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IS 12027:1987 is the Indian Standard (BIS) for silicone-based water repellents. This standard lays down the requirements and test methods for silicone-based water repellent solutions used for application on masonry and concrete surfaces. It covers essential properties such as silicone content, flash point, drying time, pH, and performance criteria like water absorption and depth of penetration.
silicone-based water repellents
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Waterproofing and Damp-Proofing
! This is a water repellent, not a waterproofing membrane. It works by lining pores to repel water and is not suitable for bridging cracks or withstanding hydrostatic pressure.
! The substrate must be thoroughly clean, dry, and free of any contaminants or efflorescence before application to ensure proper penetration and performance.
! Pay close attention to the flash point (30°C min) for safety during storage and application, especially in poorly ventilated areas.
EN 1504-2:2004CEN (European Committee for Standardization), Europe
HighCurrent
Products and systems for the protection and repair of concrete structures - Definitions, requirements, quality control and evaluation of conformity - Part 2: Surface protection systems for concrete
Covers hydrophobic impregnation systems for concrete, which is a primary application for silicone repellents.
BS 6477:1992BSI (British Standards Institution), UK
HighWithdrawn
Specification for water repellents for masonry surfaces
Directly specified requirements for silicone-based water repellents for masonry, very similar in intent to IS 12027.
Key Differences
≠IS 12027 is primarily a compositional standard, specifying a minimum silicone content (5% for ready-to-use). In contrast, EN 1504-2 is purely performance-based and does not specify chemical composition, focusing instead on performance outcomes like penetration depth and water absorption.
≠EN 1504-2 specifies a more extensive and quantitative set of performance criteria, including depth of penetration (Class I vs II), CO2 permeability, and resistance to severe chemical attack, which are not present or are less detailed in IS 12027.
≠The Indian standard is applicable to general 'masonry surfaces,' with tests on materials like sandstone. The European standard is specifically written for the protection of 'concrete' and mandates testing on a standardized reference concrete specimen.
≠IS 12027 includes requirements for the material in its container, such as flash point (min 30°C) and storage stability. EN 1504-2 does not specify these, as they are typically covered by broader European regulations on chemical products (e.g., REACH, CLP).
Key Similarities
≈The fundamental purpose of all standards is to define requirements for liquid-applied treatments that reduce water ingress into porous mineral substrates without sealing the surface.
≈A core performance test in both IS 12027 and EN 1504-2 is the measurement of water absorption by capillarity, comparing treated versus untreated specimens to quantify the effectiveness of the water repellent.
≈Both standards mandate that the treatment must not significantly hinder the substrate's natural ability to dry out. IS 12027 has a 'Water Vapour Permeability' test, while EN 1504-2 requires hydrophobic impregnations to be Class I (highly vapour permeable).
≈Both standards include a requirement to test for durability against alkalis, recognizing that these treatments will be applied to cementitious or lime-based materials. IS 12027 specifies immersion in lime water, while EN 1504-2 includes performance testing after alkali exposure cycles.
Parameter Comparison
Parameter
IS Value
International
Source
Silicone Content (Ready-to-use)
Minimum 5% by mass
Not specified; performance-based standard
EN 1504-2:2004
Capillary Water Absorption
Treated specimen absorption must be ≤ 10% of untreated specimen
Absorption coefficient < 0.1 kg·m⁻²·h⁻⁰.⁵ AND absorption rate < 7.5% compared to control
EN 1504-2:2004
Depth of Penetration
Minimum 2 mm (on sandstone)
Class I: < 10 mm; Class II: ≥ 10 mm (on concrete)
EN 1504-2:2004
Water Vapour Permeability
Drying rate must be ≥ 80% of untreated specimen
Must be Class I (highly permeable): Sd < 5 m
EN 1504-2:2004
Alkali Resistance Test
Retain repellency after 21 days in saturated lime water
Performance criteria (e.g., capillary absorption) must be met after exposure to a defined alkaline solution (e.g., KOH/NaOH)
EN 1504-2:2004
Flash Point (Solvent-based)
Minimum 30°C
Not specified in the standard; covered by separate chemical safety regulations (CLP)
EN 1504-2:2004
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Minimum silicone content, percent by mass5.0
Minimum flash point (Abel)30 °C
Maximum drying time, surface dry4 hours
Maximum water absorption after 24 hours immersion5.0 %
Minimum depth of penetration on concrete block2 mm
pH value6.0 to 8.0
Tables & Referenced Sections
Key Tables
Table 1 - Requirements for Silicone Based Water Repellents
What is the minimum required silicone content for a repellent to comply with this standard?+
A minimum of 5.0 percent by mass is required as per Table 1.
What is the main performance test for this material?+
The key performance tests are the water absorption test (max 5% absorption after 24h) and the depth of penetration test (min 2 mm on concrete block) as specified in Table 1.
Is this material film-forming?+
No, it is a penetrative treatment. The standard specifies it should not leave any oily or greasy appearance after application and should be non-staining.
What is the required drying time?+
The surface should be dry in a maximum of 4 hours, as per Table 1.