Overview
ISO 13638:2021 - "Building and civil engineering sealants - Determination of resistance to prolonged exposure to water" - specifies a laboratory method to evaluate how sealants perform after prolonged water exposure. The standard measures the effect of water immersion (at ambient or elevated temperatures) combined with cyclic extension/compression on a sealant’s ability to fulfil its essential function, principally its capacity to withstand joint movement. This test procedure helps assess sealant durability and suitability for water-exposed building and civil engineering applications.
Key Topics
- Test principle: prepare bonded sealant specimens between two substrates, immerse in water for specified periods, then subject specimens to repeated cyclic movement to simulate service stress.
- Conditioning methods:
- Method A - 28 days at (23 ± 2) °C and 50 ± 10 % RH.
- Method B - Method A plus repeated heat/water cycles (70 °C oven and distilled water) to accelerate effects.
- Water immersion: immersion in distilled water at (23 ± 2) °C, (40 ± 2) °C or (50 ± 2) °C for 3 weeks (typical), with repetition as specified.
- Cyclic movement: amplitude set to 50% of the sealant’s movement accommodation (per ISO 11600), using ±6.25 %, ±10 % or ±12.5 % cycles at (5.5 ± 0.5) mm/min; specimens are held in extension/compression for 24 h per stage.
- Failure criteria and inspection: visual inspection for adhesion/cohesion loss; failures exceeding 2 mm depth (outside excluded end zones) constitute specimen failure. Tests repeat until specified acceptance or multiple failures occur.
- Apparatus & specimen preparation: substrates per ISO 13640 (mortar, anodized aluminium, or glass), spacers, anti-adherent film, temperature-controlled immersion containers, and a cyclic test machine.
- Reporting requirements: include sealant type and batch, substrate, primer, mixing ratio, conditioning method, immersion temperature, amplitude, total number of cycles, inspection results, and any deviations.
Applications
Who uses ISO 13638:2021 and why:
- Sealant manufacturers - to validate product formulations for wet-service durability and support product data sheets.
- Testing laboratories - to perform standardized water-resistance testing for compliance, comparison, or R&D.
- Specifiers, architects and engineers - to choose sealants suitable for water-exposed joints in buildings and civil works.
- Quality managers and procurement - to require objective evidence of water resistance in supply contracts and performance specifications.
Practical benefits include improved durability assessment, risk reduction for water-exposed joints, and clearer evidence for performance claims.
Related Standards
- ISO 11600 - classification and requirements for sealants (movement accommodation).
- ISO 9046 / ISO 9047 - adhesion/cohesion test methods at constant and variable temperatures.
- ISO 13640 - specifications for test substrates.
- ISO 6927 - sealant vocabulary and terms.