ASTM C518 is a standard test method for measuring the steady-state thermal transmission properties of insulation materials using a heat flow meter apparatus. This test method is used to determine the thermal conductivity and resistance of insulation materials, such as foams, fibers, and rigid boards, under steady-state conditions.

Last Updated: September 18th, 2023 First Published :


Why Do You Need ASTM C518 and What Does It Mean?

ASTM C518, which is a test technique, is the Standard Test Method for Steady-State Thermal Transmission Properties using the Heat Flow Metre Apparatus. Using a hot plate and a cold plate along with heat flux transducers to gauge how heat in the material moves between the two plates, you may test your material physically. This test is used to determine the thermal conductivity of a wide range of materials with variable conductivity levels and thicknesses.

The most typical application of this test is to determine precisely how effective insulation is. The ASTM C518 test can produce both an R-Value and a K-Value (thermal conductivity) (thermal resistance). These measures allow you to show consumers how a specific material may be superior to others as insulation while also proving that it complies with federal rules for insulation materials.

For insulation and systems, the ASTM C518 is a requirement of the building code.

Other Typical Tests Conducted Using ASTM C518

This test method can be used to evaluate the thermal conductivity and thermal resistance characteristics of materials such as window materials and other construction materials in addition to insulation.

The ASTM C518 may be preferable in some circumstances to the ASTM C177. While the Heat Flow Meter Apparatus is used in the ASTM C177 test, a Guarded Hot Plate Apparatus is used in place of it.

Video 01:Thermal Conductivity Measurements by HFM (ASTM C518) [SUPERSEDED]


ASTM C518 is an important test method for measuring the steady-state thermal transmission properties of insulation materials using a heat flow meter apparatus. This standard provides detailed guidance on the test conditions, sample preparation, measurement procedures, and reporting requirements for accurately determining the thermal conductivity and resistance of insulation materials.

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