1.0 Scope. 1.1 This method applies to techniques that employ Electrical Impedance (EI) moisture meters and scanners to non-destructively locate and evaluate the comparative moisture condition within insulated roofing systems. 1.2 This method is applicable to roofing and waterproofing systems wherein insulation is placed above the deck and in contact with electrically non-conductive single-ply or built-up roofing and waterproofing membranes and systems such as coal tar, asphalt, bitumen, thermoplastics, fiberglass, polyurethane foam and similar electrically non-conductive membrane materials. 1.3 This method is applicable to roofing and waterproofing systems incorporating electrically non-conductive rigid board insulation made from materials such as organic fibers, perlite, cork, fibreglass, wood fibre, polyisocynurate, polystyrene, and polyurethane, phenolic foam, sprayed foam, composite boards and other similar electrically non-conductive materials. 1.4. Metal and other electrically conductive surface coverings and near surface embedded metallic components are not suitable for surveying with impedance methods because of the electrical conductivity of these materials. Black ethylene propylene diene terpolymer (EPDM) may produce false positive readings when tested with this method due to the materials high dielectric constant. Aluminum foil on top-faced roof insulation or waterproofing membranes will give false positive readings, however liquid-applied, aluminum solar reflective coatings will not normally affect impedance scanner readings. 1.5 Classification of Meters & Scanners using this technology may be Electrical Impedance (EI) and Electrical Capacitance (EC) based. Note 1- The terms are often interchanged when describing moisture meters. Capacitance meters are purely capacitive as they do not have a resistive component. Impedance meters combine both capacitance and resistance as a testing method having both a capacitive and a resistive component. Impedance is more suited to the measurement of different types of materials and constructions found in roofing systems as both components, capacitive and resistive allow for a more versatile testing and measurement arrangement. 1.6 This method addresses criteria for non-destructive impedance moisture scanner such as specification and minimum equipment standard. 1.7 This method addresses meteorological conditions and limitations for performing impedance inspections. 1.8 This method addresses the effect of the roof construction, material differences, and exterior surface conditions on the impedance moisture inspections. 1.9. Due to the wide variation of material combinations used in roofing systems, this methodology may not be appropriate for all applications. 1.10 This method is intended to be used in conjunction with the moisture scanner manufacturers operation instructions and interpretive data where available. 1.11 This method addresses operating procedures, operator qualifications, and operating practices. 1.12 Where appropriate, or when results need to be quantified utilize core sampling in conjunction with gravimetric analysis to confirm and quantify moisture content in the system. 1.13 This method does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Extreme caution should be taken when accessing, walking or using scanning equipment on the roof surfaces, or elevated locations, when using ladders, and when raising and lowering equipment to elevated locations.
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
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