ASTM C1199-22 PDF Download

ASTM C1199-22 is a standard test method that provides requirements, guidelines, and calibration procedures for measuring the steady-state thermal transmittance of fenestration systems using hot box methods. The test method specifically applies to fenestration systems installed vertically in a test chamber. It refers to the thermal transmittance, U, of the fenestration system in the absence of solar radiation and air leakage effects.

The test method describes how to determine the thermal transmittance, U_s, of a fenestration product (test specimen) under well-defined environmental conditions. The thermal transmittance is an important test result that is also reported using Test Method C1363. The test report must include a detailed description of the environmental conditions in the thermal chamber during the test.

For rating purposes, the test method also provides a standardized thermal transmittance, U_ST, which allows for comparison of test results from different laboratories with different thermal chamber configurations. The test method specifies two methods for calculating the standardized thermal transmittance: the Calibration Transfer Standard (CTS) Method and the Area Weighting (AW) Method. The selection of the method depends on the thermal transmittance value and the ratio of test specimen surface area to wetted surface area.

The standard also includes a discussion of terminology and underlying assumptions for measuring the thermal transmittance. It provides important information for ensuring accurate and consistent measurement of the thermal performance of fenestration systems.