to three different ignition scenarios' " !425 B rated monitorenclosure was easily ignited using a )6. 7 8 9 needle flame and resulted in a $ea/ ++ of )8:: 7 8;/9' The ignition threat distance )determined using the measured radiant heat flu# distribution for thisfire was found to be );. 7 -; cm for $iloted ignition of a stac/ of $a$er and )--8 7 8. cm for ignitionof insulated cotton fabric' The )86 7 6 /9 fire resulting from ignition of a /eyboard was used as amore se(ere ignition source for the monitor housings' Tests were also $erformed using a radiant heat

$anel to simulate an e#isting burning item' "ll of the monitor s$ecimens achie(ed ignition and at least$artial burn%u$ from the larger ignition sources' The full%scale test results were e#amined to determinethe degree of correlation with the bench%scale results' The !425 (ertical burn test showed goodagreement with the needle flame ignition results and the bench%scale $ea/ ++ showed someualitati(e agreement with the /eyboard fire and radiant $anel full%scale results' "ll of the resins

e#hibited com$le# $hysical beha(ior when burning )i'e' melting and charring which made com$arisonwith small scale tests more difficult'

INTRODUCTION

"lthough fires originating from consumer electronics are rare, the ha0ard $resented whene#$osed to a small e#ternal ignition source )such as a candle is not well /nown'


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scale fire tests and com$ared the ran/ed $erformance to the fire $erformance of model electronicenclosures e#$osed to a 6 /9 $ro$ane sand burner' The results showed reasonable ualitati(eagreement between the o(erall bench%scale and full%scale $erformance' The 1lame +etardant ?hemical"ssociation )1+?" s$onsored a study by the National Bureau of Standards )NBS in -2.. 6 thatshowed a significant reduction in the fire ha0ard of T@ cabinets using flame retardant materials'Se(eral re$orts5%A by the Swedish National Testing and +esearch Institute )S> and the National

"ssociation of State 1ire Marshals )N"S1M com$ared the fire growth of off%the%shelf $rinters,com$uter monitors and ?>!s to the !425 ran/ing of the enclosure material and concluded thatenclosures using B rated $lastics are (ulnerable to ignition by a small flame and can lead to flasho(erof a room'

BENCH-SCALE FIRE TESTING

Three standardi0ed bench%scale flammability tests were used to characteri0e a set ofcommercially a(ailable resins' The bench scale flammability tests included the ?one ?alorimeter test)"STM < -6;5, the !425 (ertical burn test, and the Glow 9ireIgnitability Tem$erature test )G9IT)I


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une#$ected since the u$ward flame s$read and meltingDdri$$ing mechanisms inherent to the !425 testare not ca$tured by the geometry of the cone'

Ta"le # Summary of Bench Scale Test +esults at ;: /9Dm8heat flu#'

?one ?alorimeter measurements were also$erformed at 6 different heat flu# le(els using the6'8 mm thic/ s$ecimens' The heat release ratecur(es for the non%1+ I>S sam$le at incidentflu#es of 6: /9Dm8, ;: /9Dm8, and 2: /9Dm8areshown in 1igure -' The results show a greater++$ea/and shorter time to ignition with increasing

heat flu# and the general sha$e of the ++ cur(ewas unchanged' This trend was obser(ed for mostof the materials e#amined howe(er some materials)such as C%>?D"BS%N1+ showed a decrease in

$ea/ ++ as the heat flu# was increased'

It has been shown that a steady state energybalance can be used to $redict the functionalrelationshi$ between the steady ++ and e#ternalheat flu#2' ++ssJ++oK+>)e#t' In thise#$ression the intrinsic heat release rate, ++o, re$resents the heat flu# at 0ero e#ternal flu# and theheat release $arameter, +>, re$resents the material sensiti(ity to e#ternal flu# and has been used to

$redict fire $ro$agation' It was obser(ed that for a wide range of $olymers the ++o(alue was a good$redictor of !425 $erformance, where self%e#tinguishing materials generally had a ++oof less than-:: /9Dm8'-:

0 50 100 150 200 250 300 3500

200

400

600

800

1000

1200

1400

1600

1800

Time (s)

H

RR(kW/m2)

3-HIPS-NFR - 30kW/m2



1igure -' ++ cur(es for 6%I>%N1+ )!425 B6'8 mm sam$le thic/ness'


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" summary of the ?one results at 6 differente#ternal heat flu# le(els is shown in Table 8'Because many of the materials in Table 8 arethermally thin and charring, a steady ++was ne(er reached' The ++o and +>

(alues were determined using a linearregression of the initial $ea/ ++ (alue' Ingeneral, larger (alues of ++o and +>relate to increased fire ha0ard' " com$arisonof the ++oand !425 ran/ings is shown in1igure 8' 1rom this limited data set it a$$earsthat the criteria for self e#tinguishingmaterials )@%: and @%- is that the ++o isless than ;:: /9Dm8' "lthough these resultsare ualitati(ely meaningful, their uantitati(e(alues are uestionable due to the large uncertainly in choosing an a$$ro$riate steady ++' Becausethe !425 ran/ing can de$end on sam$le thic/ness )ie' material -8 from Table -, it cannot be

determined solely from an intrinsic $ro$erty such as ++o'

Ta"le $%Summary of ?one results at three heat flu# le(els, s$ecimen thic/ness J 6'8 mm'

Sam$leIdentification

>ea/ eat +elease+ate )/9Dm8

Time To SustainedIgnition )s

++:)/9Dm8

+>)/LD/L

Irradiation )/9Dm8 6: ;: 2: 6: ;: 2:

-%>?%N 5;A 5.8 ;68 -26 CA -A 58: -'6

8%I>S%B1+ 6:5 5C- ;CC .A 6- 2 8-- 5'-

6%I>S%N1+ --:.-8C

; -C86 -;- ;: -C .56 .'C

5%>?%N1+ A65 A:6 2.5 ;:: -82 5: ;5. 5'C

;%>?%B1+ 68- 656 56A 8C: A. 85 8;5 8':C%>?D"BS%N1+ .;: A2: AC8 -6A ;C 8- .AA %-'5

A%"BS%B1+ 856 6A: ;-; -8C ;: -A -8C 5'5

.%>?D"BS%>1+ 58. ;CA C-- -;5 ;6 86 6A. 8'.

2%I>S%B1+ 26: AC: .8A -6C 55 -A 2:2 %-'8

-:%>?%B1+ -2- -CA 8;. 5C- A8 -C -66 -'6

--%>>%B1+-C;

:8:2

: 862- 88- C8 8: -6.6 --'A

-8%>>%N 8C; 66A 628 ;: 8; -: 8-. 8':

-6%>>%B1+-C.

288:

C 8;82 -85 5C -8 -62C -6'8

-5%>>%B1+-CA

A88:

: 8;.- --: 6; -C -656 -5'6

-;%>>%N 6-; 5.A ;6: -5: 5. -2 8C- 6'8

-A%>@?%N1+ -A2 856 6:; -:6 86 -- -8. 8':

-.%I>S%>1+ 62- 55; C62 2. 6: 2 8;- 5'8

-2%"BS%>1+ 8C8 826 5;5 22 6C -- -5. 6'6

FULL-SCALE FIRE TESTING

The full scale tests were $erformed under a 6 m suare e#haust hood designed to accommodatesustained fires with a net heat release rate )++ of u$ to - M9' The e#haust mass flow rate was set

to 8 /gDs )6C:: S?1M for these tests to $ro(ide o$timal resolution for fires less than 5:: /9 in si0e'

eat release rate measurements were based on the well%established o#ygen consum$tion $rinci$le--, -8

'" com$lete descri$tion of the hardware and test setu$ can be found in the final re$ort -6'

Figure 2. Comparison of UL94 ranking andintrinsic HRR for 3.2 mm specimens.


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The ; materials used in the full scale tests re$orted here were selected to re$resent a wide range of fire$erformance in the bench scale tests' " list of materials used in these tests and a summary of resultsfrom 6 bench%scale tests )6'8 mm thic/ sam$les are gi(en in Table 6' The full scale s$ecimen masslisted in Table 6 is the combined mass of the front and rear $ieces of the $re%assembled monitorenclosure'

Ta"le &% Summary of bench%scale $erformance for materials used in full%scale tests, and initial mass of combustible material on full scale s$ecimens'

+esinIdentification

?one $ea/++ )/9Dm8;: /9Dm8

!425?lassification

G9IT )o? DG91T )o?

1ull%ScaleS%N1+ -6:A B A;: D A8; 866;

-6%>>%B1+ -2-C @%8 .:: D 2C: -222

-.%I>S%>1+ 62. @%- NT 85;6

-%>?%N ;.C @%: .8; D 2C: 8.62

A%"BS%B1+ 5:2 @%: A;: D 2C: 8C.6

F!ll-scale s'eci(ens

Two $iece -23 ?+T com$uter monitor housings )1igure 6 were molded from the materials listed inTable 6' The a(erage s$ecimen wall thic/ness was )6': 7 :'8; mm' The fire characteri0ation was

$erformed using both real and simulated internal com$onents' The simulated internal frame consistedof -'C mm steel sheet metal formed roughly into the sha$eof the real com$onents' ra$ed o(er the frame was asheet of aluminum foil that ser(ed to increase the lateralcross section of the sheet metal frame' The frame alsoser(ed to $artially su$$ort the $lastic enclosure during thefire test and shield interior surfaces from radiation' The

frame was thus intended to achie(e the same ualitati(eeffects that real monitor com$onents ha(e on a fire' Thereal internal com$onents consisted of a cathode ray tube)?+T and other (arious electronic com$onents, some ofwhich were combustible' The 88 cm # 82 cm o$ening atthe base of the enclosure was co(ered with -'C mm sheetmetal' The s$ecimen was $laced on a bric/ such that themid%length side lower edge was ). 7 - cm from the tablesurface'

I)niti*n S*!rces

Small local ignition source: " small local ignition source re$resenting a ty$ical candle si0ed flame wasused for these tests' " :'; mm I'' needle flame burner was used to $roduce an n%butane flame with aheight of )8: 7 - mm' The fuel mass flow rate was measured as ):'.5 7 :':8 mgDs and the net heatrelease rate of this flame was calculated as )6A'; 7 8 9' The flame was a$$lied mid%length along theside of the s$ecimen, )6 7 - cm abo(e the lower edge' This em$hasi0ed both the $otential for u$wardflame s$read and for the de(elo$ment of an interacti(e melt $ool fire on the table surface' The initialflame a$$lication was for a $eriod of 8: s' If the burning s$ecimen e#tinguished within C: s, the flamewas immediately re%a$$lied for C: s' The C: s a$$lication was re$eated 6 times for a total flamea$$lication time of 8:: s' In the case that a hole was formed in the s$ecimen, the test flame was mo(edlaterally to remain in contact with the enclosure )chasing the receding material' This ignition methodwas designed to $ro(ide information on the fire $erformance of the eui$ment when e#$osed to alocali0ed short duration ignition source, and also the $ossibility of a much longer duration ignition

source such as an unattended candle'

Large ignition source (radiant heat panel): The res$onse of the s$ecimens to a larger ignition source

1igure 6' -23 ?om$uter monitor s$ecimenused in full%scale testing'


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was simulated using a 5. cm # 66 cm natural gas radiant heat $anel' This was intended to re$resent asituation where the monitor was not the first item in(ol(ed in a fire' The centerline heat flu# was )8- 7- /9Dm8at a location -; cm from the front surface of the $anel' " remo(able co$$er $late shutterwas used to $rotect the s$ecimen from the heat flu# $anel $rior to the start of the test' The shutter waswater cooled and $ainted blac/ to minimi0e the tendency of the gas%fired $anel to increase intem$erature when shielded' " -'C mm I'' o$en tube burner was used to $roduce a -: cm n%butane

$ilot flame with a net heat release rate of )-A. 7 ; 9' This $ilot was a$$lied in a location similar tothat of the needle flame the entire side of the monitor was irradiated' In some tests it was held incontact with melted material that had fallen to the table to$'

Large ignition source (polystyrene keyboard): " generic, non%1+ $olystyrene /eyboard was used asan ignition source for the monitor s$ecimens in some tests' The total weight of the /eyboard was);.: 7 ; g' The /eyboard was $laced under the front be0el of the monitor and ignited using the 8: mmneedle flame described $re(iously' The needle flame was a$$lied for 8: s to the side of the 12 /ey'Tests were also conducted using only the /eyboard to determine its contribution to the heat release rate'

Heat Fl!+ Meas!re(ents

"n array of four total heat flu# gauges )Schmidt%Boelter ty$e, C mm diameter sensor face, -6 mmdiameter body was $laced in a $osition to (iew one side of the burning ob=ect )right side of 1igure 5'The goal of the array was to obtain data on the distribution of radiati(e heat flu# (ersus distance alonga line $er$endicular to the ob=ect surface being (iewed' This information is used below to infer thema#imum distance at which different materials could be ignited as a result of radiati(e heating from theob=ect fire' The four gauges were arranged as follows' The front and rear gauge were on the samehori0ontal a#is, both facing along this a#is, and se$arated by 8; cm to 6: cm' The remaining twogauges were on a single (ertical a#is, both facing in the same direction as the first two, i'e', toward theside of the burning ob=ect' That (ertical a#is was dis$laced ; cm from the hori0ontal a#is of the firsttwo gauges' The two gauges on this (ertical a#is were se$arated (ertically by a distance of -;'6 cm,symmetrically abo(e and below the hori0ontal a#is of the first two gauges' This arrangement ultimatelysu$$lies three measures of the heat flu# (ersus $er$endicular distance away from the (iewed surface of

the burning ob=ect' In addition, since this distribution de$ends also on the height at which it ismeasured, the two (ertical gauges $ro(ide a first order correction for this effect' Since the gauges )andtheir $hysical su$$orts had a finite si0e and could be within the field of (iew of those behind them,corrections had to be made to their readings for this shadowing'

Nee,le Fla(e I)niti*n Res!lts

None of the 5 flame retarded materials $roduced a measurable fire when e#$osed to the 8: mm needleflame for a total a$$lication time of 8:: s' The monitor enclosure molded using the non flame retardantmaterial, 6%I>S%N1+, was easily ignited during the initial 8: s a$$lication of the flame and $roduceda fire that consumed the entire monitor housing' The ++ cur(es for these s$ecimens are shown in1igure 5' The initial test flame was a$$lied at 5 min into the data file for all tests described here' The

fire growth and $ea/ ++ on the monitors with the simulated internal frame )test - and 5 in 1igure 5were (ery re$roducible' 1or each of the s$ecimens the fire grew slowly during the first 6 min thenra$idly accelerated to its $ea/ (alue during the ne#t 6 min' The $resence of the ?+T )test 8C in 1igure5 decreased the fire growth rate and lowered the $ea/ ++ by a$$ro#imately 6: '

The total mass loss measurement in this series of tests was com$romised by se(eral factors' Thecalcium silica sheet below the s$ecimen contained roughly 6 water weight )-;: g that $artially(a$ori0ed during the test' In addition, some of the glass from the ?+T was e=ected from the monitorduring the test' 1or these reasons it was not $ossible to distinguish the mass loss due to the burning

$lastic from the o(erall mass loss' The initial weight of the monitor enclosures for tests -, 5 and 8Cwas )866; 7 ; g' The combined e#$anded relati(e uncertainty )2; confidence le(el of the $ea/heat release rate measurement was 7-8 , based on $ro$agation of measurement uncertainty'


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0 5 10 15 20 25 30 350

50

100

150

200

250

Time (min)

HRR(kW)

monitor 1monitor 4monitor 26

1

4

26

tign= 4 min

1igure 5' eat release rate cur(es for needle flame ignition of -23 monitors' Ignition flame a$$lied tos$ecimen at t J 5 min' Image of monitor test, 6%I>S%N1+, near $ea/ heat release rate )right' "rrayof heat flu# gauges is shown on right side of image

Ke"*ar, Fire I)niti*n Res!lts

The /eyboard ignition tests were $erformedfollowing the needle flame ignition methodfor the four flame retarded s$ecimens that didnot ignite and had only local fire damage tothe enclosure' Tests conducted tocharacteri0e the stand%alone /eyboard as anignition source showed an a(erage $ea/ ++of 88'A /9, a$$ro#imately -: min afterignition' 9hen the /eyboard burned, its resin

did not flow outward more than - cm to 8cm' Thus, when used as an ignition source, itwas essentially stationary' >ortions of themonitor )the front be0el immediately abo(eit were $artially immersed in its flames'More remote $ortions of the monitor sawonly limited radiation from the /eyboard fire

$lume'

The ++ cur(es for the /eyboard fire ignition of the monitors are shown in 1igure ;' The ++ datafor the stand alone /eyboard fire test is also shown in this figure for reference' 9ith the e#ce$tion ofmaterial A%"BS%B1+, the monitor s$ecimens were ignited by the burning /eyboard and the enclosures

were com$letely consumed by the resulting fire' uring the test of monitor A%"BS%B1+, only theenclosure material directly in contact with the fire from the burning /eyboard was ignited' Thecontribution of the enclosure to the $ea/ ++ was between -: /9 and 8: /9 and the rear half of theenclosure was not in(ol(ed in the fire'

Of the 1+ s$ecimens, material -6%>>%B1+ e#hibited the greatest ha0ard when e#$osed to the /eyboardfire' Once ignited the fire uic/ly grew into a large $ool fire that co(ered the entire test surface' Theedge of the test surface was $rotected with aluminum foil to contain the melt $ool, howe(er a smallamount of burning $lastic s$illed o(er the edge' It should be noted that $oly$ro$ylene is not ty$icallyused for electronic enclosure housings'

The monitors using materials -%>?%N and -.%I>S%N had similar $erformances in the /eyboardfire ignition configuration' "lthough the $ea/ ++ was lower than s$ecimen -6%>>%B1+, the fires$read to the rear $art of the enclosure and consumed most of the mass of the enclosure' This resultillustrates that the fire ha0ard is not the same for all @%: rated materials' "s with all of the s$ecimens,

1igure ;' ++ cur(es for /eyboard ignition of -23com$uter monitors'

: ; -: -; 8: 8; 6: 6; 5::

;:

-::

-;:

8::

8;:

Time )min

*++)/9,

Stand alone /eyboard-%>?%N )@%:A%"BS%B1+ )@%:-6%>>%B1+ )@%8-.%I>S%>1+ )@%-

tign= 4 min 7

13

1

18

k


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the $resence of the real ?+T delayed the fire growth and lowered the $ea/ ++' This is likel dueto the considera!le heat sink of the massi"e CRT. # summar of the peak HRRresults is gi"en in Ta!le 4.

Ta"le .% Summary of $ea/ heat release rates for all full%scale fire tests'

S'eci(en ID

UL/.Ratin)0&%$ (( CRT

Nee,le Fla(eI)niti*nHRR'ea12134

Ke"*ar,I)niti*nHRR'ea12134

Ra,iant PanelI)niti*nHRR'ea12134

>S%/eyboard

B

%%%% 88'; %%%% %%%%

>S%/eyboard %%%% 88'C %%%% %%%%

>S%/eyboard %%%% 86 %%%% %%%%

-%>?%N

@%:

No no%ign 5C $24

-%>?%N No no%ign -8: $$%

-%>?%N es no%ign ;; %%%%

-%>?%N No no%ign ;; %%%%

6%I>S%N1+B

No 2&' %%%% 24&6%I>S%N1+ No 2&& %%%% $9&

6%I>S%N1+ es $44 %%%% %%%%

A%"BS%B1+

@%:

No no%ign 55 no%ign

A%"BS%B1+ No no%ign 6- 2(

A%"BS%B1+ es no%ign 6; %%%%

-6%>>%B1+

@%8

No no%ign 8:; $93

-6%>>%B1+ No no%ign -22 $)%

-6%>>%B1+ es no%ign -.: %%%%

-.%I>S%>1+

@%-

No no%ign --; ''

-.%I>S% >1+ No no%ign .2 94

-.%I>S% >1+ es no%ign A6 %%%%

Ra,iant Heat Panel I)niti*n Res!lts

The results of the radiant heat $anel ignition ofthe monitor s$ecimens are summari0ed inTable 5' "ll of these tests were $erformedusing the s$ecimens with simulated internalcom$onents' The radiant $anel was $ositionedso that a 8- /9Dm8total heat flu# was im$osed

at the $oint on the side of the s$ecimen wherethe local ignition source was a$$lied' "s in the

$re(ious tests a barrier of foil was a$$lied tothe edge of the su$$ort surface to $re(entmaterial from dri$$ing onto the floor anddamaging the load cell and instrument wires'Two 6'8 mm thic/ steel bars were $ositioned infront of the heat $anel to $re(ent the enclosurefrom ti$$ing o(er and contacting the face of the

$anel' 5 min after the start of the test the water%cooled radiation shield was remo(ed and the $ilot flame was immediately a$$lied to the side of themonitor'

S$ecimen -%>?%N was easily ignited with this method and the fire uic/ly consumed the entire

Figure ). HRR cur"es for radiant heat panel*forced ignition+ of $9+ monitors.

: ; -: -; 8: 8; 6::

;:

-::

-;:

8::

8;:

Time )min

*

++)/9,

-%>?%N )@%:6%I>S%N1+ )B

A%"BS%B1+ )@%:-6%>>%B1+ )@%8

-.%I>S%>1+ )@%-

3

131

7

18

tign= 4 min


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s$ecimen and grew to e#ceed -:: /9 in si0e' The time from ignition to $ea/ ++ was about 5 min'"s e#$ected, the non%1+ I>S s$ecimen, shown in 1igure C, ignited and uic/ly de(elo$ed into a large

$ool fire in less than ; min' The A%"BS%B1+ s$ecimen did not ignite during the first two attem$ts' "llof the material on the side of the enclosure melted away from the -: cm $ilot flame before it couldignite' uring the third attem$t, shown in 1igure C, the $ilot flame was lowered to remain in contactwith the de(elo$ing melt $ool on the surface of the calcium silicate board' The enclosure ignited and

slowly s$read to the far side of the s$ecimen' The ++ had a $ea/ of 8; /9 nearly -; min after theinitial flame a$$lication' Similar beha(ior was obser(ed for the -6%>>%B1+ s$ecimens, e#ce$t that theresult was a larger fire' Only after a$$lying the $ilot flame to the melt $ool for a$$ro#imately ; mindid the fire begin to $ro$agate to the other sides of the enclosure' Once ignited howe(er the fire grew(ery uic/ly and had a similar growth rate and $ea/ ++ to the /eyboard fire ignition method of thesame material' The heat release rate cur(e of the -.%I>S%N )!425 @%- s$ecimen ignited using theradiant $anel and $ilot flame is also shown in 1igure C' The a(erage $ea/ heat release rate, 2- /9,was substantially lower than the I>S resin with no flame retardant'

Treat *5 I)niti*n *5 Oter O"6ects

"ny fire $oses an ignition threat to ob=ects in its surroundings' Such ignition could occur by one of

se(eral modes includingE direct flame contact with the surface of another ob=ect, mo(ement of flamingmaterial, and remote ignition by radiation' 1or the $ur$ose of com$aring relati(e fire ha0ard we willconsider only radiati(e ignition here' "n im$ortant feature of radiati(e ignition is that below some flu#le(el )corres$onding to some distance away from the radiating fire $lume, the surface of the heatedob=ect will not get hot enough to be ignitable e(en if a $ilot flame is $resent' The distance beyondwhich this is true defines the threat radius3 of the fire'


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ifferent target ob=ects ha(e differing ignitability as a result of their s$ecific chemical and $hysical$ro$erties' Since it is not $ossible to ma/e $redictions for all ob=ects which may $lausibly be near anelectronic eui$ment fire, surrogate materials are used' ere we consider two materials which aresurrogates for common ob=ects of interest in the (icinity of a des/to$ com$uter' The first is a stac/ of

$a$er' S$ecifically, the surrogate material is a 8';5 cm thic/ unbound $ile of co$ier $a$er' This is asurrogate for boo/s, maga0ines, manuals or $rinter $a$er that could be on a des/ to$' The second is a

medium weight cotton fabric which is a surrogate for a dra$e or for the seatbac/ of an u$holstered des/chair' The fabric is -:: cotton and weighs :'5- /gDm8)-8 o0Dyd8' The $iloted ignition beha(ior ofthese materials was measured in the ?one ?alorimeter o(er a flu# range from A: /9Dm8down to theminimum flu# for ignition' In the monitor fires, the heat flu# that would im$inge on a target ob=ectrises and falls as the monitor fire builds and recedes, therefore the ?one data cannot be used directly'Instead, it forms the basis for inferring the effecti(e ignition $ro$erties of the surrogate material' "sim$le thermal ignition model is used to findeffecti(e $ro$erty (alues which closely re$roducethe measured ignition beha(ior from the ?one'These $ro$erties are the ignition tem$erature and the

a$$arent thermal inertia )$roduct of density ), heat

ca$acity )c and thermal conducti(ity )/' "

com$arison of the cone ignition data and the ignitionmodel for the cotton fabric material is shown in1igure A' Gi(en these effecti(e ignitability

$ro$erties and the measured heat flu# (ersus timefrom the monitor fire tests, this information can beused in the model)s to $redict the farthest distancefrom the fire at which ignition of the surrogatematerials can =ust occur'

Since the number of heat flu# gauges was uitelimited, only some $ortion of the flu# (ersusdistance $rofile was measured in each test and it

was necessary to e#tra$olateDinter$olate themeasured (alues' igital images of the fire,ta/en from behind the flu# gauges, were used todetermine an a$$ro#imate area of the fire whichwas then used to account for $artial shadowingof the rear gauges and to e#tra$olate the flu#distribution based on the radiati(e (iew factor'1igure . shows this (iew factor basede#tra$olation cur(e and the $oint measurements

for one of the monitor s$ecimens' ,ecausethe -u data ha"e su!stantial"aria!ilit /due to the tur!ulent nature

of the 0re plume1 it is simpler toapproimate the transient nature ofthe -u ! using a aussian timedependence. The aussian is speci0ed to match the peak -u and its time idthat (& 5 of the peak. # detailed description of the -u gauge geometr ignitionmodel and etrapolation methods can !e found in the full report$3.

1igure A' +adiati(e ignition of cotton fabric in the?one ?alorimeter'

1igure .' @iew%factor based e#tra$olation cur(e and

flu# measurements from /eyboard ignition of -%>?%N monitor'


11/13

Table ; shows the com$uted ma#imum $iloted ignition reach (alues for the cotton fabric and the $a$er'This was done only for a select set of fire tests since it was uite labor intensi(e' The cases re$ortedhere are for the monitor enclosures containing the $seudo%?+T interior the main goal is a com$arisonof the differing resins, $lus some guidance regarding acce$table3 fire si0es' The results for the cottonfabric were com$uted for the two e#tremes adiabatic bac/ surface or eual bac/ and front surface heatlosses )re%radiation $lus con(ection' The ignition beha(ior of the $a$er surrogate was com$uted with a

thermally thic/ model using a 8'; cm de$th' This is thic/ enough that the bac/ surface condition isirrele(ant on the time scale reuired for ignition' The relati(e error in the ma#imum ignition threatdistance was estimated to be less than 8;'

Ta"le 7% +esults of ma#imum ignition threat distance analysis'2a48nee,le 5la(e i)niti*n9 2"48 1e"*ar, i)niti*n9 2c48 ra,iant eat 'anel i)niti*n%

Resin(confguration)

PeakHRR(kW)

Max.IgnitionDistance(m)Non-insulatedCottona!ric

Max.IgnitionDistance(m)InsulatedCottona!ric

Max.IgnitionDistance(m)"tack o#Pa$er

36 H786:FR/a1

2&& &.%$ $.$2 &.('

$36886,FR /!1 $9' &.)( &.9% &.()

$'6H7868FR/!1

'9 &.3) &.() &.29

%6#,6,FR /!1 3$ :. #. :. #. :. #.

$68C6:H /!1 $2& &.3) &.(' &.3$

$68C6:H /c1 $24 &.3) &.($ &.2);e!oard /a1 22.( &.$2 &.2% &.&'

The best%beha(ed case was for A%"BS%B1+ for which ignition reach (alues could not be directlycalculated )indicated by N'"' in Table ;' The reason for this was that the fire sto$$ed before it

$ro$agated as far along the side as the flu# gauge array and the $ea/ flu# (alues recorded e(en for thefront flu# gauge, were less than 5 /9Dm8'


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The results from the bench%scale tests and the full%scale monitor tests are shown in Table C' The bench%scale test results are for 6'8 mm thic/ sam$les' The full%scale $ea/ ++ results in Table C re$resentthe largest of the re$licate measurements' Pualitati(ely, the !425 (ertical burn test ga(e the bestindication of the full%scale monitor fire $erformance when e#$osed to the needle flame ignition source'"ll of the materials that self%e#tinguished in the !425 test resisted sustained ignition in the full%scale

monitor tests' The time to ignition in the ?one and the Glow 9ire Ignition Tem$erature were the$oorest indicators of full%scale fire $erformance in these tests' "lthough the $resence of a flameretardant additi(e can cause a material to ignite faster and at a lower tem$erature, these factors did nothel$ $redict whether or not the flame would $ro$agate once ignited' The $ea/ ++ from the ?one wasnot a good $redictor of the full%scale res$onse to the local ignition source in this study' " notablee#am$le of this is the $oly$ro$ylene s$ecimen )-6%>>%B1+ that has a (ery high $ea/ ++ in the ?one

but did not ignite when e#$osed to the needle flame' The ?one results com$ared more fa(orably withthe full%scale monitor tests ha(ing a larger ignition source' The two s$ecimens with the highest $ea/++ in the ?one tests also $roduced the largest fires when e#$osed to the /eyboard fire and radiant

$anel ignition sources' More research is needed to de(elo$ and inter$ret bench%scale tests ca$able of$redicting full%scale $erformance' The most reliable e#isting measure is full%scale testing, assuming thea$$ro$riate ignition scenario can be identified'

Ta"le ;% ?om$arison of Bench%Scale and 1ull%Scale test results'

CONCLUSIONS

>rogressi(ely larger and more intense ignition sources caused the burning of an increasingnumber of tested resins' The use of flame retardant materials )including non%halogenated $ro(idedadeuate $rotection against the needle flame that re$resented a candle si0e3 ignition source' The fireha0ard from needle flame ignition of the enclosure ha(ing a non%flame%retarded material )6%I>S%N1+was significant and resulted in the threat of fire s$read to nearby ob=ects' The /eyboard fire ignitionsource $roduced a significant fire ha0ard for all but one )A%"BS%B1+ of the monitor enclosures' Theradiant heat $anel used to simulate an e#isting fire $roduced significant burning for all of the monitors$ecimens'

Se(eral bench%scale flammability measures were assessed for ability to $redict full%scale monitor

beha(ior with limited success' The !425 (ertical burn test was a good indicator of the li/elihood of thefull%scale s$ecimens to resist sustained ignition by a candle si0e3 flame' The ?one ?alorimeter testwas a reasonable indictor of the res$onse of the monitor s$ecimens to ignition by a nearby burningob=ect' The Glow 9ire Ignition Test was a $oor indicator of the full%scale res$onse to an o$en flameignition source'

The radiant ignition of remote ob=ects was analy0ed for se(eral of the monitor fires' " 8:: /9 )$ea/++ fire $roduced a threat distance of -'- m for u$holstery fabric' " )8: to 8; /9 )$ea/ ++ fire

$roduced a threat distance of :'6 m for u$holstery fabric' " $ea/ ++ of less than -: /9 would li/ely$roduce a minimal radiant ignition threat to its surroundings, com$arable to the threat of direct flamecontact' >eri$heral items )such as the /eyboards in this study are often made from non%1+ materialsand can ser(e as an ignition source for other items if ignited'

ACKNO3LEDGEMENTS


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The authors would li/e to than/ Scott illon and Qen Stec/ler from the "T1 1ire +esearch4aboratory for their assistance in $erforming the full%scale e#$eriments' The following indi(iduals alsomade contributions to this wor/E Sanghyun ong, "le# Morgan, Tony Qingsbury, Susan 4andry,ouglas 9et0ig, +obert Bac/strom, a(id roducts, NBS%S>A52, -2.., Gaithersburg, $'-%.C'

5 Simonson, M', +e$ort for the 1ire Testing of ?om$uter Monitors, +6--;-, S> -222'

; Simonson, M', +e$ort for the 1ire Testing of es/=et >rinters, >::;.5., S> 8:::'

C Simonson, M', +e$ort for the 1ire Testing of One >rinter and Two ?>!Rs, >::.CC5, S> 8:::'

A Bliss, ', Simonson, M', 1ire >erformance of IT

fire performance of fr polymers bundy f&m 2005

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