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Life Cycle Analysis of Glass vs. Polycarbonate
Sidelights
Natalie HenryJaymie Meliker Mike Turnbull
Melissa Vernon
April 14, 1999
Agenda
• Goals• System Overview• Life Cycle Costs • Impacts - Energy, Solid Waste, Air, Water• Drivers• Summary• Recommendations
Goal
• Evaluate two automobile sidelight systems• Sidelight = all windows except windshield
• Polycarbonate: – 40% lighter than glass– 200 times more resistant to shatter
• Glass:– scratch resistant
System Overview
Data Sources:
– Eco-profiles of the European Plastics Industry: polycarbonate
– Life Cycle Inventories for Packaging: packaging glass
Assumptions
• Packaging glass data equivalent to flat glass
• PC does not need scratch resistant coating • Equivalent mfg, recycling practices in
Europe & US• Identical mechanisms for window function
during use phase
Polycarbonate Flow DiagramAutomotive Assembly
Sidelight ProductionPC ManufacturingAcquisition, Refining & Processing of Raw
Materials
Coke
Natural Gas
Coal, Oil or Gas
Sodium Bisphenol A Production
Package & ship pellets
Cut pellets
Polymerisation: Chemical reaction
of inputs
Extrusion
Phosgene production
Injection mold pellets
Assemble sidelightsSilkscreen
ceramic frit
Package & ship sidelight
Glass Flow DiagramAcquisition, Refining & Processing of Raw
Materials
Sidelight Production Automotive Assembly
Glass Manufacturing
Draw glass over molten
tin
Cut glass
Package & ship glass
Annealing lehr: Cool glass
Melting furnace
Limestone
Carbon
Cullet
Package & ship sidelight
Silkscreen ceramic frit
Bending lehr: Shape glass
Assemble sidelights
Silica (sand)
Dolomite
Soda Ash
Limestone
Salt cake
Rouge
Cut and drill holes in glass
Mix raw materials
Vehicle of Study• Vehicle: Chevy Express G Van• Total surface area of sidelights = 51 sq ft• Useful life of van = 110,000 miles• Fuel Economy = 16.4 mpg
Life Cycle Costs
Polycarbonate Glass
Cost ofsidelights
$156.06 $25.50
Gasolinecosts
$51.73 $86.22
Landfill costs $1.39 $2.31
TOTAL $209.18 $114.03
Energy Consumption: Per Vehicle
03,0006,0009,000
12,00015,000
Matl.Acquisition
& Mfg
Use End of Life Total
Life Cycle Phase
Ener
gy (M
J)
Glass
PC
Solid Waste: Per Vehicle
020406080
Matl.Acquisition &
Mfg
Use End of Life Total
Life Cycle Phase
Mas
s (k
g)
Glass
PC
Air Emissions: Per Vehicle
0
200
400
600
800
CO2 CO
Mas
s (k
g)
Glass
PC
Air Emissions: Per Vehicle
0
5
10
15
20
Lead Aromatic HCs and Organo-Halogens
Mas
s (g
)
Glass
PC
Air Emissions: Per Vehicle
01000200030004000
NOX ParticulateMatter
SOX
Mas
s (g
)
Glass
PC
Wastewater: Per Vehicle
0
2
4
6
8
Wastew ater
Vol
ume
(m3 )
Glass
PC
Water Emissions: Per Vehicle
0
5000
10000
15000
20000
Chlorine Dissolved Solids
Mas
s (g
)
Glass
PC
Energy, Solid Waste, Water Emissions Summary
Glass PC SignificanceEnergy 0 0 Resource
DepletionSolid Waste - + Landfill VolumeWaste Water: Volume + - Volume Cl + - - Toxic/Carcinogen Metals + - Toxic Dissolved Solids - + Decrease O2 Suspended Solids - + Decrease O2
Air Emissions Summary
Glass PC SignificanceCO2 - + Global WarmingMethane + - Global WarmingCO - + ToxicNOx - + Ground level OzoneHydrocarbons - + Ground level OzonePM + - ToxicSO2 + - Acid RainAromaticHydrocarbons
+ - - Carcinogen
Organo-halogens
+ - - Carcinogen
Lead - + ToxicCFCs + - Ozone Depleting
Key DriversManufacture Use End of Life
Environmental Reduce toxicityof raw materials
Increaserecyclability
Performance Avoid scratching Avoid scratchingReduce noise
Cost Reduce cost ofraw materials
Legal Clean Air ActClean Water Act
ANSI/SAE Z26.1 RCRA
Environmental Recover energy Increase fueleconomy
Increaserecyclability
Performance Decreasecracks, flaws
Increasepassenger safety
Cost Increase fueleconomy
Legal Clean Air ActClean Water Act
ANSI/SAE Z26.1 RCRA
PC
Gla
ss
Summary of Results
Glass• Lower environmental
impact in Mfg phase• Lower total:
– Particulate matter– SO2
• Lower total cost
Polycarbonate• Lower environmental
impact in Use phase• Lower total:
– NOx & HC– Solid waste– CO– Lead in air emissions
Overall: Neither product system is more environmentally friendly
Recommendations
PC Manufacturers• Reduce manufacturing
costs• Improve scratch
resistant coating• Develop single unit for
sidelight & encapsulation
Glass Manufacturers• Reduce/recover
energy used in manufacturing
• Increase recycled content from 15% to 50%
Overall: Improve mpg of automobile End of life material recovery and recycling
Questions & Answers