Eco Priority Guide: Adhesives, Tapes & Fasteners

Eco-Priorities

Look for materials in the product database that address the following priority issues:

Priority Order

Mechanical fixers

Mortar

Mineral

Adhes.

(Grout)

Natural adhesive

Synthetic solvent or water based

Synthetic, UV cured

1

Env. Tox.

GHG

GHG

 

GHG

Env. Tox.

GHG (low order)

GHG

Env. Tox.

Env. Tox.

2

Resources

Env. Tox.

Health

 

Health

Resources

3

Habitat

Resources

Resources

 

Resources

 

Red Light?

 

 

 

 

 

 

Example

Bolts, screws

Portland Cement

 

e.g. Casein, Soy

Mineral glues, epoxy

 

*'Red Light' issues are issues that are high-concern and are an eco-design basis for not using the product.

Overview

Adhesives have in a few short decades become ubiquitous in our homes and workplaces. In EU houses it is not uncommon for more than half a tonne of glues and mastics to be used, which is quite likely to apply also in Australia (Berge 2000). And yet our understanding of the life-cycle and effects of these adhesives on our health and environment is far from complete. For example, indoor air quality has been identified in recent years as one of the most significant public health issues facing Australia (CASANZ 2002), and adhesives and their use play a major role in determining indoor air pollutants, especially in the weeks and months after construction, and in the health of construction workers. Carpet applications are a significant source of adhesive emissions, with standard practice in commercial applications being to spread adhesive over the entire floor area to be carpeted.

Quick Guide

Mechanical Fasteners (e.g. steel, galvanized and chromium plated metal fixings)

For:

· Can enable or facilitate disassembly (excluding nail plates)

· Higher-value items, typically have low wastage levels on site

· Do not offgas in use. Non-toxic in use.

· Waste products relatively inert

Against:

· Use of metals with limited or quite limited reserves

· Some metals (e.g. chromium) high in embodied energy, and highly toxic

· Higher on-site energy requirements to fix

 

Mortars (OPC or lime)

For:

· Potential to facilitate disassembly

· Relatively low-energy product overall

Against:

· Modern mortars usually high-strength OPC's that effectively prevent high-value reuse of bricks and disassembly

· OPC has significant energy requirements and emissions associated. Kiln efficiency varies widely

Grouts (mineral adhesives)

For:

· Fixing material for high-durability ceramic products.

 

Against:

· Bond strength typically prevents disassembly

· Typically has a high proportion of acrylate (energy, toxicity and pollution loads) with cementitious base. In some countries acrylate-cement glues must be deposited at special tips.

Natural Adhesives

For:

· Low energy production

· Non-toxic except where fungicides used

· Low environmental impact

· Low-zero VOC, any VOC's not solvent or hydrocarbon based

Against:

· If not treated with fungicides are susceptible to moisture and rot. Additional protection and care required.

· Some contain animal constituents, an ethical issue for some users.

Synthetic 'solvent' or water-based adhesives

For:

· High-strength, high durability bond

· Can be moisture and rot-resistant

Against:

· Very high energy requirements in production

· Significant health impacts from VOC's from some products in production and use phase with emissions commonly including styrene, acetone, phenol, formaldehyde, butadiene (refer 'chemicals' article)

· Glues may take days, weeks or months to fully cure, emitting low levels of ongoing VOC's

· Use of many toxic and hazardous products in production

· Significant GHG emissions

Synthetic UV Cured

For:

· Much lower or extremely low VOC's as polymerisation is based on external energy source (e.g. UV beam) rather than evaporation of solvents.

· Highly stable/ zero VOC product after factory curing

Against:

· Factory only, not suitable for onsite use

· Production uses many toxic and hazardous products

· Higher energy requirements in curing phase

Making a Decision

Commentary

Mechanical fixing is generally preferable in the overall context of designing for maintainability, reuse and disassembly. The ubiquitous use of adhesive fasteners is one of the greatest barriers to future recycling of our current building stock.

The practice of gluing and nailing solid timber floors, for example, is driven by the desire for a 'squeak-free' floor. In large part the significant recycled timber industry of today is founded upon timber floor recycling. Although solid timber floor specification has been very strong in the sustained 10-yr housing boom, it is unlikely that any of these tens of thousands of floors will be able to be reused in 30-60 years time.

Natural glues have significant environmental advantages over synthetic glues, not the least of which being reduced VOC's for interior applications e.g. workstation assembly (refer Maxton Fox workstation).

In the synthetic glues PVAC and EVA ('water based' glues) are considered the least problematic.

Epoxy glues are considered one of the most problematic. It is a highly effective allergen and according to Berge, 'at places of work exposed to it, up to 80% of the work force have developed epoxy eczema' (Berge 2000). It is considered inert once cured.

It should be noted that water-based glues have significant VOC emissions, and to reduce their use of aromatic solvents (hydrocarbons) use significant quantities of other chemicals (e.g. acrylic) that have significant environmental loads. Refer the product guide for low VOC adhesives for common applications.

Decision-Making Checklist

  1. Appropriate Use: does a thing have to be made? If so, does it create a net benefit?
  2. Fate: start with the end in mind. Design for reusability or recyclability or at worst low/zero toxicity disposal/ energy recovery. Does waste = food?
  3. Energy: consider the product's likely net energy balance over its life. Will it save more energy than it uses?
  4. Biodiversity: is it likely that the product has had a negative impact on biodiversity? Are there any known Red Light issues?
  5. Toxicity: is the product toxic and/or persistent and/or bioaccumulative in the environment at any stage in its life cycle? Are there known 'Red light' issues?
  6. Resources: does the product use scarce resources?
  7. Is the product socially sustainable?
  8. Systems approach: does use of the product create or allow whole of design synergies?

Further Information

Refer to the Technical Guide section for information on:

· Overview and statistics on sector
· Embodied energy figures
· Relevant standards and eco-assurances
· Less-toxic products & alternatives
· Case studies
· Recommendations
· Further links and references

Selected Links & Resources

Australian Environmental Labelling Association Standards Register:
Overview: the Adhesives pdf contains detailed information about what adhesives should/shouldn't contain to meet Eco-Label environmental standards. Has useful links to Eco-labelling and LCA resources.
www.geca.org.au/geca-standards.html

CRI: Carpet and Rug Institute
Overview: An American Industry site that explains basic issues around carpet and carpet adhesive selection. See article on Indoor Air Quality and Frequently Asked questions, for general information on what the hazards for human health are in carpets.
Source: carpet-rug.com/

Oikos
Overview: contains information about a range of environmentally preferable adhesives, however is limited in use to American manufacturers. 
http://oikos.com/library/index.html

References

Berge, B. (2000). Ecology of Building Materials. Oxford, Butterworth Heinemann.
CASANZ (2002). Indoor Air Quality in Australia: A Strategy for Action. Canberra, Federation of Australian Scientific and Technological Societies.

 

All external links last accessed on 27/03/13.