NACE TM21423

Abstract

General This test method uses a thermesthesiometer (TM) instrument and defines specific test procedures and conditions to standardize the method for determining the temperature limits of the coating that pertain to personnel protection. These temperature limits are different from the service temperature limit of the insulative coating. This test method describes only one specific test, using the thermesthesiometer, for insulative coating systems. The reader is cautioned that other testing may be required for particular services. The user is responsible for investigating the need for other testing. Inclusion of other test methods is beyond the scope of this standard. This test method includes procedures to determine substrate and surface temperature limits for exterior insulative coatings used on hot equipment and piping. These coatings are used in a typical temperature range of 27 to 191 °C (80 to 375 °F) and thicknesses of approximately 0.1 to 5 mm (4 to 200 mil). They are typically liquid and applied onto primed substrates by spray application. The coating temperature limits are based on the temperature of the metal substrate to which the coating is bonded, or the temperature at the surface of the coating. These limits are used in relation to personnel protection against thermal burns to the skin. The end user and coating manufacturer can determine the coating’s ability to provide personnel protection based on the temperature limits on the substrate or the coating surface. The limits based on the metal substrate temperature shall be used to determine the minimum coating thickness required for a specific service temperature. (See Section 2, definition of Substrate Temperature Limit of the Coating.) The limits based on the coating surface temperature shall be used to validate that an existing or newly applied insulative coating is acceptable for personnel protection. See Section 2, definition for Surface Temperature Limit of the Coating. Test variables include coating thickness and the metal substrate temperature. The criteria used in this test method to determine the temperature limits are in accordance with ASTM C1055 and ASTM C1057. The thermesthesiometer shall be used in accordance with the design parameters in ASTM C1057 and calibrated in accordance with NBS(2) TN-816.5 This test method does not apply to conventional insulation materials that are typically greater in thickness than insulative coatings and are applied as blocks or forms to the equipment or piping. This test method is intended to be performed in the laboratory. Commercial primers that are not part of the insulation coating system, such as thermal spray coatings, shop primers, pre-primer coatings (blast retaining coatings), etc., shall not be included in this test unless they are approved by the insulation coating system manufacturer or the facility owner before commencement of the testing. (2) National Institute of Standards and Technology (NIST), 100 Bureau Drive, Stop 8500, Gaithersburg, MD 20899-8500. (Formerly the National Bureau of Standards [NBS]).