Abstract
Workers often perform tasks on high temperature equipment and piping. As they move about this equipment they may have unintentional contact with the hot surfaces resulting in burns to the skin. Thermal insulation is generally installed on metallic equipment at 60°C (140°F) or higher for personnel protection (PP). Insulative coatings are an alternative to the use of traditional insulation for PP where strict heat retention is not required. Although the external surface of the insulative coating (covering a hot surface) may heat up to temperatures greater than 60°C, it can be touched at a much higher temperature (with no resulting skin burns) than for a hot metal substrate because of the coating's lower thermal conductivity. This is a well known fact, but the perception of many plant personnel, who work with insulation and specify it, is that the coating surface must also be less than 60°C. This report presents work that validates the use of an insulative coating for PP in accordance with ASTM C1055, C1057, and ISO 13732-1. Test variables included coating thickness, metal substrate temperature, ambient air temperature, surface roughness and hot vs. ambient coating application. In addition to determination of the burn thresholds, the results confirm that significantly higher surface temperatures, greater than 60°C, are allowed for insulative coatings without harm to personnel. This report also shows how the surface temperature limits (or burn thresholds) are affected by the variables listed above.
