Overview
ISO 7390:2002 - Building construction - Jointing products - Determination of resistance to flow of sealants - specifies a laboratory method to measure the resistance to flow (sag) of sealants used in vertical joints. The test quantifies loss of cohesion under the sealant’s own weight after exposure to defined temperatures, helping manufacturers and specifiers evaluate sealant performance in real-world vertical applications.
Key topics and requirements
- Test principle: Measure how far a sealant flows (sags) from a U-profile due to gravity after thermal conditioning.
- Specimen geometry: U-profiles of non-porous, smooth material (example: anodized aluminium) with a specimen length of (150 ± 1) mm. Alternative internal cross-sections (for instance 10 ± 0.2 mm width and depth) may be used as specified.
- Backing strip: Polyethylene (PE) sheet used to cover the inner base; thickness about 0.5 mm; length stability under test conditions is required.
- Conditioning temperatures: Ventilated convection ovens at (70 ± 2) °C, (50 ± 2) °C, and a refrigerated container at (5 ± 2) °C are specified for temperature exposure.
- Procedures: Two positional procedures
- Procedure A - specimen placed vertically; measure downward movement of the bottom edge after conditioning.
- Procedure B - specimen oriented horizontally with open surface vertical; measure projection beyond the U-profile front.
- Duration and measurement: Each specimen is conditioned for 24 hours; flow is recorded with a measuring device scaled to 0.5 mm and reported to the nearest 1 mm.
- Test report: Must include laboratory details, reference to ISO 7390, sealant type and batch, profile type and dimensions, chosen procedure, measured flow per specimen, test temperature, and any deviations.
Applications and users
- Useful for sealant manufacturers (quality control and R&D), independent test laboratories, architects and specifiers setting performance requirements, and contractors/building inspectors assessing suitability for vertical jointing.
- Practical uses:
- Compare sag resistance across product formulations.
- Verify compliance with project or regulatory performance criteria.
- Inform selection of sealants for façades, window/door joints and other vertical surfaces exposed to temperature extremes.
Related standards
- Normative reference: ISO 6927 (Sealants - Vocabulary) for consistent terminology.
- ISO 7390 data is commonly used alongside other jointing-product tests (adhesion, elasticity, durability) when specifying complete sealant performance.
Keywords: ISO 7390:2002, resistance to flow of sealants, sealant flow test, building construction, jointing products, vertical joints, U-profile, sealant sag.
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