We are working on a number of projects where a large amount of internal metal staircases and other architectural steel elements need finishing and painting on site. These are generally 2 pack polyurethane high solid content paints that are sprayed on site to achieve a durable finish. Past versions of SCAQMD Rule 1113 allowed a VOC content of 500 g/l for these products under the 'Metallic Pigmented Coatings' category but this has now dropped to 150 g/l. Since the introduction of LEEDv4, these products also need to meet VOC emissions testing requirements which poses a further challenge.

After speaking with all the big names in paint manufacturing, they all told us that at present they do not have equivalent paints that would also meet these new VOC requirements. Some of them confirmed that they are developing water based top coats but these are far away from being VOC tested (mainly as their primary market is the automotive industry).

Before painting, these steel structures also require filling (to bridge gaps and imperfections), which is generally done with a metal body filler putty (also primarily used by the automotive industry). The amount of filler used tends to be relatively small so we can still meet the 75% VOC emissions evaluation requirement although I suspect on small projects this might be an issue.

Has anyone else came across this problem and if so, could you share how you have overcome this?