ASTM C647 - 19

    Standard Guide to Properties and Tests of Mastics and Coating Finishes for Thermal Insulation

    Active Standard ASTM C647 | Developed by Subcommittee: C16.33

    Book of Standards Volume: 04.06

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    Significance and Use

    4.1 Each of the properties listed should be considered in selecting materials for specific projects. A list of the selected properties with limiting values assigned will form a part of the product specification.

    4.2 All of the properties are not required, and all of the tests outlined are not required. A condition to any specification must be an evaluation of the proposed use to determine which properties shall be required.

    4.3 Membrane reinforcements are frequently specified and used with mastics and coatings. Service properties of such systems of finishes are often different from the unreinforced finishes; therefore, it is essential to test specimens of the reinforced system.

    1. Scope

    1.1 This guide identifies properties of mastics and coating finishes characterizing their performance as finishes for thermal insulation.

    1.2 These properties relate to application and service. Each property is defined, and its significance and suggested test methods are described.

    1.3 The properties appear in the following order in this guide.



    Application Properties








    Wet Flammability




    Temperature and Humidity Range


    Surface Wetting and Adhesion


    Gap Filling and Bridging


    Sizing and Sealing


    Corrosion or Solvent Attack


    Drying Time and Curing Time




    Storage Stability


    Freeze-Thaw Stability


    Service Properties


    Specimen Preparation


    Outdoor Durability


    Environmental Resistance


      Temperature Limits


      Chemicals and Water Resistance


      Mold and Mildew Resistance


    Surface Flammability


    Water-Vapor Transmission Rate




    Damage Resistance


      Impact Resistance


      Abrasion Resistance


    Stress Resistance










    Other Properties


    1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

    1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    C168 Terminology Relating to Thermal Insulation

    C419 Practice for Making and Curing Test Specimens of Mastic Thermal Insulation Coatings

    C461 Test Methods for Mastics and Coatings Used With Thermal Insulation

    C488 Test Method for Conducting Exterior Exposure Tests of Finishes for Thermal Insulation

    C681 Test Method for Volatility of Oil- and Resin-Based, Knife-Grade, Channel Glazing Compounds

    C755 Practice for Selection of Water Vapor Retarders for Thermal Insulation

    C792 Test Method for Effects of Heat Aging on Weight Loss, Cracking, and Chalking of Elastomeric Sealants

    D36/D36M Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus)

    D56 Test Method for Flash Point by Tag Closed Cup Tester

    D92 Test Method for Flash and Fire Points by Cleveland Open Cup Tester

    D93 Test Methods for Flash Point by Pensky-Martens Closed Cup Tester

    D543 Practices for Evaluating the Resistance of Plastics to Chemical Reagents

    D562 Test Method for Consistency of Paints Measuring Krebs Unit (KU) Viscosity Using a Stormer-Type Viscometer

    D638 Test Method for Tensile Properties of Plastics

    D747 Test Method for Apparent Bending Modulus of Plastics by Means of a Cantilever Beam

    D790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials

    D822/D822M Practice for Filtered Open-Flame Carbon-Arc Exposures of Paint and Related Coatings

    D903 Test Method for Peel or Stripping Strength of Adhesive Bonds

    D968 Test Methods for Abrasion Resistance of Organic Coatings by Falling Abrasive

    D1310 Test Method for Flash Point and Fire Point of Liquids by Tag Open-Cup Apparatus

    D1640 Test Methods for Drying, Curing, or Film Formation of Organic Coatings

    D1654 Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments

    D1729 Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials

    D1849 Test Method for Package Stability of Paint

    D2196 Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational Viscometer

    D2243 Test Method for Freeze-Thaw Resistance of Water-Borne Coatings

    D2354 Test Method for Minimum Film Formation Temperature (MFFT) of Emulsion Vehicles

    D2444 Practice for Determination of the Impact Resistance of Thermoplastic Pipe and Fittings by Means of a Tup (Falling Weight)

    D2453 Test Method for Shrinkage and Tenacity of Oil- and Resin-Base Caulking Compounds

    D2485 Test Methods for Evaluating Coatings For High Temperature Service

    D2507 Terminology of Rheological Properties of Gelled Rocket Propellants

    D3134 Practice for Establishing Color and Gloss Tolerances

    D3274 Test Method for Evaluating Degree of Surface Disfigurement of Paint Films by Fungal or Algal Growth, or Soil and Dirt Accumulation

    D3361/D3361M Practice for Unfiltered Open-Flame Carbon-Arc Exposures of Paint and Related Coatings

    D3828 Test Methods for Flash Point by Small Scale Closed Cup Tester

    D4339 Test Method for Determination of the Odor of Adhesives

    D5590 Test Method for Determining the Resistance of Paint Films and Related Coatings to Fungal Defacement by Accelerated Four-Week Agar Plate Assay

    E84 Test Method for Surface Burning Characteristics of Building Materials

    E96/E96M Test Methods for Water Vapor Transmission of Materials

    E162 Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source

    E659 Test Method for Autoignition Temperature of Chemicals

    F1249 Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor

    G21 Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi

    ICS Code

    ICS Number Code 91.100.60 (Thermal and sound insulating materials)

    UNSPSC Code

    UNSPSC Code 30141500(Thermal insulation)

    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/C0647-19

    Citation Format

    ASTM C647-19, Standard Guide to Properties and Tests of Mastics and Coating Finishes for Thermal Insulation, ASTM International, West Conshohocken, PA, 2019,

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