Personnel Protection

Surfaces in the temperature range of 140F will burn bare skin, setting the upper safe level as referenced within the ASTM C1057 Personnel Protection standard. This standard is based on the principal of being able to safely touch a hot surface with bare skin for 3-5 seconds. The standard was established using a thermesthesiometer, a device that measures heat transfer in a way that's similar to human skin. 

Reducing Surface Temperature

Surface temperatures up to the 350-400F range can be reduced to safe levels with ceramic insulation coatings. The 320F-350F range may be considered a practical upper limit to ceramic coatings if there's a high probability of exceeding that range for extended periods of time. If that upper limit is not exceeded then protection can be provided with thicknesses as low as 0.080-0.120". Ceramic coating can be applied while equipment is in service with the benefit that application time can be significantly reduced.

PERSONNEL PROTECTION AND CERAMIC-BASED INSULATION COATING THICKNESS FOR WORST CASE AMBIENT TEMPERATURE OF 38C OR 101 F

The following chart is a quick reference guide to determine minimum thickness for ceramic-loaded latex insulation coating for Personnel Protection (PP) limits of 60C/137F based on definitions of ASTM C1055 and ASTM C1057 together with ISO 13732-1:2006.

The chart represents 5 second skin exposure on hot surfaces based on surface measurements using the ASTM/ISO defined surface measurement instrument, a thermesthesiometer. This specialized instrument is used based on its ability to accurately measure “heat flux”, the rate of heat energy transfer through a given surface.

The thermesthesiometer used for reading heat flux energy at the insulation coating surface measures heat in the same manner as human skin. The references below further explain the industry standards and provide links to more detailed data.  

SURFACE TEMPERATURE VALUES FOR CERAMIC INSULATION COATING

Coating Thickness

40 mils

0.040"

80 mils

0.080"

120 mils

0.120"

160 mils

0.160"

Substrate Temperature

Surface Temp

Surface Temp

Surface Temp

Surface Temp

150 Fahrenheit

107

n/a

n/a

n/a

200 Fahrenheit

111

107

105

105

250 Farhenheit

120

111

111

108

300 Fahrenheit

130

119

117

113

350 Fahrenheit

146

135

125

124