Electrical Problems Electrical Problems May Have Sparked May Have Sparked Swiss Air Flight 111 Swiss Air Flight 111

CrashCrash* Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html)* Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html)

Urs Urs Zimmermann Zimmermann (Pilot) and the (Pilot) and the planes flight planes flight recorder.recorder.

The exact The exact cause of the cause of the crash is crash is unknown, unknown, however, however, evidence evidence points towards points towards a rapid and a rapid and deadly deadly electrical fireelectrical fire

Rapid FireRapid Fire * Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html) * Pictures Taken from Web Site (http://www3.ns.sympatico.ca/mr.187/photos.html)

According to record Zimmerman According to record Zimmerman noticed smoke at approximately noticed smoke at approximately 10,000m and 16 minutes later, 10,000m and 16 minutes later, the plane slammed into the the plane slammed into the Atlantic Ocean off Peggys Cove, Atlantic Ocean off Peggys Cove, N.S. Canada.N.S. Canada.• According to Susan Bradley, a According to Susan Bradley, a

spokeswoman for Boeing, Kapton was spokeswoman for Boeing, Kapton was the primary coating on the wiring in the primary coating on the wiring in Swissair Flight 111Swissair Flight 111 (Maclean’s Sept 21, 1998 v111 n38 p20(1)) (Maclean’s Sept 21, 1998 v111 n38 p20(1))

How Safe is Kapton How Safe is Kapton WiringWiring

Picture taken from web site (www.ece.msstate.edu/hvl/research.html)Picture taken from web site (www.ece.msstate.edu/hvl/research.html)

Patrick Price (Expert with the former Patrick Price (Expert with the former Boeing Co. in Seattle) on Kapton wiringBoeing Co. in Seattle) on Kapton wiring• ““It’s like taking an incendiary bomb on It’s like taking an incendiary bomb on

board”board” (Maclean’s, Sept 21, 1998 v111 n38 p20(1)) (Maclean’s, Sept 21, 1998 v111 n38 p20(1))

In 1982 the U.S. navy stopped using In 1982 the U.S. navy stopped using Kapton wiring in jet fighters when cracks Kapton wiring in jet fighters when cracks in wires coated with Kapton were linked in wires coated with Kapton were linked to on-board fires.to on-board fires. (Maclean’s, Sept 21, 1998 v111n38 p20(1)) (Maclean’s, Sept 21, 1998 v111n38 p20(1))

Scientists have found Kapton is prone to Scientists have found Kapton is prone to rare but catastrophic “arc tracking” rare but catastrophic “arc tracking” when the wire is subjected to chafing, when the wire is subjected to chafing, vibration, and moisture. vibration, and moisture. U.S. News and World Report, Sept U.S. News and World Report, Sept

28, 1998 v125 n12 p44(1))28, 1998 v125 n12 p44(1))

If a wire cracks, electricity can arc to If a wire cracks, electricity can arc to nearby material, setting it on fire. This is nearby material, setting it on fire. This is known as a flash over which burns at a known as a flash over which burns at a searing 1,000 C.searing 1,000 C.

Deadly GamesDeadly Games

Swiss Air Flight 111 had approximately 240 km Swiss Air Flight 111 had approximately 240 km of wires running through it to bring passengers of wires running through it to bring passengers a premium video and gambling system in a premium video and gambling system in today’s intensely competitive market for today’s intensely competitive market for business and first-class flyers.business and first-class flyers.

Each seat aboard Swiss Air Flight 111 had a Each seat aboard Swiss Air Flight 111 had a video screen that pops out of the armrest like video screen that pops out of the armrest like a tray table. Passengers could play video a tray table. Passengers could play video games, music, or even gamble.games, music, or even gamble.• It was this luxury which could have lead to It was this luxury which could have lead to

the crash.the crash. The system costs about 2 million or more The system costs about 2 million or more

dollars per plane and was developed by dollars per plane and was developed by Interactive Flight TechnologiesInteractive Flight TechnologiesTMTM. A struggling . A struggling company which said it wants out of the in-company which said it wants out of the in-flight-entertainment business.flight-entertainment business.• This web of wires from each seat to central This web of wires from each seat to central

computers aboard the plane generates a computers aboard the plane generates a greater possibility for an electrical disaster.greater possibility for an electrical disaster.

(Time, Nov 9, 1998 p58(1))(Time, Nov 9, 1998 p58(1))

Advanced Kapton Advanced Kapton Material is Being Material is Being

Used Today Used Today

Since 1993 Kapton has been Since 1993 Kapton has been improved by wrapping it in a improved by wrapping it in a tough Teflon coating.tough Teflon coating.

In an article I found from In an article I found from 1998 FAA officials said that 1998 FAA officials said that old forms of Kapton may old forms of Kapton may soon be removed from soon be removed from hundreds of planes.hundreds of planes.

Boeing company spokesman Boeing company spokesman John Thom said that “Kapton John Thom said that “Kapton was and is certified for use was and is certified for use on commercial airplanes”on commercial airplanes” (Maclean’s, (Maclean’s,

Sept 21, 1998 v111 n38 p20(1))Sept 21, 1998 v111 n38 p20(1))

Some Pictures from Some Pictures from the aftermaththe aftermath

Picture taken from web site (http://www3.ns.sympatico.ca/mr.187/photos.html)Picture taken from web site (http://www3.ns.sympatico.ca/mr.187/photos.html)

At left is one of the most At left is one of the most recognizable photos from recognizable photos from the tragedy as rescuers the tragedy as rescuers try in vain to find try in vain to find survivors. Pictured at survivors. Pictured at right is the Emergency right is the Emergency Service Paying tribute to Service Paying tribute to Flight 111Flight 111

Fire Prevention in Fire Prevention in PlanesPlanes

Picture taken from web page (http://www.airliners.net/open.file?id=13250)Picture taken from web page (http://www.airliners.net/open.file?id=13250)

The Federal Aviation The Federal Aviation Administration or FAA announced Administration or FAA announced in October of 1998 that Mylar in October of 1998 that Mylar insulation used in nearly 12,000 insulation used in nearly 12,000 passenger jets must be replaced passenger jets must be replaced to reduced the chance of fire.to reduced the chance of fire. (U.S. News (U.S. News

and World Report, Oct 26, 1998 p17(1))and World Report, Oct 26, 1998 p17(1))

• It is believed that this type of It is believed that this type of insulation was set ablaze by a short insulation was set ablaze by a short circuit in the electrical equipment circuit in the electrical equipment aboard the Swiss Air Flight 111aboard the Swiss Air Flight 111

Luxury isLuxury isnot alwaysnot alwaysbetterbetter Picture from web site Picture from web site

(http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/)(http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/)

The high tech video system aboard The high tech video system aboard Flight 111 used Microsoft Windows Flight 111 used Microsoft Windows NT software, with wires connected to NT software, with wires connected to

a central computer.a central computer. (Time, Nov 9,1998 p58(1))(Time, Nov 9,1998 p58(1))

• Investigators found that the wires had Investigators found that the wires had been connected to the same electrical been connected to the same electrical pathways that powered vital parts of the pathways that powered vital parts of the aircraft.aircraft.

– Therefore, if there is a problem with the Therefore, if there is a problem with the video system, then there is a problem with video system, then there is a problem with the whole plane.the whole plane.

In the future this type of video In the future this type of video system should be connected to a system should be connected to a separate area of the plane where separate area of the plane where vital networks in the plane will not be vital networks in the plane will not be affected thus buying time for an affected thus buying time for an emergency landing.emergency landing.

Firefighting Firefighting Training for Pilots Training for Pilots and Preventionand Prevention

Web site (http.www.tsb.gc.ca/EN/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)Web site (http.www.tsb.gc.ca/EN/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)

The investigation into Swiss Air Flight The investigation into Swiss Air Flight 111 revealed safety deficiencies in crew 111 revealed safety deficiencies in crew training and awareness, and procedures training and awareness, and procedures related to in-flight firefighting.related to in-flight firefighting.• The TBS safety board issued the following The TBS safety board issued the following

recommendations to address safety recommendations to address safety deficienciesdeficiencies

– A lack of a coordinated and comprehensive A lack of a coordinated and comprehensive approach to in-flight firefighting.approach to in-flight firefighting.

– Smoke/fire detection and suppression systems Smoke/fire detection and suppression systems are insufficientare insufficient

– There are no smoke/fire detection and There are no smoke/fire detection and suppression systems in the cockpit or cabin or suppression systems in the cockpit or cabin or any area not considered a fire zone. any area not considered a fire zone.

– The importance of making prompt preparations The importance of making prompt preparations for a possible emergency landing is currently for a possible emergency landing is currently not recognized.not recognized.

– This is due to company policy and the feeling that This is due to company policy and the feeling that it is an inconvenience. it is an inconvenience.

– Access to critical areas within the aircraft are Access to critical areas within the aircraft are inadequate.inadequate.

– There has been little or no training provided to There has been little or no training provided to aircraft crew on how to access areas behind aircraft crew on how to access areas behind electrical or other panelselectrical or other panels

Material For Fire Material For Fire PreventionPrevention

HalonHalon (Washington Monthly, Sep 1997 v29 n9 p44(2)) (Washington Monthly, Sep 1997 v29 n9 p44(2))

• Pressurized bottles of Halon – a highly Pressurized bottles of Halon – a highly effective fire fighting agent – have long been effective fire fighting agent – have long been used in the cargo holds of larger jets but is used in the cargo holds of larger jets but is not used in smaller planesnot used in smaller planes

– Brings us to the fact that in general the Brings us to the fact that in general the larger the vehicle the safer it usually is larger the vehicle the safer it usually is due to greater regulations. due to greater regulations.

A Plastic Called PHAA Plastic Called PHA (Discover, August 1999 v20 i8 p11) (Discover, August 1999 v20 i8 p11)

• PHA is a plastic which only emits water vapor PHA is a plastic which only emits water vapor when it burns, and it brakes down into a flame-when it burns, and it brakes down into a flame-resistant compound.resistant compound.

There is also the possibility of There is also the possibility of Flame Retardant MaterialFlame Retardant Material (Class Notes) (Class Notes)

• Chlorine and Fluorine when added to Chlorine and Fluorine when added to material help in fire resistance.material help in fire resistance.

– Trade off would be the hazardous smoke this Trade off would be the hazardous smoke this type of compound produces when it does type of compound produces when it does burn.burn.

– Flash overs due to electricity arcing burn at a Flash overs due to electricity arcing burn at a searing 1,000 C.searing 1,000 C.

Crash StatisticsCrash StatisticsLarger The Vehicle Larger The Vehicle

the Saferthe Safer

Some airline safety facts Some airline safety facts (Web Site (http://www.air-transport.org/public/speeches/view1997.asp?UniqueID=38))(Web Site (http://www.air-transport.org/public/speeches/view1997.asp?UniqueID=38))

• You are more likely to die You are more likely to die by being kicked to death by by being kicked to death by a donkey than in a plane a donkey than in a plane crashcrash

• You are more likely to be You are more likely to be crushed by a falling objectcrushed by a falling object

• You are much more likely You are much more likely to be killed by your spouseto be killed by your spouse

You have one chance in You have one chance in about 7 million from about 7 million from dying in an plane crashdying in an plane crash

Average TimeAverage TimeTo React To React To A FireTo A Fire(http://www.nifc.gov/gallery/manter.html)(http://www.nifc.gov/gallery/manter.html)

The average time between The average time between when an in-flight fire is when an in-flight fire is detected and when the detected and when the aircraft either ditches, aircraft either ditches, conducts a forced landing, or conducts a forced landing, or crashes is about 17 minutes. crashes is about 17 minutes. (http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)(http://www.tsb.gc.ca/ENG/TSB_Investigations/Swissair/site_pages/saf…/FireRecs_2000dec4.ht)

• Some examplesSome examples

TypeType DateDate MinutesMinutes

AN-12AN-12 19671967 <10<10

B-707B-707 19731973 ~7~7

B-747B-747 19871987 1919

MD-11MD-11 19981998 2020

Increase Your Increase Your ChancesChances

Handy Hints For The Handy Hints For The Nervous Traveler Nervous Traveler (http://www.amigoingdown.com)(http://www.amigoingdown.com)

• 70% of incidences in 70% of incidences in recent year occur on take-recent year occur on take-off or landingoff or landing– Try to book non-stop flightsTry to book non-stop flights

• Take note of where the Take note of where the nearest emergency exit isnearest emergency exit is

• Choose a large aircraftChoose a large aircraft– The larger the vehicle the The larger the vehicle the

better your chancesbetter your chances

Does Fate Alone Does Fate Alone Decide Who Decide Who

SurvivesSurvives

Most Likely NoMost Likely No 71% of the people who die in 71% of the people who die in

crashes die after the plane crashes die after the plane comes to a compete stop. comes to a compete stop. (People Weekly, Oct (People Weekly, Oct

20, 1997 v48 n16 p125(3))20, 1997 v48 n16 p125(3))

You can increase your chances You can increase your chances by knowning your surroundingsby knowning your surroundings• How many isles to the exitHow many isles to the exit• In case of fire if you can hold your In case of fire if you can hold your

breath for 30 seconds that’s how breath for 30 seconds that’s how long it takes to exit the aircraft long it takes to exit the aircraft normally.normally.

• Don’t try and get your duffel bag Don’t try and get your duffel bag in case of a crashin case of a crash

• Pay attention to the safety Pay attention to the safety procedures (life vests)procedures (life vests)

Where Where To SitTo Sit(http://www.aircrash.org/burnelli/)(http://www.aircrash.org/burnelli/)

If you’re worried about If you’re worried about impact impact (People Weekly, Oct 20, 1997 v48 n16 p125(3))(People Weekly, Oct 20, 1997 v48 n16 p125(3))

• Sit in the backSit in the back If you’re worried about a If you’re worried about a

fuel firefuel fire• Sit forward of the leading Sit forward of the leading

edge of the wingedge of the wing If your worried about the If your worried about the

plane breaking upplane breaking up• Sit by the over-wing exitsSit by the over-wing exits

– This is the strongest part of This is the strongest part of the aircraft due to the fuel the aircraft due to the fuel being carried in the wingsbeing carried in the wings

Improved Electrical Improved Electrical Apparatus Insulation Apparatus Insulation

MaterialMaterial

One way to improve Wiring in planes One way to improve Wiring in planes is to use an improved insulation is to use an improved insulation materialmaterial• Currently many electrical wires Currently many electrical wires

use porcelain and glass insulatorsuse porcelain and glass insulators• An ethylene and vinyl acetate An ethylene and vinyl acetate

copolymer (EVA) tested better in copolymer (EVA) tested better in the lab these forms of insulation the lab these forms of insulation (Polymer Engineering and Science:Jul. 1996, V.S. Ivanov, I.I. Migunova, N.A. Kalinina, G.N. (Polymer Engineering and Science:Jul. 1996, V.S. Ivanov, I.I. Migunova, N.A. Kalinina, G.N. Aleksandrov)Aleksandrov)

– As discussed in class copolymers As discussed in class copolymers usually increase a materials ability to usually increase a materials ability to withstand an impactwithstand an impact

– Copolymers would help in wires that Copolymers would help in wires that would be subjected to rough would be subjected to rough conditionsconditions

– Kapton currently has problems under Kapton currently has problems under rough conditionsrough conditions

Radiation-Induced Radiation-Induced CurrentCurrent (ChemAbsStudent, “Studies on radiation-induced current in (ChemAbsStudent, “Studies on radiation-induced current in

polymeric insulating materials and their fine sturcture”, J. Master. Sci 17 no 10 (1982):3052-6)polymeric insulating materials and their fine sturcture”, J. Master. Sci 17 no 10 (1982):3052-6)

Degradation in crystalline Degradation in crystalline materials such as materials such as PolyethylenePolyethylene

Degradation in non-Degradation in non-crystalline materials such crystalline materials such as ethylene-propylene as ethylene-propylene rubber used for wire rubber used for wire insulationinsulation• For radiation-induced current For radiation-induced current

degradation is affected more degradation is affected more by the degree of crystallinity by the degree of crystallinity than its perfection.than its perfection.

Method For Improving The Method For Improving The Environmental Stress-Environmental Stress-

Crack Resistance or (ESCR) Crack Resistance or (ESCR) (J. Appl. Poym. Sci. 16, no 9 (1972): 2375-86)(J. Appl. Poym. Sci. 16, no 9 (1972): 2375-86)

(ESCR) is a critical factor in (ESCR) is a critical factor in wire insulationwire insulation• In studying the effect of rubber In studying the effect of rubber

on (ESCR) the choice of a base on (ESCR) the choice of a base resin is importantresin is important– Depending on the resin and rubber Depending on the resin and rubber

combination you choose the combination you choose the (ESCR) can double or increase by (ESCR) can double or increase by 50-fold.50-fold.

– Kapton could be improved with Kapton could be improved with slight variations in its production slight variations in its production and perhaps different types of and perhaps different types of resins should be looked atresins should be looked at

• For exampleFor example– The higher the molecular weight of The higher the molecular weight of

Polyisobutylenes the more Polyisobutylenes the more effective its performance as a effective its performance as a stress crack additivestress crack additive

Polymers – Good Polymers – Good InsulatorsInsulators

Polymers are good Polymers are good insulators because they insulators because they are covalently bonded are covalently bonded and their electrons are all and their electrons are all tightly bound. tightly bound.

Polymers – Polymers – Conductors!?Conductors!?

Doping of polymers with Doping of polymers with strong electron acceptors strong electron acceptors such as iodine can cause such as iodine can cause polymers to conduct polymers to conduct nearly as well as metals.nearly as well as metals.

Doping to polyacetylene Doping to polyacetylene causes it’s conductivity causes it’s conductivity to be 10to be 101010 times higher times higher than pure than pure polyacetalylene.polyacetalylene.

Polymers - Good Polymers - Good Conductors!?Conductors!?

This flexible electronic This flexible electronic circuit functions even circuit functions even when it’s bent. when it’s bent.

http://focus.aps.org/v6/http://focus.aps.org/v6/st18.htmlst18.html

Uses of KAPTON - Uses of KAPTON - PropertiesProperties

Maintains its mechanical Maintains its mechanical stability at very high and very stability at very high and very low temperatureslow temperatures

resists high mechanical stress resists high mechanical stress during assembly operationsduring assembly operations

has excellent electrical has excellent electrical insulation and thermal insulation and thermal propertiesproperties

has outstanding resistance to has outstanding resistance to most chemicals, lubricants and most chemicals, lubricants and fuelsfuels

allows space and weight allows space and weight savingssavings

Uses of KAPTON - Uses of KAPTON - ElectronicsElectronics

In electronic equipment, In electronic equipment, KAPTON is used as substrate KAPTON is used as substrate material for Flexible Printed material for Flexible Printed Circuits and punched, bonded Circuits and punched, bonded or formed high performance or formed high performance part in small miniature part in small miniature switches. It can be etched in switches. It can be etched in alkaline solns.alkaline solns.

Bar Code LabelsBar Code Labels Heat Sinks, to ensure optimal Heat Sinks, to ensure optimal

heat transfer between film heat transfer between film and power transistorsand power transistors

Masking tapesMasking tapes

Uses of KAPTON - Uses of KAPTON - Bondable Bondable ApplicationApplication

Can be bonded, coated or Can be bonded, coated or laminated to allow the laminated to allow the following requirementsfollowing requirements• BeltsBelts• Thermal insulator in ironsThermal insulator in irons• Fuel sensorsFuel sensors• Smoke hoodsSmoke hoods• Blood bagsBlood bags

Uses of KAPTON - Uses of KAPTON - Electronic Electronic InsulationInsulation

Wire and cable insulationWire and cable insulation formed coil insulation of formed coil insulation of

traction motorstraction motors Magnet wire insulationMagnet wire insulation transformer and transformer and

capacitor insulationcapacitor insulation

Uses of KAPTON - Uses of KAPTON - AutomotiveAutomotive

Alternator heat sink Alternator heat sink insulator padsinsulator pads

Air bag (diaphragm)Air bag (diaphragm) Flexible circuitsFlexible circuits Spark plug bootSpark plug boot

Uses of KAPTON - Uses of KAPTON - AerospaceAerospace

Cockpit sun shadeCockpit sun shade SpeakersSpeakers Flexible CurcuitryFlexible Curcuitry Acoustic insulationAcoustic insulation Thermal blanketsThermal blankets

Uses of KAPTON - Uses of KAPTON - Thermal Thermal ManagementManagement

Heat sinkHeat sink Power suppliesPower supplies Heater circuitsHeater circuits Copier belts Copier belts Carrier beltsCarrier belts Coil insulationCoil insulation

Thermal Thermal Degradation – Degradation – Experimental Experimental MethodsMethods

Thermogravimetry(TG)-Thermogravimetry(TG)-measures loss in weightmeasures loss in weight

Differential scanning Differential scanning calorimetry(DSC)calorimetry(DSC)

Differential thermal Differential thermal analysis-heat absorption analysis-heat absorption or evolution due to either or evolution due to either physical or chemical physical or chemical changes occurring within changes occurring within the polymer is measuredthe polymer is measured

Thermal Thermal Degradation Degradation ReactionsReactions

Depolymerisation Depolymerisation ReactionsReactions• Characterized by the Characterized by the

breaking of the main breaking of the main polymer chain backbone so polymer chain backbone so that at any intermediate that at any intermediate stage the products are stage the products are similar to the parent similar to the parent material in the sense that material in the sense that the monomer units are still the monomer units are still distinguishable. The distinguishable. The ultimate product may be ultimate product may be monomer. monomer.

Thermal Thermal Degradation Degradation ReactionsReactions

Substituent ReactionsSubstituent Reactions• It is the substituents attached It is the substituents attached

to the backbone of the to the backbone of the polymer molecules which are polymer molecules which are involved so that the chemical involved so that the chemical nature of the repeat unit is nature of the repeat unit is changed although the chain changed although the chain structure may remain intact. structure may remain intact.

• See reaction example, page See reaction example, page 2424

Radical Radical Depolymerisation Depolymerisation ReactionReaction

Degradation Reaction Degradation Reaction exampleexample• Poly(metyl methacrylate)Poly(metyl methacrylate)• Between 300-400 Between 300-400 ooC, see C, see

exampleexample

Oxidation of Oxidation of PolymersPolymers

Degradation of polymers Degradation of polymers usually increases in the usually increases in the presence of oxygenpresence of oxygen

RR· + O· + O22 ROO· ROO· ROO· + RH ROO· + RH ROOH + R· ROOH + R· TerminationTermination

• 2R· 2R· R-R R-R• R· + ROO· R· + ROO· ROOR ROOR

• 2ROO· 2ROO· ROOR + O ROOR + O22

Photo-degradationPhoto-degradation

Wavelengths of light from sun Wavelengths of light from sun range from infrared (>700nm) to range from infrared (>700nm) to the visible spectrum (400-700nm) the visible spectrum (400-700nm) to ultra-violet (<400nm). to ultra-violet (<400nm).

Energy of 700nm photon is 170 Energy of 700nm photon is 170 kJ/mol and energy of 300nm kJ/mol and energy of 300nm photon is 390 kJ/molphoton is 390 kJ/mol

Strength of C-C and C-H bond are Strength of C-C and C-H bond are 420 and 340 kJ/mol respectively420 and 340 kJ/mol respectively

It is clear that the energies of the It is clear that the energies of the UV and possibly the visible UV and possibly the visible components of sunlight are components of sunlight are sufficient to break chemical sufficient to break chemical bondsbonds

Insulation Insulation Requirements for Requirements for WiresWires

Requirements for Requirements for Machine-tool Wires Machine-tool Wires and Cablesand Cables

Who Sets the Who Sets the Standards?Standards?

Requirements specified in Requirements specified in the National Electrical the National Electrical Code (ANSI/NFPA 70)Code (ANSI/NFPA 70)

Also used in the National Also used in the National Fir Protection Association Fir Protection Association Electrical Standard for Electrical Standard for Industrial Machinery Industrial Machinery (ANSI/NFPA 79)(ANSI/NFPA 79)

How Are the How Are the Standards Set?Standards Set?

The polymer insulation and The polymer insulation and the finished wires must the finished wires must comply with a flame test comply with a flame test and are for use at and are for use at temperatures of 90 temperatures of 90 °C (194 °C (194 °F) or lower in dry locations°F) or lower in dry locations

Must comply at Must comply at 60 60 °C (140 °C (140 °F) or lower where exposed °F) or lower where exposed to moisture, oil, or coolantsto moisture, oil, or coolants

Insulation Insulation Requirements for Requirements for WiresWires

Requirements for Requirements for Machine-tool Wires Machine-tool Wires and Cablesand Cables

Who Sets the Who Sets the Standards?Standards?

Requirements specified in Requirements specified in the National Electrical the National Electrical Code (ANSI/NFPA 70)Code (ANSI/NFPA 70)

Also used in the National Also used in the National Fir Protection Association Fir Protection Association Electrical Standard for Electrical Standard for Industrial Machinery Industrial Machinery (ANSI/NFPA 79)(ANSI/NFPA 79)

How Are the How Are the Standards Set?Standards Set?

The polymer insulation and The polymer insulation and the finished wires must the finished wires must comply with a flame test comply with a flame test and are for use at and are for use at temperatures of 90 temperatures of 90 °C (194 °C (194 °F) or lower in dry locations°F) or lower in dry locations

Must comply at Must comply at 60 60 °C (140 °C (140 °F) or lower where exposed °F) or lower where exposed to moisture, oil, or coolantsto moisture, oil, or coolants

How Are the How Are the Standards Set?Standards Set?

The polymer insulation and The polymer insulation and the finished wires must the finished wires must comply with a flame test comply with a flame test and are for use at and are for use at temperatures of 90 temperatures of 90 °C °C (194 °F) or lower in dry (194 °F) or lower in dry locationslocations

Must comply at Must comply at 60 60 °C (140 °C (140 °F) or lower where °F) or lower where exposed to moisture, oil, or exposed to moisture, oil, or coolantscoolants

Mils mm Mils mm Mils mm Mils mm Mils mm

22 - 7; 20 - 12 AWG

30 0.76 27 0.69

15

0.38 13 0.33 4 0.1

10-Nov 30 0.76 27 0.69 20 0.51 18 0.46 4 0.19, 8 45 1.14 40 1.02 30 0.76 27 0.69 5 0.137, 6 60 1.52 54 1.37 30 0.76 27 0.69 5 0.135, 4 - 2 60 1.52 54 1.37 40 1.02 36 0.91 6 0.15

1/4/2000 80 2.03 72 1.83 50 1.27 45 1.14 7 0.18213 - 500 kcmil

95 2.41 86 2.18 60 1.52 54 1.37 8 0.2

501 - 1000

110 2.79 99 2.51 70 1.78 63 1.6 9 0.23

Minimum thickness of any point of nylon jacket

a A conductor is appropriate for use with a cross-sectional area that does not correspond to one of the AWG or kcmil sizes in Table when the finished wire or cable complies with the marking requirement in and with each of the following:a) The conductor shall have a dc resistance that is not larger than the resistance determined by interpolation(by cross-sectional area) between the resistances of the next larger and smaller sizes shown inthe applicable Table or .b) The number of strands, the thicknesses of insulation, the thickness of any nylon jacket, and other particulars shallcomply with the requirements applicable to the next smaller size shown in Table .

Conduct

ora size

NEC construction A (Nylon jacket not used) NEC construction B

Minimum average thickness of the

insulation

Minimum thickness of any point of the

insulation

Minimum average thickness of the

insulation

Minimum thickness of any point of the

insulation

Aircraft Crashes Aircraft Crashes Due to Failure in Due to Failure in WiresWires

Short examples of Short examples of Kapton related Kapton related crashed in aircraft and crashed in aircraft and what is being done to what is being done to prevent any further prevent any further mishapsmishaps

August 19,1980 August 19,1980 Saudi Arabian Saudi Arabian Airlines Tri-starAirlines Tri-star

After take off from Riyadh Airport After take off from Riyadh Airport a fire broke out in the rear cargo a fire broke out in the rear cargo compartment.compartment.

Plane returned to Riyadh as Plane returned to Riyadh as flames broke through the cabin flames broke through the cabin floor and filled the cabin with floor and filled the cabin with smokesmoke

Upon investigation Kapton wires Upon investigation Kapton wires were found burnt out, and the were found burnt out, and the insulation destroyedinsulation destroyed

Also the wires had fractured Also the wires had fractured ends , a sign of arcing, no other ends , a sign of arcing, no other source for ignition could be source for ignition could be foundfound

January 14, 1985 January 14, 1985 British Monarch British Monarch Airline Boeing 757Airline Boeing 757

On a flight from the Canary On a flight from the Canary Islands to Luton the aircraft Islands to Luton the aircraft has a serious wire bundle has a serious wire bundle explosionexplosion

As smoke begins to enter the As smoke begins to enter the cabin the pilot is able to make cabin the pilot is able to make a forced landing in Portugala forced landing in Portugal

An investigation showed that An investigation showed that moister dripped onto the moister dripped onto the wiring below the lavatory and wiring below the lavatory and wet arc tracking occurred wet arc tracking occurred causing the bundle explosioncausing the bundle explosion

November 5, 1990 November 5, 1990 Philippine Airlines Philippine Airlines Boeing 737Boeing 737

Plane is being delayed for Plane is being delayed for take off when explosion take off when explosion occursoccurs

The explosion was in the The explosion was in the fuel tank fuel tank

After investigation the After investigation the most probable cause was most probable cause was determined to be a spark determined to be a spark from a faulty wire from a faulty wire creating an explosioncreating an explosion

March 17, 1991 March 17, 1991 Delta Airlines Delta Airlines Lockheed Tri-starLockheed Tri-star

Plane is on way to Atlanta Plane is on way to Atlanta from Frankfurt when a from Frankfurt when a fire breaks outfire breaks out

Aircraft makes an Aircraft makes an emergency landing in emergency landing in Goose Bay Goose Bay

Upon an investigation the Upon an investigation the most probable cause of most probable cause of the fire was electrical the fire was electrical arcing in the wire bundlearcing in the wire bundle

Some Action Being Some Action Being TakenTaken

Following a Valujet crash Following a Valujet crash in Florida in 1998 Al Gore in Florida in 1998 Al Gore has headed a special has headed a special commissin to determine commissin to determine the ageing effects on the ageing effects on airplane wiringairplane wiring

Other countries plan on Other countries plan on doing the similar thingdoing the similar thing

However, the tests will be However, the tests will be non-intrusivenon-intrusive