LIFE CYCLE ASSESSMENT

One.of.the.main.difficulties.of.reducing.the.environmental.impact.of.any.activity.is.quantifying.it.in.

order.to.contain.it..Although.methods.for.evaluating.environmental.impact.are.numerous.and.they.

differ.in.their.ability.to.identify,.measure,.and.interpret.the.impact,.they.generally.have.the.follow-ing.limitations.in.common:

•. They.are.developed.for.each.single.case.

•. They.cannot.predict.the.reliability.and.stability.of.the.results.through.sensitivity.analysis.

•. There.is.no.basis.of.a.life.cycle.approach.as.hitherto.considered.

Of.the.various.methods,.only.the.methodology.known.as.life.cycle.assessment.(LCA).gets.over.the.

above-mentioned.limitations,.because.it.evaluates.environmental.impact.on.a.set.of.presupposi-tions.that.objectively.evaluate.resource.consumption.and.waste.disposal.of.a.generic.company—

or.rather.the.whole.life.cycle.of.that.company’s.product..This.is.carried.out.by.determining.the.

amounts.of.exchange.flow.between.the.product.life.cycle.and.ecosphere,.that.is,.all.the.transfor-mational.processes.involved.from.the.extraction.of.raw.materials.to.their.return.to.the.ecosphere.in.

the.form.of.waste.

2.9.1  M

ethoDological

 P

reMises

, P

roPerty

, 

anD

 s

tructure

The.ISO.14040.standards.detail.the.general.criteria.and.methodological.structure.on.the.basis.of.

which.to.carry.out.the.principal.phases.of.a.complete.LCA..These.derive.from.a.set.of.criteria.estab-lished.by.the.Society.for.Environmental.Toxicology.and.Chemistry.(SETAC).in.the.early.1990s..

The.basic.definition.of.an.LCA.summarizes.SETAC’s:.an.LCA.consists.of.compiling.and.evaluat-ing.inputs,.outputs,.and.the.potential.environmental.impacts.of.a.product.through.its.life.cycle..The.

methodological.structure.is.based.on.certain.premises:

•. Environmental.interaction.analysis.of.the.basic.activities.of.the.chain.known.as.the.life cycle is.a.cradle-to-grave.analysis.

•. The.life.cycle.approach.is.holistic.(as.discussed.earlier).

•. Analyzing.environmental.effects.is.from.a.multicriteria.viewpoint.evaluating.the.entire.

panorama. of. impact. categories. and. environmental. damage. that. could. be. affected. by.

product-ecosphere.interaction.

•. Evaluations.and.activity.comparisons.are.based.on.a.functional.unit.and.thus.on.the.principle.

•. Goal and scope definition defines.the.analysis.goals.and.the.overall.preliminary.assump-tions. on. which. they. are. based.. The. evaluation. types. are. also. defined. (those. aimed. at.

improving.the.system.or.comparing.alternatives).as.are.the.system.limits,.the.functional.

unit.reference,.the.assumptions.and.parameters.for.inventory.and.allocation,.and.the.impact.

categories.

•. Inventory analysis. (LCI). includes. the. compilation. and. quantification. of. the. inputs. and.

outputs.of.the.whole.life.cycle..The.data.used.for.this.might.come.from.various.sources.

including.direct.measurements,.as.well.as.data.from.databases.and.literature.

•. Impact assessment. (LCIA)—Inventory. data. are. expressed. as. potential. environmental.

impacts,.evaluating.their.size.and.significance..Conventionally,.inventory.flows.are.classified.

(classification).and.characterized.quantitively.in.relation.to.different.impact.categories.(char-acterization)..Impact.data.can.subsequently.be.normalized.(normalization).and.weighted.

(weighting).to.obtain.single.indices.of.environmental.impact.

•. Interpretation. (ISO)/improvement analysis. (SETAC)—The. LCI. and. LCIA. results. are.

evaluated.in.relation.to.the.prime.objectives.so.that.conclusions.and.improvements.can.be.

made.

As.Figure.2.6.shows,.the.structure.according.to.the.four.main.phases.described.above.is.common.to.

the.LCA.method.(SETAC).and.the.ISO.norms.

Classification

Impact assessment Mandatory Interpretation

Optional

SETAC framework

ISO 14040 framework

Valuation

Selection

Goal and scope definition

Goal and scope

FIGURE 2.6 LCA.framework.according.to.SETAC.and.ISO.14040.

The.only.significant.differences.can.be.found.in.the.impact.assessment.phase.and.in.the.inter-pretation.and.improvement.phase..In.the.first.phase.(LCIA),.the.SETAC.setup.differs.to.the.ISO.

standard.because.evaluating.impact.is.more.rigid,.not.only.in.their.classification.and.characteriza-tion,.but.also.by.concluding.with.a.valuation.that.includes.weighting.the.different.types.of.impact.

to. obtain. results. that. can. be. compared. or. aggregated. depending. on. which. are. used. in. the. final.

decision.

In.the.second.case,.there.is.a.net.distinction.between.mandatory.and.optional.procedures..The.

former.include.selecting.which.environmental.effects.to.consider.selection,.classification,.and.char-acterization..Optional.procedures.include.normalization,.grouping,.and.weighting, which.involve.

processing.the.results.of.the.characterization.phase.to.obtain.synthetic.indices.that.enable.a.complex.

evaluation.

As.regards.the.last.phase,.SETAC.differs.from.ISO:

•. In.the.first.case,.improvement analysis.focuses.on.how.to.make.improvements.in.environ-mental.performance.

•. In.the.second.case,.interpretation.means.more.extensive.intervention.that.includes.sensi-tivity.analyses,.uncertainty.evaluations.of.the.results,.and.the.formulation.of.conclusive.

recommendations.

2.9.2  e^co-i^{nDicators to} Q^uantify environMental i^MPact

The.environmental.impact.properties.of.materials.and.processes.can.be.evaluated.by.LCA.tech-niques.already.seen.as.a.method.of.identifying.and.quantifying.the.resources.used,.and.the.waste.or.

emissions.generated,.through.inventory.data.with.a.subsequent.evaluation.of.environmental.impact.

In. the. initial. setup,. LCA. does. not. provide. unequivocal. conclusions. about. any. given. product,.

material,.or.process,.but.relies.on.appropriate.interpretation..This.gives.rise.to.the.following.two.

problems:

•. LCA.results.are.difficult.to.interpret..Product.impact.on.a.single.category.(global.warming,.

hole.in.the.ozone.layer).can.be.defined,.but.the.total.impact.on.the.environment.remains.

unknown..This.is.due.to.the.lack.of.unequivocal.weightings.for.each.single.effect.on.over-all.impact.

•. Generally,.carrying.out.a.detailed.LCA.is.a.complex.operation.requiring.masses.of.data.

and.lots.of.time..This.means.that.a.complete.LCA.could.not.be.carried.out.during.the.first.

phases.of.designing.a.new.product.

The.Eco-Indicator 99 method.was.developed.for.product.design.and.helps.quantify.and.compare.

results.provided.by.LCA..The.method.has.proved.useful.for.designers.to.translate.LCA.results.into.

easily.applicable.numerical.values.called.eco-indicators.

Use.of.eco-indicators.can.help.resolve.the.applicability.of.LCA.in.two.ways:

•. Identifying.single.scores.which.are.capable.of.expressing.overall.environmental.impact

•. Developing.an.eco-indicator.database.for.most.common.materials.and.processes

Eco-indicators.are.based.on.defining.the.damage.arising.from.the.relationship.between.impact.

categories.and.the.damage.to.man’s.health.and.the.ecosystem..In.particular,.the.following.three.

types.of.damage.are.considered:

•. Human health.considers.the.number.and.duration.of.human.illnesses,.and.the.number.of.

years.lost.due.to.premature.death.caused.by.the.environment—climate.change,.the.reduc-tion.in.the.ozone.layer,.carcinogenic.effects,.and.respiratory.effects.

•. Ecosystem quality—Effects.on.different.animal.species,.principally.on.vascular.systems.

and.microorganisms—eco-toxicity,.acidification,.and.soil.usage.

•. Resources—Energy. required. to. extract. raw. materials. and. fossil. fuels. and. consequent.

resource.impoverishment.

Eco-Indicator.99.provides.values.for.most.types.of.process,.summarized.as.follows:

•. Materials.production—Eco-indicators.refer.to.the.production.of.1.kg.of.material..To.obtain.

these. values,. all. materials. production. processes. were. taken. into. account. including. raw.

material.extraction.and.its.transport.during.all.the.refinement.phases..The.production.of.

industrial.goods.(machinery,.buildings,.etc.).has.not.been.considered.

•. Production.processes—Eco-indicators.are.impact.values.of.the.primary.and.secondary.treat-ments.and.manufacturing.processes.of.various.materials,.each.expressed.in.an.appropriate.

unit.(a.significant.parameter.of.the.process)..Production.process.values.include.quotas.for.

emissions.and.required.energy..Even.in.this.phase.industrial.goods.have.not.been.included.

•. Transport—Eco-indicators.are.expressed.in.tons.per.kilometer..Emissions.caused.by.fuel.

extraction. and. refinement. are. accounted. for. as. well. as. the. emissions. during. transport..

Usually,. the. units. of. measurement. are. tons. per. kilometre,. but. others. can. be. used.. An.

unloaded.return.journey.is.also.accounted.for..The.impact.of.industrial.goods.(e.g.,.those.

relating.to.producing.the.truck,.building.the.roads.and.railways,.the.availability.of.cargo.

planes.in.airports,.etc.).are.also.included.in.calculating.eco-indicators,.as.their.contribution.

is.significant.

•. Energy.production—Eco-indicators.for.electricity.and.heat.take.into.account.fuel.extraction.

and.production,.the.transformation.of.energy,.and.the.generation.of.electricity.by.which-ever. fuel. (in. Europe).. Apart. from. their. average. values. for. Europe,. other. eco-indicators.

have.been.formulated.for.other.nations.according.to.the.technologies.used.to.produce.the.

electricity.

•. Retirement.and.recycling.scenarios—Eco-indicators.are.expressed.in.kilograms.of.retired.

material.differentiated.according.to.type.and.method.of.waste.treatment..Not.all.products.

are.retired.in.the.same.way,.so.eco-indicators.are.careful.to.account.for.specifics..Paper,.

glass,.and.plastic.can.be.collected.separately.and.recycled..If.a.product.is.only.partly.recy-clable,.it.is.better.off.in.the.city’s.recycling.program..Scenarios.for.both.cases.have.been.

evaluated,. and. in. addition,. some. alternatives. introduced. such. as. incineration. and. some.

other.types.of.recycling.of.materials.

2.10 INTRODUCING ENVIRONMENTAL FACTORS IN THE DESIGN PROCESS Although.the.most.significant.questions.about.the.environmental.aspects.of.industrial.production.

•. Life.cycle.oriented.product

•. Harmonization.of.a.wide.range.of.requisites

•. Simultaneous.structure,.integrated.with.design

Only.on.the.basis.of.these.premises.can.a.process.of.product.development.be.conceived.that.embod-ies.life.cycle.sustainability.and.the.ideal.of.a.product,.used.and.retired.with.the.least.impact.on.the.

environment.

In document Mechanical Design (2) (Page 45-49)