Heat reflective polyurethane coating

[TechnoWest]

Peers,
I need assistance identifying a manufacturer of polyurethane coatings designed to reduce heating from solar radiation. The application is a steel handrail where I'm required to reduce the surface temperature 20F-30F. I am aware that color selection will make a difference. White might be the best color choice but not cosmetically acceptable. I need a tintable polyurethane paint with tinting colors designed for minimal apsorption change in the infrared range.

Brent Bergman
Techno Coatings, Inc.

 

[kenvlach]

To minimize solar heat gain, you want high visible reflectance and high infrared emittance. The problem with metals is low IR emittance. IR reflection only matters if dealing with a local heat source (furnace or exhaust system). See 'Radiation Control Fact Sheet' and links therein at

http://www.ornl.gov/sci/roofs+walls/facts/SolarRadiationControl.htm

The best paints for minimizing heat gain are white, such as titanium oxide pigmented.

For more links, see

http://eetd.lbl.gov/HeatIsland/CoolRoofs/

http://eande.lbl.gov/CoolRoof/metal.htm#metal

 

[IRstuff]

The paint layer should also be THICK, to minimize the thermal conduction to your hand, particularly from the hot steel underneath.

Another possibility is to make the painted surface bumpy, to minimize the contact area with the hand.

TTFN

 

[TechnoWest]

Both ideas, thickness and textured surfaces, may offer some promise. As a follow-on, paint manufacturers now have access to pigments that offer a range of visual colors and minimal reduction in IR reflectance. Shepherd Color and Ferro Inc. are two manufactures that may be able to help. Ferro offers examples of a medium brown color that is 47 degrees cooler than a conventionally pigmented brown in the same color.

Brent Bergman
Techno Coatings, Inc.