Number 9, March 2005

» Chrysotile better than PVA
» Another product to be banned by France?
» Cancer in the kitchen?
» Up in the air (by Sophie Stone)
» Read for you : Solving the asbestos imbroglio in the United States
» The final proof

Chrysotile better than PVA

This is the simple conclusion of the National Institute of Engineering and Industrial Technology of Portugal which recently conducted a study to compare, in terms of eco-efficiency, the life cycle of chrysotile fibre-cement roofing sheets and polyvinyl alcohol (PVA) fibre-cement roofing sheets.

The conclusion of the study is the following:
“If the objective of the study were to compare the environmental impact associated with the life cycle of the types of fibre-cement and, from this, extract information that would be used as a basis for future decision-making processes in the Company (Cimianto – Sociedade Técnica de Hidraulica), then the results obtained allow the following conclusion to be drawn: AT (asbestos) sheets are economically and ecologically more favourable, in other words, they are more eco-efficient.”

Products under analysis

Two types of fibre-cement sheets were studied and compared with each other:

- 177 AT – 2.00 m profile sheets, containing chrysotile asbestos fibres;
- 177 NT FS – 2.00 m profile sheets, containing PVA (polyvinyl alcohol) fibres.

Both types have the same length and width, and each sheet of both types provides 1.89 square meter of roof coverage for buildings. Note that they serve the same purpose: protecting the interior of buildings from the weather. They do not have the function of providing thermal insulation.

The analysis for chrysotile was based on a 50-year service life scenario.

The analysis for PVA was based on a 50-year and a 30-year service life scenario.

Economically better

To manufacture one palette of chrysotile fibre-cement roofing sheets (60 sheets) will cost 183.47 Euros, plus 5.53 Euros for its packaging. Manufacturing one palette of PVA fibre-cement roofing sheets (60 sheets) will be 242.76 Euros (50 years of service and 339.86 Euros for 30-year service life). For the packaging, it will cost 8.42 Euros (50-year and 11.79 Euros for 30-year).

The grand total cost of manufacturing one palette of chrysotile fibre-cement roofing sheets will be 197.58 Euros (this includes the price for the basic material, the packaging, the energy needed and the cost for waste management over 50 years).

The grand total of money needed to manufacture a palette of PVA fibre-cement roofing sheets will be 264.90 Euros (includes all the previous mentioned above) for a 50-year service life and 370.86 Euros for a 30-year service life.

Ecologically better

One needs to spend 7.77 Euros in energy to manufacture one palette of chrysotile fibre-cement roofing sheets and 10.71 Euros for the same in PVA (50-year and 14.99 Euros for 30-year scenario).

A palette of chrysotile fibre-cement roofing sheets will cost 0.81 Euros in waste management and a PVA palette will cost 3.01 Euros (50-year service life) or 4.21 Euros (30-year service life).