EPA/600/R-99/023
February 1999
Life Cycle Design of
Air Intake Manifolds
Gregory A. Keoleian and Krishnendu Kar
Gregory A. Keoleian, Project Director
Center for Sustainable Systems
School of Natural Resources and Environment
University of Michigan
Dana Bldg. 430 E. University
Ann Arbor, Ml 48109-1115
Phase I: 2.0 L Ford Contour Air Intake Manifold
Project Leaders
Wayne Koppe, Powertrain Environmental Engineering
Phillip Lawerence, Environmental Quality Office
John Sullivan, Scientific Research Laboratory
Mia Costic, Scientific Research Laboratory
Ford Motor Company
Dearborn, Michigan
Assistance Agreement # CR 822998-01-0
Project Officer
Kenneth Stone
National Risk Management Research Laboratory
Office of Research and Development
US Environmental Protection Agency
Cincinnati, OH 45268
-------
1. Notice
This publication was developed under Cooperative Agreement No. 822998-01-0 awarded by
the U.S. Environmental Protection Agency. EPA made comments and suggestions on the document
intended to improve the scientific analysis and technical accuracy of the document. However, the
views expressed in this document are those of the University of Michigan and EPA does not
endorse any products or commercial services mentioned in this publication.
-------
II. Foreword
The U.S. Environmental Protection Agency is charged by Congress with
protecting the Nation's land, air, and water resources. Under a mandate of national
environmental laws, the Agency strives to formulate and implement actions leading to a
compatible balance between human activities and the abilities of natural systems to
support and nurture life. To meet these mandates, EPA's research program is providing
data and technical support for solving environmental problems today and building a
science knowledge base necessary to manage our ecological resources wisely, understand
how pollutants affect our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for
investigation of technological and management approaches for reducing risks from threats
to human health and the environment. The focus of the Laboratory's research program is
on the methods for the prevention and control of pollution to air, land, water, and
subsurface resources; protection of water quality in public water systems; remediation of
contaminated sites and groundwater; and prevention and control of indoor air pollution.
The goal of this research effort is to catalyze development and implementation of
innovative, cost-effective environmental technologies; develop scientific and engineering
information needed by EPA to support regulatory and policy decisions; and provide
technical support and information transfer to ensure effective implementation of
environmental regulations and strategies.
This work was sponsored by the National Risk Management Research Laboratory
(NRMRL) of the U.S. Environmental Protection Agency. Since 1990, NRMRL has been
at the forefront of development of Life Cycle Assessment as a methodology for
environmental assessment. In 1994, NRMRL established an LCA team to organize
individual efforts into a comprehensive research program. In addition to project reports,
the LCA team has published guidance manuals, including "Life Cycle Assessment:
Inventory Guidelines and Principles (EPA/600/R-92/245)" and "Life Cycle Design
Framework and Demonstration Projects (EPA/600/R-95/107)".
This publication has been produced as part of the Laboratory's strategic long-term
research plan. It is published and made available by EPA's Office of Research and
Development to assist the user community and to link researchers with their clients.
E. Timothy Oppelt, Director
National Risk Management Research Laboratory
in
-------
III. Abstract
This life cycle design project was a collaborative effort between the Center for
Sustainable Systems (formerly National Pollution Prevention Center) at the University of
Michigan, a cross functional team at Ford, and the National Risk Management Research
Laboratory of the U.S. Environmental Protection Agency. The project team applied the
life cycle design methodology to the design analysis of three alternative air intake
manifolds: a sand cast aluminum, brazed aluminum tubular, and nylon composite. The
design analysis included a life cycle inventory analysis, environmental regulatory/policy
analysis, life cycle cost analysis and a product/process performance analysis. These
analyses highlighted significant tradeoffs among alternatives.
The life cycle inventory indicated that the sand cast aluminum manifold consumed the
most life cycle energy (1798 MJ) compared to the tubular brazed aluminum (1131 MJ)
and nylon composite (928 MJ) manifolds. The manifold contribution to the vehicle fuel
consumption dominated the total life cycle energy consumption. The cast aluminum
manifold generated the least life cycle solid waste of 218 kg per manifold, whereas the
brazed aluminum tubular and nylon composite manifolds generated comparable quantities
of 418 kg and 391 kg, respectively. Red mud generated during alumina production
accounted for 70% of the total life cycle solid waste for the brazed tubular manifold while
the nylon component of auto shredder residue was responsible for 53% of the total waste
for the nylon composite manifold.
The life cycle cost analysis estimated Ford manufacturing costs, customer gasoline costs,
and end-of-life management costs. The nylon composite manifold had the highest
estimated manufacturing costs which were about $10 greater than the two aluminum
manifold designs. The use phase gasoline costs to the customer over the lifetime of the
vehicle, however, for the composite and the aluminum brazed tubular manifolds were
about $6 and $5 cheaper, respectively, compared to the cast aluminum manifold. End-of-
life management credits of $4.10 for the cast aluminum manifold and $2.30 for the
brazed aluminum tubular manifold would accrue to Ford under automobile take back
legislation. In addition, 20 performance requirements were used to evaluate each design
alternative.
This report was submitted in partial fulfillment of Cooperative Agreement number
CR822998-01-0 by the National Pollution Prevention Center at the University of
Michigan under the sponsorship of the U.S. Environmental Protection Agency. This
work covers a period from November 1, 1994 to May 31, 1997 and work was completed
June 1, 1997.
IV
-------
IV. Contents
1. Project Description 1
1.1 Introduction 1
1.2 Project Description 1
1.3 Product Selection 2
1.4 Goal and Significance 2
1.5 Objectives 3
2. Systems Analysis 4
2.1 Scope 4
2.2 Product Composition 4
2.3 Boundaries and Assumptions 5
2.4 Product System for Composite Manifolds 6
2.5 Product System for Sand-Cast Aluminum Manifolds 8
2.6 Product System for Multi-Tube Brazed Aluminum Manifolds 10
3. Data Collection and Analysis 12
3.1 Methodology 12
3.2 Life Cycle Inventory Analysis 14
3.2.1 Material Production 14
3.2.2 Manufacturing 19
3.2.3 Use 26
3.2.4 Retirement 28
3.3 Cost Analysis 29
3.3.1 Material Production 29
3.3.2 Manufacturing 31
3.3.3 Use 32
3.3.4 Retirement 32
3.4 Performance Analysis 34
3.4.1 Manufacturing Phase 34
3.4.2 Use 36
4. Results and Discussion 37
4.1 Environmental Burdens 37
4.1.1 Energy 37
4.1.2 Solid Waste 39
4.1.3 Air Emissions 40
4.1.4 Water Effluents 42
4.2 Cost 43
4.2.1 U.S. Scenario 43
4.2.2 German Scenario 44
4.3 Decision Analysis and Integration 45
4.3.1 Decision-Making 45
4.3.2 Scope 45
4.3.3 Identification of Key Drivers 46
4.3.4 Decision Analysis 47
4.3.5 Performance Analysis 48
4.3.6 Cost Analysis 49
4.3.7 Environmental Analysis 51
4.4 Proposed Environmental Metrics 54
4.4.1 Proposed Metrics 54
4.4.2 Discussion 55
5. Conclusions 57
References 60
-------
IV. Contents (continued)
Appendix A: Life Cycle Inventory Calculations A.I
Appendix B: Life Cycle Design Framework B.I
Appendix C: Life Cycle Design Reports C.I
Appendix D: Acronyms D.I
VI
-------
V. Acknowledgment
We wish to thank Ford Project Team for collaborating with us on this project.
The cross functional team included members from Powertrain Engineering, Scientific
Research Laboratory, Materials Engineering, Casting Operations,and Environmental and
Safety Engineering. Wayne Koppe, Powertrain Engineering, was a key champion and
team leader of this project. Other members of his staff including Fred Heiby, Cymel
Clavon, David Florkey, and Mitch Baghdoian played an important role data collection for
this project. John Sullivan and Mia Costic from the Scientific Research Lab provided
valuable technical support throughout the project. Mia Costic played a major role in the
data collection phase of the life cycle inventory analysis. Gerald Czadzeck, intake
manifold design engineer, provided performance and cost information and knowlegde of
the product development process. Philip Lawrence from the Environmental Quality
Office provided key corporate environmental policy information and was instrumental in
initiating this project. Bernd Gottselig contributed information regarding recycling and
other end-of life issues as well European data. George Good was helpful in gathering
data on aluminum casting operations. Mike Johnson assisted in providing the corelation
between mass reduction and fuel consumption.
In addition we wish to thank Ken Martchek from Alcoa and William Haaf and David
Doyen from DuPont for providing material production and manfuacturing inventory data,
and for reviewing sections of this report.
Robb Beal and David Spitzley from the National Pollution Prevention Center assisted in
the data analysis phase of this project.
vn
-------
1. Project Description
1.1 Introduction
Integration of environmental considerations into the design process represents a complex
challenge to designers, managers and environmental professionals. A logical framework in-
cluding definitions, objectives, principles and tools is essential to guide the development of more
ecologically and economically sustainable product systems. In 1991, the U.S .Environmental
Protection Agency collaborated with the University of Michigan to develop the life cycle design
framework [1][2][3]. This framework is documented in two publications: Life Cycle Design
Guidance Manual [1] and the Life Cycle Design Framework and Demonstration Projects [3].
Two demonstration projects evaluating the practical application of this framework have been
conducted with AlliedSignal and AT&T. AT&T applied the life cycle design framework to a
business phone [4] and AlliedSignal investigated heavy duty truck oil filters [5]. In these projects
environmental, performance, cost, and legal criteria were specified and used to investigate design
alternatives. A series of new demonstration projects with Dow Chemical Company, Ford Motor
Company, General Motors Corporation, United Solar and 3M Corporation have been initiated
with Cleaner Products through Life Cycle Design Research Cooperative Agreement CR822998-
01-0. Life cycle assessment and life cycle costing tools are applied in these demonstration
projects in addition to establishing key design requirements and metrics. This report provides a
description of the Ford Motor Company project that investigated the design of air intake
manifolds. An overview of the life cycle design framework is provided in Appendix B of this
document. A list of Project Reports from other life cycle design demonstration projects is also
provided in Appendix C.
1.2 Project Description
This pilot project with Ford Motor Company applied the life cycle design (LCD) framework
and tools to the design of powertrain parts. The project began November 1, 1995. A cross-
functional core team from Ford Motor Company, shown in the following list, participated with
University of Michigan project team members.
Division Team Member
Powertrain Operations (engine) Wayne Koppe
Powertrain Operations (engine) Gerald Czadzeck
Powertrain Operations (engine) David Florkey
Powertrain Operations (engine) Fred Heiby
Powertrain Operations (engine) Cymel Clavon
Powertrain Operations (engine) Mitch Baghdoian
Environmental Quality Office Phil Lawrence
Scientific Research Laboratory John Sullivan
Scientific Research Laboratory Mia Costic
Materials Engineering Norm Adamowicz
Casting Operations George Good
Advanced Vehicle Technology Steve Church
Advanced Vehicle Technology Mike Johnson
Environmental & Safety Engineering Susan Day
Environmental & Safety Engineering Bruce Hoover
Environmental & Safety Engineering Bemd Gottselig
-------
Besides the Ford core team, Ken Martchek from Alcoa and David Doyen and Bill Haaf from
DuPont participated as external stakeholders by providing valuable data and comments.
1.3 Product Selection
This project is a comparative assessment of the following three types of intake manifolds for
a 2.0 1, 1995 Contour engine: composite, sand-cast aluminum and multi-tube brazed aluminum .
Existing and prototype manifolds were selected for this project based on the availability of data
and relative comparability of engine size. At present, 1995 Contours/Mystiques are equipped
with a nylon composite intake manifold. Aluminum manifolds, which can be manufactured by
several different processes including sand casting, permanent mold casting, die casting, lost foam
process and multi-tube brazing, were considered as alternatives.
Recently, Ford of Europe along with Stuttgart University in Germany performed a life cycle
inventory analysis of sand-cast aluminum and composite intake manifolds [6]. The project team
used this study as an initial source for inventory data. Sand casting was selected by Ford's
manifold design group as an alternative process for manufacturing a prototype aluminum
manifold as a backup for the composite manifold. The multi-tube brazed manifold is currently
used in a low volume production for the 1.9 1 Ford Escort. This manifold was not considered as
an alternative for the composite manifold by Ford's manifold design group because of its
manufacturing complexity and higher manufacturing cost compared to the sand-cast manifold.
1.4 Goal and Significance
The goal of this project is to develop simplified life cycle environmental and cost metrics that
can be used by Ford's design engineer for product design. Such a simplified tool will help Ford's
management to develop guidelines for integrating environmental requirements into product
design, that incorporates corporate environmental policies, specifications and guidelines. The
results of this project will be used by Ford's DFE training program as a case study to demonstrate
the applicability of life cycle design tools to product design engineers.
-------
1.5 Objectives
The automobile sector in recent years has seen a significant increase in the demand for glass
reinforced polyamide 66 as a result of OEMs switching to nylon air intake manifold from the
traditional aluminum manifold.
The objective of this project is to integrate the life cycle design framework and tools with
existing product design tools for alternative intake manifolds.
Specific objectives of this project include:
Compare nylon and aluminum intake manifolds based on multicriteria matrices
Evaluate key criteria and metrics for material selection
Facilitate cross-functional team interaction and networking to (effectively) use the
internal resources within Ford
Demonstrate the value of LCD as an engineering design method to management
and note barriers associated with its use
-------
2. Systems Analysis
2.1 Scope
This study considers the entire life cycle of an air intake manifold from materials production
through end-of-life management. Comparisons are made between the 2.74 kg composite
manifold currently used in 2.0 1 1995 Ford Contours, a 6.5 kg sand-cast backup (used as a
prototype for the composite manifold) and a 3.43 kg multi-tube brazed manifold currently used in
the 1.9 1 Escort engine. For uniform baseline comparison, the 1.9 1 Escort manifold (3.43 kg) is
converted to a 2.0 1 equivalent by multiplying the weight ratio of the two engines (1.05). The
converted 2.0 1 multi-tube brazed manifold weighs 3.62 kg.
2.2 Product Composition
The composite manifold consists of 33% glass reinforced nylon (PA6.6 GF33), brass (UNS
C36000) inserts and stainless steel (304 steel) EGR tube. UNS C36000 brass, which is more
commonly known as 360 brass, consists of 77% copper, 20% zinc and 3% lead. 360 brass has a
high scrap content and is usually made at the extruder's facility. In this analysis, 360 brass is
assumed to be composed of 99 % scrap [7]. 304 stainless steel is made from, 100% scrap [8].
The sand-cast aluminum manifold consists of 100% secondary aluminum. The multi-tube
brazed aluminum manifold consists of 4 bent, extruded tubes and an extruded air collection
chamber screwed to the motor block through a sand-cast flange. The sand-cast flange section
comprises 65% of the manifold weight; the extruded sections account for the remaining 35%.
Material for the sand-cast flange section consists of 100% secondary aluminum, whereas the
extruded sections are assumed to be made of 70% primary and 30% secondary aluminum [9]
which is a representative mix of extruded parts. Thus, overall the multi-tube brazed manifold
consists of 24.5% primary aluminum and 75.5% secondary aluminum. Product composition by
mass for each manifold is shown in Figure 2-1.
7 T-
6 --
5 -
4 -
D brass 360
D stainless steel 304
PA6.6GF33
D secondary aluminum
D primary aluminum
Nylon Composite
Sand cast
Type of Intake Manifold
Figure 2-1. Product Composition of Intake Manifolds
Brazed Al Tubular
-------
2.3 Boundaries and Assumptions
Table 2.1. Boundaries and Assumptions for LCD of Intake Manifolds
LC Stage
Composite
Sand-Cast Aluminum
Multi-Tube Brazed Aluminum
Material Mass of product materials
production calculated by material balance for
nylon, brass and stainless steel
shown in Figures 2-2 through 2-4.
Assumed nylon resin from virgin
& in-house scrap; primary copper,
zinc and lead; and stainless steel
from scrap.
Tin-bismuth alloy production is
not included.
Mass of product materials is
calculated by a material balance
model for secondary aluminum as
shown in Figure 2-5.
Secondary aluminum production
involves conversion of separated
scrap into ingot.
Production of sand and salt are not
included.
Mass of product materials is
calculated by a material balance
model for primary and secondary
aluminum, shown in Figure 2-6.
Primary and secondary aluminum
production are included.
Production of sand, salt and
aluminum-silica filler material are
not included.
Manufac- Lost core process includes
turing inductive melting of the 30kg tin-
bismuth core and average energy for
injection molding of 2.13 kg of
PA6.6 GF33 resin for the 2.07 kg
manifold.
0.1% scrap rate is assumed as
testing loss for each manifold; start-
up scrap is calculated to be 2.67%
for the nylon resin.
15% scrap rate for extrusion and
stamping is assumed.
Stainless steel EGR tube
production includes billet from
electric arc furnace, rolling,
extrusion and stamping. Scale loss
during rolling excluded.
Brass fittings production includes
melting/mixing scrap with virgin
materials to produce billet,
extrusion and cutting.
95% recycling efficiency is
assumed for all in-house scrap.
The average efficiency factor for
natural gas is 0.89. Electricity
production efficiency is 0.32 [10].
Energy for the production of a
sand-cast aluminum manifold is
obtained from for 7.557 kg of
molten aluminum.
The overall scrap includes
production scrap (5.67%) and
machining scrap (10%).
The crucible furnaces for sand
casting are assumed to be gas fired.
The average efficiency factor for
natural gas is 0.89.
Process wastes for sand casting are
filter dust, sand and salt slag. Mass
of filter dust, salt slag and sand per
kg of manifold is about 0.046 kg,
0.45 kg and 1.85 kg.
95% recycling efficiency is
assumed for in-house scrap.
Energy for the production of the
sand-cast flange is obtained from
2.731 kg of molten aluminum.
Production energy for the extruded
part is obtained from for 1.537 kg of
billet consisting of 70% primary and
30% secondary aluminum.
Overall scrap includes machining
scrap (10%), extrusion scrap (15%)
and production scrap (5.67%).
Process waste and emissions for
sand casting are evaluated, while
process waste for extrusion is
neglected.
95% closed-loop recycling
efficiency is assumed for all in-
house scrap.
The average efficiency factor for
natural gas is 0.89. Electricity
production efficiency is 0.32 [10].
Use The contribution of manifold weight to use phase energy consumption for a 1995 Contour over an assumed
150,000 mile life was calculated by assuming that weight is linearly proportional to fuel consumption without
considering secondary weight.
Contour tail pipe emissions data obtained from EPA emission testing laboratory.
Manifold contribution to vehicle emissions is obtained by assuming that emissions are proportional to vehicle
mass; the allocation rule is accurate for CO2 but for other gases the relationship is non-linear.
Retirement During the dismantling stage, it is assumed that no manifolds are recovered and sold for reuse
Mass balances for materials in the retirement stage are shown in Figures 2-2 through 2-6..
An overall 5% loss in recovering all metals (aluminum, brass and stainless steel) is assumed in the shredding and
separation stage; breakdown of the loss between shredding and separation is unknown.
The base case scenario assumes 100% nylon disposed to landfill.
-------
2.4 Product System for Composite Manifolds
The product system for the composite manifold consists of the following life cycle stages:
Material production
Manufacturing
Use
Retirement
Nylon
Production of poly amide 6.6 (PA6.6)
Production of glass fibers
Compounding of PA6.6 with 33% glass fiber to produce PA6.6 GF 33 pellet
Brass
Production of primary copper, zinc and lead
Mixing of 1% primary metals with 99% brass scrap to produce 360 brass billet
Stainless steel
Production of stainless steel slab in an electric arc furnace from 100% scrap
Lost core process of manufacturing the nylon manifold
Extrusion and machining to manufacture the brass inserts
Rolling, stamping, extrusion and brazing to manufacture the stainless steel EGR
tube
Assembly of the manifold
Use of the manifold
Recycling of metal parts
Disposal of nylon and unrecoverable shredded metal parts
The life cycle material balance of nylon, brass and stainless steel are shown in Figures 2-2,
2-3 and 2-4 respectively. The material balance model is based on the assumptions indicated in
Table 2-1. For the nylon manifold, 95% of in-house scrap resulting from start-up loss and testing
is crushed and melted along with virgin nylon 6.6 during injection molding. Figure 2-2 shows
that the mass of scrap recycled is 5.6 g, whereas the mass of virgin resin processed is 2.073 kg.
solid waste
(neg)
-------
Figure 2-2. Life cycle of the composite manifold
Figure 2-3. Life Cycle of Brass Inserts
-------
(0.4 g)
Figure 2-4. Life Cycle of the Stainless Steel EGR Tube
The tin-bismuth core for the lost core process of manufacturing the composite manifold is
recycled almost completely within the plant [11] [6]. However, a certain quantity of virgin tin-
bismuth alloy is added to offset melting and handling losses. The environmental burden for the
production of virgin tin-bismuth alloy is not considered in this analysis. The environmental
burdens for equipment such as the mold, injection tool, furnace, extruders, stamping and cutting
machines are also not included.
Figure 2-3 shows that the billet for extruding brass tubes consists of 260.2 g of purchased
scrap, 65.7 g of in-house scrap, 2.54 g of primary copper, 0.66 g of primary zinc and 0.1 g of
primary lead. We assume that 95% of purchased scrap consists of brass recovered from retired
manifolds; thus 247 g of purchased scrap comes from previous manifolds while the remaining
13.2 g is recovered from other products.
Figure 2-4 shows that the 0.41 kg stainless steel EGR tube consist of a 195 g extruded part
and a 215 g stamped part. Assuming 15% scrap for extruding and stamping [12], the mass of billet
required for extrusion is 224.3 g and the mass of sheet required for stamping is 247.3 g. The billet
can be directly cast into the desired shape from an electric arc furnace, whereas the sheet is
produced from a billet in a rolling mill. Thus, the mass of stainless steel processed is 471.5 g. It
is assumed that scrap generated from extrusion and stamping is transported to steel plants and
recycled with 95% efficiency. The mass of recycled scrap converted into new products is
therefore 58.8 g. This scrap is clean compared to scrap steel generated from the manifold's end-
of-life. Shredded stainless steel has to be separated from other nonferrous materials at a
nonferrous separator's facility. Assuming 95% efficiency in shredding and separating, the mass
-------
of stainless steel scrap recycled back to the manifold is 389.5 g. The mass of scrap from other
products is 23.2 g.
2.5 Product System for Sand-Cast Aluminum Manifolds
The product system for the sand-cast aluminum manifold consists of the following life cycle
stages:
Material production Pretreatment of separated scrap
Smelting, refining and casting to produce secondary ingot
Manufacturing Sand casting
Assembly into the engine block
Use Use of the manifold
Retirement Shredding, separation of aluminum scrap and disposal of unrecoverable scrap
The life cycle material balance for the sand-cast aluminum manifold is shown in Figure 2-5.
The sand-cast manifold consists of 100% secondary aluminum. Scrap from the manifold
includes production and testing scrap of 0.37 kg (5.67%) and machining scrap of 0.687 kg (10%).
95% of the scrap (1.005 kg) is assumed to be recycled within the plant. This scrap is put directly
into the melting furnace along with 6.552 kg of secondary aluminum ingot. In this model, it is
assumed that 95% of aluminum from retired manifolds is recycled back into additional manifolds
as secondary aluminum ingot. The 6.552 kg secondary aluminum ingot consists of 6.175 kg
aluminum from the recycled manifold and 0.377 kg of secondary aluminum from other products.
The material production stage involves pretreatment of separated scrap and smelting and
refining. Pretreatment typically involves sorting and processing step to remove contaminants and
cleaning processes. Smelting and refining operations involve charging, melting, fluxing,
demagging, degassing, alloying, skimming and pouring stages. The sand casting process
involves preparation of green sand and pattern, melting and mixing of ingot with in-house scrap,
and holding and pouring the molten metal into the pattern. The environmental burden for green
sand and salt production, and sand and salt slag recycling is outside the boundary of this analysis.
-------
Solid waste (process)
sand (600 g)
salt slag (145 g)
filter dust (300 g)
Figure 2-5. Life Cycle of the Sand-cast Aluminum Manifold
10
-------
2.6 Product System for Multi-Tube Brazed Aluminum Manifolds
The product system for the multi-tube brazed aluminum manifold consists of the following
life cycle stages :
Material production Primary aluminum
Bauxite mining, refining
Alumina production
Electrolysis
Melt cleaning and casting to produce primary ingot
Secondary aluminum
Pretreatment of separated scrap
Smelting and refining to produce secondary ingot
Manufacturing Sand casting to produce the flange section
Extrusion to produce the tube and air collection chamber
Bending of tubes and brazing of components
Assembly into the engine block
Use Use of the manifold
Retirement Shredding, separation of aluminum scrap and disposal of unrecoverable scrap
Figure 2-6 illustrates the life cycle material balance for a multi-tube brazed manifold
consisting of a sand-cast flange, extruded tubes and an extruded air collection chamber. Overall
scrap from the manufacturing process includes production / testing scrap of 0.2 kg (5.67%) from
the entire manifold, machining scrap of 0.248 kg (10%) from the flange section and extrusion
scrap of 0.2 kg (15%) from extruded sections.
In this model, it is assumed that all machining scrap from sand casting is remelted and fed
back into the flange with 95% efficiency. Production and extrusion scrap are assumed to be
recycled into extruded products with 95% efficiency. Aluminum extruders use all in-house scrap
to produce billets and purchase only primary ingot and scrap. It is assumed that the manifold
manufacturer receives the sand-cast flange from another supplier, then extrudes tubes and air
collection chambers and brazes different sections to produce the multi-tube brazed manifold.
The assembly and extrusion scrap are assumed to be recycled internally within the plant. The
mass of scrap recycled internally for extruded parts is 0.38 kg. The mass of scrap from retired
manifolds used for extruded parts is 0.081 kg. The mass of primary ingot used for extruded
parts, assuming 70% primary and 30% secondary aluminum in the billet, is 1.076 kg. The mass
of secondary ingot used for the sand-cast flange section is 2.496 kg. The mass balance shows
3.439 kg (95%) of aluminum recycled from the manifold and 0.862 kg of manifold material
leaving the system for application in another product system. No credit was given to the system
for this 0.862 kg of post-consumer aluminum.
11
-------
Solid waste (process)
sand (230 g)
salt slag (55 g)
filterdust (114.6 g)
1 1
Solid waste other products
(181 g) (862 g)
Figure 2-6. Life Cycle of the Multi-tube Brazed Aluminum Manifold
12
-------
3. Data Collection and Analysis
3.1 Methodology
This chapter describes environmental, cost and performance analyses for three intake
manifold designs. A life cycle inventory analysis was conducted following EPA and SETAC
guidelines. The inventory analysis of each manifold was reviewed by material suppliers and
Ford team members. A life cycle cost analysis was performed according to conventional
practices [13]. Manufacturing and warranty costs to Ford, use phase (gasoline) costs to
customers, and end-of-life costs and salvage material credits to auto recyclers were evaluated.
This analysis did not address externality costs not reflected in the market system. A total cost
assessment [14] of manifold manufacturing was not conducted. Specifically, hidden costs not
accurately allocated by Ford's internal accounting system, probabilistic (with the exception of
warranty) costs, and less tangible costs (e.g., potential increased productivity and revenues
associated with environmentally preferable products) were not evaluated.
Environmental and cost data in each life cycle stage were obtained for the mass of materials
as indicated in Table 3-1.
Environmental data evaluated are material, energy and waste. Environmental data in the
material production stage were obtained from suppliers (DuPont and Alcoa)[l5][9][l6] and other
published sources [6][17][18][19][20]. Environmental data in the manufacturing stage were
obtained from published sources [I2][2l][22][23][24][25][ll][6][26][27] and engineering models for
different manufacturing processes. Environmental data in the use phase were obtained from fuel
economy and emissions data for the 1995 Contour [28]. In the retirement phase, environmental
data evaluated are shredding energy, nonferrous separation energy and transportation energy
[29][APC, I994a]. Emissions and wastes for different life cycle stages were obtained as the sum of
process and fuel-related wastes. A major objective of the investigation was to demonstrate the
life cycle design approach to Ford participants. The timeline for this project precluded primary
inventory data collection in several cases. This study insures data transparency. A complete
documentation of the inventory analysis is provided in Appendix A.
Cost data evaluated were material cost, manufacturing cost, use cost and retirement cost. The
material costs were evaluated from unit cost ($/kg) data obtained from American Metal Market
[30] in 1995, whereas the manufacturing costs were estimated by Ford's manifold design group.
The use costs were obtained as the price of gasoline consumed [31]. The retirement costs were
estimated from the retirement spreadsheet model of APC [32] and data obtained from several
other sources [33][29].
Performance data evaluated were manufacturability, cycle time and warranty.
Manufacturability was estimated from manufacturing unit processes of different manifolds [11] [6]
and cycle time data provided by Ford's manifold design group.
The details of the calculation process and data for the three manifold systems are included in
Appendix A.
13
-------
Table 3-1. Mass of Materials at Different Life Cycle Stages for the Three Manifold Systems
Input, Product Material
Manifold
Sand-cast
manifold
Multi-tube
brazed
manifold
Composite
manifold
LC Stage
Material
production
Manufacturing
Use
Retirement
Material
production
Manufacturing
Use
Retirement
Material
production
Manufacturing
Use
Retirement
Type
Secondary aluminum
ingot
Molten aluminum
Sand-cast manifold
Sand-cast manifold
Secondary aluminum
ingot
Primary aluminum
ingot
Molten secondary
aluminum
Billet
Multi-tube brazed
manifold
Multi-tube brazed
manifold
Primary lead ingot
Primary copper ingot
Primary zinc ingot
Scrap stainless steel
Virgin nylon resin
Brass billet
Stainless steel billet
Stainless steel strip
Molded resin
Composite manifold
Composite manifold
(kg/IM)
6.552
7.557
6.500
6.500
2.496
1.076
2.731
1.537
3.620
3.620
9.87xlO-5
2.53 xlO-3
6.58xlO-4
0.471
2.073
0.329
0.224
0.247
2.129
2.740
2.740
Output, Product Material
Type
Molten aluminum
Sand-cast manifold
Sand-cast manifold
Secondary aluminum
ingot
Molten aluminum
Billet (70% primary +
30% secondary)
Sand-cast flange
Extruded parts
Multi-tube brazed
manifold
Secondary aluminum
ingot
Scrap aluminum
Brass billet
Stainless steel billet
Stainless steel strip
Molded nylon resin
Brass fittings
Stainless steel EGR
tube
Lost core manifold
Composite manifold
Brass scrap
Stainless steel scrap
(kg/IM)
7.557
6.500
6.500
6.175
2.731
1.537
2.353
1.267
3.620
2.496
0.081
0.329
0.224
0.247
2.129
0.260
0.410
2.070
2.740
0.247
0.389
14
-------
3.2 Life Cycle Inventory Analysis
The complete Life Cycle Inventory for each manifold system is shown in Appendix A.
3.2.1 Material Production
Composite Manifold
The composite manifold consists of 33% glass reinforced nylon, brass and stainless steel
materials. Environmental data for the production of these materials are based on analysis of the
following processes.
Nylon
Environmental data for the material production of nylon, glass fiber and primary brass were
obtained from [15]. Table 3-2 shows a short list of cumulative material production data for nylon,
brass and stainless steel. Nylon production data represent average data at a DuPont facility.
Environmental data, from drilling to the refinery, for natural gas and petroleum were provided by
Chem Systems. DuPont provided data on the production of adipic acid, hexamethylenediamine,
A-H salt and PA6.6.
15
-------
Table 3-2. Environmental Data for Materials Production of the Composite Manifold
Primary Energy
Waste (g/IM)
Air emissions
(MJ/IM)
Carbon dioxide
Particulates
Nitrogen oxide
Sulfur dioxide
Carbon monoxide
Hydrocarbon
Methane
Fluorine
Hydrochloric acid
Heavy metals
Halogenated hydrocarbon
Solid -waste
Water effluents
Dissolved solids
BOD
COD
Suspended solids
Acids
Heavy metals
Oils
Nitrates
Chlorides
water (1)
Halogenated hydrocarbon
IM = intake manifold
297
8530.0
16.1
36.0
62.0
23.0
6.0
82.0
1.0
0.5
4xlO-4
S.lxlO'3
956.0
701.0
3.0
25.0
116.0
4.0
0.6
1.5
1.6xlO-2
51.0
20200.0
6.8xlO-2
source: [151 [341
Nylon processing begins after petroleum and natural gas are transported to refineries where
benzene, ethylene, propylene and butadiene are produced by desulfurisation and steam cracking
[6]. Acrylonitrile is produced from propylene. Benzene is used to produce cyclohexane and
adipic acid, whereas adiponitrile, an intermediate compound is produced from butadiene, adipic
acid, ammonia and acrylonitrile. Adiponitrile is used to produce hexamethylenediamine, which
along with adipic acid are the source material for the production of A-H salt. An aqueous A-H
salt solution of 40-60% is heated 200-300° C at 8-25 bars for 1- 30 hours to produce PA6.6 resin.
Glass fibers are produced from colemanite, limestone, kaolin and silica by melting, refining,
homogenizing and temperature setting between 1200 - 1650°C.
Brass
360 brass alloy consists of 77% copper, 20% zinc and 3% lead; it is composed of 99% scrap
and 1% virgin metals [7][35]. Brass extruders use in-house scrap and purchase scrap from scrap
16
-------
dealers. The purchased scrap may be either 260 or 360 brass. The ratio of copper, zinc and lead
are then varied to obtain the desired specifications of the 360 brass [7][35]. In this analysis, it was
assumed that purchased scrap consists of 100% 360 brass. Therefore, the fraction of copper, zinc
and lead added is 0.77, 0.20 and 0.03 respectively. Because the mass of virgin metals added is
3.292 g, environmental burden in the material production stage was evaluated for 2.535 g of
copper, 0.658 g of zinc and 0.099 g of lead.
Stainless steel
Stainless steel 304 is produced from 100% scrap through remelting, mixing and alloying in
an electric arc furnace. The environmental burden for stainless steel production was obtained
from Franklin Associates [34].
Sand-Cast Manifold
The sand-cast manifold consists of 100% secondary aluminum. Secondary aluminum
production involves two general operations- scrap pretreatment and smelting/ refining.
Pretreatment includes sorting, carbonizing and briquetting [36]. The smelting/refining operation
includes melting down, melting in salt bath furnace, dross processing, melt cleaning and casting
(alloying). As shown in Table 3-3, environmental data for secondary aluminum production were
obtained from several sources and representative data were used for this analysis. For example,
primary energy for secondary aluminum production was obtained from five different sources
[6][17][18][19][20]; the average energy was calculated to be 17.9 MJ /kg ± 10.0 (99% confidence
interval). This variation resulted from different assumptions such as the inclusion of energy to
transport scrap, shredding and decoating, type of furnace used and power source efficiency.
Waste and emissions data were obtained from [6], except CC>2 which was obtained from [17].
Multi-Tube Brazed Manifold
Production of the multi-tube brazed aluminum manifold requires processing 1.067 kg
primary aluminum and 2.496 kg of secondary aluminum. Primary aluminum production is a
two-step process that refines bauxite into alumina by the Bayer process and reduces alumina to
aluminum metal by electrolytic reduction in the Hall-Herault process [37]. The molten aluminum
is subsequently cleaned and cast into ingot. Table 3-3 shows the environmental burden from
primary aluminum production. These data were obtained from several sources; representative
data were used in this analysis. For example, primary energy for primary aluminum production
was obtained from five different sources [6] [17] [18] [19] [20] and average energy was calculated to
be 177.9 MJ /kg ± 28.3 (99% confidence interval).
Primary aluminum production has been identified as a major source of fluorocarbon
emissions (CF4 and Cfis) which has a very high global warming potential. The global warming
potentials (GWPs) on a mass basis and a time horizon of 100 years are reported to be 6300 for
CF4 and 12,500 for 2^6 [38]. Average emissions of CF4 and 2^6 are based on a world mix of
20% Modern Prebake, 40% Prebake, 29% VS Soderberg, and 11% HS Soderberg potlines [38].
If one assumes 0.08 kg / mt for Modern-Prebake, 0.4 kg/mt for Prebake, 0.7 kg/mt for VS
Soderberg, and 0.9 kg/mt for HS Soderberg one obtains a crude estimate of specific CF4
emissions to be about 0.5 kg/mt for this global mix [38]. This same study reported 20:1 as the
17
-------
ratio of mass concentration of CF4 to Cfi(,. Using this study, the mass concentrations of CF4 and
CiFe were calculated to be 0.5 kg/mt and 0.025 kg/mt respectively.
Solid waste from alumina production is digested in a caustic solution to dissolve the available
alumina. After recovery, 60% of the caustic solution by mass (consisting mostly of iron oxide
and silica) is disposed to landfills. This residue is commonly known as red mud; it comprises
most of the solid waste from primary aluminum production. Since red mud remains alkaline, it
causes itching upon exposure to humans. Research is currently going on to recover the red mud
and use it for soil amendment, but currently about 99% of red mud is disposed to landfill [9]
Estimates for red mud waste varied from 2 kg/kg (Europe) to 3 kg/kg (Western Australia) of
aluminum depending on the bauxite content in the ore. For example, Alcoa's Western Australia
facility processes a lower bauxite content ore compared to the Jamaican facility and therefore
generates more red mud than the Jamaican facility [9]. In this analysis, an average value for red
mud of 2.63 kg / kg.
Emissions for primary aluminum production were calculated as the sum of emissions from
alumina production, anode production, electrolysis and energy contribution. For 862 and NOX,
alumina production data were obtained from Alcoa [9]; the remaining data were obtained from
Eyerer et al [6]. CC>2 emissions were not available for individual processes and were obtained as
an aggregate value for primary and secondary aluminum production [17].
Primary aluminum processing has a considerably higher environmental burden in terms of
energy use (9.9 times), solid waste (49 times), CO2 (15 times) and water consumption (7 times)
than secondary aluminum processing.
18
-------
Table 3-3. Environmental Data for Primary and Secondary Aluminum Production
Metrics
Energy (MJ/kg)
Solid waste (kg / kg)
alumina production 1
alumina production 2
alumina production 3
average alumina production (red mud)
electrolysis
cleaning/casting
energy
smelting
energy supply
Total
Air emissions (kg /kg)
CO2
CO
S02
NOX
Particulates
HC
FC
HC1
H2
Others
Water use (m3 /kg)
Water effluents (kg/kg)
Dissolved solids
Suspended solids
BOD
COD
Acids
Metal ions
Lead
Tar
Fluorides
Others
Primary Al
163.73
188.40
171.20
170.00
196.3
2.0
3.0
2.9
2.63
3.57 xlO-2
2.0 xlO'2
0.27
2.96
13
1.65xlO-2
9.19xlO-2*
2.85x10-2*
1.96x10-2*
3.77xlO-3
5.25 x 10-4
l.OxlO-3
11.44*
2.55
0.013
1.27
31.47
3.60
0.97
0.003
0.002
0.001
5.77
Secondary Al
16.76
13.25
15.60
18.00
26.00
4.3x10-2
1.87x10-2
0.062
0.86
2.21 x 10-4
1.33xlO-3**
3.58xlO-3**
3.57xlO-4**
2.61 x 10-3
1.3 xlO-3
7.5 x 10-4
5.0 xlO'5
1.6**
l.lxlO-4
3.0 xlO-5
l.OxlO-4
Data Source
[6]; German condition
[17]; Alcoa Worldwide operations
[18]; Swiss study
[19]; European study
[20]; US condition
[9]; estimate Europe
[9]; estimate Western Australia
[6]; German condition
average of alumina 1, 2, 3 production
[6]; German condition
[6]; German condition
[6]; German condition
[6]; German condition
[6]; German condition
Reasonable average condition
[17]; Alcoa worldwide operations
[6]; Europe condition
*[9], **[6] Europe condition
*[9], **[6] Europe condition
*[9], **[6] Europe condition
[6]; German condition
[38]; estimated global average
[6]; German condition
[6]; German condition
[6]; German condition
*[9]; estimate Western Australia
**[6]; German condition
[6]; German condition
19
-------
3.2.2 Manufacturing
Composite Manifold
Manufacturing composite manifolds involves producing nylon manifolds, brass inserts and
stainless steel EGR tubes, and assembling the different components into finished products.
Environmental data for different aspects manufacturing are discussed below.
Nylon Manifold
Nylon manifolds are manufactured by the lost core process. The lost core process consists of
the following unit processes:
Casting melt cores of tin-bismuth alloy
A core-casting machine molds two 30 kg tin-bismuth cores per cycle. The
weight of a core for this manifold could not be obtained directly from Montaplast
or CMI, who are the direct suppliers of the manifold in Europe and the US.
However, for a European 2.0 1 Ford Sierra with a 2.068 kg composite manifold,
Montaplast was reported to use two 30 kg cores [6]. The lost core process used by
Siemens Automotive to manufacture a 1.63 kg composite intake manifold for a
Chrysler Neon uses two 35 kg tin-bismuth cores per cycle [11]. In this analysis,
two 30 kg cores were assumed for the 2.07 kg composite manifold. The cycle
time for casting two cores was obtained from the Ford core team as 3 minutes [39],
which implies a cycle time of 1.5 minutes per core. The environmental burden for
core casting was not considered in this analysis.
The cores are cast at 340° F (171° C) and the centers are still molten when the
parts are placed on the conveyor [11]. The conveyor transports 30 parts through a
core cooling area, where the temperature of the cores are dropped to 80° F (27°
C), to the injection molding machine. The environmental burden for
transportation via conveyor was not considered in this analysis.
Injection molding the cores with nylon 6.6
The cores are overmolded with nylon in an injection molding machine to
produce manifolds with a hollow interior. The outer surface of the manifold is
obtained by pressing the molten resin against several molds. The edge of the mold
gives the partition line on the manifold. For these manifolds, an estimated 800-ton
injection molding machine is used [39]. The cycle time for injection molding the
composite manifold is 1.5 minutes.
The average energy for a 500-ton injection molding machine is reported to be
65.92 kW [40]. Assuming that injection molding energy is proportional to machine
tonnage, the average energy for an 800-ton machine is 105.47 kW. Therefore, the
energy for a cycle time of 1.5 minutes was estimated to be 9.5 MJ. For a 2.073 kg
injection-molded manifold , this results in an energy density of 4.58 MJ / kg. The
energy density for injection molding was compared with data from other sources.
For example, Eyerer et al [6] used the Boustead database for calculating injection
molding energy, which states an electricity consumption of 1.16 kWh for 1.03 kg
20
-------
nylon. This results in an energy density of 4.05 MJ/kg. The Franklin database [34]
reported an electricity consumption of 800 kWh for 1000 Ib of plastic, which results
in an energy density of 6.35 MJ/kg. The Ford core team reported a primary energy
consumption of electricity of 4300 BTU/lb [20] which results in 3.2 MJ / kg of
resin. The average energy density for injection molding was calculated to be 4.54
MJ / kg. The total electrical energy consumed for 2.129 kg resin injection molded
(as shown in Figure 2-2) was evaluated to be 9.66 MJ / IM.
A portable robot loads the cores into the mold, cuts the spurs and unloads
finished parts. Molded manifolds with cores travel on a vertical conveyor into the
melt-out tank [11].
Inductive melting of the core
The cores are placed in an inductive melting furnace for a 45-minute melt-out
stage. Since it takes 1.5 minutes to overmold a core with nylon resin, the total
number of cores that pass through the 45-minute melt-out stage is 30. The melting
furnace is heated above the melting point of the tin-bismuth alloy, 320° F (160° C),
which is well below the 491° F (255° C) melting point of nylon. The molten alloy
sinks to the bottom of the tank and is gravity fed to a heated storage tank.
Because the energy for inductive melting could not be directly obtained from
suppliers (Montaplast or CMI) of the manifold, it was indirectly estimated from
pilot experiments on inductive melting of tin-bismuth alloy for the lost core process
for one intake manifold [41]. In this experiment, a 250 kW furnace was used to melt
the core of one manifold in a 1 minute cycle time. The furnace was 80% efficient in
converting electricity to heat, but only 80% of this heat was actually used to melt the
tin-bismuth alloy because of its complex geometry. The furnace used for
manufacturing the Contour composite manifold melts 30 cores in a 45-minute cycle
time. Heat loss per core in a large furnace holding 30 cores is expected to be
smaller than the heat loss from a furnace that holds a single core because of
efficiencies of scale. So the maximum electric energy needed for inductive melting
of one core was estimated to be 250 kW. Electric energy for a 1.5-minute cycle
time was therefore 22.5 MJ / IM.
Washing/rinsing
Another robot transfers the empty manifolds into a four-stage hot water washer
to rinse off all traces of glycol. The rinse water is subsequently vacuum distilled so
that the glycol (which costs about $6 / gal) can be recycled [11]. The energy for
washing/rinsing operations was not considered in this analysis.
Post molding assembly
A conveyor takes the clean parts to a series of manual finishing stations where
operators install brass inserts, ultrasonically weld a plastic cap over a hole in the
plenum (used to locate the cores securely in the injection mold), and leak-test the
part [11][6]. The energy for post molding assembly was not considered in this
analysis.
21
-------
Thus, the electrical energy consumed per intake manifold was calculated to be 32.16 MJ / IM.
Taking into account the energy required to extract and process fuels and the losses in combustion
and distribution, this corresponds to a primary energy of 100.5 MJ / IM. A primary energy
density of 47.2 MJ / kg was evaluated for 2.129 kg of nylon resin processed to produce 2.07 kg
manifold.
Brass inserts
Manufacturing of brass inserts can be divided into the following unit processes:
Billet production
Manufacturing of brass inserts begins with the production of billet at a brass
extruder's facility. Brass 360 billets for extrusion are produced by mixing and
melting 99% scrap with 1% primary metals consisting of 77% copper, 20% zinc and
3% lead. The melting is done in a inductive furnace. Typical energy densities for
melting 360 brass are reported by Ajax Magnetothermic Corporation to vary from
6.5-7.0 Ib / kWh [42]. An average energy density of 6.75 Ib / kWh (1 . 176 MJ / kg)
was used in this study. These data were obtained by experimental test, rate test and
theoretical analysis of furnace design. The mass of billet produced was 329.2 g.
Tube production
Tube is produced by extruding hot billet. In this analysis, it was assumed that
billet production and tube making is a continuous operation. This avoids reheating
cold billet and saves energy in the extruder's facility. The extrusion energy density
(Eex) is obtained from [12] as:
( K 1
E = - x In r
where, for brass [12][43]
K = extrusion constant = 35, 000 psi = 241.3 MPa,
r = density = 8400 kg / m3 ,
cp = specific heat = 0.38 kJ / kg-K and
Tfe = efficiency accounting for nonuniform deformation and friction = 0.6
The extrusion ratio r is the ratio of the cross-sectional area of the hollow tube
to the cross-sectional area of the billet. The diameter of the billet was assumed to
be 9" (0.2286 m) and the hollow tube was 5 cm in diameter and 3 mm thick.
Therefore, the extrusion ratio was calculated to be 740. The electrical energy for
extrusion was evaluated from EQ(3. 1) as 0.32 MJ/kg. The mass of tubes extruded
was 329.2 g.
Machining
Machining for brass inserts involves cutting, inside and outside threading, and
tapering. The cutting energy density for copper alloy (brass) was obtained from
Kalpakjian [12] as 1.4-3.3 J / mm3. An average cutting energy of 2.35 J / mm3 was
22
-------
assumed for brass. Volume of material removed was obtained by multiplying the
area of the tube machined by an average cutting length of 1 mm. Machining is
normally done in a lathe, which is electrically operated. Overall machining energy
(electrical) was estimated to be 8745 J for 0.329 kg of brass tube in the manifold
The total electrical energy for manufacturing brass inserts was evaluated to be 0.58 MJ / IM;
primary energy density for 0.329 kg brass tube manufactured was calculated to be 5.51 MJ / kg.
Stainless Steel EGR Tube
The stainless steel EGR tube consists of brackets, tubes, fasteners, nuts and screws. The
mass of each component was estimated by multiplying the volume of a geometrically equivalent
shape with a density of 7900 kg / m3 for stainless steel. Results are listed in Table 3-3.
Table 3-3. Weight of the Stainless Steel EGR Tube
Manufacturing Process
Rolling and stamping
Extrusion
Brazing and assembly
Part
Bracket (a) attached to the shank portion (horizontal & vertical)
Rhombus shaped bracket attached to the fuel delivery section
TOTAL stamped part
Tube
Nuts and screws attached to bracket (a)
Hollow conical fastener attached to the tube
TOTAL extruded part
TOTAL EGR tube
Mass (g/IM)
25.4
169.6
195.0
185.1
21.4
8.5
215.0
410.0
The following unit processes are used to manufacture the stainless steel EGR tube:
Rolling
The energy for rolling was estimated by evaluating the energy for preheating
the slab in a reheat furnace and the deformation energy required for hot rolling the
workpiece.
Preheating energy
Slabs are heated in a reheat furnace to remove surface defects, soften the steel
for rolling, maintain the austenitic temperature region during rolling and dissolving
carbides and nitrides that are to be precipitated at a later stage of processing [44].
The heating is done in a batch type soaking pit or continuous furnace. Most existing
furnaces combust fuel, oil, natural gas or coke oven gas [44]. Furnace energy
depends on the length of the furnace and the slab charging temperature. Both hot
and cold slabs can be charged in a furnace. The amount of fuel saved increases with
an increase in the slab charging temperature. The energy balance for a 5 zone
pusher-type slab reheating furnace with insulated skids is 1.91 MJ / kg [44]. 40% of
this energy, which amounts to 0.76 MJ / kg, is reported to be used for steel making;
this is in agreement with other slab heating data of 0.74 MJ / kg [45] . 20% of the
energy is dissipated as radiation loss from surfaces, 32% is lost from stacks and 8%
23
-------
is lost to the skid-pipe cooling water [44]. In this analysis, it was assumed that the
furnace is heated by natural gas.
Deformation energy
Deformation energy was obtained from the specific power curve for stainless
steel, which is 60 hp-hr / ton (or 0.177 MJ / kg) [46] [44]. The rollers are electrically
operated.
Stamping
Stamping involves cutting sheet metal by subjecting it to shear stresses, usually
between a punch and a die. The major variables in stamping are the punch force,
speed of the punch, lubrication, surface condition of the punch and die materials,
their corner radii and the clearance between the punch and die. Primary energy for
stamping was taken from [19] as 1019 MJ for a 280 kg raw body in white stainless
steel part. This results in a primary energy density of 3.64 MJ / kg. Thus, the site
electricity consumption for stamping was estimated to be 1.16 MJ / kg.
Extrusion
Extruding stainless steel involves reheating billet to approximately 1000° C and
forcing the hot billet through a die opening (hot extrusion). The specific heating
energy is evaluated from thermodynamics as:
Cp-AT
Eh=^- (3.2)
where the specific heat for stainless steel Cp is 0.51 kJ/kg-K and % is the efficiency
of the furnace in transferring heat to the stainless steel billet = 0.4. Therefore,
reheating energy is 1.27 MJ / kg. Reheating is done in a natural gas furnace. The
energy for hot extruding stainless steel billet was obtained from EQ(3.1). For
stainless steel, K = 400 MPa. The billet diameter was assumed to be 9" and the tube
was 1.8 cm in diameter and 3 mm thick. Therefore, the extrusion ratio was
calculated to be 528. The extrusion energy (electricity) for stainless steel was
therefore 0.53 MJ/kg.
Thus, the overall electricity energy for producing the stainless steel EGR tube was calculated
to be 0.45 MJ / IM. The total natural gas energy for EGR tube production was evaluated to be
0.76MJ/IM.
Sand-Cast Manifold
Manufacturing energy for sand-cast aluminum manifolds includes transportation, machining
and sand casting in a foundry. Sand casting energy consists of melting, holding and distributing
molten metal. The site energy for sand casting is obtained from site energy for gravity die
casting, which is about 39.36 MJ/kg [21]. For every 6.5 kg sand-cast manifold there is a 0.687 kg
casting/machining loss and a 0.37 kg scrap loss. Because of this waste, 7.557 kg of aluminum
24
-------
must be processed to manufacture a 6.5 kg sand-cast manifold. Therefore, the total energy for
manufacturing a sand-cast manifold was estimated to be 297.44 MJ.
Most common furnaces in aluminum foundries are crucible type, which are either gas-fired,
electric arc or induction furnaces [21] [12]. The exact mix of gas-fired and electric-powered
(electric arc or induction) furnaces in a foundry is difficult to predict. However, the Ford core
team reported that most furnaces for sand casting in Ford facilities are gas fired. Thus, the
primary energy required for manufacturing a sand-cast manifold was calculated to be 334.21 MJ.
Process wastes for sand casting were obtained from Scott et al [24] and McKinley et al [25] as
quantities of chemicals released in the green sand process for sand casting in an iron foundry as
indicated by EQ(3.3). The results are shown in Table 3-4.
m
Ce xQxTs
e s
(3.3)
where,
m
= emission factor in kg of air emissions per kg of metal poured
Ce sc = concentration of air emissions in mg per m3
Q = flow rate through the stack = 1000 1 / min
Ts = sampling time = 30 min
Mm = mass of metal poured = 40 kg
Table 3-4. Emission Factors for Sand Casting
Air Emissions
Sulfur dioxide
Hydrogen sulfide
Hydrogen cyanide
Ammonia
Nitrous oxide
Formaldehyde
Acrolein
Total aldehyde
Total aromatic amines
Benzene
Toluene
m-xylene
o-xylene
Napthelene
Phenol
Concentration |Ce| , (mg / m3)
12.0
39.5
5.6
3.1
26.7
0.2
0.1
3.0
1.0
29.0
3.0
<1.0
<1.0
<1.0
6.2
Emission Factor |me | , (kg / kg)
9.0xlO-6
29.6 xlO-6
4.2 xlO'6
2.3 xlO-6
20.0xlO-6
l.SxlO-7
7.5 xlO'8
2.2 xlO-6
7.5 x ID'7
21.7 xlO-6
2.2 xlO'6
7.5 x ID'7
7.5 x ID'7
7.5 x ID'7
4.6xlO-6
source: [24] [25]
25
-------
It was assumed that bonding green sand in iron and aluminum foundries has the same
property; therefore, process emissions become a function of the mass of metal poured. Process
wastes for extrusion and brazing were neglected. The waste and emissions associated with
electricity and natural gas use were obtained from Franklin Associates [10].
Multi-Tube Brazed Manifold
Manufacturing energy for a multi-tube brazed aluminum manifold involves sand casting the
flange portion, extrusion and brazing.
The extrusion process generates 15% scrap [12], which results in a scrap loss of 0.20 kg for
each manifold. In addition, a machining loss of 0.248 kg is estimated to be associated with the
sand cast portion of the manifold. The mass of molten aluminum sand cast was 2.731 kg for the
2.483 kg flange section and the mass of billet extruded was 1.537 kg for the 1.337 kg of the
extruded section. A further 0.2 kg is lost in production, resulting in a final multi-tube brazed
manifold weight of 3.62 kg.
Sand casting
The energy for the sand-cast flange, assuming a 39.36 MJ/kg energy density [21],
was calculated to be 107.49 MJ.
Extrusion
The average energy for extrusion was obtained from averaging extrusion data
from three different plants in Europe [22] and the average data for extrusion in a
U.S. extrusion mill [23]. The extrusion data include remelting primary aluminum
ingot and mixing it with scrap to produce a billet, reheating the billet and forcing
the billet through a die opening [12] [22] [23]. The average primary energy for
extrusion was calculated to be 16.76 MJ / kg.
Brazing
The four bent, extruded tubes (5 cm diameter and 3 mm thickness) are brazed to
an air collection chamber and a cast flange. There are a total of eight brazed joints
divided equally between the cast flange and the air collection chamber. Typical
brazing length for aluminum tubes was assumed to be 0.15 mm [12][26][27]. The
commercial filler material for brazing aluminum contains 91% aluminum and 7%
silica and has an average density of 2601 kg / m3. The total mass of filler material
to be brazed was calculated to be about 1.6 grams. The specific heat of fusion for
aluminum is 0.356 MJ / kg and the mean specific heat for the filler material is 0.92
KJ / kg-K. The temperature difference for the furnace and room temperature for
furnace brazing applications was about 900 K. Therefore, the minimum energy
supplied for brazing was calculated from thermodynamics as 1.9 KJ.
The primary energy for casting, extruding, and brazing was calculated to be 120.77 MJ, 25.76
MJ, and 0.006 MJ respectively. Therefore, the total primary energy for the multi-tube brazed
manifold was 146.54 MJ.
26
-------
3.2.3 Use
Use phase energy and wastes were calculated for an assumed manifold life of 150,000 miles
(241,350 km) in a 1995 Contour with the weight and fuel economy data indicated in Table 3-5.
Table 3-5. Weight and Fuel Economy Data for a 1995 Contour
Parameter Metrics
Test weight 1471 kg or 3250 Ib
Fuel economy 7.46 1 / 100 km or 31.5 mpg
Weight to fuel economy 10% weight reduction = 4% fuel
correlation consumption reduction
The contribution of the manifold to vehicle fuel consumption, F^, was obtained using the
following correlation:
=M,M xLx
FE
(i)
L. M
where,
Af
= fuel (liters) used over the life of intake manifold (L)
M!M= mass of the intake manifold
MV = test weight (mass) of vehicle = 1471 kg
Af
TT7 = fuel consumption correlation with mass. For a 1995 Contour the correlation was
obtained from the Ford core team as: 10% weight reduction is equivalent to 4% fuel
consiimrvhon reduction Therefore
consumption reduction. Therefore,
Af
AM
= 0.4
FE(J) = fuel consumption in liters/km. For a 1995 Contour 7.46 1/100 km. Therefore, FE =
0.0746
L = life of intake manifold = 241,3 50 km
The lifetime fuel consumption and energy for the three manifolds are indicated in Table 3-6.
Table 3-6. Fuel Consumption and Use Phase Energy Contribution of Intake Manifolds
Manifold Type
Composite manifold
Sand-cast manifold
Multi-tube brazed manifold
Weight
(kg)
2.74
6.50
3.62
Fuel Consumption
F(|)| (liter) F(ga|)| (gallons)
13.41 3.54
31.82 8.40
17.72 4.86
Energy (MJ)
563.76
1337.39
744.77
27
-------
Air emissions and waste were evaluated as the sum of combustion and precombustion
emissions and waste.
Combustion Emissions
Air emissions evaluated from EPA test results are carbon monoxide (CO), hydrocarbon (HC)
and nitrogen oxides (NOX). CO2 emission are based upon stoichiometric combustion, assuming
that gasoline has a mean chemical formula of CH] 9 and a density of 0.74 kg /1. This resulted in
3.16 kg of CO2 emission per kg of gasoline combusted. Table 3-7 shows the tailpipe emissions
data for a 1995 Contour.
Table 3-7. Certified Emission Data for the 1995 Contour
Description 1995 Contour
EPA test # 94-28-48
Engine family name SFM2.0VJGFEA
Vehicle ID # 5NB1-2.0-H-238
Air emissions (me', kg / mile)
CO2 0.281 *
CO l.llxlO-3
Cold CO 4.56 xlO-3
Hydrocarbon 1.0 xlO"4
Nonmethane Hydrocarbon 8.5 x 10~6
NOX 1.2 xlO-5
Evaporative 7.2 xlO"5
Emission data include deterioration factors [28]
* CO2 emissions reported is not certified and is obtained
using stoichiometry
The mass of air emissions over the life of an intake manifold was obtained from the mass of
air emissions per vehicle miles traveled using EQ (3.5).
m = m,xFE, > x F, , (35}
e e' (gal) (gal) \J-~>)
where,
me = mass (kg) of air emissions allocated to the manifold
me, = mass of vehicle air emissions per mile (kg/mile)
FE(gal) = vehicle fuel economy (miles per gallon)
F(gal) = lifetime fuel (gallons) consumption allocated to manifold
Precombustion Waste
Precombustion wastes (air emissions, waterborne waste and solid waste) per 1000 gallons of
gasoline consumed were obtained from the Franklin database [10]. The Franklin waste data were
multiplied by gasoline used in gallons per manifold to obtain wastes in kg per manifold.
28
-------
Total use phase wastes were obtained by summing precombustion and combustion waste.
The use phase energy and waste were calculated by neglecting the secondary weight effect. This
means that the intake manifold is replaced in the vehicle without altering any other parts.
3.2.4 Retirement
Retirement of the manifold is characterized by the following steps:
Transportation from the dismantler as part of the whole vehicle to the shredder
(100 miles).
Shredding.
Transportation from the shredder to the non-ferrous separators (200 miles).
Separation of aluminum, brass and stainless steel from automotive shredder
residue (ASR) and other nonferrous metals.
Disposal of nonrecovered metal (5%) and nylon to landfills (200 miles).
For the composite manifold, 0.247 kg of brass and 0.3895 kg of stainless steel
is recycled back into the manifold.
For the sand-cast manifold, 6.175 kg of shredded aluminum is separated and
recycled back into the manifold.
For the multi-tube brazed manifold, 3.439 of shredded aluminum is recycled.
2.577 kg of the shredded aluminum is recycled back into the manifold and the
remaining 0.862 kg leaves the system for another application. 2.496 kg of
recycled aluminum is used as ingot for sand casting the flange section and
0.081 kg of recycled aluminum is used as scrap for extruding four tubes and
an air collection chamber.
The energy data for these steps are:
Shredding energy = 0.097 MJ / kg (42 BTU / Ib); shredding energy was
obtained from Texas shredder (1995).
Separation energy for aluminum = 0.1 MJ / kg; separation energy was
obtained from Huron Valley Steel (1995).
Transportation energy = 2.05 MJ / ton-mile [10]. Shredders and separators are
run by electric motors. Transportation trucks are diesel operated. Total waste
in the retirement stage from electricity and diesel fuel use was obtained from
Franklin [10].
29
-------
3.3 Cost Analysis
A life cycle cost analysis was performed which accounted for explicit costs to manufacturers,
customers, and end-of-life managers. The life cycle cost analysis traces the conventional costs
accrued to manufacturers, customers, and end-of-life vehicle managers associated with the air
intake manifold. Hidden or indirect costs, probabilistic costs (with the exception of warranty),
and less tangible costs (e.g., potential increased productivity and revenues associated with
environmentally preferable products), however, were not investigated. For example, special
permitting, reporting , tracking and other hidden environmental costs that may be associated with
the use of hazardous materials in the manufacturing phase were not analyzed. While a more
detailed accounting of these costs would provide more accurate data for decision making, such a
total cost assessment was outside of the scope of this life cycle design project.
Since the Contour is marketed and used in Europe, the cost analysis includes a European
(German) scenario as well as a US scenario. The objective of this scenario analysis was to
explore differences in market conditions that affect the use phase and end-of-life stages of the air
intake manifold. The German scenario accounts only for differences in gasoline and landfill
disposal costs; no attempt was made to estimate the differences in material costs and
manufacturing costs in Germany.
3.3.1 Material Production
Material costs were evaluated using EQ(3.6). The material costs were evaluated only to show
their relative contribution to the total manufacturing cost of each manifold system.
C^jC.xM, (3.6)
where,
c; = cost of ith material purchased
M; = mass of 1th material purchased
n = total number of different material in the manifold
Composite Manifold
The composite manifold consists of three materials (n=3): nylon resin, brass and stainless
steel. Thus, EQ(3.6) reduces to:
Cmflcom=CnxMn+CbxMb+CsxMs (3.7)
where,
C
mafl
material cost of the composite manifold
cn = material cost of the nylon resin = $2.53 / kg
cb = material cost of the 3 60 brass = $1.54 /kg
cs = material cost of the 304 stainless steel = $0.77/kg
Mn = mass of the nylon resin purchased = 2.0729 kg
Mb = mass of 360 brass purchased = 0.2635 kg
MS = mass of 304 stainless steel purchased = 0.4715 kg
30
-------
Thus, Cmafl =$6.013
' mat! com -"
Sand-Cast Manifold
The sand-cast manifold consists of 100% secondary aluminum (n=l). Thus, EQ(3.6) reduces
to:
Cma4sc=CsaxMsa (3.8)
where,
C
matl
= material cost of the sand-cast manifold
csa = material cost of secondary aluminum ingot = $1.89 / kg
Msa = mass of secondary aluminum purchased = 6.552 kg
Thus, Cmaflsc= $12.38
Multi-Tube Brazed Manifold
The multi-tube brazed manifold consists of primary and secondary aluminum (n=2). Thus,
EQ(3.6) reduces to:
Cmaflmtb=CpaxMpa+CsaxMsa (3.9)
where,
C
= material cost of the multi-tube brazed manifold
mtb
cpa = material cost of the primary aluminum ingot = $2.12 / kg
csa = material cost of secondary aluminum ingot and scrap = $1.89 / kg
Mpa = mass of primary aluminum purchased = 1.076 kg
Msa = mass of secondary aluminum purchased = 2.577 kg
Thus, Cmaflmtb=$7.15
For the German scenario analysis, material costs were considered to be equivalent to US
costs.
3.3.2 Manufacturing
Manufacturing costs consists of two main components: fixed costs, which include production
and prototype tooling and development costs, and variable costs.
Because manufacturing costs were proprietary, indirect cost estimates were
used. The variable manufacturing cost of the manifold is estimated as one
sixth of the part cost of the dealer. Thus,
31
-------
(3.10)
The differential cost of the composite manifold without the EGR tube and the
sand-cast manifold is $3.00. The cost of the EGR tube was estimated by
Ford's manifold design group as $8.50. Therefore,
= $11.50
(3.11)
As of August, 1995, the dealer part cost for the composite intake manifold for
the 1995 Ford Contour is $300.95 and the dealer cost for the multi-tube brazed
manifold for the 1995 Ford Escort is $244.78 . Thus,
dealer
dealer
mtb
= $300.95
= $244.78
These costs were obtained from Ford dealers in Ann Arbor, MI [47] [48].
There is a price revision every three months.
Thus, variable manufacturing costs were computed as:
np = $50.16
= $40.80
'var. manf
= $38.66
Estimates of the fixed manufacturing costs, which include production and
prototype tooling and development costs, were provided by the Ford project
team.
= $3.90
mp
= $2.90
;b
= $2.70
Thus, the total manufacturing costs for different manifolds were obtained as:
|CJ = $54.06
C
C
mfg
mfg
= $43.70
= $41.36
For the German scenario analysis, manufacturing costs are based on the U.S. costs.
32
-------
3.3.3 Use
In the use phase gasoline costs to the users and warranty costs to Ford were evaluated. It was
assumed that the manifolds perform without maintenance costs to the owner over 150,000 miles.
The US average cost (cf) for gasoline was estimated as US $1.24 / gallon [49]. The German
average cost (cf) for gasoline was estimated as US $3.34 / gallon [49]. Lifetime use phase fuel
cost (cuse) of the manifold was obtained from the life time fuel consumption (F(ga|)) as:
F
feal)
(3.12)
Lifetime fuel consumption (F(gai)) was obtained from Table 3-6. The lifetime fuel costs for
both the US and Germany are presented in Table 3-8.
Table 3-8. Lifetime Use Phase Fuel Costs for US and Germany
Fuel Costs (US $)
Cast Aluminum Brazed Aluminum Nylon Composite
Tubular
US 10.42 5.80 4.39
Germany 28.06 15.62 11.82
Warranty costs which are based on repair rates and service part costs were estimated by Ford
to be $0.10, $0.04, and $0.08 for the cast aluminum, brazed aluminum tubular and nylon
composite manifolds respectively.
3.3.4 Retirement
A cost analysis for each stage of the retirement process was conducted. The value of a used
1991 Escort multi-tube brazed manifold was found to be $50.00 [50]. The 1991 Escort manifold,
however, weighs more than the 1995 Escort manifold. Although some aluminum manifolds are
recovered during the dismantling stage, no data are available to estimate the fraction sold for
used parts. Therefore, this credit was not incorporated in the life cycle cost analysis.
Intake manifolds are transported from dismantlers to the shredders as part of the retired
vehicle. Transportation cost from dismantlers to shredders, assuming a 100-mile average
distance [10] are: flattened hulks - $0.12 / ton-mile, unflattened hulks - $0.18 / ton-mile.
Assuming a 50% split between flattened and unflattened hulks, total transportation cost is $0.15 /
ton-mile. This value was used for this analysis.
Total costs and credits to shredder operators were obtained from the APC retirement
spreadsheet model [32] as $1 16.64 / hulk and $125.21 / hulk respectively. Shredding cost (csh)
includes hulk sale value (ch), transportation cost (ct), disposal cost (cd)and the processing cost
(cpr) as shown in EQ (3.13).
Csh=Ch+Ct+Cd+Cpr (3.13)
33
-------
Because the actual processing cost was not available, it was estimated using EQ(3.13)
assuming a 1992 average automobile. The average weight of a 1992 vehicle was 1425.22 kg [51].
The material composition of this automobile includes 953.41 kg of ferrous material, 136.82 kg of
non ferrous metals, 254.54 kg of nonmetals and 80.45 kg of fluids [51]. Assuming the dismantler
drains all fluids and transports the remaining materials to the shredder, the weight of each hulk
sold to the shredder is 1344.77 kg. The APC study assumed a hulk sales value (ch) to the
shredder to be $30.00 and a transportation cost of $0.12 / ton-mile [32]. In this model, the metal
portion (1090.23 kg) of the hulk was assumed to be transported from shredders to metal recyclers
an average distance of 200 miles and the nonmetal portion (254.54 kg) was assumed to be
transported from shredders to landfills an average distance of 100 miles. Thus the total cost for
transportation (ct) was calculated to be $32.14. The APC study assumed a disposal fee for
nonhazardous waste of $75.00 / ton. Because automotive shredder residue (ASR) in the US is
classified as nonhazardous, the total cost for disposing (cd) 254.54 kg of nonmetal ASR was
calculated to be $21.00. The processing cost (cpr) for the hulk was estimated from EQ (3.13) to
be $33.50.
Table 3-9 itemizes costs for an intake manifold's end-of-life management.
Table 3-9. Itemized Cost Description for Different ELV Managers per Manifold
ELV Managers
Dismantler
Shredder
Non-Fe Processor
Total cost
Total value
Cost Descriptors Composite
manifold, 2.74 kg
transportation (a)
transportation to metal
recycler (b)
transportation to landfill (c)
disposal (d)
processing (e)
processing (f)
scrap value (g)
sum: (a) through (f)
(g)
$0.045
$0.017
$0.028
$0.070
$0.068
$0.190
$0.680
$0.420
$0.680
Sand-Cast
manifold, 6.5 kg
$0.110
$0.160
$0.004
$0.011
$0.160
$1.360
$5.930
$1.81
$5.93
Multi-Tube Brazed
manifold, 3.62kg
$0.060
$0.090
$0.002
$0.006
$0.090
$0.750
$3.300
$1.00
$3.30
The processing (separation) cost for aluminum, stainless steel and brass were estimated by
Huron Valley Steel to be $0.22 / kg, $0.27 / kg and $0.34 / kg respectively [29]. The scrap value
for aluminum, brass and stainless steel were obtained from American Metal Market to be $0.96 /
kg, $1.54 / kg and $0.77 / kg respectively.
Retirement cost information for end-of-life vehicle (ELV) managers as described above was
converted to cost per manifold as shown in Table 3-8. The US disposal cost was calculated using
a national average tipping fee of $30.25 / ton [33]. The European average tipping fee was
estimated as US $275 / ton [52]. Because of cost data availability limitations, other European
end-of-life costs were considered to be equivalent to US costs.
US total retirement costs for the composite, sand cast and multi-tube brazed manifold are
$0.42, $1.81 and $1.00 respectively. European total retirement costs are $0.63, $1.84 and $1.02
respectively. The scrap value of the composite, sand cast and multi-tube brazed manifolds is
$0.68, $5.93 and $3.30 respectively.
34
-------
3.4 Performance Analysis
3.4.1 Manufacturing Phase
Manufacturing unit processes for the three manifold systems are shown in Table 3-10.
Table 3-10. Manufacturing Unit Processes for the Three Manifold Systems
Manifold
Component
Manufacturing Unit Process
Composite
Nylon manifold
Brass fittings
Stainless steel EGR tube
casting tin-bismuth melt cores
injection molding
- mold and core insertion
- overmolding
inductive melting tin-bismuth core
washing
post manifold assembly
extrusion
machining
stamping
extrusion
brazing
Sand cast
Aluminum manifold
1 green sand preparation
mold and core insertion
gating and riser preparation
1 melting and pouring
1 post casting machining
Multi-tube brazed
Sand-cast aluminum flange
Extruded tubes and air
collection chamber
green sand preparation
mold and core insertion
gating and riser preparation
melting and pouring
post casting machining
extrusion
bending of tubes
arrangement
brazing
Composite Manifold
It can be seen from Table 3-10 that the composite manifold involves three different materials
and requires eleven unit processes for manufacturing. The lost core process consists of five
different unit processes. The cycle time for injection molding is 1.5 minutes, the cycle time for
core casting is 3 minutes and the cycle time for core melt out is 45 minutes.
In the lost core process, maintaining an appropriate core casting temperature and controlling
core dimensional change during injection molding presents significant challenges to manufac-
turers. Getting the time-temperature cycle right on the core casting tool is critical [11]. If cores
are cooled too fast they crystallize and become brittle, but if cores are cooled too slowly portions
can still remain molten when the core is overmolded by nylon resin. The most critical part of the
lost core process is accounting for melt loss of cores during injection molding. Since the tin-
bismuth core alloy has a lower melting temperature (320° F - 160° C) than nylon resin (491° F -
255° C), some core metal may get melted when it is overmolded with molten nylon resin. Nylon
resin loses its heat while melting part of the core layer and also undergoes stress relief and
shrinkage during the melt-out stage. Therefore, in lost core process design, these dimensional
changes are built into the tool design [11].
35
-------
Because the core material has to be melted every time, lost core molding is a very energy
intensive process. In addition, the stainless steel EGR tube increases overall complexity because
it requires three different manufacturing processes.
Sand-Cast Manifold
The sand-cast manifold was the only one-piece manifold studied. As indicated in Table 3-10,
sand casting involves five different unit processes. A typical cycle time for manufacturing a
sand-cast manifold is 14 minutes. This includes 1 minute for core fabrication, 2 minutes for
casting, 5 minutes for cooling, 0.5 minute for premachining pressure testing, 0.5 minute for
machining and 2 minutes for washing, assembly, testing and packaging. The tool life for a
typical aluminum manifold is about 250,000 cycles. The die life is about 1 x 105 to 2 x 105 mold
parts before reconditioning.
Multi-Tube Brazed Manifold
The multi-tube brazed Escort manifold is comprised of a cast aluminum flange, four bent
aluminum tubes and an air collection chamber joined together by brazing. The aluminum tubes
and the collection chamber are manufactured by extrusion. After extrusion, aluminum tubes are
bent into desired shapes by a movable mandrel. The casting is placed into a die and pressurized
hydraulic fluid turns out the four openings from inside [6]. Table 3-10 indicates that the multi-
tube brazed manifold involves nine different manufacturing unit processes that include five
processes for sand casting. The cycle time for a multi-tube brazed manifold was not available,
but it is expected to be higher than that of a sand-cast manifold because of extrusion and brazing.
3.4.2 Use
The smoother wall of the multi-tube brazed manifold is expected to lead to less frictional loss
compared to the rough-walled, sand-cast manifold. This theoretically translates into higher
volumetric efficiency and higher power output at the same throttle opening. However, Ford test
engineers reported no significant difference in power between engines equipped with rough-
walled, sand-cast manifolds and smooth-walled, composite manifolds at part throttle. At full
throttle a 2% increase in power for the composite manifold was obtained. Similar conclusion can
be inferred about smoother-walled, multi-tube brazed manifolds.
Ford's manifold design group reported that composite manifolds deform to the shape of the
engine where they are used and therefore cannot be remounted on another vehicle after
retirement. Ford's manifold engineers could not confirm reports of defects due to heat
deformation for the 1995 Contour manifold. The stainless steel EGR tube is expected to transfer
most of the heat away from the manifold.
Seven warranty claims related to composite manifolds were filed for a 7-month period during
which 55,000 1995 Contours were sold. This is a defect rate of 0.13 per 1000 vehicles. Because
the sand-cast manifold was not used in actual vehicle production, warranty data for this manifold
are not available. For the multi-tube brazed Escort manifold, 262 warranty claims were filed in
the last five years during which 1,438,593 vehicles were sold . This is a defect rate of 0.18 per
1000 vehicles. These warranty data include manufacturing flaws, assembly errors, mis-bins
(wrong parts serviced) and accident repairs.
36
-------
4. Results and Discussion
In this chapter, the methodology described in Chapter 3 is used to evaluate environmental
burdens and cost metrics for sand-cast aluminum, multi-tube brazed aluminum and composite
intake manifolds. All results are expressed per one intake manifold (IM).
Environmental burdens evaluated are energy, solid waste, air emissions and water effluents,
based on the mass of manifold materials shown in Figure 2-1.
4.1 Environmental Burdens
4.1.1 Energy
Figure 4-1 shows life cycle primary energy requirements for the three manifolds. It can be
seen that a sand-cast manifold has the highest life cycle energy, followed by a multi-tube brazed
manifold and a composite manifold. Overall life cycle energy requirements for a sand-cast
manifold is about 1.9 times higher than that of a composite manifold. A multi-tube brazed
manifold requires 1.2 times the life cycle energy of a composite manifold. Most of these
differences occur during use and are directly attributable to manifold weight.
1800 j
1600 --
1400 --
g- 1200 --
1000 --
D Aluminum: sand cast
D Aluminum: multi-tube brazed
Composite
943
Matl. prod
Mnf. Use
Life Cycle Stage
Retirement
Total
Figure 4-1. Life Cycle Energy of Intake Manifolds
A composite manifold requires the most material production energy as a result of producing
virgin resin from petroleum and natural gas. Stainless steel and brass are mostly composed of
secondary materials and contribute a small amount to the overall composite manifold energy
profile. Production of a multi-tube brazed manifold requires 1.076 kg of primary ingot and 2.496
kg of secondary ingot. Primary aluminum production is about 10 times as energy intensive as
secondary aluminum production. This results in about double the material production energy for
a multi-tube brazed manifold compared to a sand-cast manifold, although the sand-cast manifold
37
-------
weighs 1.8 times more. For sand-cast, multi-tube brazed and composite manifolds, material
production accounts for about 7%, 21% and 27% of total life cycle energy respectively.
Sand-cast manifolds are the most energy intensive to manufacture compared to other
manifolds. The higher energy for manufacturing sand-cast manifolds is due partly to their higher
mass and the higher energy density for sand casting. Primary energies for different
manufacturing processes are shown in Table 4-1. The details of the methodology used to
evaluate these data was presented in Chapter 3. Table 4-1 shows that sand casting is the most
energy intensive manufacturing process for aluminum and extrusion is the most energy intensive
process for stainless steel. Stamping energy for stainless steel is relatively small. Lost core
process for manufacturing nylon manifold is the most energy intensive process among all
manufacturing process studied. Melting of the tin-bismuth core accounts for 70% of the total
manufacturing energy for lost core process. The rest 30% can be attributed to injection molding.
For a sand-cast manifold, manufacturing represents about 19% of life cycle energy; for a
multi-tube brazed manifold, manufacturing accounts for about 13% of the life cycle energy; and
for a composite manifold, manufacturing represents about 11% of life cycle energy.
Table 4-1. Primary Energy for Different Manufacturing Processes
Material
Aluminum
Nylon
Brass
Manufacturing
process
Sand casting
Extrusion
Brazing
Lost core
process
Extrusion
Primary Energy
MJ/kg
44.22
16.76
3.72
47.21
5.51
Source and Representativeness
Sand casting data representative of Europe [21]
Extrusion data representative of average European and US
plant data [22] [23]
Brazing data obtained using engineering model
Injection molding data average of US and European
Plant specific data for inductive melting is used
Brass extrusion data typical US plant [42] [7]
Energy for hot extrusion is obtained using engineering model
[12]
Stainless steel Rolling
Stamping
Extrusion
2.70
0.20
3.08
All steel data typical US [44] [45]
1 Extrusion and stamping data are obtained using engineering
model [12]
As Figure 4-1 shows, the use phase dominates in terms of energy consumption. Use phase
energy is directly proportional to manifold weight. For a sand-cast manifold, the use phase
represents about 74% of life cycle energy; for a multi-tube brazed manifold, the use phase
represents about 66% of the life cycle energy; and for a composite manifold, the use phase
represents about 61% of life cycle energy.
Retirement represents on average only 0.4% of life cycle energy for these manifold systems
and can be neglected to streamline analysis.
38
-------
4.1.2 Solid Waste
Figure 4-2 shows that the multi-tube brazed manifold and the nylon composite generate the
greatest amount of life cycle solid waste. Material production of primary and secondary
aluminum for a multi-tube brazed manifold results in 76% of its overall life cycle solid waste.
As shown in Table 3-3, red mud generated during alumina production accounts for 87% of solid
waste for primary aluminum processing. The major components of solid waste from a composite
manifold in the material production stage include mine tailings, combustion ash, mineral waste,
sludge and polymer solids. On average, about 0.93 kg per kg of solid waste is generated from the
production of materials for the composite manifold.
4.5 j
4 --
3.5 --
D Aluminum: sand cast
D Aluminum: multi-tube brazed
Composite
Matl. prod
Mnf.
Use
Life Cycle Stage
Retirement
Total
Figure 4-2. Life Cycle Solid Waste of Intake Manifolds
Solid waste in the manufacturing stage is comprised of process waste from sand casting,
product waste and energy waste. Sand casting waste consists of fume dust and a 5% loss in
recycling sand and salt slag. Product waste consists of a 5% loss in recycling scrap generated
from manifold production. The process and product waste for a sand-cast manifold are 1.045 kg
and 0.052 kg respectively. For a multi-tube brazed manifold, the process and product waste are
0.4 kg and 0.255 kg respectively. Process waste for a composite manifold in the manufacturing
stage is primarily due to electricity generation and amounts to about 0.79 kg per intake manifold;
product waste is 9.52 g per intake manifold.
Solid waste during use primarily results from waste generated in the production of gasoline.
Retirement solid waste includes a 5% loss in recycling metals at the end-of-life of the
vehicle. For the composite manifold, in addition to 5% metals waste, all the nylon (2.07 kg) ends
up as solid waste.
39
-------
4.1.3 Air Emissions
Figure 4-3 shows life cycle pollutant emissions for the three manifold systems. The majority
of pollutant emissions are in the form of nonmethane hydrocarbons (NMHC), NOX, CO and 862.
CO, NOX and NMHC releases are highest for a sand-cast manifold, followed by a multi-tube
brazed manifold and a composite manifold. However, the trend is different for CH/i, SO2 and
PM-10.
D Aluminum: sand cast
D Aluminum: multi-tube brazed
Composite
NMHC
CH4 NOx
Life Cycle Stage
SO2
PM-10
Figure 4-3. Life Cycle Pollutant Emissions of Intake Manifolds
The contribution of the intake manifold to the total vehicle use phase emissions was
estimated assuming that these emissions are proportional to gasoline consumption. Although this
relationship is valid for carbon dioxide, this allocation is probably not accurate for the other
pollutants that are controlled by the catalytic converter.
The air emissions data for material production reported is expected to be highly uncertain and
a comparison between the three systems is not recommended. A comparison of material
production inventory data from two different sources showed a much greater variation in results
for air and water emissions than was found for energy and solid waste [53].
Figure 4-4 shows that total greenhouse gas emissions for composite and multi-tube brazed
manifolds are essentially similar. A sand-cast manifold is associated with about 1.5 times more
greenhouse gas emissions compared to a composite manifold. This differential is primarily due
to the heavier weight of a sand-cast manifold, which results in significantly greater greenhouse
emissions during use.
40
-------
120 -r
100 --
n Aluminum: sand cast
D Aluminum: multi-tube brazed
Composite
Matl. prod
Mnf. Use
Life Cycle Stage
Retirement
Total
Figure 4-4. Life Cycle Greenhouse Gas Emissions for Intake Manifolds in CO2 Equivalents
Figure 4-4 also illustrates that most greenhouse gases are released during the use phase for
sand-cast and multi-tube brazed manifolds. For a sand-cast manifold, use phase greenhouse gas
emissions represent about 76% of the life cycle total, while the use phase accounts for about 61%
of total greenhouse gas emissions for a multi-tube brazed manifold. This difference is attributable
to releases of CF4 and 2^6 during primary aluminum production. Although only 0.56 g of these
fluorocarbons are released in the production of primary aluminum for a multi-tube brazed mani-
fold, their global warming potential is so much higher than CC>2 (6300 for CF4 and 12500 for
C2?6 where CO2 = 1) that greenhouse gas emission in CO2 equivalents for producing multi-tube
manifolds is 19.9 kg compared to just 5.9 kg for sand-cast manifolds. This, coupled with much
lower use phase emissions (46.7 kg vs. 83.8 kg for sand cast) due to the lighter weight of a multi-
tube manifold, results in a significantly lower percentage of total greenhouse gas emissions
occurring during the use phase.
For similar reasons, the use phase accounts for only about 48% of total life cycle greenhouse
gas emissions for a composite manifold; materials production accounts for 43% . Nitrous oxide
(N2O, GWP = 270) releases during nylon production result in the highest greenhouse gas emis-
sions of all the manifolds during this phase. N2O constitutes 71% of greenhouse emissions in
nylon material production, CC>2 for most of the remainder. In addition, the lighter weight of a
nylon manifold results in the lowest CO2 emissions during use. Thus, greenhouse emissions are
nearly evenly distributed between material production and use for a composite manifold rather
than being concentrated in the use phase.
It is apparent from this discussion that greenhouse gas emissions do not exactly parallel life
cycle energy requirements for these manifolds. Use phase energy for sand-cast, multi-tube brazed
and composite manifolds accounts for 74%, 66% and 61% of life cycle energy respectively; green-
house gas emissions for these manifolds, 76%, 61% and 48%. These differences result from the
high global warming potential of halogenated carbons released during material production.
41
-------
Figure 4-5 shows how much of the greenhouse gas emissions associated with each manifold
are actually CO2. Use and manufacturing emissions are all in the form of CO2 and are thus the
same in Tables 4-4 and 4-5. As this table illustrates, greenhouse gas emissions associated with
sand-cast manifolds are essentially all in the form of CO2 while CO2 emissions make up a
smaller percentage of overall greenhouse emissions for the other manifolds.
120 -r
100 --
tM
O
O
80 --
.9. 60 --
D Aluminum: sand cast
D Aluminum: multi-tube brazed
Composite
Matl. prod
Mnf.
Use
Life Cycle Stage
Retirement
Total
Figure 4-5. Life Cycle CO2 Emissions of Intake Manifolds
4.1.4 Water Effluents
Figure 4-6 shows that the majority of water effluents on a mass basis are in the form of
dissolved solids, the highest of which are associated with a composite manifold, the lowest with
a multi-tube brazed.
42
-------
900 T
_ 800 --
D Aluminum: sand cast
D Aluminum: multi-tube brazed
Composite
0.8 0.40.3 0.6 1.3 0.2
Life Cycle Stage
Figure 4-6. Cumulative Life Cycle Water Effluents of Intake Manifolds
4.2 Cost
4.2.1 U.S. Scenario
Table 4-2 shows that the life cycle costs of the two aluminum manifolds are similar. That of
the composite manifold is approximately $10.76 more than that of the aluminum manifolds. The
material cost of a sand-cast manifold is about $5.23 higher than that of multi-tube brazed and
$6.87 higher than composite manifold. The higher material cost of a sand cast manifold is due to
its higher weight compared to a multi-tube brazed manifold.
Table 4-2. Life Cycle Costs of Intake Manifolds (in U.S. dollars)
Composite
U.S. German
Sand-cast
U.S. German
Multi-tube brazed
U.S. German
Material cost
Manufacturing costs*
fixed
variable
Use phase costs**
End of life costs***
Salvage value
Life cycle cost
$6.01
$3.90
$50.16
$4.47
$0.42
$0.68
$58.27
$6.01
$3.90
$50.16
$11.90
$0.42
$0.68
$65.70
$12.38
$2.70
$38.66
$10.52
$1.81
$5.93
$47.76
$12.38
$2.70
$38.66
$28.16
$1.81
$5.93
$65.40
$7.15
$2.90
$40.80
$5.84
$1.00
$3.30
$47.24
$7.15
$2.90
$40.80
$15.66
$1.00
$3.30
$57.06
* Manufacturing costs were estimated from data provided by Ford, for the German scenario analysis
manufacturing costs were based on U.S. conditions.
** Use phase costs include both fuel and warranty costs.
*** End of life costs include transportation (dismantler, shredder, and landfill), disposal, and processing.
43
-------
The sum of the manufacturing and warranty cost for a multi-tube brazed manifold was
estimated to be about $2.28 higher than a sand-cast manifold because of increased manufacturing
complexity. The estimated manufacturing and warranty costs of a composite manifold is about
$12.67 more than that of a sand-cast manifold. Manufacturing accounts for the majority of life
cycle costs for sand cast (87%), multi-tube brazed (93%) and composite (93%) manifolds.
Ford's manifold costs include both material purchase, manufacture, and warranty. Ford's cost is
estimated $37.34 for a sand-cast manifold, $41.44 for a multi-tube brazed manifold and $53.87
for a composite manifold.
Gasoline cost to the user of a sand-cast manifold over a useful life of 150,000 miles is about
$4.62 more than that of a multi-tube brazed manifold and $6.03 more than that of a composite
manifold. These differences reflect the effect of weight on gas mileage.
In the retirement stage, a sand-cast manifold requires more to process, but has an aluminum
scrap value that is results in a net cost $1.82 lower than the multi-tube brazed manifold. A
composite manifold requires the lowest processing cost in the retirement stage, because its major
constituents are disposed to landfills rather than recovered.
4.2.2 German Scenario
In contrast to the US scenario, the life cycle costs of the two aluminum manifolds, shown in
Table 4-2, diverge greatly due to the higher cost of gasoline in Germany. This results in the
heavier cast aluminum manifold having a life cycle cost $8.35 greater than the multi-tube brazed
manifold and only a marginally lower cost than the composite manifold.
44
-------
4.3. Design Analysis and Integration
4.3.1 Decision-Making
The life cycle inventory analysis, life cycle cost analysis, and performance analysis presented
in the previous chapter reveal significant tradeoffs among each of the three intake manifold
designs. The selection of the preferred manifold design using a complex and diverse set of
criteria and data can be aided by a structured decision analysis process. A formalized process
was applied in this project to highlight some of the challenges in evaluating environmental
performance and integrating environmental performance with other criteria. Inherent in the
decision making process are tradeoffs, judgments required for weighting criteria, and uncertain
and incomplete data.
4.3.2 Scope
It is useful to recognize the difference between the planning process and the detailed design
process. The planning process at Ford begins between 36 and 48 months before a vehicle is
launched into production. During this process various elements of the design may be selected
such as materials and manufacturing processes. A preferred design may be proposed but an
alternative design may also be developed as a prototype which can be substituted in the event that
unanticipated problems occur which no longer favor or prohibit the original preferred design.
The intake manifold must accommodate vehicle system, powertrain subsystem, and engine
specific requirements. Consequently, the manifold design should be evaluated in the context of
these larger system boundaries. This decision analysis presented here however will be limited
primarily to the manifold system.
The life cycle inventory and cost analyses were based on U.S. conditions where possible.
Since the Contour is marketed globally the product development team should consider factors
that are unique to Europe and other markets. For example, the life cycle cost analysis is very
sensitive to the price of gasoline. The use phase cost would triple or quadruple if the German
gasoline price was substituted for the U.S. price.
The decision making process is also influenced by the time horizon considered. Strategic
planning can be an important element of the design process and lead to more ecologically
sustainable design solutions. Decision makers may weigh greenhouse emissions more heavily
when taking a long range perspective compared to a short term development cycle.
45
-------
4.3.3 Identification of Key Drivers
A wide range of factors influence the selection of alternative manifold designs. Design
requirements and guidelines serve to guide the decision making process. The multi-criteria
requirements matrices are a tool for identifying and organizing key requirements.[3][5][53] Ford
guidelines, corporate directives and policies as well as external requirements such as government
regulations were identified. The set of internal and external environmental "requirements"
examined are presented in Table 4-3. These environmental "requirements" can be used to
interpret results from the life cycle inventory and cost analyses. Design decision making occurs
in the context of the business and external forces impacting the business and its products.
Table 4-3. Internal and External Environmental Requirements
Internal External
Energy
- Corporate citizenship - CAFE
- Minimize facility energy (Manufacturing - Voluntary pledge of German auto industry to reduce
Environmental Leadership) CC^ emissions
- Meet platform fuel economy targets
Materials
- Ford targets for recycled content of plastic resin (D109, - Reduce materials used, increase materials recycled,
A120, Manufacturing Environmental Leadership) and reduce waste
- Substance use restrictions (WSS-M99P9999 also
known as HEX9)
- Reduce part/vehicle weight
Waste
- Protect health and environment (Policy Letter 17) - European guidelines for reducing waste going to
- Recyclability targets (Directive F-111) landfill:
- Reduce manufacturing waste (A-120) maximum 15% by weight2002
maximum 5% by weight2015
- Voluntary initiatives to reduce greenhouse emissions
46
-------
4.3.4 Decision Analysis
A framework for decision analysis is necessary to integrate "requirements" and the results
from life cycle inventory and cost analyses to select among the alternative intake manifolds. Two
basic approaches can be taken for analyzing life cycle results. The full set of results can be
evaluated together or environmental, performance, and cost data can be evaluated separately.
The latter approach enables the decision maker to determine which design is most preferred
environmentally, which is beneficial in understanding and comparing the environmental profile
of each design.
The original matrix that Ford used to evaluate alternative manifold designs prior to this
project is shown in Table 4-4. The rankings for each criteria are also shown. The individual
weighting factors are not provided here for reasons of confidentiality, and therefore, the overall
scores (weighting factor x ranking) could not be computed.
Table 4-4. Original Ford Requirements Matrix
Requirements
120k Durability
First Time Quality Capable
Airflow/Performance
Weight
Fastener Compatibility
Joint Sealing
Material Dimensional Stability
Flammability Resistance
High Temperature Performance
Low Temperature Performance
Positive Pressure Capability
NVH-Structural
NVH-Acoustical
Prototype Lead Times
Prototype Tooling Cost
Production Lead Times
Variable Cost
Production Tooling Cost
Appearance
Established Supply Base
Manufacturing Flexibility
Component Integration Opportunity
Design Flexibility
Cast
Aluminum
10
6
6
4
10
8
10
10
10
10
10
10
6
10
6
4
Ranking
Brazed
Aluminum
Tubular
6
6
8
6
10
8
10
8
6
4
6
6
6
8
4
6
4
4
2
6
Nylon
Composite
10
8
10
2
6
4
2
2
2
4
4
2
4
2
4
6
2
8
6
2
47
-------
This project offers a more comprehensive assessment of each manifold by incorporating
additional environmental and cost data. The decision analysis structure proposed for this project
is shown in Figure 4-7.
Figure 4-7. Decision Analysis Structure
4.3.5 Performance Analysis
Each manifold alternative must meet basic performance criteria to become a viable candidate
for a particular design application. Weighting factors for the performance criteria are dependent
on specific vehicle platform objectives. For example, the NVH-Acoustical (noise, vibration, and
harshness) criterion would be weighted higher for a luxury car relative to an economy car. The
cast aluminum manifold generally had higher rankings compared with the nylon composite or the
brazed aluminum tubular manifolds. The nylon composite manifold, however, was preferred for
several important criteria, including, first time quality capability, weight, and component
integration opportunity. The three manifolds investigated in this project meet these criteria. As
Table 4-4 shows, most of the requirements in the original Ford matrix were performance criteria.
The components of the performance analysis are shown in Figure 4-8.
48
-------
1
Manufacturing
Performance
Analysis
i
i
Design
Selection
A
i
Cost Analysis
Use
End-of-Life
Environmental
Analysis
Figure 4-8. Components of the Performance Analysis
4.3.6 Cost Analysis
The cost analysis has three major components as shown in Figure 4-9.
Performance
Analysis
1
Ford Costs
(Manufacturing
and Warranty)
Design
Selection
A
i
Cost Analysis
A
Environmental
Analysis
i
\
Gasoline Costs
End-of-Life
tus us
Europe ^Europe
Figure 4-9. Components of the Cost Analysis
49
-------
Life cycle costs can be grouped according to those direct costs incurred by Ford and those
costs occurring outside Ford's cost domain. Ford manufacturing costs are a primary criteria for
making a business decision. In addition, warranty costs are direct costs borne by Ford due to
product defects or improper assembly of the manifold on the engine. The life cycle costs incurred
outside of Ford's domain during the use and retirement phases represent costs to the customers
and vehicle recyclers. Gasoline costs in Germany are much more significant than in the U.S. and
therefore this criterion was evaluated for both U.S. and German conditions. In Germany, gasoline
costs are an important factor in vehicle purchasing decisions for a greater fraction of customers
than in the US. Consequently, as shown in Figure 4-10, the cast aluminum manifold may be
cheaper to produce, but the effect of higher gasoline costs on vehicle sales must also be consi-
dered. The CAFE standard in the U.S. can also be an important factor in weighing alternative
designs. This factor depends on how well specific vehicle platform weight targets are being met
and how close the company is to violating CAFE standards. The cost of end-of-life vehicle
management may become an important criteria since legislation is being discussed in Europe
requiring OEM take back of automobiles at no cost. In this scenario, retirement costs would
become part of the total Ford manifold cost as indicated in Figure 4-11. Figure 4-10 indicates
that, the aluminum cast and the brazed aluminum tubular manifolds would provide a greater end-
of-life credit compared to the nylon composite manifold.
$60.00 j
$50.00 --
$40.00 --
$30.00 -
$20.00 -
$10.00 --
$(10.00) -L
D Ford Cost (Manufacturing and Warranty)
Customer Gasoline Costs
D End of Life Credit
US German
Cast Aluminum
US German
Brazed Al Tubular
US German
Nylon Composite
Figure 4-10. Life Cycle Costs for Intake Manifolds for US and Germany
50
-------
$60.00
$50.00
$40.00
$30.00
$20.00
$10.00
S-
!
"
QFor
!
d Cost (including EOL credit)
!
!
!
US German
Cast Aluminum
US German
Brazed Al Tubular
US German
Nylon Composite
Figure 4-11. Life Cycle Costs under Take Back for Intake Manifolds for US and Germany
4.3.7 Environmental Analysis
The environmental analysis includes both the LCI analysis and a regulatory/policy analysis as
shown in Figure 4-12.
Regulatory
and/or Policy
Analysis
LCI Analysis
Figure 4-12. Components of the Environmental Analysis
51
-------
Energy
Currently, no specific corporate guidelines or government regulations and policies encourage
a reduction in the total life cycle energy. Several "requirements" are directed at specific stages of
the life cycle. For example, Ford's Manufacturing and Environmental Leadership Program seeks
to minimize facility energy consumption [54]. CAFE in the US and a voluntary pledge of the
German auto industry to reduce CO2 emissions focuses on use phase energy. Among the three
manifold designs the nylon composite best meets all energy related requirements and consumes
the least life cycle energy, as shown in Figure 4-1 of Section 4.1.1. For this case, no tradeoffs
emerge, although an impact assessment may consider the source of energy (coal, natural gas,
petroleum, etc.).
Materials
Ford internal requirements addressing life cycle materials include targets for recycled content
of plastic resin, substance use restrictions, and vehicle/part weight reductions goals [54]. It is
difficult to establish specific guidelines for interpreting the life cycle materials metrics presented
in Table 4-5. Ideally, each design would minimize the total materials used including primary and
secondary materials, maximize the total materials recycled, and reduce waste. It is well recog-
nized that these criteria can easily conflict with other environmental objectives such as minimiz-
ing life cycle energy. The total material mass of the cast aluminum manifold design is greatest
but the manifold utilizes secondary aluminum and it is currently being recycled during end-of-life
management of the vehicle. The brazed aluminum tubular manifold uses less total material but
incorporates primary aluminum. This manifold is also recycled in the end-of-life phase. Both
aluminum manifolds use phenol and formaldehyde to form molds for casting. The nylon
manifold uses the least total material but incorporates the greatest quantity of primary material,
which currently is not recycled during the end-of-life phase.
Table 4-5. Materials Metrics for Intake Manifolds (per IM basis)
Cast Aluminum Brazed Aluminum Nylon Composite
Tubular
Product mass (kg) 6.5 3.62 2.74
Primary material content 0.0% 25% 76%
Restricted substances (kg) 0.017 0.017 0
Waste
The inventory category waste includes solid waste, air pollutant releases, and waterborne
pollutant releases. The life cycle "waste" inventory results were presented in Figures 4-2 through
4-6. Interpretation of the inventory results presents several challenges which are addressed
and/or are being investigated as part of life cycle impact assessment methodology.
The aluminum cast manifold generated the least amount of life cycle solid waste as was
shown in Figure 4-2. No guideline, however, currently exists at Ford which seeks to minimize
life cycle solid waste. Ford internal requirements address both manufacturing waste and end-of-
52
-------
life solid waste minimization. The minimization of material production solid waste is not
specified as part of Ford's material procurement guidelines. Consequently, Ford's internal policy
would favor the aluminum cast and the brazed aluminum tubular manifolds equally even though
a significant amount of solid waste in the form of red mud is generated with the brazed
aluminum tubular system. The European guidelines for reducing the amount of waste going to
landfill will probably lead to further emphasis on end-of-life waste compared with solid waste
generated in other life cycle phases.
Several techniques were tested for characterization of the air emissions and waterborne
emissions inventory results. The critical volume approach was applied in an attempt to
normalize the set of air pollutant emissions. EPA Criteria Air Pollutant Standards were used for
this normalization, however, standards do not exist for all of the pollutants inventoried in this
analysis. Similarly, a variety of sources were investigated to normalize water emission data. A
comparison of material production inventory data from two different sources showed a much
greater variation in results for air and water emissions than was found for energy and solid waste
[55]. Consequently, it was recommended that the air and water emissions data not be weighted
heavily in the environmental analysis.
53
-------
4.4 Proposed Environmental Metrics
An important objective of this demonstration project is to develop environmental metrics that
could be used by design engineers to evaluate design alternatives. Ideally a comprehensive LCA
could be conducted for each design, but data availability, costs, and time constraints currently
limit its applicability [56]. Two main criteria were used in proposing environmental metrics:
reliability in guiding environmental improvement and data availability to evaluate the metrics.
The reliability of the metrics addresses whether the metrics in combination with other
environmental requirements will lead to the same outcome as a comprehensive environmental
analysis such as an LCA. For the metrics to be practical, design engineers need to be able to
evaluate the metrics without having to collect a large set of additional data. Consequently, these
metrics should not include emission factors or energy parameters that are not readily accessible
from an internal database.
4.4.1 Proposed Metrics
Metrics were proposed by applying the above criteria. The proposed metrics for materials,
energy and waste are given in Tables 4-6, 4-7, and 4-8 respectively. Table 4-9 is provided to
allow comparison of the proposed metrics to the results of the life cycle analyses.
Table 4-6. Proposed Materials Metrics for Intake Manifolds
Primary Material in Finished Part (kg)
Cast Aluminum Brazed Aluminum Nylon Composite
Tubular
Aluminum - 0.89
Nylon - - 1.39
Glass Fiber - - 0.68
Brass - - 0.003
Total - 0.89 2.07
Table 4-7. Proposed Energy Metrics for Intake Manifolds
Energy (MJ)
Cast Aluminum Brazed Aluminum Nylon Composite
Tubular
Material Production 169 246 268
Operation 1,339 746 565
Total 1,508 991 833
54
-------
Table 4-8. Proposed Waste Metrics for Intake Manifolds
Waste (kg)
Cast Aluminum Brazed Aluminum Nylon Composite
Tubular
Part Solid Waste (end-of-life) 0 0 2.07
CO2 Mat. Production 5.59 13.88 9.25
CO2 Operation 84.09 46.66 35.32
Table 4-9. Summary of Life Cycle Analyses for Intake Manifolds
Cast Aluminum Brazed Aluminum Nylon Composite
Tubular
Life Cycle Energy (MJ) 1798 1131 928
Life Cycle Materials
Product mass (kg) 6.5 3.62 2.74
Primary material content 0 25% 76%
Restricted substances (kg) 0.017 0.017 0
Life Cycle Waste
Life cycle solid waste (kg) 2.18 4.18 3.91
Life cycle GWP 107.9 73.8 73.6
(CO2 kg equivalents)
4.4.2 Discussion
The reliability of the environmental metrics in estimating life cycle environmental burdens
can be tested by comparing the results provided in Tables 4-6 to 4-8 with the life cycle inventory
data reported in Figures 4-1 to 4-6. With the exception of the part solid waste metric, close
agreement between metrics and inventory results indicates that the metrics are reasonable
surrogates.
For the three intake manifold designs, the mass of primary product material input into the
manufacturing stage can be approximated by analyzing the mass of primary material in the
finished part. No primary material is required in manufacturing the cast aluminum design.
For the brazed aluminum manifold the mass of primary aluminum in the extruded tubes was
estimated to be 0.887 kg while the inventory analysis calculations indicated that 1.08 kg of
primary aluminum from bauxite is used. The difference is largely determined by the material
efficiency for part fabrication. For part fabrication steps with large scrap rates, the environmental
metric based on the mass of finished part will be a less accurate indicator of primary material
usage.
The energy metrics which address the material production and operation stages of the life
cycle account for a large fraction of the life cycle energy consumption. The energy metrics
indicate the same trend in energy consumption among the three manifold designs as was
55
-------
indicated by the total life cycle energy data. The use phase energy metric is identical to the
calculation made in the life cycle inventory analysis for the use phase. A discrepancy exists
between the material production energy metric and the material production energy calculated
from the life cycle inventory analysis. This discrepancy originates from two sources. The first
source of discrepancy can be attributed to differences in material input requirements which was
discussed above. Differences in material production energy data is a second source of discrep-
ancy. The inventory analysis drew on several published data sets whereas the environmental
metrics were calculated using data compiled by Ford. The exclusion of manufacturing energy
from the energy metrics can introduce significant error for manufacturing processes that are
energy intensive, such as casting.
The life cycle waste metrics included part solid waste and carbon dioxide emissions from
material production and operation. The solid waste metric only addresses one discrete life cycle
stageend-of-life management. For the aluminum manifolds this metric does not account for
any of the total life cycle solid waste. In the case of the nylon composite manifold it accounts for
approximately 53 percent. By adopting this metric, however, more emphasis and responsibility
would be placed on this stage of the life cycle. The carbon dioxide emissions track closely with
energy consumption and the carbon dioxide metrics provide a reasonable estimate of the emis-
sions computed by the LCI. Again the level of discrepancy between the metrics and the LCI
depend on the validity of the assumptions in the model used to define the metrics. As more
reliable data becomes available, the model can be refined to provide a more accurate description
of the system.
In the absence of a life cycle inventory analysis, environmental metrics may be used to
improve environmental decision making during design analysis. Caution must be taken in
applying the metrics developed in this study to other air intake manifold design applications.
Whenever such simplifying assumptions and boundary truncations are applied the
comprehensiveness and reliability of the results will be reduced accordingly. These metrics do
however direct designers attention to upstream and downstream aspects of the product life cycle
that may not otherwise be fully considered. In addition, designers should not make decisions
based on individual metrics but rather the entire set. For example, if the solid waste metric was
the only criteria used to evaluate plastic vs. metallic materials in automotive applications, then
plastics would not likely be used on automobiles. In the case of the manifold, however, the
operation phase energy metric favors the nylon composite manifold. Consequently, tradeoffs
exist which must be weighed in decision making.
56
-------
5. Conclusions
This demonstration project with Ford applied the life cycle design framework to air intake
manifold design. This project was successful in providing environmental, cost, performance,
regulatory, and policy data for enhancing the design analysis of three alternative air intake mani-
folds: cast aluminum, brazed aluminum tubular, and nylon composite. Significant tradeoffs
among the three designs were highlighted and the value of the life cycle design framework was
discussed. Limitations of life cycle design methodologies and tools as well as organizational
barriers affecting their implementation were also characterized.
The design analysis consists of three basic components: environmental analysis, cost analy-
sis, and performance analysis. The multi-criteria requirements matrix was useful in identifying
and organizing key requirements for design analysis. Requirements specified internally by Ford
and requirements set externally such as government regulations were compiled using the matrix
structure. Life cycle inventory analysis and life cycle cost analysis were specific tools used to
evaluate design alternatives.
The life cycle inventory analysis indicated significant environmental tradeoffs among alter-
native manifold designs. The life cycle energy consumption for the cast aluminum, brazed
aluminum tubular, and nylon composite manifolds were 1798 MJ, 1131 MJ, and 928 MJ per
manifold, respectively. The use phase energy accounted for a major fraction of this energy: 74%
for the cast aluminum, 66% for the brazed aluminum tubular, and 61% for the nylon composite;
which indicates the significance of manifold mass on life cycle energy. The solid waste profile
had a different distribution across the life cycle. The use phase solid waste originating from the
gasoline fuel cycle contributed only a small portion of the total solid waste. The cast aluminum
manifold generated the least life cycle solid waste, 218 kg per manifold, whereas the brazed
aluminum tubular and nylon composite manifolds generated comparable quantities of 418 kg and
391 kg, respectively. Red mud generated during alumina production accounted for 70% of the
total life cycle solid waste for the brazed tubular manifold while the nylon component of auto
shredder residue was responsible for 53% of the total waste for the nylon composite manifold.
The life cycle inventory analysis provides a comprehensive set of data to support the
environmental analysis of the manifold system. Life cycle inventory analysis results were
interpreted with respect to Ford internal environmental policies, guidelines, and goals as well as
external environmental requirements such as existing and proposed government policies and
regulations. The multicriteria requirements matrices were useful in identifying and recording
both regulatory and non-regulatory environmental requirements. No specific Ford policy states
that the total life cycle environmental burdens for each automotive part and component should be
minimized. Rather different policies and guidelines address discrete stages of the life cycle.
Ford and other OEM's set vehicle weight targets which guide individual part and component
development. The life cycle energy results indicated that manifold weight accounted for between
61% and 74% of the manifold life cycle energy. Consequently, weight targets set by
manufacturers for vehicles and vehicle subsystems have a strong impact on life cycle energy for
an individual part or component.
57
-------
Corporate Average Fuel Economy (CAFE) is an important regulatory driver influencing
vehicle fuel economy targets and weight targets. CAFE standards for passenger cars have been
stagnant over the last decade [57] and new car corporate average fuel economy has followed a
similar trend. In addition, there is a very weak cost driver for pushing vehicle demand toward
more fuel efficient vehicles. On the other hand, pressures to reduce manufacturing and material
production energies are primarily economic.
Both internal and external environmental requirements emphasize reduction of post-
consumer solid waste to a greater extent than waste generated in other life cycle phases. For
example, European guidelines provide specific targets for the reduction of post-consumer solid
waste disposed in a landfill. Similar measures for material production and manufacturing stages
do not exist. Consequently, from a business perspective it is may appear beneficial to reduce
post consumer waste which is governed by external requirements rather than reduce material
production waste which is not affected by a specific waste policy. Again economic incentives
exist to reduce manufacturing wastes.
The life cycle cost analysis was useful in identifying key cost drivers influencing the
economic success of each design alternative. Costs can be organized into current and potential
(future) manufacturing costs borne by Ford, customer costs, end-of-life management costs, and
externality costs associated with each life cycle phase. The nylon composite manifold had the
highest estimated manufacturing costs which were about $10 greater than the two aluminum
manifold designs. The stainless steel EGR tube only required for the nylon composite manifold
accounted for this differential cost. However, the use phase gasoline costs to the customer over
the lifetime of the vehicle, however, was least for the composite manifold. The gasoline costs
associated with the composite and the aluminum brazed tubular manifolds were about $6 and $5
less, respectively, than the cast aluminum manifold. The gasoline costs are much more
significant in Germany and have a greater influence on vehicle purchasing decisions. As
indicated previously, gasoline costs in the U.S. are a relatively weak economic driver for
reducing energy consumption in the use phase.
Under take back legislation in Europe the OEM will incur the end-of-life costs. In this case,
end-of-life credits resulting from the net salvage value of recycled manifolds would benefit Ford
directly. Credits of $4.10 for the cast aluminum manifold and $2.30 for the brazed aluminum
tubular manifold would accrue to the OEM. The salvage value of the brass and stainless steel
associated with the nylon composite manifold offset waste disposal costs of glass-reinforced
nylon. Otherwise, the nylon composite manifold would result in greater costs to Ford under the
current European end-of-life management infrastructure.
A total of 20 performance requirements were used to evaluate each design alternative. Each
of the three manifolds satisfied basic performance requirements for manufacturing and vehicle
operation. Meeting basic performance requirements is an essential first step by which feasible
candidates are screened for further design analysis. Particular emphasis was given to several
manufacturability performance criteria which have a strong effect on manufacturing costs.
Several performance requirements are also interconnected with environmental requirements.
For example, durability can have a major impact on the environmental profile of a product.
Each manifold met 120K durability requirements but a longer useful life could facilitate manifold
58
-------
reuse as a replacement part. Many manufacturability requirements influence scrap rates which
also have a direct impact on environmental burdens.
This project revealed several organizational factors affecting the successful implementation of
life cycle design projects. Comprehensive evaluation of the total life cycle system necessitated
the participation of a cross functional team with a broad range of expertise. This project educated
many members of the team on the life cycle design methodology. The multi objective analysis
served to introduce the project team to the full spectrum of issues constraining the manifold
system. It was recognized due to the model complexity and data intensity that a comprehensive
evaluation should not be performed in the final stages of design but rather it would be performed
in the planning stages. As a planning tool for product development life cycle design can highlight
opportunities for improvement by identifying major environmental burdens, costs, regulatory and
policy issues to target. As a planning tool alternative materials and design strategies can be
explored. The project team also discussed the challenge of predicting trends in future end-of-life
management infrastructure that could impact a new vehicle that may not be retired until ten years
later. This time lag introduced a significant level of uncertainty into the design analysis process.
Several members of the project team advocated characterizing the different environmental
burdens into a single score to facilitate the use of the life cycle assessment methodology by
design engineers. A variety of techniques were investigated including translating the
environmental burdens into monetary costs, applying the critical volume approach,
environmental theme method and other impact assessment methods[58] . None of the
approaches were found to be acceptable to the project team due to limitations in evaluating
parameters needed for these different models. A single score approach may also limit the design
team from exploring how major environmental burdens are distributed across the product life
cycle. In addition, the direct relationship between these burdens, and cost, performance,
regulatory and policy factors can be more clearly understood if burdens are itemized.
Integration of performance, cost and environmental requirements to form an overall design
decision matrix was studied. Emphasis of the project team was more on framing the design deci-
sion rather than on actually recommending a preferred manifold design. Each manifold design
had a superior set of attributes. The project team favored the aluminum brazed tubular and nylon
composite manifolds over the sand cast aluminum manifold due to their weight differentials. For
this manifold application, the aluminum tubular design offered significant manufacturing cost
savings relative to the nylon composite design. This may have overshadowed the slightly better
life cycle energy performance of the nylon composite manifold. An important benefit of the life
cycle design framework is that it clarifies the complex set of factors that influence the likelihood
for success of a business decision. Tradeoffs are made explicit and interrelationships between
design objectives are made apparent.
An air intake manifold is only one component of the powertrain system which is part of the
total vehicle system. Consequently, it makes only a relatively small contribution to the overall
environmental burdens of an automobile. More widespread application of the life cycle design
methodology to other vehicle components and systems, however, can result in substantial oppor-
tunities for improvement. This project served to demonstrate the value of life cycle systems
thinking in design and will hopefully be extended to other parts and components, as well as
higher level vehicle systems in the future.
59
-------
References
1. Keoleian, Gregory A., and Dan Menerey. Life Cycle Design Guidance Manual:
Environmental Requirements and the Product System. US EPA, Office of Research and
Development, Risk Reduction Engineering Laboratory, Cincinnati, OH, 1993.
2. . Sustainable development by design: Review of life cycle design and related
approaches. Journal of the Air and Waste Management Association 44 (5): 645-668
(1994).
3. Keoleian, Gregory A., Jonathan Koch, and Dan Menerey. Life Cycle Design Framework and
Demonstration Projects: Profiles ofAT&TandAlliedSignal. US Environmental
Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH
EPA/600/R-95/107, 1995.
4. Keoleian, Gregory A., Werner J. Glantschnig, and William McCann. Life cycle design:
AT&T demonstration project. IEEE International Symposium on Electronics and the
Environment, San Francisco, 2 May. Piscataway, NJ: Institute of Electrical and
Electronic Engineers, 1994.
5. Keoleian, Gregory A. Pollution prevention through life cycle design. Pollution Prevention
Handbook, ed. Harry M. Freeman, 253-292. New York: McGraw-Hill, 1995.
6. Eyerer, P., M. Schuckert, and Th Dekorsy. Life Cycle Analysis of Automotive Air Intake
Manifolds of Aluminum and PA 6.6 GF 35. Institut fur Kunststoffpriifung und
Kunststoffkunde, Universitat Stuttgart, Stuttgart, Germany, 1992.
7. Bustamalti, Tony. Deeco Industries, personal communication, January 1996.
8. Steel Recycling Institute. Recycling Scrapped Automobiles. Pittsburgh, PA: SRI, 1994.
9. Martchek, Ken. Alcoa, personal communication, August 1995.
10. Franklin Associates. Appendix A: Energy Requirements and Environmental Emissions for
Fuel Consumption. Franklin Associates, Prairie Village, KS, 1992.
11. Naitove, Matthew H. Blow molding. Plastics Technology (Aug): 45-47 (1994).
12. Kalpakjian, Serope. Manufacturing Engineering and Technology. Reading, MA: Addison-
Wesley, 1995.
13. Dhillon, B. S. Life Cycle Costing: Techniques, Models, and Applications. New York:
Gordon and Breach, 1989.
14. White, Allen L., Monica Becker, and James Goldstein. Total Cost Assessment: Accelerating
Industrial Pollution Prevention Through Innovative Project Financial Analysis. US
EPA, Office of Pollution Prevention and Toxics, Washington, DC, 1992.
60
-------
15. Material Production Inventory Data for Glass-Reinforced Nylon (PA 6.6 GF33) and Brass
(UNS 36000). David Doyen, and Bill Haaf. Dupont, Wilmington, DE, 1995.
16. Martchek, Kenneth J., Eden S. Fisher, and Richard A. Schultz. The total environmental
potential of aluminum in automobiles. SAE Total Life Cycle Conference, Vienna, 16
October. Warrendale, PA: Society of Automotive Engineers, Technical Paper 951834,
1995.
17. Alcoa. Environmental Life Cycle Considerations of Aluminum in Automotive Structures.
Aluminum Company of America, Automotive Structures, Southfield, MI Environmental
Papers 1-4, 1994.
18. SFOEFL. Ecobalance of Packaging Materials State of 1990. Swiss Federal Office of
Environment, Forests, and Landscape, Berne, Switzerland, 1991.
19. IISI. Competition Between Steel and Aluminum for the Passenger Car. International Iron
and Steel Institute, Brussels, 1994.
20. Sullivan, J. L., and J. Hu. Life cycle energy analysis for automobiles. SAE Total Life Cycle
Conference, Vienna, 16 October. Warrendale, PA: Society of Automotive Engineers,
SAE Paper 951829, 1995.
21. Titchell, Ian. Cost and energy savings in aluminum foundries. The Foundryman (Apr): 105-
108 (1992).
22. Hydro Aluminum. Aluminum: Today's Automotive Solution. Livonia, MI, 1994.
23. Arthur D. Little. Status and Evolution of the US Aluminum Industry: Implications for
Natural Gas. Gas Research Institute, Chicago, IL GRI-88/0025, 1988.
24. Scott, W. D., C. E. Bates, and R. H. James. Chemical emissions from foundry molds. AFS
Transactions 98: 203-208 (1977).
25. McKinley, M. D., I. A. Jefcoat, and W. J. /Frederick, C. Herz. Air emissions from foundries:
A current survey of literature, suppliers and foundrymen. AFS Transactions 105: 979-
990(1993).
26. Schwartz, M. Brazing. London: Chapman & Hall, 1995.
27. Humpston, Giles, and David M. Jacobson. Principles of Soldering and Brazing. Materials
Park, OH: ASM International, 1993.
28. U.S. EPA. Highway Vehicle Emission Estimates II. US Environmental Protection Agency,
Office of Mobile Sources, Washington, DC, 1995.
29. Osterberg, Dick. Huron Valley Steel, personal communication, December 1995.
30. American Metal Market. American Metals Market, July 19, p. 6 (1996).
61
-------
31. Lockhart, Jim. American Petroleum Association. Personal communication, April 1995.
32. APC. Economics of Recovery and Recycling. American Plastics Council, 1994.
33. NSWMA. National Solid Waste Management Association, personal communication, May
1995.
34. Franklin Associates. Material Production Database. Franklin Associates, Prairie Village,
KS, 1995.
35. Jensby, Paul. Chicago Extruded Metals, January 1996.
36. Pacific Environmental Services. AP-42 Section 12.8 Background Report: Secondary
Aluminum. US Environmental Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC, 1995.
37. . AP-42 Section 12.1 Background Report: Primary Aluminum. US Environmental
Protection Agency, Office of Air Quality Planning and Standards, Research Triangle
Park,NC, 1995.
38. Harnisch, Jochen, Reinhard Borchers, and Peter Fabian. Estimation of tropospheric trends
(1980-1995) for CF4 and C2Fg from stratospheric data. Proceedings of Pollution of the
Troposphere and Stratosphere, 1995.
39. Czadzeck, Jerry. Ford Motor Company, personal communication, August 1995.
40. Ogando, Joseph. Drive retrofits slash energy bills. Plastics Technology (Jan): 15-17 (1
1995).
41. Rugg, Michael. Inducto Heat, personal communication, January 1996.
42. Tenzek, Tony. Ajex Magnetothermic Corp., personal communication, January 1996.
43. Bosch. Automotive Handbook. Stuttgart, Germany: Bosch, 1993.
44. Ginzburg, Vladimir B. Steel-Rolling Technology. New York: Marcel Dekker, 1989.
45. Matsukawa, T., and Y. Yoshibe. Recent Developments in Reheating Furnaces. Nippon Steel
Technical Report No. 20, 1982.
46. Roberts, William L. Hot Rolling of Steel. New York: Marcel Dekker, 1983.
47. Varsity Ford. Varsity Ford, personal communication, August 1995.
48. Gene Butman Ford. Gene Butman Ford, personal communication, August 1995.
49. El A. International Energy Annual., 1993.
50. D&R Auto Parts, personal communication, May 1995.
62
-------
51. AAMA. AAMA Motor Vehicle Facts & Figures. American Automobile Manufacturers
Association, Detroit, MI, 1994.
52. Gottselig, Bernd. Personal Communication, June 7. Detroit, MI: Ford Motor Company,
1996.
53. Keoleian, Gregory A., and Jeff S. McDaniel. Life Cycle Design of Instrument Panels: A
Common Sense Approach. SAE International Congress and Exposition, Detroit,
Michigan, 24 February. Warrendale, PA: SAE International, Technical Paper 970695,
1997.
54. Ford Information. Detroit, MI: Ford Motor Company, 2 1996.
55. McDaniel, Jeff. Application of Life Cycle Assessment and Design Tools to Instrument
Panels: Analysis for Common Sense Initiative Pilot Project. Masters Thesis. Ann
Arbor, MI: University of Michigan, 1996.
56. Keoleian, Gregory A. The application of life cycle assessment to design. Journal of Cleaner
Production 1 (3-4): 143-149 (1994).
57. Keoleian, G. W., K. Kar, M. Manion, and J. Bulkley. Industrial Ecology of the Automobile:
A Life Cycle Perspective. SAE, 1997.
58. Baumann, Henrikke, and Tomas Rydberg. Life cycle assessment: A comparison of three
methods for impact analysis and evaluation. Journal of Cleaner Production 2 (1): 13-20
(1994).
63
-------
Appendix A
Life Cycle Stage : Material Production
Aluminum Composite Conditions /Assumptions
Metrics
Energy, primary (MJ
Waste
Solid (kg/IM)
Sand cast
/IMIJ.17E+02
4.04E-01
Air emissions (kg / IM)
CO2
Particulates
NOx
SO2
CO
CH4
NMHC
FC (CF4+C2F6)
HCI
Halogenated HC
Heavy metals
Fluorine
H2
5.70E+00
2.34E-03
2.35E-02
1.15E-02
1 .45E-03
1 .70E-02
5.24E-05
8.52E-03
4.91 E-03
Water effluents (kg/IM)
Dissolved solids
BOD
COD
Suspended solids
Acids
Heavy metals
Tar/oil
Fluorides
Chlorides
Nitrates
Water consumption (1 /
7.21 E-04
1 .97E-04
M) 1.04E+01
Multi-tubebrazed
2.36E+02
3.34E+00
1 .61 E+01
2.20E-02
3.96E-02
1 .03E-01
1 .83E-02
6.49E-03
4.08E-03
5.65E-04
3.24E-03
1 .87E-03
2.74E-03
1 .37E-03
3.39E-02
1 .40E-05
4.13E-03
1.12E-03
2.15E-06
1 .08E-06
1 .63E+01
Contour
2.56E+02
9.31 E-01
8.35E+00
1 .53E-02
3.54E-02
5.96E-02
2.26E-02
8.17E-02
5.21 E-03
4.51 E-04
3.07E-06
3.45E-07
1 .20E-03
7.01 E-01
2.63E-03
2.55E-02
1.16E-01
2.66E-03
3.29E-07
1 .54E-03
5.10E-02
1 .64E-05
2.02E+01
MASS OF MATERIALS PROCESSED & MATERIAL COMPOSITION:
Sand cast aluminum manifold:
mass of secondary aluminum ingot = 6.552 kg
Multi-tube brazed aluminum manifold:
mass of primary aluminum ingot = 1 .076 kg
mass of secondary aluminum ingot = 2.496 kg
Composite manifold:
mass of virgin nylon processed = 2.129 kg
mass of stainless steel scrap processed = 0.4715 kg
stainless steel is produced in electric arc furnace that use 100% scrap
UNS C36000 brass is produced from 99% scrap and 1% primary ingot
mass of primary brass ingot processed = 0.00329 kg
INVENTORY DATA
Aluminum manifold
Energy
Avg. energy density for sec. Al = 17.9 MJ / kg [Kar & Keoleian, 1996]
Avg. energy density for prim. Al = 177.9 MJ / kg [Kar & Keoleian, 1996]
Waste
most data are obtained from [Eyerer et al., 1992] for European condition
the Stuttgart data for European condition are representative of typical
US conditions [Kar & Keoleian, 1996]
Average red mud of 2.63 kg / kg for primary aluminum production is
incorporated into solid waste [Martchek, 1995][Eyerer et al., 1992]
Following data are obtained from other sources:
- CO2 [Alcoa, 1994], FC [Harnisch & Borchers, 1995]
- SO2, NOx - alumina production [Martchek, 1995],
- solid waste, water consumption [Martchek, 1995]
Composite manifold
nylon, glass fiber and brass data are obtained from [DuPont, 1995]
stainless steel data are obtained from [Franklin, 1996]
A.1
-------
Appendix A
Life cycle stage : Manufacturing
Aluminum Composite Conditions /Assumptions
Metrics
Energy (MJ/IM)
electricity (utility)
natural gas (comb)
Prim, energy, elec
Prim, energy, Natlgas
Prim, energy, TOTAI
Sand cast
2.97E+02
2.97E+02
3.34E+02
3.34E+02
Waste (process+elec)
Solid (kg/IM)
- processing scrap 1
- electricity/natl. gas
TOTAL Solid
ossHOE+00
1 .86E-01
1 .28E+00
Air emissions (kg / IM)
Particulates
CO2
NOx
SO2
CO
CH4
NMHC
Aldehydes
Kerosene
Ammonia
Lead
H2S
HCN
Acrolyn
Aromatic amines
Benzene
Toluene
Xylene
Napthalene
Phenol
1 .24E-03
1 76E+01
2.74E-01
1 .69E-03
4.71 E-02
2.12E-01
1 .70E-05
1 .76E-05
2.24E-04
3.17E-05
5.67E-07
5.67E-06
1 .64E-04
1 .70E-05
1.13E-05
5.67E-06
3.51 E-05
Water effluents (kg/IM)
Dissolved solids
Suspended solids
BOD
COD
Acids
Oil
Metal ions
Sulfides
Phenolics
Iron
2.49E-01
Multi-tube
1 .25E+02
2.89E+00
1 .22E+02
9.02E+00
1 .38E+02
1 .47E+02
4.32E-01
1 .37E-01
5.69E-01
2.34E-03
6.94E+00
1 .02E-01
5.60E-03
1 .76E-02
3.52E-06
7.70E-02
6.58E-06
1 .70E-07
6.79E-06
3.29E-09
8.09E-05
1.15E-05
2.05E-07
2.05E-06
5.94E-05
6.14E-06
4.10E-06
2.05E-06
1 .27E-05
9.00E-02
6.73E-07
4.39E-07
1 .24E-06
2.23E-07
2.23E-07
1.11E-07
4.19E-04
1.11E-07
4.13E-04
3.40E+01
3.32E+01
7.57E-01
1 .04E+02
8.51 E-01
1 .05E+02
9.52E-03
7.97E-01
8.07E-01
2.17E-02
6.61 E+00
3. 11 E-02
5.74E-02
6.93E-03
4.05E-05
5.94E-03
5.05E-06
1 .96E-06
5.05E-06
3.78E-08
2.65E-03
7.73E-06
5.05E-06
1 .42E-05
2.56E-06
2.56E-06
1 .28E-06
4.81 E-03
1 .28E-06
4.75E-03
Sand cast manifold
energy density for sand casting = 39.36 MJ/kg [Titchell, 1992]
natural gas fired furnace for melting and holding [Titchell, 1992]
efficiency factor for natural gas = 0.89 [Franklin, 1992]
primary energy equivalent = Energy for sand casting / 0.89
recycling efficiency of sand, salt slag and scrap = 95%
energy and waste for the production of green sand not included
total waste = energy (natl. gas) waste + process waste
energy wastes are obtained from [Frankiln, 1992]
Multi-tube brazed manifold
energy(natl. gas) density for sand casting = 39.36 MJ/kg [Titchell, 1992]
energy (primary) density for extruding aluminum = 16.76 MJ / kg
M(aluminum cast) = 2.731 kg, M(aluminum extruded) = 1 .537 kg
E (electricity) for brazing = 1 .9E-03 MJ/IM
energy for brazing is obtained using engg. model
total waste = energy(natl. gas+electricity) waste + process waste
energy wastes are obtained from [Franklin, 1992, 1995]
95% internal recycling of sand, salt slag and scrap
Composite manifold
Nylon
M(process)=2.129kg,M(virgin resin)=2.073kg,M(recycled scrap)=0.056kg
inductive melting of tin-bismuth alloy, 250 kW, 1 .5 min. cycle time
E(electrical) for melting furnace = 22.5 MJ / IM
Average injection molding energy density = 4.54 MJ / kg
E(total electrical) = 4.54*2.129+22.5 = 32.165 MJ
Energy for transfer by robot, washing and insertion is neglected
95% of in-house scrap recycled, 55 solid waste
Brass
M(billet extruded)=0.329 kg
E(melting) = 1 .18 MJ / kg (induction furnace)
E(extrusion)=0.32 MJ / kg using engg. model, E(cutting) = 0.08745 MJ / IM
E(total) = 0.581 MJ/IM
95% of in-house scrap recycled, 5% solid waste
Stainless steel (SS)
tubes and fasteners are extruded, brackets are rolled and stamped
M(extruded) = 0.22425 kg, M(rolled/stamped) = 0.24725 kg
E(extrusion) = 0.53 MJ/kg(electricity)+1 .27 MJ/kg(natl. gas), engg. model
E(rolling) = 0.177 MJ/kg (electricity)+1 .91 MJ/kg (natl. gas), engg. model
E(stamping) =1.16 MJ/kg (electricity), [MSI, 1994]
E(total electricity) =0.45 MJ/IM, E(total natl. gas) = 0.757 MJ/IM
95% of in-house scrap recycled, 5% solid waste
Total composite manifold
solid waste = product waste + waste associated with energy production
energy production wastes are obtained from [Franklin, 1992, 1995]
A.2
-------
Appendix A
Life Cycle Stage : Use
Aluminum Composite Conditions /Assumptions
Mass (kg /I M)
Energy (MJ/LIM)
Waste
Solid (kg/LIM)
Sand cast
6.5kg
1 .34E+03
1 .37E-01
Air emissions (kg / LIM)
CO2
CO
CH4
NMHC
NOx
Particulates
SO2
Aldehydes
Ammonia
Lead
8.38E+01
3.37E-01
2.56E-01
1 .64E-01
1 .60E-02
1.21E-01
1 .52E-03
1 .52E-03
1.14E-05
Water effluents (kg /LIM)
BOD
COD
Suspeneded solids
Dissolved solids
Metal ion
Oil
Phenol
Sulfide
Acid
1 .52E-03
4.19E-03
2.29E-03
3.08E-01
3.81 E-04
7.62E-04
3.81 E-04
3.81 E-04
7.62E-04
Multi-tube
3.62 kg
7.45E+02
7.64E-02
4.67E+01
1 .92E-01
1 .43E-01
9.14E-02
8.92E-03
6.73E-02
8.49E-04
8.49E-04
6.37E-06
8.49E-04
2.34E-03
1 .27E-03
1 .72E-01
2.12E-04
4.25E-04
2.12E-04
2.12E-04
4.25E-04
2.74 kg
5.64E+02
5.78E-02
3.53E+01
1 .42E-01
1 .08E-01
6.91 E-02
6.74E-03
5.09E-02
6.42E-04
6.42E-04
4.82E-06
6.42E-04
1 .77E-03
9.63E-04
1 .30E-01
1 .61 E-04
3.21 E-04
1 .61 E-04
1 .61 E-04
3.21 E-04
life of intake manifold (LIM) is assumed to be 150,000 miles
vehicle type = Contour, 1995
Enerqy
energy is obtained from fuel economy to weight correlation
test eight of vehicle = 3250 Ib = 1471 kg
fuel economy = 31 .5 mpg
10% weight reduction = 4% fuel economy reduction
total energy = combustion + precombustion energy
Waste
tail pipe combustion emissions are obtained from US EPA's
National Vehicle and Fuel Emissions Laboratory, Ann Arbor under the
Freedom of Information Act
total waste = (combustion+precombustion) waste
precombustion wastes are obtained from [Franklin, 1995]
A.3
-------
Appendix A
Life Cycle Stage : Retirement
Aluminum Composite Conditions /Assumptions
Mass (kg /I M)
- recycled into manifolc
Sand cast
6.18E+00
- recycled into other products
- recycled to manifold qs ingdtBE+OO
- recycled to manifold as scrap
- disposed to landfill
3.25E-01
Shredders (.097 MJ/kg)
Energy, E (MJ / IM)
Separation
Energy, E (MJ / IM)
- aluminum
- brass
- stainless steel
-ASR
E(Sepn., MJ / IM)
E(Shred+Sepn) (MJ/IM)
TOTAL electricity (MJ /
TOTAL electricity
6.31 E-01
6.18E-01
6.18E-01
1 .25E+00
M) 1.25E+00
3.90E+00
converted to primary energy
Transportation
- ASR-landfill, 200 miles
- metal recycled, 300 m
TOTAL diesel energy
TOTAL diesel energy
1 .47E-01
les4.19E+00
4.33E+00
5.16E+00
converted to primary energy
TOTAL primary ener
Waste (kg /IM)
Solid (kg/IM)
gy 9.06E+00
3.55E-01
Air emissions (kg / IM)
CO2
CO
NMHC
CH4
Kerosene
NOx
Particulates
SO2
Aldehydes
Ammonia
Lead
5.90E-01
3.22E-03
1 .47E-03
1 .52E-06
7.36E-08
4.44E-03
1 .28E-03
3.08E-03
7.96E-05
5.60E-06
4.19E-08
Multi-tube
2.58E+00
8.62E-01
2.50E+00
8.10E-02
1 .81 E-01
3.51 E-01
2.58E-01
2.58E-01
6.09E-01
6.09E-01
1 .90E+00
8.18E-02
1 .75E+00
1 .83E+00
2.18E+00
4.08E+00
1 .95E-01
2.65E-01
1 .38E-03
6.33E-04
7.43E-07
3.59E-08
1 .95E-03
5.92E-04
1 .44E-03
3.36E-05
2.38E-06
1 .78E-08
7.32E-01
7.32E-01
2.10E+00
2.66E-01
3.69E-02
4.23E-02
6.83E-02
1 .48E-01
4.13E-01
4.13E-01
1 .29E+00
9.51 E-01
4.96E-01
1 .45E+00
1 .72E+00
3.01 E+00
2.11E+00
1 .96E-01
1 .08E-03
4.89E-04
5.04E-07
2.44E-08
1 .48E-03
4.24E-04
1 .02E-03
2.66E-05
1 .87E-06
1 .40E-08
Recvclinq conditions
Sand cast aluminum manifold
95% of manifold recycled, 5% disposed tp landfill
6.175kg aluminum from manifold recycled into the manifold
0.377 kg of secondary ingot is supplied from other products
Multi-tube brazed aluminum manifold
95% of manifold recycled, 5% disposed tp landfill
3.439 kg aluminum from manifold recycled
2.577 kg of aluminum recycled back into the manifold
0.862 kg of aluminum leaves the manifold system
Composite manifold
100% nylon appears as ASR and is disposed to landfill
95% of brass and stainless steel recycled, rest 5% disposed to landfill
mass of brass recycled = 0.247 kg
mass of stainless steel recycled = 0.39 kg
recycling metrics for brass and stainless steel also include the other
scrap recycled
Energy
Shredding energy obtained from Texas Shredder
Energy = 0.097 MJ / kg
Separtion energy obtained from Huron Valley Steel
Energy (ASR) = 0.033 MJ / kg
Energy (aluminum) = 0.1 MJ / kg
Brass and stainless steel requires additional energy
to separate
Additional energy for SS = 2.53 kJ / kg
Additional energy for brass = 41 .85 kJ / kg
Energy (SS) = 0.10253 MJ / kg
Energy (brass) = 0.14185 MJ /kg
Shredders andd separators are elctricity operated
Transportation is through diesel trucks
Energy = 2.05 MJ /ton-mile
All energies are converted to primary enrgy by
dividing with appropriate efficiency factors
Efficiency factor (elctricity) = 0.32
Efficiency factor for diesel = 0.84
Waste
Electricity and diesel waste are obtained from
Franklin database [1992]
95% of metals are assumed to be recovered and 5%
are disposed to landfill
A.4
-------
Appendix A
Water effluents (kg /IM)
BOD
COD
Suspended solids
Dissolved solids
Metal ion
Oil
Phenols
Sulfides
Acids
Iron
5.60E-06
1 .54E-05
8.38E-06
1.17E-03
1 .40E-06
2.79E-06
1 .40E-06
1 .82E-04
9.62E-08
1 .78E-04
2.38E-06
6.53E-06
3.56E-06
4.98E-04
5.94E-07
1.19E-06
5.94E-07
8.89E-05
4.69E-08
8.71 E-05
1 .87E-06
5.14E-06
2.80E-06
3.90E-04
4.67E-07
9.33E-07
4.67E-07
6.04E-05
3.19E-08
5.91 E-05
A.5
-------
Appendix A
CUMULATIVE INVENTORY
ALUMINUM COMPOSITE
Sand cast Multi-tube Lost core
ENERGY, MJ / IM
Matl. processing
Manufacturing
Use
Retirement
TOTAL
SOLID WASTE, kg/ IM
Matl. processing
Manufacturing
Use
Retirement
TOTAL
CO2, kg / IM
Matl. processing
Manufacturing
Use
Retirement
TOTAL
Total Life Cycle
Air emissions, kg / IM
CO2
CO
NMHC
NOx
SO2
CH4
PM-10
Water effluents, kg / IM
Dissolved solids
Suspended solids
BOD
COD
Acids
Oil
Heavy metals
Cost, $ / IM
Material cost
Manufacturing cost
Gasoline cost
End-of-life cost
Scrap value
TOTAL cost
117.28
334.21
1337.39
9.06
1797.94
0.40
1.28
0.14
0.36
2.18
5.70
17.60
83.80
0.59
107.69
107.69
0.39
0.47
0.47
0.14
0.02
0.02
5.58E-01
2.30E-03
1 .53E-03
4.21 E-03
1 .48E-03
7.65E-04
5.79E-04
12.38
26.28
9.82
1.81
-5.93
44.36
236.10
146.54
744.77
4.08
1131.49
3.34
0.57
0.08
0.20
4.18
16.13
6.94
46.70
0.27
70.04
70.04
0.23
0.22
0.23
0.18
0.01
0.03
2.65E-01
1 .29E-03
2.22E-03
3.62E-02
4.55E-03
4.26E-04
1 .33E-03
7.15
33.65
5.47
1.00
-3.30
43.97
256.29
104.59
563.76
3.01
927.65
0.93
0.81
0.06
2.11
3.91
8.35
6.61
35.30
0.20
50.45
50.45
0.17
0.12
0.14
0.17
0.08
0.04
8.34E-01
1.17E-01
3.28E-03
2.73E-02
2.98E-03
3.24E-04
1 .63E-04
6.01
44.14
4.14
0.42
-0.68
54.03
A.6
-------
Appendix B. Life Cycle Design Framework
Primary elements of the life cycle design framework are (Keoleian, Koch, and Menerey 1995):
Product life cycle system
Goals
Principles
Life cycle management
Development process
Product Life Cycle System
Life cycle design and management requires an accurate definition of the product system, including
both spatial and temporal boundaries. The product system can be organized by life cycle stages and
product system components. Life cycle stages include materials production, manufacturing and assembly,
use and service, and end-of-life management as shown in Figure B-l.
r
Material Production
i r
Manufacturing
ir
Use
i r
End-of-Life Management
Figure B-1. Product Life Cycle System
Product, process and distribution components further characterize the product system for each life
cycle stage as shown in Figures B-2 and B-3. This organization in contrast to LCA convention can better
accommodate product and process design functions. The time frame for a design project ranges between
a short term horizon that may emphasize incremental improvements in the product system or a long range
view that explores next generation designs.
B.I
-------
Process Materials
Open loop
Recycle
Remanufacture
Reuse
Closed
loop
Labor
Energy
Product Materials
By-product
Primary Product
Waste
Open loop
Recycle
Remanufacture
Reuse
Waste
(gaseuus, liquid, solid)
Figure B-2. Flow Diagram Template for Life Cycle Subsystem
Process Materials
Process Materials
Product
Materials
materials & waste from
energy for operation
operation
Figure B-3. Distribution Component Flow Diagram
Goals
The broad goal of life cycle design is to design and management products that are ecologically and
economically sustainable. Necessary conditions for sustainability include: sustainable resource use
(conserve resources, minimize depletion of non-renewable resources, use sustainable practices for
managing renewable resources), pollution prevention, maintenance of ecosystem structure and function,
and environmental equity. All of these conditions are interrelated and highly complementary. Economic
sustainability requires that the product system meet basic cost, performance, legal and cultural criteria.
B.2
-------
The specific environmental goal of life cycle design is to minimize the aggregate life cycle
environmental burdens and impacts associated with a product system. Environmental burden include
resource inputs and waste outputs which can be classified into impact categories according to life cycle
impact assessment methods. (Guinee et al. 1993; SETAC 1993a; Weitz and Warren 1993) General
impact categories include resource depletion and ecological and human health effects. No universally
accepted method for aggregating impacts is available.
Principles
There are three main themes for guiding environmental improvement of product systems in life
cycle design: systems analysis of the product life cycle; multicriteria analysis of environmental,
performance, cost, and legal requirements and issues (see specification of requirements section); and
multistakeholder participation and cross-functional teamwork throughout the design process. The
following principles relating to each of these themes have been derived from our empirical research.
Many of these principles of life cycle design are already considered best design practice.
Systems Analysis
Systems analysis focuses on understanding the behavior of individual components of a system and the
relationships between the collection of components that constitute the entire system. In addition the
relationships between the system under study and higher order/larger scale systems should be analyzed.
Both time and space dimensions must be addressed.
1. The product life cycle is a logical system for product management and design because it encompasses
the total physical flow of product materials through the economy.
2. Successful design initiatives should establish clear system boundaries for analysis. The scope of a
design activity can be restricted to smaller system boundaries such as individual life cycle stages or
process steps, but this will inherently limit the opportunities for improvement.
3. Studying the relationship between product materials and related process/distribution components -
systems that transform/transport the product material along the life cycle - is critical towards
improving the product system design.
4. The breadth of system boundaries depends on the vision of the organization; less responsible firms do
not address environmental issues much beyond the manufacturing domain whereas more ecologically
responsible corporations will address the full product life cycle. The broader perspective may not yield
immediate economic benefits but should lead to long term success.
Multiobjective Analysis
A successful design will satisfy multiple objectives including performance, cost, legal and
environmental requirements. Many design requirements will overlap and reinforce each other while others
conflict and limit design possibilities.
1. Specifying design requirements for both guiding improvement and evaluating alternatives is a critical to
efficient product design and management. Clearly defined requirements that are both internal and
external to an organization reduce uncertainty in decision making.
2. Understanding the interactions and conflicts between performance, cost, legal, and environmental
requirements serves to highlight opportunities as well as vulnerabilities. In some cases,
environmentally preferable designs may not be adopted because they do not show a direct cost
advantage to the manufacturer, are not supported by regulations, or do not demonstrate performance
advantages.
3. Unless more specific guidance can be offered through well-established corporate environmental
policies and goals or national environmental policies or goals design teams must rely on. their personal
knowledge and experience to make complex tradeoffs. Tradeoffs often exist among environmental
B.3
-------
criteria, such as minimizing waste, energy and emissions as well as between environmental, cost,
performance and legal criteria. Judgment is ultimately required to weight and rank criteria.
Multistakeholder Participation
The stakeholders that control the life cycle of a product can be considered part of a virtual
organization. Some stakeholders share a common goal for enhancing the overall economic success of the
product, while maximizing their own individual profit. Minimizing life cycle burdens, however, may not be
a priority. Identifying the actors that control the life cycle of a product and their interests is a first step in
achieving better life cycle management of a product.
1. Harmonizing the often diverse interests of stakeholders (suppliers, manufacturers, customers, waste
managers, regulators, investors) into a product design that is technically, economically, socially and
ecologically feasible/optimal is a fundamental challenge of design.
2. Partnerships are helpful in implementing changes that affect more than one stage or activity in the life
cycle.
3. Initiatives to reduce life cycle environmental burdens will be limited in their effectiveness by the
degree to which stakeholders recognize this a common goal for product design and management.
Life Cycle Management
Life cycle management includes all decisions and actions taken by multiple stakeholders which
ultimately determine the environmental profile and sustainability of the product system. Key stakeholders
are users and the public, policy makers/regulators, material and waste processors, suppliers,
manufacturers, investors/shareholders, the service industry, and insurers. The design and management
decisions made by the manufacturer of the end-use product may have the greatest influence over the life
cycle environmental profile of a product system. It is useful to distinguish between environmental
management by internal and external stakeholders. A major challenge for product manufacturers is
responding to the diverse interests of external stakeholder groups.
The environmental management system (EMS) within a corporation is the organizations structure
of responsibilities, policies, practices, and resources for addressing environmental issues. Several
voluntary EMS standards and guidelines have been developed (BS7750, ISO 14,001, GEMI). Although
EMS activities have emphasized proactive measures in addition to regulatory compliance, traditionally
these systems have only addressed the manufacturing domain of the corporation (Marguglio 1991) and did
not cover end-of-life management or material acquisition processing stages.
Life Cycle Development Process
The product development process varies widely depending on the type of product and company
and the design management organization within a company. In general, however, most development
processes incorporate the key activities shown in Figure B-4. For life cycle design this process takes
place within the context of sustainable development and life cycle management.
B.4
-------
Sustainable Development
-i-
Feedback for next
generation design
improvement and
strategic planning
| Life Cycle Management |
NeedsAnalysis
Requirements
Design Solutions
Implementation
Evaluation occurs
throughout the
development process
Consequences
social welfare
resource deoletion
ecosystem & human
health effects
Figure B-4. Life Cycle Development Process
The life cycle design framework emphasizes three important design activities: specifying
requirements to guide design improvements, selecting strategies for reducing environmental burden, and
evaluating design alternatives.
The specification of requirements to guide design and management decisions is a fundamental
activity for any design initiative (Gause and Weinberg 1989). Techniques for assisting development teams
in establishing environmental design criteria have not been widely implemented. A multilayer requirements
matrix has been developed as a tool to identify, organize, and evaluate environmental, cost, performance,
legal and cultural design criteria (Keoleian and Menerey 1993; Keoleian and Menerey 1994; Keoleian,
Koch, and Menerey 1995). DFX or Design for X strategies (Gatenby and Foo 1990) such as design for
recyclability, disassembly, and remanufacturability have been more widely promoted. Life cycle
assessment tools for evaluating product systems (Vigon et al. 1993; Heijungs et al. 1992; Guinee, de Haes,
and Huppes 1993; SETAC 1993b; SETAC 1991) have probably received the most attention in the last two
decades. The practical application of LCA tools by product development engineers, however, is limited
(Keoleian and Menerey 1994; White and Shapiro 1993). It is the refinement and application of these three
types of design and analysis tools that will lead to the most effective implementation of life cycle design
and DFE.
Specification of Requirements
Specification of requirements is one of the most critical design functions. Requirements guide
designers in translating needs and environmental objectives into successful designs. Environmental
requirements should focus on minimizing natural resource consumption, energy consumption, waste
generation, and human health risks as well as promoting the sustainability of ecosystems. A primary tool
of life cycle design is the multicriteria matrices for specifying requirements shown in Figure D-5. Other
tools for guiding designers include design checklists and guidelines.
The matrices shown in Figure B-5 allow product development teams to study the interactions and
tradeoffs between environmental, cost, performance and legal requirements. Each matrix is organized by
life cycle stages and product system components. Elements can then be described and tracked in as much
detail as necessary. Requirements can include qualitative criteria as well as quantitative metrics.
B.5
-------
f Legal
Product
INPUTS
Process
OUTPUTS
Distribution
Material
Production
Manufacture
SAssembly
Use&
Service
mental |~|
End-of-Life
Managemer
Figure B-5. Multicriteria Requirements Matrix
Design Strategies
Selecting and synthesizing design strategies for meeting the full spectrum of requirements is a
major challenge of life cycle design and management. General strategies for fulfilling environmental
requirements are product oriented (product life extension, remanufacturability, adaptability, serviceability,
and reusability); material oriented (recycling, substitution, dematerialization); process oriented; and
distribution oriented (optimize transportation and packaging). An explanation of each strategy is provided
in The Life Cycle Design Guidance Manual (Keoleian and Menerey 1993).
Design Evaluation
Analysis and evaluation are required throughout the product development process as well as
during strategic planning by management. Approaches for design evaluation range from comprehensive
analysis tools such as life cycle assessment (LCA) to the use of single environmental metrics. LCA tools
can be broadly classified as SETAC related methodologies (Vigon et al. 1993; Heijungs et al. 1992;
SET AC 1993b), semi-quantitative matrix evaluation tools (Graedel, Allenby, and Comrie 1995; Allenby
1991), and other techniques such as the Environmental Priority Strategies (EPS) system (FSI 1993). If
environmental requirements for the product system are well specified, design alternatives can be checked
directly against these requirements. Several tools for environmental accounting and cost analysis are also
emerging (US EPA 1989) (White, Becker, and Goldstein 1992) (US EPA 1995) (SNL 1993). Cost
analysis for product development is often the most influential tool guiding decision making. Key issues of
environmental accounting are: measuring environmental costs, allocating environmental costs to specific
cost centers, and internalizing environmental costs.
In principle, LCA represents the most accurate tool for design evaluation in life cycle design and
DFE. Many methodological problems, however, currently limit LCA's applicability to design (Keoleian
1994). Costs to conduct a LCA can be prohibitive, especially to small firms, and time requirements may
not be compatible with short development cycles (Sullivan and Ehrenfeld 1992) (White and Shapiro 1993).
Although significant progress has been made towards standardizing life cycle inventory analysis, (SETAC
1991) (Heijungs et al. 1992) (Vigon et al. 1993) (SETAC 1993b) results can still vary significantly
(Svensson 1992) (Curran 1993). Such discrepancies can be attributed to differences in system boundaries,
rules for allocation of inputs and outputs between product systems, and data availability and quality issues.
Incommensurable data presents another major challenge to LCA and other environmental analysis
tools. A large complex set of inventory data can be overwhelming to designers and managers who often
lack environmental training and expertise. The problem of evaluating environmental data remains
inherently complicated when impacts are expressed in different measuring units (e.g., kilojoules, cancer
risks, or kilograms of solid waste). Furthermore, impact assessment models vary widely in complexity and
uncertainty.
Even if much better assessment tools existed, LCA has inherent limitations in design and
management, because the complete set of environmental effects associated with a product system can not
B.6
-------
be evaluated until a design has been specified in detail (Keoleian 1994). This limitation indicates the
importance for requirements matrices, checklists and design guidelines which can be implemented during
conceptual design phases.
B.7
-------
References
Allenby , Braden R. 1 99 1 . Design for environment: A
tool whose time has come. SSA Journal, no.
September: 6-9.
Curran, Mary Ann. 1993. Broad -based environmental
life cycle assessment. Environmental
Science and Technology 27, no. 3: 430-436.
FSI. 1993. The Product Ecology Report:
Environmentally-Sound Product
Development Based on the EPS System,
Federation of Swedish Industries,
Stockholm, Sweden.
Gatenby, David A., and George Foo. 1990. Design for
X (DFX): Key to Competitive, Profitable
Products. AT&T TechnicalJournal 69, no. 3
Gause, Donald G., and Gerald M. Weinberg. 1989.
Requirements: Quality Before Design. New
York: Dorset House.
Graedel, T. E., B. R. Allenby, and P. R. Comrie. 1995.
Matrix approaches to abridged life cycle
assessment. Environmental Science and
Technology 29, no. 3: 134-39.
Guinee, J. B., H. A. Udo de Haes, and G. Huppes.
1993. Quantitative life cycle assessment of
products 1: Goal definition and inventory.
Journal of Cleaner Production l,no. 1: 3-13.
Guinee, Jeroen. B., Reinout Heijungs, Helias. A. Udo
de Haes, and Gjalt. Huppes. 1993.
Quantitative life cycle assessment of
products 2: Classification, valuation and
improvement analysis. Journal of Cleaner
Production 1, no. 2: 81-91.
Heijungs, R., J. B. Guinee, G. Huppes, R. M. Lankreijer,
H. A. Udo de Haes, A. Wegener Sleeswijk,
A. M. M. Ansems, P. G. Eggels, R. vanDuin,
andH. P. de Goede. 1992. Environmental
Life Cycle Assessment of Products - Guide,
Center of Environmental Science, Leiden,
Netherlands.
Keoleian, Gregory A. 1994. The application of life
cycle assessment to design. Journal of
Cleaner Production l,no. 3-4: 143-49.
Keoleian, Gregory A., Jonathan Koch, and Dan
Menerey. 1995. Life Cycle Design
Framework and Demonstration Projects:
Profiles ofAT&TandAlliedSignal,
EPA/600/R-95/107. US Environmental
Protection Agency, National Risk
Management Research Laboratory,
Cincinnati, OH.
Keoleian, Gregory A., and Dan Menerey. 1993. Life
Cycle Design Guidance Manual:
Environmental Requirements and the
Product System, US EPA, Office of Research
and Development, Risk Reduction
Engineering Laboratory, Cincinnati, OH.
-. 1994. Sustainable development by design:
Review of life cycle design and related
approaches. Journal of the Air and Waste
Management Association 44, no. 5: 645-68.
Marguglio, B. W. 1991. Environmental Management
Systems. New York: Marcel Dekker.
SETAC. 1991. Workshop Report - A Technical
Framework for Life-Cycle Assessment
Washington, DC: Society of Environmental
Toxicologists and Chemists.
-. 1993a. Workshop Report - A Conceptual
Framework for Life-Cycle Impact
Assessment Pensacola, FL: Society of
B.8
-------
Environmental Toxicology and Chemistry.
-. 1993b. Workshop Report - Guidelines for
Life-Cycle Assessment: A Code of Practice
Pensacola, FL: Society of Environmental
Toxicology and Chemistry.
SNL. 1993. Life Cycle Cost Assessment: Integrating
Cost Information into LCA, Project
Summary, Sandia National Laboratories,
Albuquerque, NM.
Sullivan, Michael S., and John R. Ehrenfeld. 1992.
Reducing life-cycle environmental impacts:
An industry survey of emerging tools and
programs. Total Quality Environmental
Management 2, no. 2: 143-57.
Svensson, Goran. 1992. Experience from the inventory
phase of LCA studies. First NOH European
Conference: Design for the Environment,
1.1.1,1-8.
US EPA. 1989. Environmental Audit Program Design
Guidelines for Federal Agencies,
EPA/130/4-89/001. US Environmental
Protection Agency, Office of Federal
Activities, Washington, DC.
-. 1995. An Introduction to Environmental
Accounting as a Business Management
Tool: Key Concepts and Terms, US
Environmental Protection Agency, Office of
Pollution Prevention and Toxics,
Washington, DC.
Vigon, B. W., D. A. Tolle, B. W. Cornary, H. C.
Latham, C. L. Harrison, T. L. Bouguski, R. G.
Hunt, and J. D. Sellers. 1993. Life Cycle
Assessment: Inventory Guidelines and
Principles , EPA/600/R-92/245. US
Environmental Protection Agency, Risk
Reduction Engineering Laboratory,
Cincinnati, OH.
Weitz, Keith A., and John L Warren. 1993. Life Cycle
Impact Assessment: Framework Issues,
Draft, US Environmental Protection Agency,
Office of Air Quality, Planning and
Standards, Research Triangle Park, NC.
White, Allen L., Monica Becker, and James Goldstein.
1992. Total Cost Assessment: Accelerating
Industrial Pollution Prevention Through
Innovative Project Financial Analysis, US
EPA, Office of Pollution Prevention and
Toxics, Washington, DC.
White, Allen L., and Karen Shapiro. 1993. Life cycle
assessment: A second opinion.
Environmental Science & Technology 27,
no. 6: 1016-17.
B.9
-------
Appendix C
Life Cycle Design Reports
The following list provides reference information for other LCD reports available from the
National Technical Information Service (NTIS: www.ntis.gov or 800-553-6847) or the EPA's
National Service Center for Environmental Publications (www.epa.gov/ncepi or 800-490-9198).
Report Title
Report Number
Available From
Life Cycle Design Guidance Manual:
Environmental Requirements and the Product System
full report
summary report
Life Cycle Design Framework and Demonstration Projects:
Profiles of AT&T and AlliedSignal
full report
Life Cycle Design of Amorphous Silicon Photovoltaic Modules
full report
summary report
Life Cycle Design of Milk and Juice Packaging Systems
full report
summary report
Life Cycle Design of a Fuel Tank
Life Cycle Design ofln-Mold Surfacing Film
full report
summary report
Life Cycle Design of Air Intake Manifolds:
Phase II: Lower Plenum of the 5.4L F-250 2.0 Air Intake
Manifold, Including Recycling Scenarios
full report
EPA/600/R-92/226 EPA
PB93-164507AS NTIS
EPA/600/SR-92/226 EPA
EPA/600/R-95/107 EPA
PB 97-193106 NTIS
EPA 600/SR-97/081 EPA
PB 98-100423 NTIS
EPA 600/SR-97/082 EPA
PB 98-447856INZ NTIS
EPA600/SR-97/118 EPA
full report EPA600/R-01/058 EPA
EPA600/R-01/059 EPA
Additional Information
Additional information on life cycle design publications and research can be found on our
website (http://css.snre.umich.edu) under the heading Research.
C.I
-------
Appendix D
Table D-l. Acronyms
APC American Plastics Council
ASR Automotive Shredder Residue
CAFE Corporate Average Fuel Economy
DFE Design For Environment
EGR Exhaust Gas Return
ELY End-of-Life Vehicle
EPA United States Environmental Protection Agency
GWP Global Warming Potential
EVI Intake Manifold
LC Life Cycle
LCA Life Cycle Analysis
LCD Life Cycle Design
LCI Life Cycle Inventory
NPPC National Pollution Prevention Center
NRMRL National Risk Management Research Laboratory (EPA)
NVH Noise, Vibration and Harshness
OEM Original Equipment Manufacturer
SET AC Society of Environmental Toxicology And Chemistry
D.I
------- |