Material Selection In The Context Of Sustainable Buildings

Ingo Ratsdorf, BE Arch. Architect, Building Biologist, ANZIA

What is it about?What is it about?

Presentation structured into two parts:

1) Introduction to Material Life Cycle Life cycle stages Implications on sustainability

2) The selection process Shortlisting Decision making

Part 1: IntroductionPart 1: Introduction

Materials for sustainable buildings mirror similar stages as those of buildings:

Design Raw material acquisition Production Use End-of-life

Each stage has environmental impacts

Product designProduct design

Modern products are designed for useful service life

No consideration for end-of-life Clever design would make product reusable,

recyclable Product should feed production of new items of

equal or better quality

ProductionProduction

Production involves raw materials and energy Creates pollution, by-products and waste Cradle-to-Gate LCA stops here Environmental certification stops here Embodied energy rating usually stops here

In-Use stageIn-Use stage

Product incurs transport to site Dealing with leftovers Maintenance required to achieve durability Maintenance products have own lifecycle

End-Of-LifeEnd-Of-Life

Disassembly for reuse or recycling Reusability rarely possible Recycling cycles limited, paper up to 7 times,

aluminium and PET virtually unlimited Energy for recycling needs consideration Downcycling is a one-way-street and renders

materials useless Disposal is a waste of material and money

Part 2: Selection ProcessPart 2: Selection Process

Environmental certification and Cradle-to-Gate LCA can be misleading as it (usually) does not consider the impact of the In-Use and Disposal stage

Eco-Certified products will incur transportation, maintenance and might eventually end up in landfill too.

LCA tools give an insight to performance and might refute common perception

LCA Example: TransportLCA Example: Transport

Environmental performance of cladding materials:No allowance for transport.

LCA Example: TransportLCA Example: Transport

Environmental performance of cladding materials:Allowance for 8000km transport for cedar only.

LCA Example: FlooringLCA Example: Flooring

The following tables are taken from the LCA tool BEES 4.0.The results are for a functional unit of 1 ft2 – 0.09 m2 for a period of 50 years.

LCA Example: FlooringLCA Example: Flooring

You cannot trust your perception Impact is not determined by “natural” or

“artificial” but by manufacture, use and disposal Economics should take into account long term

effects on human health and the environment Transport can have significant impact

Selection processSelection process

LCA LCA good way Not available for all products Little data available in NZ Not available for the common specifier

1. Blacklisting Materials1. Blacklisting Materials

List materials that should be avoided Contains (potentially) hazardous substances Proven or strongly expected impact on

environment or human health Asbestos, Arsenic, Chromium, Benzene,

Formaldehyde, ...

2. Greylisting Materials2. Greylisting Materials

Materials that are not preferred Blacklist candidates with no viable substitution

option or contribute to the mitigation of environmental impact

Indefinitely recyclable materials containing blacklist substances without exposing them

3. Whitelisting3. Whitelisting

Materials that are deemed to be safe Non toxic Indefinitely recyclable Biodegradable Low embodied energy

ShortlistingShortlisting

Divide materials into the three groups Request detailed product information Make an educated guess on embodied energy Check biodegradability and recyclability Support local products – avoid transport Throughly check environmental certification Check production and disposal options

ConclusionConclusion

No straightforward selection method Check your construction, not just the material

selection Suitability is connected with use and detailing Material selection is integral part of the design

and cannot be done at any later stage