ASTM D150 AC Loss Characteristics and Permittivity of Solid Electrical Insulation

    What is ASTM D150? 

    ASTM D150 is a standard test method to determine the relative permittivity, dissipation factor, loss index, power factor, phase angle, and loss angle of solid electrical insulating materials. This test method positions a specimen between electrodes, measures the specimen’s capacitance and dissipation at a specified frequency, and then calculates the values as if the measuring standards were lumped impedances. The frequency range is from below 1 Hz to several hundred megahertz. ASTM D150 (Standard Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation) determines the ability of an insulating material to store and dissipate electrical energy, and is useful for comparing materials, quality control, and development of insulation and capacitor dielectrics. Technicians take specimens and measure them at the desired frequencies and temperatures to evaluate the changes in AC loss. Engineers compare the results to the dielectric properties of electrical insulating materials. 

    Read more

    Get Certified ASTM D150 Testing for Reliable Dielectric Performance 

    Certification confirms that solid insulating materials exhibit permittivity and loss values within the range that are consistent with the applicable ASTM D150 procedures and the buyer’s needs. ASTM D150 is a certified test that is used to test the permittivity and dissipation factor of a material before the manufacturer accepts it for insulation or capacitor applications. Testing and certification ensure the reliability of the design of electrical equipment and verify dielectric characteristics.

    What is the Scope of ASTM D150? 

    ASTM D150 is a standard test that covers the determination of relative permittivity, dissipation factor, loss index, power factor, phase angle, and loss angle of specimens of solid electrical insulating materials. It tests AC losses over frequencies ranging from below 1Hz to many hundreds of MHz. These test methods generally describe various electrodes, apparatus, and measurement techniques, such as contacting and non-contacting (fluid displacement) electrode systems.

    Read more

    The primary purpose of the ASTM D150 test is to determine the properties of solid insulating materials subjected to alternating electric fields. Manufacturers and designers use this test for insulation selection, capacitor dielectric evaluation, and aging studies.

    The scope of ASTM D150 includes 

    • Material type: Solid electric insulating materials. 
    • Purpose: To measure characteristics of power loss due to AC and permittivity. 
    • Properties measured: Relative permittivity (dielectric constant), Dissipation factor, Loss index, Power factor, Phase angle, Loss angle. 
    • Method: The technicians put the specimen between the electrodes and measure the capacitance and dissipation at the specified frequency.
    • Result: Reported permittivity and dissipation factor at each of the frequencies and temperatures.
    • Frequency range: < 1 Hz to hundreds of megahertz.
    • Electrode systems: Contacting electrodes, Non-contacting (fluid displacement) electrodes, and Guarded electrodes.
    • Applications: Selection of electrical insulation, capacitor dielectrics, high-frequency insulation, and aging studies.

    What are the Uses of ASTM D150 Testing?

    ASTM D150 testing provides manufacturers and designers with a way to determine how much energy an insulating material stores and loses under AC fields. The engineers then compare the results to other materials and to predict heating in service. This standard-

    • Measures the relative permittivity of solid insulating materials.
    • Measures power factor, loss index, and dissipation factor.
    • Allows comparison of materials of similar permittivity using the dissipation factor.
    • Helps with the selection of materials with low loss for high-frequency applications.
    • Monitors aging changes in dissipation factor.
    • Gives general information about electrodes, apparatus, and measurement techniques.
    • Supports product development and quality control. 

    What Materials Can Be Tested Under ASTM D150? 

    ASTM D150 covers solids and other dielectric solids that are used for electrical insulation, such as plastics and films, ceramics, and other insulating materials. Typical uses are insulators for cables, motors, and transformers or dielectrics for capacitors. Users also consult ASTM standards for the specific material under test when a material needs special treatment. 

    Why is ASTM D150 Important? 

    ASTM D150 provides a standard method of measuring AC loss and permittivity for manufacturers. Low AC loss minimizes heat generation and the impact of the material on the remainder of the electrical network. Furthermore, the dielectric loss at a particular loss index is directly proportional to the frequency; thus, higher frequencies require lower loss values. 

    ASTM D150 Equipment and Sample Preparation Guide

    ASTM D150 uses capacitance measuring equipment and an electrode system appropriate to the specimen. Technicians condition and prepare the specimen, and apply or place electrodes. This arrangement enables them to accurately measure the capacitance and dissipation. 

    Read more

    Sample and Specimen DetailsTechnicians test specimens of solid electrical insulating material, prepared and conditioned for AC loss and permittivity measurement. 
    Specimen PreparationTechnicians condition each specimen and prepare its surfaces so the electrodes make consistent contact. 
    Electrode and Specimen Configuration Technicians select contacting electrodes applied to the specimen or non-contacting electrodes using fluid displacement, and they use guarded electrodes to control fringing capacitance. 
    InstrumentationCapacitance bridges or Q-based measuring circuits, a specimen holder with electrodes, and temperature control equipment for tests at each required temperature. 

    Testing Procedures and Requirements for ASTM D150  

    Technicians first condition the specimen and set up the electrode system. They then measure the dissipation and capacitance for each of the required frequencies and temperatures. They subsequently determine the values of permittivity and dissipation factor based on the measured values. The test methods describe stray and fringing capacitance effects, which the technician considers during the calculation.

    Read more

    Specimen Conditioning Technicians condition the specimen as the material requires before measurement. 
    Electrode Setup Technicians apply contacting electrodes or arrange a fluid displacement system around the specimen. 
    Capacitance and Dissipation Measurement Technicians measure capacitance and dissipation at each required frequency and temperature.
    Calculation of Permittivity and Loss Technicians calculate relative permittivity, dissipation factor, and related values from the measurements, including corrections for stray and fringing capacitance. 
    Result Reporting Technicians report specimen dimensions, conditioning, electrode type, and the values at each temperature and frequency. 

    ASTM D150 Testing Process and Data Collection

    Testing starts once technicians set up the specimen and determine the system of electrodes. Then they mount the specimen in the holder and put the measuring circuit into operation. They then make capacitance and dissipation measurements at each desired frequency and temperature. Next, they repeat the measurements as the temperature is changed. Lastly, they determine permittivity and dissipation factor and write them along with the test conditions. 

    The image depicts a solid insulating specimen held between electrodes in a measurement fixture for permittivity and dissipation factor measurement as per ASTM D150.
    ASTM D150 Permittivity and Dissipation Factor Measurement of an Insulating Specimen

    Common Challenges and Troubleshooting

    To obtain accurate ASTM D150 results, good electrode contact, controlled temperature, and corrections for stray and fringing capacitance are required. Poor electrode contact or moisture in the specimen may affect the measured loss. Technicians need to check the electrodes and condition the specimen prior to measuring. Technicians also achieve reliable results when measuring samples at the same frequencies and temperatures.

    ASTM D150 Analysis Results and Interpretation

    This report summarizes the permittivity and dissipation factor found in the tested insulating specimen. It displays the values of the measurements, specimen data, and the frequencies and temperatures employed. This interpretation compares the results with the material specification or design requirement.

    Read more

    • Technicians measure the relative permittivity and dissipation factor at each frequency and temperature.
    • Technicians record the specimen dimensions, conditioning, and electrode type.
    • Technicians link the loss index and dissipation factor with the heat that the material is expected to dissipate in service.
    • Technicians consider that the change in dissipation factor with aging is often more significant than the initial value.
    • Manufacturers and designers use the results to support insulation selection and quality control. 

    Link to ASTM D150 

    FAQ

    What is the frequency range of ASTM D150?
    It spans a range from a few hundred Hz to a few hundred MHz. Technicians operate the frequencies required for the application.
    Matestlab conducts testing in accredited laboratories and through experienced engineers throughout the US and Canada. Communicate your needs, and the team (ASTM D150) agrees on the scope of accreditation for your project.
    Technicians employ capacitance measuring circuits, an electrode specimen holder, and temperature control equipment. They adopt an electrode and measurement method suitable for the material and frequency range they are going to measure.
    Please provide material information and testing needs via the Matestlab website and/or email. The team then agrees on the needs for the specimen, shipment procedures, and timeline.
    Matestlab’s laboratory network covers the US and Canada. The team will process requests from other regions on a case-by-case basis and arrange shipping and reporting.

    Updated on October 29, 2026

    Dr Ruchika Yogesh
    About Author
    Dr Ruchika Yogesh
    Dr. Ruchika Yogesh is a serial entrepreneur, material science and AI/ML enthusiast, medicinal chemistry subject matter expert (SME), scientific/medical copyeditor, and a researcher.
    Know More
    Testimonials
    Real results
    Engineers trust us with what matters most
    Why Choose Matestlab?
    Matestlab is a unified testing services partner based in the USA. Matestlab offers raw material and product testing services through accredited, expert laboratories primarily based in the USA. Matestlab supports physical, thermal, chemical, electrical, mechanical, environmental, and characterization testing needs through its global network of 2200+ accredited testing laboratories. Matestlab's in-house materials science experts curate and design comprehensive testing programs matched to the sample material and specific testing need, with regulatory requirements and confidentiality in mind.

    If you are looking for a managed and trusted testing partner to achieve your research goals, feel free to schedule a meeting with us or send us a request at connect@matestlabs.com to learn more about our services. For a quick quote, call us at (302)244-7710. We are happy to serve you.
    Start Your Testing
    Project Today
    Define your requirements and get access to
    specialized laboratories ready to deliver results
    Start Testing
    Contact us
    Partners with us
    Clients
    Vendors
    Process for testing
    • STEP 01

      You share your testing requirements

    • STEP 02

      You share your sample(s)

    • STEP 03

      We deliver your test reports

    Get your testing done

    Let us know your testing requirements and we will be right back with a solution.

      Let us root for each other. Collaborate to grow, expand, and accelerate our businesses.

      Partner with us