Architects memo no.
90: February 2008
in the valley of the blind
The enthusiastic manner in which local businesses are embracing sustainable
practices is compelling evidence that we really do want to do the right
thing. And why not? Sustainability makes good sense. While it may mean
somewhat different things to different people, the definition from the
American Heritage dictionary 'Capable of being continued with minimum
long-term effect on the environment' seems to encapsulate the nub of
When Environmental Choice NZ was set up, industry was given the opportunity
to input into the criteria. The paint industry presented a strong case
that any paint considered must first pass a recognised quality standard.
The thinking was that, first and foremost, the paint must be able to
do its job. There was, at that time, evidence from overseas that poorly
performing paints, sold as environmentally friendly, had, in fact, a
greater environmental footprint because of the need for more frequent
To their great credit, ECNZ heeded this advice, ahead of several overseas
jurisdictions who are only now adding actual performance to their criteria.
Given the performance requirements, the main thrust of Environmental
Choice was to lower heavy metal content, the use of hazardous materials
Rarely is anything completely straightforward, even in the case of
heavy metals. There are several heavy metals including copper, chromium
and zinc which, although toxic, are considered, at low levels, to be
essential to human health. Selenium which, because of the high levels
in grass in some of the mid-western states of the USA, causes toxicity
in grazing animals, needs to be added to animal feed here because our
low levels can cause deficiency problems.
VOCs are also a contentious subject as discussed in Memo 81. The rational
facts of the matter are that the small levels of the relatively low
toxicity solvents, especially the sort that are used in waterborne paints,
are never going to be the cause of any serious environmental problems
either short or long-term. Further, there is no waterborne paint - even
zero VOC paint - that would not form a better film with the addition
of a little solvent. And yet the paint issues in sustainability seem
to have come down to a Dutch auction over VOC levels.
Even the quasi-regulators seem to have lost direction, or, at least,
not to have kept up with technology. A low sheen acrylic is restricted
to a very low VOC per litre under some green programmes, whether it
be a conventional latex type or whether it be a waterborne enamel. The
former are relatively mature technology while the latter are actively
replacing high VOC alkyd enamels. The anomaly is that a 200gm solventborne
enamel is happily accepted by the green legislators while a 55gm VOC
low sheen waterborne enamel replacement with nearly a quarter of the
VOCs is not! Crazy.
There should be no discrimination between solvent and waterborne systems.
A set of performance parameters should be laid down for a paint and
a target VOC set. Paints must firstly meet the performance requirements
and, only then can they be selected on VOC.
The use of renewable resources is seen as an important element in achieving
sustainability. For the paint industry, if this is able to be achieved
from materials or byproducts that would otherwise go to waste, then
this would be very desirable. The reality is, however, that the major
renewable resource used by the paint industry are vegetable oils, which
would otherwise be used for human consumption or animal feed.
There is a certain moral dilemma here. The major swing in America to
using maize as a raw material for bio-fuel has already seen a tightening
of supply (and hence a rise in prices) to the animal feed market. Further
shifts in this direction could produce profound distortions in the agriculture
Resene's stance is unequivocal. We believe that our best contribution
to sustainability is to offer longevity and thus reduce the need for
repainting. Reducing toxicity has always been a way of life at Resene
but quality remains paramount.
If you will forgive the use of brand names, the following example fully
illustrates our stance:-
A wall on a public convenience is to be coated with a gloss finish.
System A is Resene Quick Dry undercoat and Resene Hi-Glo. The wall
gets tagged regularly and, because the graffiti bites deeply into the
Resene Hi-Glo, repeated cleaning fails to remove it and the wall must
be repainted. This is a monthly occurrence.
System B replaces the Resene Hi-Glo with Resene Uracryl, a two-pack
acrylic urethane. The tagging gets wiped off easily and, because of
this, after a while the tagging stops. The system is still performing
in the second half of its second decade.
Does Uracryl have a high VOC? - yes. Is the VOC toxic? - somewhat but
not very. Does the system continue 'outgassing' during its life? - no.
Can uncured isocyanates be dangerous if sprayed? - yes. Is the cured
film toxic in any way? - no. Is this a sustainable system? - oh yes