Paint and chemicals LCA: formulation, VOC and coverage efficiency
In chemical products, impact can concentrate in components that are small by mass. Formulation precision, solvent choice and area covered as the functional unit.
By clca Editorial TeamLast updated
The most common error in chemical product LCA is assuming impact tracks mass share. Filler may be half the mass of a paint yet carry a small share of the impact, while an additive at two per cent can account for most of the total in certain impact categories.
Model formulation components separately
A paint typically comprises binder resin, pigment, filler, solvent and additives. Each has a different production chain and is represented by a separate activity in the background database. Using one generic 'paint' activity makes it impossible to evaluate design decisions.
Titanium dioxide pigment is the textbook case. Providing opacity in white paint, it is around fifteen to twenty per cent by mass but has an energy-intensive production chain and is the single largest footprint line in most formulations. Optimisations that leave the TiO₂ share untouched deliver little.
Water-based versus solvent-based
Moving to water-based paint greatly reduces volatile organic compound (VOC) emissions and delivers a clear gain in the photochemical ozone formation indicator. That does not mean automatic superiority in every category: water-based systems need different binder chemistry and some applications require a thicker film or an extra coat.
- VOC shows up primarily in the photochemical ozone formation indicator
- Solvent production and solvent combustion are separate lines; both must be counted
- Drying time and energy can change in water-based systems
- Application loss (overspray) is decisive in industrial coating
- Packaging and cleaning solvent are skipped in most studies but are not small
Functional unit: area covered, not litres
The correct functional unit for paint is not 'one litre' but 'one square metre covered for a defined durability period'. Differences in hiding power between two products can make a per-litre comparison meaningless: a denser, more expensive paint that covers in one coat can produce less total impact.
Durability is the second dimension. An exterior paint lasting ten years versus one lasting five differs by a factor of two on an annualised basis. Repainting brings not only new paint production but surface preparation and labour with it.
Tags
- paint LCA
- chemical products
- VOC
- formulation
- functional unit
- sector LCA
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