Introducing a streamlined life cycle assessment approachfor evaluating sustainability in defense acquisitions

K. A. Scanlon • C. Cammarata • S. Siart

Published online: 5 June 2013

� Springer Science+Business Media New York 2013

Abstract We introduce a methodological approach for

conducting a streamlined life cycle assessment (SLCA) of

defense systems. The approach is recommended for

application in those cases where assessors are faced with

alternative options for the design of a defense system and

where quantitative data describing the system inputs are

limited. Also, it is intended to be used to assist sustain-

ability-minded decision makers, those who recognize the

importance of sustaining resources while preventing

adverse impacts to mission, human health, ecosystem

health, air, water, and land. The approach includes defining

the scope and boundaries of the system, and its alternatives,

inventory data collection, impact assessment, and inter-

pretation. Results from the SLCA can be used to compare

performance of two or more alternatives in terms of

impacts to these areas of concern. The unique features of

this approach include the screening of system processes

using the activity profile, collection of resource input data

for the processes with the greatest potential for impacts,

and application of scoring factors unique to the impact

categories assessed. The approach is rigorous, systematic,

and intended to promote informed acquisition decisions

that consider principles of sustainable design. Future

research activities will include the application of the

methodological approach to acquisitions for defense and

other industries.

Keywords Streamlined life cycle assessment (SLCA) �Acquisition � Energy � Chemicals and materials � Water �Land � Sustainable design

1 Introduction

In this article, we introduce a methodological approach for

conducting a streamlined life cycle assessment (SLCA)

that can be used to promote informed decisions regarding

sustainability in defense acquisitions of weapons systems,

subsystems, or components. Derived from the standardized

method for life cycle assessment (LCA), as documented in

the ISO 14040 series, our SLCA’s intended use is to

identify and help prevent impacts to mission, human

health, and the environment resulting from a system’s life

cycle resource use. The SLCA introduced here is intended

to compare two or more systems, subsystems, or compo-

nents with the same function (e.g., alternatives with similar

expectations of performance) on the basis of potential

mission, human health, and environmental impacts. When

used in early conceptual and design decisions, the SLCA

results can be used to: design new defense systems or

improve on legacy systems undergoing notable modifica-

tions to require less resources over the system’s life cycle;

reduce the likelihood of financial and resource burdens

associated with impacts; or support robust and informed

trade-off analyses. A demonstration of the SLCA approach

introduced in this article will be conducted and docu-

mented in future publications.

Life cycle assessment is used to evaluate and quantify

the flow of substances, specifically materials and energy

inputs and outputs, and environmental releases from the

network of processes that make up a system. It is defined to

include four iterative phases: goal and scope definition, life

Electronic supplementary material The online version of thisarticle (doi:10.1007/s10669-013-9450-9) contains supplementarymaterial, which is available to authorized users.

K. A. Scanlon � C. Cammarata (&) � S. Siart

Concurrent Technologies Corporation, 100 CTC Drive,

Johnstown, PA 15904, USA

e-mail: cammarac@ctc.com

123

Environ Syst Decis (2013) 33:209–223

DOI 10.1007/s10669-013-9450-9

cycle inventory analysis, life cycle impact assessment, and

interpretation (ISO 2006). An LCA can be both time and

resource intensive, as data collection for inventory analyses

and implementation of characterization factors for impact

assessment models can take months to complete. Such

characteristics make traditional LCA unworkable under the

resource-constrained and time-limited realities imposed on

defense acquisitions personnel.

Although LCAs are often impractical for use during

defense acquisition decision making, the results of such

studies could serve as critical data points used to inform

trade-off analyses in early design and technology devel-

opment activities. Such information could help personnel

involved with defense acquisitions to identify design

alternatives that present lower risk to military operations

and human and environmental health. These impacts often

result in hidden costs (e.g., medical monitoring, environ-

mental controls, remediation, convoys for fuel and water)

for operators downstream from production, and such costs

are rarely accounted for in acquisition cost estimates.

Identification of potential life cycle impacts during design

and technology development provides acquisition person-

nel with the opportunity to design out these risks, ulti-

mately resulting in reduced life cycle costs.

Our proposed SLCA differs from LCA in its approach to

scope, data requirements, and the range of impacts asses-

sed. In keeping with the criteria for SLCA promoted by

Todd and Curran (1999), the approach introduced in this

article is rigorous, systematic, and designed to provide

sufficient information for comparative decision support.

The methodological approaches for LCA and SLCA are

viewed as points on a continuum and the use of SLCA does

not preclude assessors from conducting an LCA (Todd and

Curran 1999; Hochschorner and Finnveden 2003). If

resources are available, an LCA may be conducted in lieu

of, or in addition to, the SLCA. However, unlike the

standardized method for LCA documented in the ISO

14040 series, a prescriptive or standardized method for

SLCA does not exist. Streamlined life cycle assessments

using varying methodological approaches have been

defined, documented, and implemented in practice (Todd

and Curran 1999; Graedel et al. 2005). For example, Gra-

edel et al. (2005) developed semi-quantitative assessment

matrices to perform SLCAs of four helicopters and the

principal subsystems (e.g., airframe, electronics) compos-

ing the helicopters. The matrices addressed the perfor-

mance of the systems and subsystems in two dimensions:

concerns for the environment (e.g., energy use and pro-

duction of solid or liquid residues) and life cycle stages

(e.g., manufacture or delivery of products). Assessors

assigned each element in the matrix a rating on a scale to

indicate impacts, the results of which were used to produce

an aggregate SLCA for the system.

The methodological approach for SLCA introduced in

this article produces results that can be used to compare the

performance of two or more alternatives on a relative scale

and describe the magnitude of difference between or

among alternatives in terms of impacts to mission, human

health, or environment. Traditional LCA is time and

resource intensive because it requires analysts to collect

inventory data on inputs and outputs for each process

within the system being assessed. The proposed SLCA

approach simplifies the traditional approach by using

scoring factors, representing relevant emission and impact

characterization factors, to characterize an inventory of

inputs into specified impact categories without the need to

collect process-level inventory data. The SLCA allows

analysts to directly translate a database of inputs, which

can be collected from multiple sources (e.g., bill of mate-

rials, material safety datasheets) into units of impact that

can be compared among other alternative systems.

The units of impact are relative units and should only be

used for relative comparisons between two or more sys-

tems. Unlike traditional LCA techniques established under

the ISO 14040 series, users should not interpret the results

of a SLCA as absolute values. Instead, the resulting impact

values from the SLCA model represent each alternative’s

position, relative to all other alternatives, for a specified

impact category. These impact categories represent the

following areas of concern: mission, human health, eco-

system health, air, water, and land. An area of concern

represents a prevention point, an area where potential harm

can be minimized and protection of areas worth main-

taining can be maximized. The impact categories and areas

of concern are similar to those commonly assessed in

published LCA studies (Bare and Gloria 2008). Figure 1

illustrates the SLCA framework.

The impact categories in the right column of Fig. 1

represent the type of impacts that can result from resource

use and the environmental releases caused by such resource

use. For example, the type and quantity of energy used by a

system throughout its life cycle (resource input) will result

in greenhouse gas (GHG) emissions, which translate into

some amount of global warming (impact category).

The SLCA framework was developed for evaluation of

defense acquisitions. However, the life cycle stages and

impacts outlined in the framework are not unique to

defense acquisitions. Application of this approach to

evaluate acquisition sustainability in other industry and

government sectors is encouraged.

2 Background

Acquisition managers are responsible for acquiring defense

systems, subsystems, or components capable of meeting

210 Environ Syst Decis (2013) 33:209–223

123

performance requirements. For some systems, sustainment

activities last many decades. These systems are essential to

fulfill the defense mission by providing military forces with

the capabilities needed to deter war and protect the security

of the country. To continue to accomplish this mission

requires the use of resources (e.g., energy, water, land, and

chemicals and materials) necessary for training and readi-

ness. However, resources are costly and, in some cases,

dwindling. Without a full understanding of life cycle impacts

and costs of systems and platforms, significant impacts and

costs are often pushed downstream from acquisition program

managers to the operational, logistics, and installations

management communities. Therefore, systems must be

made more sustainable in order to meet mission require-

ments from now into the future. In the context of defense

acquisitions, a sustainable acquisition is one that involves the

wise use of resources and the minimization of corresponding

impacts and costs during the life cycle. Sustainability pro-

vides the framework necessary to ensure the longevity of

these resources (U.S. Department of Defense 2012).

Integrating sustainability into acquisition requires an

understanding of the complex defense acquisition process

including the multiple decision points and opportunities to

influence design. Early materiel and system design decisions

establish the foundation for cost, technological capability,

resource consumption, and potential impacts to mission,

human health, and environment. System design is a critical

facet of acquisitions; incorporating sustainability into

acquisition begins with integrating principles of sustainable

design which support efforts to ensure longevity of resources

and minimize impacts. The principles promoted by the

methodological approach for SLCA are outlined in Table 1.

3 Methodological approach

The actions necessary for conducting the proposed SLCA

to support the evaluation of sustainability in defense

acquisitions include scope and boundary definition,

inventory analysis, impact assessment, and interpretation.

In scope and boundary definition, the functional unit of the

system under study is defined, the scope of the study is

clarified, and system boundaries are described. Unlike

LCA, the SLCA’s scope is limited to the life cycle stages

common to defense systems and for which the acquiring

entity has direct influence over. These stages may include

raw material acquisition, production and deployment,

operations and sustainment, and end-of-life.

The inventory analysis process includes defining inputs

to the system and collecting inventory data. The inventory

of energy, chemicals and materials, water, and land inputs

include the type, source, and quantities needed across the

life cycle. Contrary to LCA, this SLCA approach does not

require an inventory of estimated environmental releases

resulting from each input and associated life cycle process.

The SLCA also differs from LCA in that data requirements

• Energy Type• Energy Source• Energy Quantity

• Hazards List• C&M Source• C&M Quantity

• Water Type• Water Source• Water Quantity

• Land Type• Incremental Land Use

Quantity• Occupation Time

EN

ER

GY

CH

EM

ICA

LS

&M

AT

ER

IAL

SW

AT

ER

LA

ND

Fossil Fuel Depletion

Energy Source Reliability

C&M Availability

C&M Recovery

Total Water Use

Global Warming

Ozone Depletion

Water Recovery Efficiency

Water Loss Efficiency

Water Scarcity

Fit-for-Use

Water Degradation

Land Degradation

Human Toxicity

Respiratory Effects

Ecosystem Toxicity

Resources (Inputs) Scoring Factors or Qualitative Scoring

Impact CategoriesM

ISSION

HU

MA

N

HE

AL

TH

EC

OSY

STE

M

HE

AL

TH

AIR

WA

TE

RL

AN

D

Smog Formation

Fig. 1 Streamlined life cycle

assessment framework. C&MChemicals and materials

Environ Syst Decis (2013) 33:209–223 211

123

are flexible. Quantitative legacy data are preferred for

inventory development; however, the SLCA approach is

robust even when using estimates based on a qualitative

scale (e.g., best to worst).

In the impact assessment phase, energy, chemicals and

materials, and land inputs are translated into impacts using

scoring factors. The SLCA uses these scoring factors to

classify the inventory of inputs into impact categories and

to determine the magnitude of impact. The methodologies

for deriving these scoring factors differ for each input type

and are summarized in Sect. 3.3.

Some impact categories (e.g., water degradation,

chemicals and materials availability, and energy source

reliability assessed using the SLCA methodology) do not

require scoring factors when characterizing impact from

inputs. Scoring factors for these impact categories are not

needed for one of two reasons: (1) Regardless of the

resulting impacts to human health and the environment, the

quantity of resources used by the system is itself a mission

impact and can be characterized by comparing the total

quantity of each resource consumed; or (2) many of the

impact categories (i.e., all water categories) use a qualita-

tive scoring framework for characterizing impact.

As a final phase in the SLCA, the results from the impact

assessment are interpreted and alternatives are compared on

a relative scale. Results from the SLCA are amenable to

visual presentation using radar charts to illustrate relative

impact values and the magnitude of the impacts.

3.1 Scope and boundary definition

Similar to LCA, our SLCA limits the scope of the analysis to

a predetermined functional unit, which is defined by the

function or performance characteristics of the system under

Table 1 Principles of sustainable design

Principles of sustainable design

Use low-impact materials that are… Non-toxic, as designated by the US Environmental Protection Agency (EPA);

From life cycle-enhancing renewable sources;

From local or regional sources (with regard to where the system is manufactured or assembled); and

Composed of recycled materials that require less energy to process than non-recycled substitute

materials

Optimize system-wide energy

consumption by…Reducing the fully burdened cost of delivered energy;

Designing manufacturing and assembly processes that minimize energy consumption;

Designing systems that employ energy efficiency technologies during the use stage of the life cycle;

Developing end-of-life scenarios for which systems can be easily disposed, recycled or reused with

minimal energy input; and

Using life cycle-enhancing renewable sources of energy

Improve system and component

design by…Extending the expected life of components and minimizing maintenance activities and materials by

improving durability;

Standardizing component function for reuse in newer versions of that same system or for reuse in

other similar systems; and

Minimizing the use of designs that far exceed specifications when such designs require additional

materials and energy and result in excess waste and pollution and when less impactful alternative

designs adequately achieve all specifications

Minimize life cycle waste by… Reusing waste materials from manufacturing, use and end-of-life activities;

Reusing system components with a longer lifetime than the systems they compose and recycling

materials to create new system components;

Increasing the life of a system through rigorous maintenance and repair schedules;

Developing waste-to-fuel capabilities; and

Integrating closed-loop system design

Minimize life cycle pollution by… Reducing the use of hazardous materials and fossil fuel energy sources that lead to pollution

emissions;

Engaging in pretreatment activities that mitigate pollution emissions; and

Collecting and treating pollution emissions before they enter the surrounding community or

ecosystem

Minimize risks to human health and the

environment by…Designing out known chemical, biological and physical hazards (including noise, radiation,

and ergonomic stressors) when technologically feasible; and

Ensuring that workplace and environmental exposures to known hazards are inherently safe

or below recognized limits

212 Environ Syst Decis (2013) 33:209–223

123

study. The primary purpose of a functional unit is to provide a

reference for which the resource requirements and resulting

impacts of a specified system are related. This reference is

necessary to ensure comparability of results across alterna-

tive systems. Being a relative analysis, comparability of

results for the SLCA is critical to ensure that comparisons are

made on a common basis. As with LCA, the functional unit

should be the same for all alternatives being evaluated.

With respect to defense acquisition, the functional unit

should be defined by the minimal requirements to meet the

stated capabilities or performance requirements necessary to

fulfill the mission. For example, if the system is required to

transport 100 combat vehicles a distance of 200 miles, then

the functional unit for the evaluation would be the transport

of 100 combat vehicles 200 miles. If the system is to meet a

capability over a 50-year period, then the functional unit

should also include this time component. For example,

consider Alternative 1, which has an expected life span of

25 years. Including this time element implies that two units

of Alternative 1 would be needed to meet the capability

requirement of 50-year life span. To demonstrate the

importance of incorporating this element of time, consider

Alternative 2 that has life span of 50 years, but the life cycle

impacts are greater than Alternative 1. When considering

that two units of Alternative 1 are needed to meet the capa-

bility, the cumulative impacts of selecting Alternative 1 may

be greater than the impacts of Alternative 2. The time and

number of mission tasks needed to fulfill a desired capability

can greatly influence the impact assessment.

In addition to the functional unit, an assessor conducting

the SLCA must also define the scope of the analysis. The

scope, which is informed by the functional unit, defines the

defense system, subsystem, or component to be included in

the SLCA and focuses on aspects of the acquired asset that

result in incremental differences in cost and impact. The

scope for each alternative should include all incremental

materiel, support, and sustainment needed to fulfill the

capability or performance requirement. For example, the

capability can be met by the acquisition of a missile, but

the newly acquired missile cannot be deployed using

existing launching platforms, and a new launching platform

must be acquired. Extending the SLCA scope to include

the launching platform ensures that all incremental impacts

(e.g., land use for the new platform) are included. The

defined scope should be the same for all alternatives being

assessed.

The system boundaries must be defined to ensure a fair

comparison among competing alternatives and limit the

scope of the study to inputs that result in the greatest impact.

The system boundaries determine the life cycle stages

included in the evaluation. A clear definition of the system

boundaries enables a better assessment for each alternative’s

impacts, while also ensuring an equitable comparison

between or among alternatives. Ideally, the boundaries

should include processes, products, infrastructure, and

activities from cradle (i.e., resource extraction and process-

ing) to grave (i.e., disposal). System boundaries that include

cradle-to-grave life cycle stages ensure that all impacts of an

alternative are accounted for and included in the evaluation.

However, situations may arise when it is appropriate to

exclude some life cycle stages from the system boundaries.

In these situations, assessors must ensure that the same life

cycle stages are excluded for alternatives in the evaluation.

3.2 Life cycle inventory analysis

The inventory analysis for the SLCA includes completing a

life cycle activity profile to identify key system inputs and life

cycle stages and then collecting data on a defense system’s life

cycle resource requirements for energy, chemicals and

materials, water, and land. The activity profile is a screening

tool that guides SLCA data collection by identifying the

resources a weapon system needs and the life cycle stages

during which those resources are being consumed. The

activity profile identifies those processes expected to drive

impacts and it narrows the data collection requirements.

Streamlined life cycle assessment assessors should com-

plete the activity profile for each alternative being consid-

ered. To complete an activity profile, assessors classify the

processes within the system boundary into one of four

activity descriptor classes: (1) active and stationary systems;

(2) active and mobile systems; (3) passive and stationary

systems; or (4) passive and mobile systems. Table 2 provides

examples for each type of activity descriptor class.

Systems that can be categorized within a particular

combination of activity descriptors possess common

Table 2 Activity descriptors for activity profile

Stationary Mobile

Active Does not move without assistance, actively consumes resources during

operation. Examples: heating and cooling system, water purification

system, etc.

Moves on its own accord, actively consumes resources

during operation. Examples: aircraft, ground vehicle, etc.

Passive Does not move without assistance, does not consume resources and does

not use support systems for mobility. Examples: satellite dish, barricade

infrastructure, etc.

Does not move on its own accord and is mobilized using

support system. Examples: trailer, bomb, etc.

Environ Syst Decis (2013) 33:209–223 213

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characteristics that can be used to filter the data collection

process. By defining and classifying activity descriptors for

each alternative system, assessors can better identify the

processes and life cycle stages that consume the most

energy, chemicals and materials, land, and water resources,

and, therefore, better focus finite resources for data col-

lection on system inputs that characterize the greatest

amount of impact. For example, assets that are both mobile

and active typically have high energy consumption during

the use stage of the life cycle and require more intensive

sustainment support due to system wear. Conversely, assets

that are stationary and active may still have high energy

demands during the use stage, but may have significantly

lower sustainment requirements due to less system wear.

Table 3 lists the life cycle stages, resources, and activity

descriptors for a completed activity profile for a generic

aircraft, which would represent a mobile and active system.

Based on the example activity profile for this generic air-

craft, the SLCA assessors would focus inventory data col-

lection efforts on energy, chemicals and materials, and water

inputs in the operations and sustainment stage of the system’s

life cycle. However, before data collection efforts begin,

assessors should identify what data are available for the

assessment. Quantitative legacy data should be used whenever

available. The data from the legacy system should match or, at

least, closely resemble the proposed function and operation

for the alternatives being evaluated. In some cases, quantita-

tive data may not exist or may be too time-consuming or

expensive to collect. As a result, assessors should use the

qualitative scoring methods established in the SLCA.

Scoring is based on a qualitative scale and represents the

order of performance (e.g., best to worst) and the

magnitude of difference in the amount of input, for a

particular resource, between or among the alternatives

being assessed. The scale may be defined between 0 and

100 %, with percentage of worst being determined by the

assessors and used consistently across all alternatives. For

example, if the assessor does not have quantitative data, but

has good reason to believe that Alternative 1 uses 10 %

fewer gallons of diesel than Alternative 2 (the worst per-

former), then Alternative 1 would have a qualitative gas-

oline input score that is 90 % that of Alternative 2.

There may be situations where quantitative data are

available for some of the resources, but not for others. For

example, quantitative data may be available for energy and

land, but not for chemicals and materials or water. In this

situation, quantitative data can be used for energy and

qualitative data methods such as scoring on a scale can be

used for chemicals and materials and water. Quantitative

data and scoring can be used in conjunction as long as the

same data type for a given resource is used across all

alternatives being assessed. Data collected on energy,

chemicals and materials, water, and land should be con-

sistent across the alternatives being assessed. If quantitative

data are collected on the energy use of one system, quan-

titative data should be collected on the energy use of all

systems in the assessment. Consistency in the type of data

that are used to compare systems is important because the

comparison is based on relative SLCA results.

The inventory data should represent the quantity of

energy, chemicals and materials, water, and land inputs

needed across the life cycle. For example, energy data

should encompasses all life cycle energy, both direct and

indirect, that is consumed by the defense system. Direct

Table 3 Example activity profile for a generic aircraft

Resources

(Inputs)

Life cycle stages

Raw material acquisition Production & deployment Operations & sustainment End-of-life

Energy N/A (no direct influence over

this life cycle stage)

Material fabrication and

assembly

Flight testing

Fuel use (direct)

Transportation of fuel to base

or depot (indirect)

Transportation of water to

depot (indirect)

Reconditioning of engines for

reuse

Recycling of aluminum frame,

scraps & electronics

Chemicals &

materials

N/A (no direct influence over

this life cycle stage)

Coatings and other solvents Resurfacing

Fuel use

Reconditioning of engines for

reuse

Recycling of aluminum frame,

scraps & electronics

Water N/A (no direct influence over

this life cycle stage)

Coatings Paint stripping (direct)

Engine and airframe cleaning

(direct)

N/A

Land use N/A (no direct influence over

this life cycle stage)

Incremental footprint for

manufacturing facility

Two additional runways

needed

New hangar needed for fleet

Additional landfill acreage

needed for solid waste

N/A not applicable

214 Environ Syst Decis (2013) 33:209–223

123

energy is energy consumed directly by the system, for

example the diesel fuel needed in a ground vehicle. Indirect

energy is not consumed directly by the system, but is

necessary to manufacture, sustain, and protect the system.

Assessing system energy consumption requires calculating

the total amount of direct and indirect energy, for each type

of energy input (e.g., diesel fuel, gasoline, natural gas)

needed to meet the minimum required capabilities. In the

example presented in Table 3, inventory data collection

should consider the quantity of direct and indirect energy

needed to meet the minimum required capabilities.

There are hundreds, maybe thousands, of chemicals and

materials that a system may use throughout its life cycle.

Users of the SLCA should use expert judgment on chemicals

and materials that need to be included in the SLCA. A

chemical or material should be included in the SLCA if it is:

known to be toxic or harmful to human health or the envi-

ronment; rare, difficult to acquire, or expensive; or critical to

the system. Additionally, assessors should be mindful of all

chemicals and materials that are used to manufacture the

system or are used to support and sustain the system. After

identifying the chemicals and materials that a system uses

throughout its life cycle, assessors need to assign quantities

to each chemical and material. For chemicals and materials,

data will typically be in mass-based units.

For water, assessors should collect inventory data for the

quantity of water withdrawn from each applicable source

(cells A, B, and C in Fig. 2), the quantity of water reused

(cells C and D in Fig. 2) or replenished to the environment

(cell E in Fig. 2), and the quantity of water lost and not

returned to the source (cell F in Fig. 2). The quantities

described above need to be assessed for each activity or

process that uses water, either directly or indirectly,

throughout a system’s life cycle. For water use, data will

typically be in units of volume.

When collecting inventory data for land, assessors should

consider the amount of incremental land that a system requires

throughout its life cycle. For the SLCA approach introduced in

this article, a system’s incremental land use should only refer

to basing space, which includes, but is not limited to, land

acreage, piers and shoreline, runways, hangers, and similar

structures. Assessors should identify the incremental amount

of physical land that is consumed and transformed to support

activities associated with testing, evaluation, basing, and

sustaining the defense system.

After identifying the incremental amount of land,

assessors should then assign a land type to the area that is

being consumed or transformed. Table 4 provides seven

categories of land types that assessors can use to categorize

each plot of incremental land used by the system (Koellner

and Scholz 2007). These categories are organized into how

intensely human activities are integrated into the existing

landscape, where high intensity indicates high levels of

human integration and low intensity indicates low levels of

human integration.

3.3 Streamlined life cycle impact assessment

Inventory data or qualitative scores, which act as a proxy for

inventory data, are assigned to impact categories and trans-

lated into potential impacts to mission, human health, and the

environment by using scoring factors. In the impact assess-

ment phase, energy, chemicals and materials, and land inputs

are translated into impacts using scoring factors. Impact

categories (e.g., water degradation, chemicals and materials

availability, and energy source reliability) that use qualita-

tive scoring methods do not require the use of scoring factors.

For energy, scoring factors are based on best available

emission factors and characterization factors derived from

risk assessment and LCA literature, including, but not

limited to, factors developed by the Intergovernmental

Panel on Climate Change (IPCC), the US Energy Infor-

mation Administration (EIA), and the EPA (EPA 1996;

Sheehan et al. 1998; IPCC 2006; McCormick et al. 2006;

Eastern Research Group 2007; Jacobson 2007; EIA 2009;

EPA 2009; International Energy Agency 2009; Goedkoop

et al. 2009; Robbins et al. 2009; EIA 2010; European

Environment Agency 2010; Bare 2011; U.S. Department of

Energy 2012). The use of energy, especially fossil fuels,

typically results in air emissions and emission factors are

linked with a specific activity (e.g., fuel combustion). The

SLCA methodology relies on these emission factors to

generalize all activities that could be associated with a

particular source of energy.

Unlike LCA, the SLCA methodology assumes that all

chemicals and materials inputs will eventually result in

outputs or emissions to environmental media (e.g., air, soil,

water). In an effort to significantly reduce the data and

Water used bysupport &

sustainmentactivities

AWater from

Environment

Water fromanother system

B

EWater returned to

original sourceD

Water reused byanother system

FWater lost & not

returned tosource

Water reusedby system

C

Fig. 2 Flow diagram for system water use

Environ Syst Decis (2013) 33:209–223 215

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modeling burdens imposed on SLCA assessors, life cycle

inventory calculations are simplified by assuming generic

probabilities for emissions. Under these assumptions, it is

possible to compare the human and ecosystem toxicity

impacts of alternatives in relative terms by multiplying the

quantity of inputs by their relevant characterization factor,

such as those developed by consensus or by the EPA (Bare

2011; USEtox n.d.). However, by estimating environmental

releases, the SLCA methodology is subject to greater error

when comparing the human toxicity and ecological toxicity

of two or more alternatives (see Supplementary Material

for more information on the evaluation of this error).

For land, the scoring factors characterize the restoration

time, that is, the number of years it will take a plot of land

to be restored to its original state after transformation. The

SLCA method uses information on the amount of time in

which the plot of land will be occupied, the transformation

type, and quantity of land transformed to estimate a land

degradation score (Koellner and Scholz 2007).

The impact categories are described in the following

sections, and Table 5 summarizes the equations (i.e.,

characterization models) that use the scoring factors to

determine impacts. For information on the derivation of the

scoring factors, a complete list of the scoring factors, or

access to the tool that supports this methodology, please

visit http://denix.osd.mil/esohacq or contact the corre-

sponding author.

3.3.1 Impacts to mission

3.3.1.1 Fossil fuel depletion The goal of this impact

category is to ensure that the amount of fossil fuels used by

each system is considered and that renewable sources of

energy be used when possible. The scoring factors account

for the expected demand of a particular fossil fuel com-

pared to that fuel’s available reserves. These factors use the

energy content for a gallon of crude oil, which also applies

to all crude oil by-products, as a baseline. Renewable and

non-fossil fuels all have scoring factors of zero because

there is no fossil fuel depletion potential.

3.3.1.2 Energy source reliability The goal of this impact

category is to ensure that the overall reliability of energy

sources used throughout a system’s life cycle is assessed.

Systems that use energy from reliable sources should be

preferred to those that use energy from unreliable sources.

An energy source is considered reliable if that source

presents a low source, economic, and resource risk.

3.3.1.3 Chemicals and materials availability The goal of

this impact category is to ensure evaluation of available

chemicals and materials in terms of supply chain risk

across the life cycle. Systems that use fewer supply-limited

chemicals or materials are preferred as are those that

present a low economic, source, and resource risk.

3.3.1.4 Chemicals and materials recovery The goal of

this impact category is to ensure that recoverable chemicals

and materials are used throughout a system’s life cycle.

Systems that use chemicals and materials in a manner that

enable recovery should be preferred.

3.3.1.5 Total water use The goal of this impact category

is to ensure the quantity of direct and indirect water used by

a system across all activities in its life cycle is considered.

Systems that use the least volume of water better enhance

the execution of the mission and therefore are preferred.

3.3.2 Impacts to human health

3.3.2.1 Human toxicity The goal of this impact category is

to identify the use of hazardous chemicals that could signifi-

cantly increase the probability of cancer or non-cancer dis-

eases in humans given elevated levels of exposure. System or

component designs that eliminate the use of these chemicals

are preferred. For both carcinogenic and non-carcinogenic

impacts, the scoring factors describe toxicity impact potential

and account for the transport of these emissions from the

environmental compartments (i.e., air, soil, water) to the

exposed population via these exposure routes. The scoring

factors are derived from the change in disease probability due

Table 4 Land categories

Land Type Description

Agriculture, high intensity Conventional arable, integrated arable, organic arable, fiber/energy crops, intensive meadow

Agriculture, low intensity Less intensive meadow, organic meadow, organic orchard, natural grassland

Artificially built environment, high intensity Built up land, continuous urban, discontinuous urban, sport facilities, industrial area—part

with vegetation

Artificially built environment, low intensity Green urban, rural settlement, rail embankments

Forest, high intensity Forest plantations

Forest, low intensity Semi-natural broad-leafed forest (either moist or arid)

Non-use Heathland, hedgerows, peat bog

216 Environ Syst Decis (2013) 33:209–223

123

Table 5 Impact assessment characterization models

Impact category Impact assessment model Model description

Fossil fuel

depletionFFDx ¼

Pnt¼1 Qt � SFt To calculate the fossil fuel depletion score for alternative x (FFDx), assessors

should multiply the quantity of each type of energy for each alternative

(Qt) by the energy type’s scoring factor (SFt) and add all results for all

types. Within this metric, alternatives with a lower FFDX have lower risk of

depleting fossil fuels, and thus, should be preferred over other alternatives

with higher scores

Energy source

reliabilityWRSx ¼ 2�

Pnt¼1 St þ Et þ Rtð Þ � TEt

TEx

� �To assess total energy source reliability risk, the assessors should assign a

risk score to each of the three criterion–source reliability (st), economic

reliability (Et), and resource reliability (Rt)–on a scale of 0 (none) to 5

(very high). Then, assessors should calculate the weighted reliability score

for alternative x (WRSx). This score is calculated by summing St, Et, and Rt

and weighting that combined score by a weighting factor. This weighting

factor is calculated by dividing the total amount of energy consumed by

energy type t (TEt), in British thermal units (Btu), by the total amount of

energy consumed by alternative X (TEx) across all energy types (also

recorded in Btu). To convert this score into a zero-to-ten scale, the

resulting summation of those results should be multiplied by 2. Using the

above criteria, alternatives presenting a low reliability risk should be

considered superior, and thus, should be preferred over other alternatives

Chemicals &

materials

availability

WASx ¼ 2�Pn

t¼1 St þ Et þ Rtð Þ � TCMt

TCMx

� �To assess total reliability risk, the assessors should assign a risk score to each

of the three criterion–source reliability (st), economic reliability (Et), and

resource reliability (Rt)–on a scale of 0 (none) to 5 (very high).Then,

assessors should calculate the weighted availability score for alternative

x (WASx). This score is calculated by summing St, Et, and Rt and weighting

that combined score by a weighting factor. This weighting factor is

calculated by dividing the total mass of input chemical or material

t (TCMt), in kilograms (kg), by the total mass of all input chemicals and

materials consumed by alternative x (TCMx) also recorded in kg. To

convert this score into a zero-to-ten scale, the resulting summation of those

results should be multiplied by 2. Within this metric, alternatives with a

lower WASX have lower availability risk, and thus, should be preferred

over other alternatives with higher scores

Chemicals &

materials

recovery

RPSx ¼ 1�Pn

t¼1Rt

Tx

� �� �

� 10Recovery potential (RPSx) can be calculated as a ratio of the summation of

all chemicals and materials mass recovered for select chemicals or

materials t (Rt) divided by the total chemicals and materials mass (Tx) used

by the alternative (x). This ratio is then subtracted from one to favor

alternatives with a lower recovery ratio. To convert this score into a zero-

to-ten scale, the resulting summation of those results should be multiplied

by 10. For this metric, a smaller RPSx represents a better recovery potential

because an alternative with a higher recovery potential has a lower impact

footprint

Total water use Wx ¼Pn

t¼1 Qt When calculating the total water used (Wx) by an alternative (x), assessors

should sum all quantities (Qt) of water for each activity type t. Within this

metric, alternatives with a lower WX use less water, and thus, should be

preferred over other alternatives with higher scores

Human toxicity HTSx ¼Pn

t¼1 Qt � SFt To calculate the human toxicity score for alternative x (HTSx), assessors

should multiply the quantity of each chemical used by each alternative (Qt)

by the chemical’s scoring factor (SFt), then add all results for all chemicals.

Within this metric, alternatives with a lower (HTSx) have lower toxicity

potential, and thus, should be preferred over other alternatives with higher

scores

Respiratory

effectsRESx ¼

Pnt¼1 Qt � SFt To calculate the respiratory effects score for alternative x (RESx), assessors

should multiply the quantity of each energy type used by alternative (Qt)

by the energy type’s scoring factor (SFt), then add all results for all types.

Within this metric, alternatives with a lower RESx have lower potential for

creating respiratory effects, and thus, should be preferred over other

alternatives with higher scores

Environ Syst Decis (2013) 33:209–223 217

123

Table 5 continued

Impact category Impact assessment model Model description

Ecosystem

toxicityETSx ¼

Pnt¼1 Qt � SFt To calculate the ecosystem toxicity score for alternative x (ETSx), assessors

should multiply the quantity of each chemical used by the alternative (Qt)

by that chemical’s scoring factor (SFt), then add all results for all

chemicals. Within this metric, alternatives with a lower total impact scores

have lower toxicity potential, and thus, should be preferred over other

alternatives with higher scores

Global warming GWPx ¼Pn

t¼1 Qt � SFt To calculate the global warming score for alternative x (GWPx), assessors

should multiply the quantity of each energy type for the alternative (Qt) by

that type’s scoring factor (SFt), then add results for all types. Within this

metric, alternatives with a lower GWPX have lower global warming

potential, and thus, should be preferred over other alternatives with higher

scores

Ozone depletion ODPx ¼Pn

t¼1 Qt � SFt To calculate the ozone depletion score for alternative x (ODPx), assessors

should multiply the quantity of each ozone-depleting substance for the

alternative (Qt) by that substance’s scoring factor (SFt), then add results for

all substances. Within this metric, alternatives with a lower ODPX have

lower ozone depletion potential, and thus, should be preferred over other

alternatives with higher scores

Smog formation SPx ¼Pn

t¼1 Qt � SFt To calculate the smog score for alternative x (SPx), assessors should multiply

the quantity of each energy type used by the alternative (Qt) by that type’s

scoring factor (SFt), then add results for all types. Within this metric,

alternatives with a lower SPX have lower smog potential, and thus, should

be preferred over other alternatives with higher scores

Water recovery

efficiencyIRx ¼ 1� BþC

AþBþC

� �To calculate the water recovery efficiency (IRx), assessors should consider

the recovered water resources (B ? C) and the total volume of water

consumed by support and sustainment (A ? B?C) activities (see Fig. 2).

To present this metric in terms consistent with other scoring metrics (i.e.,

greater value equating to a larger footprint), assessors should subtract this

efficiency from one to get the inverse water recovery efficiency. Using this

approach, the alternative with the smallest recovery efficiency has the

smallest total water use footprint and is the alternative that recovers and

reuses the largest portion of water used during system or component

operation and support and sustainment activities

Water loss

efficiencyLx ¼ 1� F

CþDþEþF

� �To calculate the water loss efficiency (Lx), assessors should consider the

water lost to transformation (F) and the total volume of water released by

support and sustainment (C ? D?E ? F) activities (see Fig. 2). To be

consistent with other scoring metrics, assessors should subtract this

efficiency from one to get the inverse efficiency. Assessors should favor

alternatives with smaller water loss efficiency

Water scarcity WSx ¼Pn

i¼1VWi

AþBþCð Þ �WSIx

¼Pn

i¼1VWi

CþDþEþFð Þ �WSIx

To calculate the water scarcity (WSX) score for a single source of water used

by a specified alternative, assessors should first estimate the total volume of

water withdrawn by the system or component (VMi) per region (i).Assessors should then calculate the percentage of the total amount of water

that VMi composes by dividing that number by the total volume of water

consumed (A ? B?C) or (C ? D?E ? F) released by support and

sustainment activities (see Fig. 2). Lastly, the assessor should multiply the

resulting number by the appropriate water scarcity index (WSIX), which is

determined by using previously established water scarcity indices.a Contact

the corresponding author for more information on calculating WSIX.

Assessors should favor alternatives with the lowest WSx

218 Environ Syst Decis (2013) 33:209–223

123

to the lifetime intake. These scoring factors are used to rep-

resent the steps along the cause–effect chain starting with the

emission of the chemicals and materials that occur in the life

cycle of the system, followed by the fate and transport through

the environment, exposure to humans, and the resulting effects

on the exposed populations.

3.3.2.2 Respiratory effects The goal of this impact cate-

gory is to ensure that the emissions from fossil fuel com-

bustion and their impact on human health are considered.

The scoring factors describe and account for the transport

of criteria air pollutants to the exposed population via air

exposure routes and the change in probability to respiratory

conditions due to the lifetime intake.

3.3.3 Impacts to ecosystem health

3.3.3.1 Ecosystem toxicity The goal of this impact cate-

gory is to ensure that hazardous chemicals, which could

lead to ecological toxicity in freshwater environments, are

considered. The scoring factors for these impact categories

represent steps along the cause–effect chain starting with

the emission of the chemicals and materials that occur in

the life cycle of the system, followed by the fate and

transport through the environment, exposure to freshwater

wildlife, and the resulting effects on the exposed popula-

tions. The scoring factors are derived from the change in

disease probability of a population due to the lifetime

intake of emission from hazardous chemicals or materials.

3.3.4 Impacts to air

3.3.4.1 Global warming The goal of this impact category

is to ensure that greenhouse gas emissions from fossil fuel

combustion and their impact on global warming are con-

sidered. The scoring factors describe and account for GHG

emissions and their incremental contribution to global

warming.

Table 5 continued

Impact category Impact assessment model Model description

Fit-for-use FFUx ¼Pn

i¼1Vi

AþBþCð Þ � FFUsx

¼Pn

i¼1Vi

CþDþEþFð Þ � FFUsx

To calculate the fit-for-use (FFUX) rating for a single source of water used by

a specified alternative, assessors should first estimate the total volume of

water required by the system or component (Vi) for that particular type of

use (i). Assessors should then calculate the percentage of the total amount

of water that Vi composes by dividing that number by the total volume of

water consumed (A ? B ? C) or (C ? D ? E ? F) released by support

and sustainment activities (see Fig. 2). Lastly, the assessor should multiply

the resulting number by the appropriate fit-for-use score (FFUsX), which is

determined by using a gradient plane of scores (0–10) that represent

various levels of water quality for both system water type requirements and

actual water type availability. Contact the corresponding author for more

information on calculating FFUsX. Assessors should favor alternatives with

the lowest FFUX

Water degradation WDx ¼Pn

i¼1Vi

AþBþCð Þ �WDsx

¼Pn

i¼1Vi

CþDþEþFð Þ �WDsx

To calculate the water degradation (WDx) rating for a single source of water

used by a specified alternative, assessors should first estimate the total

volume of water required by the system or component (Vi) for that

particular type of use (i). Assessors should then calculate the percentage of

the total amount of water that Vi composes by dividing that number by the

total volume of water consumed (A ? B ? C) or (C ? D ? E ? F)released by support and sustainment activities (see Fig. 2). Lastly, the

assessor should multiply the resulting number by the appropriate water

degradation score (WDsX), which is determined by using a gradient plane

of scores (0–10) that represent various levels of water quality for system’s

input and output of water. Contact the corresponding author for more

information on calculating WDsX Assessors should favor alternatives with

the lowest WDX

Land degradation LDSx ¼WARTx �WAOTx

where WARTx ¼Pn

i¼1 EDx � RTx

and WAOTx ¼Pn

i¼1EDx

ILUx

� �� OTx

To calculate each alternative’s land degradation score (LDSx), assessors

should sum the weighted average restoration time (WARTx) and the

weighted average occupation time (WAOTX). This score represents the

estimated average time that it would take for the incremental land used by

a given alternative to be restored to its original state. Contact the

corresponding author for more information about the land degradation

score

a Falkenmark and Rockstrom 2004; United Nations Environment Programme 2008; Maplecroft 2011; Media Analytics Ltd. 2011;

U.S. Department of Agriculture 2012

Environ Syst Decis (2013) 33:209–223 219

123

3.3.4.2 Ozone depletion The use of substances like

chlorofluorocarbons (CFCs), hydrochlorofluorocarbons

(HCFCs), and halogens for applications such as refriger-

ants and aerosols contribute to ozone depletion. The goal of

this impact category is to ensure that the use and associated

emissions of ozone-depleting substances are evaluated.

3.3.4.3 Smog formation The combustion of fuels for

energy, either directly at the source or indirectly through

the use of electricity, leads to the release of air pollutants

that may cause tropospheric smog. The goal of this impact

category is to ensure that emissions leading to smog for-

mation are evaluated.

3.3.5 Impacts to water

3.3.5.1 Water recovery efficiency The goal of this impact

category is to assess the total volume of direct and indirect water

that is recovered or reused by systems or components. Water

may be reused directly by that system or reused by other sys-

tems. The greater capacity a system has to recover and reuse

water, the less burden that system places on the environment

and any surrounding populations competing for the same water

resource. Efficient system design enhances water recovery.

Water recovery efficiency is the ratio of water withdrawn from

recovered sources to the total volume of water used by and in

support and sustainment of the system or component.

3.3.5.2 Water loss efficiency The goal of this impact

category is to ensure systems that minimize the total vol-

ume of direct and indirect water lost to transformations are

preferred. From an output perspective, the loss of water

from a system or component through transformations such

as evapotranspiration prevent the return of water to its

original source, which is detrimental to freshwater eco-

systems and local communities. Water loss efficiency is the

ratio of water lost to transformation to the total volume of

water used by and in support and sustainment of the system

or component.

3.3.5.3 Water scarcity The goal of this impact category

is to reduce water use, especially in regions where water

resources are scarce. This impact category assesses the

water scarcity of varying geographic locations by using a

scoring factor derived from water scarcity indices (Fal-

kenmark and Rockstrom 2004; United Nations Environ-

ment Programme 2008; Maplecroft 2011; Media Analytics

Ltd. 2011; U.S. Department of Agriculture 2012). The

scoring factor is used to calculate a weighted average

taking into consideration the volume of water withdrawn

from various geographic locations and the corresponding

water scarcity of the surrounding area.

3.3.5.4 Fit-for-use The goal of this impact category is to

closely match the water quality of a source with the water

quality required by a given use. For example, brackish

water will need to undergo extensive treatment in order to

become drinking water. If there is a source of water that is

closer in quality to drinking water standards, it is prefer-

ential to withdraw water from that source. Conversely, if

gray water is suitable for industrial applications, using

water that meets drinking water standards is a misuse of

resources. Matching the quality of source water with the

quality required by the use reduces the need for extensive

water treatment, which is typically energy intensive, and

minimizes the opportunity to contaminate potable water.

Fit-for-use is calculated by taking a weighted average that

uses scoring factors to represent how closely matched the

source water quality is with the quality required by the use.

3.3.5.5 Water degradation The goal of this impact cat-

egory is to promote system design that preserves water

quality. Industrial processes withdraw and use water from

the environment resulting in altered or degraded water

(e.g., increased temperature, salinity, turbidity). Systems

that minimize water degradation are preferred. Water

degradation is calculated as a weighted average of water

inputs and outputs multiplied by a scoring factor repre-

senting the extent of water degradation.

3.3.6 Impacts to land

3.3.6.1 Land degradation The goal of this impact cate-

gory is to consider land degradation resulting from the

activities of a system or component throughout its life

cycle. Systems that preserve ecosystems by reducing

incremental land use are preferred. Degradation is evalu-

ated using restoration time (Goedkoop et al. 2009). Res-

toration times represent the time it would take for an

ecosystem to regain its pre-disturbed state after a major

transformation. Land degradation is calculated by taking a

weighted average of incremental land use and restoration

times for ecosystem transformations.

3.4 Interpretation

Indexed scores (ISx) can be assigned to each alternative

within a particular impact category by calculating each

alternative’s impact in terms of a percentage score of the

worst performer. According to this indexing methodology,

the worst performer is assigned an indexed score of 100 %

and represents the outermost parameter of the scale against

which all other alternatives will be assessed. The indexed

scores for all alternatives not considered worst (Ax) can be

calculated by using Eq. 1.

220 Environ Syst Decis (2013) 33:209–223

123

ISx ¼1� Aworst � Axð Þ

Aworst

� �

� 100 ð1Þ

The resulting data can be plotted on a radar chart using a

scale of 0–100 % for each impact category. An example of how

the results can be illustrated is shown in Fig. 3. A demonstration

of the SLCA approach introduced in this article is anticipated in

the near future. Uncertainty or sensitivity analyses will be

conducted for the data used in a demonstration of the approach

and in the interpretation of results.

In this notional example, results for Alternatives 1 and 2 are

similar for several impact categories (e.g., ozone depletion

and chemicals and materials Availability). Potential impacts

to ecosystem health are less for Alternative 1 compared with

Alternative 2 and potential impacts associated with water

efficiency are less for Alternative 2 compared with Alternative

1. Trade-off analyses that prioritize water efficiency may

favor Alternative 2 if pollution control equipment could be

used to minimize potential impacts to ecosystem health. If

pollution control is not a viable option for this Alternative,

then assessors would need to evaluate trade-offs between

human and ecosystem health.

4 Discussion

The methodological approach for SLCA introduced in this

article is intended to promote the principles for sustainable

design. The SLCA should be less time and resource

intensive to complete compared with an LCA. The unique

features of this approach include the screening of processes

using the activity profile, collection of resource input data

for the processes with the greatest potential for impacts,

and application of scoring factors unique to the impact

categories assessed.

The activity profile includes the activity descriptor

which is used to highlight key characteristics of a system

that describe that system’s function or purpose. The

descriptor is used to identify activities that may result in

the greatest impacts to mission, human health, or the

environment. The activity profile plots these characteristics

by resource use and life cycle stage resulting in a roadmap

for inventory data collection. The approach is insensitive to

data type; quantitative, semi-quantitative, or qualitative

data can be used to estimate quantities of resources needed

across the system’s life cycles.

The SLCA approach does not require estimates of system

outputs and environmental releases generated throughout the

life cycle. Instead, this approach limits the inventory to

inputs, which results in a less resource-intensive data col-

lection burden. The inventory analysis results in a listing of

the quantities of energy, chemicals and materials, water, and

land needed by the defense system alternatives under study.

The quantities are then converted to impacts using scoring

factors for each of the impact categories. A scoring factor is

an indexed unit that allows the assessor to quickly estimate

Fig. 3 Radar chart showing

relative comparison of impact

scores. Distance from center

indicates increasing impact.

C&M Chemicals and Materials

Environ Syst Decis (2013) 33:209–223 221

123

the level of impact for a given impact category. It aggregates

all relevant emission factors needed to estimate outputs from

a specific input and the characterization factors needed to

convert that output to appropriate impacts. Because the

scoring factors are based on generalized emission factors and

characterization factors, the calculated impacts are not

considered as robust as those calculated using LCA; how-

ever, they should be sufficient for most trade-off analyses on

a relative scale. For more information about the derivation of

the scoring factors or for a list of the scoring factors, please

visit http://denix.osd.mil/esohacq or contact the corre-

sponding author.

The presentation of impact assessment results using the

radar chart provides decision makers with a comprehensive

comparison of performance and magnitude of impacts

between or among defense system alternatives. The chart

can be used to evaluate trade-offs and communicate results

to different audiences (e.g., product designers, policy

makers, environmental health professionals). Results can

be generated for different design options enabling assessors

to compare impacts of various design choices.

We believe that the presented SLCA approach improves

trade-off analyses by reducing subjectivity. Like LCA, the

proposed SLCA impact assessment methodology does not

remove subjective analysis across impact categories with

dissimilar metrics. However, the SLCA differs from LCA

in that it delays and refines this bias by inserting subjective

analysis post-processing. Doing so avoids skewing the

results of the impact assessment by pre-determining the

relative value of each impact category and allows stake-

holders to focus consensus-building efforts on the more

controversial indicators. Returning to the example in Sect.

3 will demonstrate this value. The two alternatives pre-

sented in Fig. 3 are very similar in terms of chemical and

material availability and recovery potential. Although these

are very important mission indicators, they will not impact

the trade-off decision in this assessment, and thus deter-

mining pre-established weights would have wasted valu-

able time and resources. Conversely, a more focused trade-

off analysis can result when evaluating impact results for

criteria where the two alternatives differ (e.g., human

health, ecosystem health and water efficiency).

5 Conclusions

In this article, we introduce a methodological approach for

an SLCA that can be used to evaluate sustainability of

defense acquisitions. The approach is rigorous, systematic,

and intended to provide guidance to decision makers.

Specifically, the SLCA aims to untangle the complex web

of relationships among impacts to mission, human health,

and environment to inform product design, or re-design,

and to justify trade-offs between areas of concern. The

approach is recommended for application in those cases

where assessors are faced with alternative options for the

design of a product system and where quantitative data

describing the system inputs are not readily available. Also,

it is intended to be used to assist sustainability-minded

decision makers, those who recognize the importance of

sustaining resources while preventing impacts to human

health, the environment, and the mission of a company, an

agency, or an industry sector. Future research activities will

include the application and demonstration of the method-

ological approach to acquisitions for defense and other

industries. With repeated application of the approach,

iterative revisions and improvements to inventory data

collection techniques and scoring factors will be necessary.

In addition, the breadth of impact categories may be

expanded to include physical hazards experienced in the

work environment (e.g., ergonomic stressors and fall haz-

ards) and the associated impacts on worker health as a

subset of the human health area of concern.

Acknowledgments The authors kindly acknowledge the leadership

and support provided by Mr. Paul J. Yaroschak, Deputy for Chemical

and Material Risk Management within the Office of the Secretary of

Defense, Department of Defense.

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