silicone-based water repellents
1987 Edition

Overview of Scope

Scope (Clause 1.1):

• Defines specifications for silicone-based water repellents intended for construction use.

Essential Parameters

Mineral Spirit Requirements for Class A & B

Notes:

• Mineral spirit must conform to these requirements to guarantee proper dilution and performance.
• Ensures water repellents retain effectiveness after dilution.

flowchart LR
    A[Silicone Water Repellent] --> B{Repellent Class}
    B -->|Class A or B| C[Dilute with Mineral Spirit or Xylene]
    B -->|Class C| D[Dilute with Distilled Water]
    C --> E{Mineral Spirit Specifications}
    E --> F[Flash Point ≥ 27°C]
    E --> G[Boiling Range 135-185°C]
    E --> H[Kauri-butanol ≥ 34]

This section clarifies preparation and quality standards for silicone water repellents.

Key Definitions in the Standard (Clause 2.0)

• Clarifies terminology related to silicone water repellents and their evaluation.
• Important terms include relative absorption, test solution formulation, and application procedures.

Relative Absorption Calculation (Clause 1.4)

[ \text{Relative Absorption (%) }= \frac{b_3 - b_1}{b_2 - b_1} \times 100 ]

Where:

• (b_1) = Specimen’s initial weight
• (b_2) = Weight after soaking
• (b_3) = Weight after drying

Test Solution Preparation Details (Clause 3.2, Table B-3)

Treatment Setup (Clause 4.1)

• Use trays sized approximately 350 x 150 x 25 mm.
• Maintain solution depth near 10 mm.

flowchart LR
    A[Test Specimen] --> B[Immersed in Test Solution]
    B --> C[Drying Stage]
    C --> D[Weight Measurements: b1, b2, b3]
    D --> E[Compute Relative Absorption]

This chapter outlines fundamental terms, formulas, and preparation techniques for evaluating silicone water repellents.

Material and Repellent Classification (Clauses 5.1 & Appendix A)

• Class A: Bricks with water absorption ≥ 15%, complying with IS 1077-1976; used for tests in Appendices C, D, E, F.
• Classes B & C: Limestone slabs per IS 1128-1974; used in Appendices C, D, E, G.

Test Solution Concentration (Clause 3.2.1)

Preparation of Solutions

• Classes A & B: Diluted with mineral spirit or xylene meeting specified criteria.
• Class C: Diluted using distilled water.

This classification facilitates correct specimen selection and solution preparation for testing.

Fundamental Requirements for Silicone Water Repellents (Clauses 1.1, 1.5, 3.2)

• Scope limited to silicone-based water repellents.
• Adhere to revised rounding-off rules for numerical data.

Test Solution Preparation

Testing Protocol

• Upon any failure in initial specimens (Clause 5.3), conduct tests on three new samples.
• Failure of any retested samples results in consignment rejection.

Additional Information

• Appendix E specifies procedures to measure water evaporation through treated surfaces (Class A).

flowchart TD
    A[Silicone Water Repellent] --> B{Material Class}
    B -->|Class A/B| C[Prepare Test Solution with Mineral Spirit or Xylene]
    B -->|Class C| D[Prepare Test Solution with Distilled Water]
    C --> E[Verify Mineral Spirit Characteristics]
    E -->|Meets Specs| F[Proceed with Testing]

This section summarizes compliance essentials to meet the standard.

Performance Standards for Silicone Water Repellents (Clauses 4.1, 5, 1.5)

• Consistency: Repellents should be easy to apply via brushing or spraying and should not visibly alter the masonry’s dry surface, besides possible temporary dye effects.

Test Solution Preparation

Testing Procedure

• Initial failures require testing on three fresh specimens.
• Any failure in retesting results in rejection of the batch.

Evaporation Testing

• Appendix E defines methods for measuring water evaporation through treated surfaces specifically for Class A materials.

flowchart TD
    A[Water Repellent] --> B{Material Class}
    B -->|Class A/B| C[Dilute with Mineral Spirit or Xylene]
    B -->|Class C| D[Dilute with Distilled Water]
    C & D --> E[Apply to Masonry Surface]
    E --> F{Specimen Testing}
    F -->|Pass| G[Accept Batch]
    F -->|Fail| H[Retest 3 Samples]
    H -->|Any Fail| I[Reject Batch]
    H -->|All Pass| G

This overview details critical performance and test requirements.

Container and Material Specifications (Clause 6)

Container Types by Material Class

Packing Details

• Bulk packaging uses steel drums.
• Containers for Class A & B must be solvent-resistant and lead-free.
• Class C prefers polyethylene containers.

Test Solution Preparation (Clause 3.2)

flowchart TD
    A[Material Class] -->|A & B| B[Use Solvent-Resistant Containers]
    A -->|C| C[Use Polyethylene or Caustic-Resistant Containers]
    B --> D[Lead-Free Metal Containers]
    D --> E[No Lead Soldering Allowed]
    F[Bulk Packaging] --> G[Steel Drums]
    H[Test Solution Preparation] --> I[Class A & B: Dilute with Mineral Spirit or Xylene]
    H --> J[Class C: Dilute with Distilled Water]

This section ensures appropriate packaging and solution preparation.

Packing and Marking Guidelines (Clause 7.1, 7.2)

Packaging

• Bulk quantities packed in steel drums.
• Class A & B materials in solvent-resistant, lead-free containers.
• Class C materials in polyethylene containers or those resistant to caustic soda (glass, mild/stainless steel).

Labelling Requirements

Packages must be sealed securely and clearly labeled with:

• Repellent class (A, B, or C)
• Manufacturer’s name
• Net weight
• Recognized trademark (if applicable)
• Manufacture date (day/month/year)
• Flammability warning if flash point is below 23°C
• Shelf life and storage instructions
• Solids content

Optional Marking

• BIS Standard Mark may be displayed to indicate conformity with BIS regulations.

This ensures product safety, proper storage, and traceability.

Guidelines for Preparing Test Solutions and Samples (Clauses 3.2, 4.1, 4.2)

Test Solution Preparation

• Classes A & B: Dilute silicone water repellent with mineral spirit or xylene meeting specified flash point, boiling range, and Kauri-butanol values.
• Class C: Dilute with distilled water.

Concentration Levels

• Class A & B: 5 ± 0.2% solids.
• Class C: 3 ± 0.2% solids.

Sample Treatment Procedure

• Use shallow trays approx. 350 x 150 x 25 mm.
• Maintain solution depth around 10 mm.
• Tray material preferably polyethylene; if metal, must be lead-free and caustic soda resistant for Class C.
• Place wire gauze on tray bottom to prevent direct contact.
• Immerse specimens face down for 15 seconds, then drain face down for 10 seconds.
• Store specimens face up at 25 ± 5°C indoors.
• Precisely measure mass before and after immersion (±0.1 g) to compute absorption.
• Refill solution to original level before next specimen.

flowchart TD
    A[Prepare Test Solution] --> B{Material Class}
    B -->|Class A/B| C[Dilute with Mineral Spirit or Xylene]
    B -->|Class C| D[Dilute with Distilled Water]
    C & D --> E[Pour ~10mm solution into tray]
    E --> F[Place wire gauze in tray]
    F --> G[Immerse specimen face down for 15s]
    G --> H[Drain specimen face down for 10s]
    H --> I[Store specimen face up at 25 ± 5°C]
    I --> J[Measure mass differences for absorption]

This process standardizes sample preparation for testing.

Early Water Repellency Test Procedure (Clause 5.2, Appendix C)

Requirements

• No visible water pooling should be absorbed by the treated brick or block within 10 minutes after applying the repellent.
• Minimum solution uptake:
  • Bricks: ≥ 4 g
  • Blocks: ≥ 1 g
• Specimens not meeting minimum uptake are discarded.

Test Solution Preparation

Test Steps

1. Prepare test solution based on repellent class.
2. Apply repellent ensuring minimum solution uptake.
3. Monitor surface for water absorption for 10 minutes post application.
4. Confirm absence of water absorption within this period.

Additional Notes

• Test conducted once per new silicone water repellent formulation.
• Classes B and C require additional 12-month weathering durability tests.

flowchart TD
    A[Prepare Test Solution] --> B[Apply to Specimen]
    B --> C{Solution Uptake ≥ Minimum?}
    C -- No --> D[Discard Specimen]
    C -- Yes --> E[Observe Water Absorption]
    E --> F{Water Absorbed Within 10 Minutes?}
    F -- Yes --> G[Test Failed]
    F -- No --> H[Test Passed]

Ensures initial water repellency compliance.

Procedure for Measuring Water Absorption (Clause 5.3, Appendix D)

Key Criteria

• Maximum allowable water absorption is 10% for any one of three test specimens.
• Specimens are immersed for 72 hours and dried for 7 days at 27 ± 2°C.

Procedure

1. Seal all sides except the test face with impermeable plates and silicone sealant.
2. Place specimens on wire gauze in a tray.
3. Immerse the test face in 10 mm of clean water for 72 hours.
4. Remove specimens, wipe surfaces, immediately reseal non-test faces.
5. Weigh specimens with ±1 g accuracy.
6. Dry specimens test face upward in a ventilated room for 7 days at 27 ± 2°C.
7. Re-weigh specimens.

Water Absorption Calculation

[ \text{Water Absorption (7)} = \frac{W_2 - W_1}{W_1} \times 100 ]

Where:

• (W_1) = Weight after initial sealing
• (W_2) = Weight after immersion

Notes

• Specimens with solution pickup below 4 g for bricks or 1 g for blocks are rejected.
• Only specimens meeting minimum solution uptake proceed to absorption testing.

flowchart TD
    A[Specimen Preparation] --> B[Seal all surfaces except test face]
    B --> C[Place on wire gauze in tray]
    C --> D[Immerse test face in 10 mm water for 72 hrs]
    D --> E[Remove & wipe specimens]
    E --> F[Seal other faces immediately]
    F --> G[Weigh specimens (W1)]
    G --> H[Dry specimens 7 days at 27 ± 2°C]
    H --> I[Weigh specimens again (W2)]
    I --> J[Calculate Water Absorption %]

This ensures precise water absorption measurement.

Durability Assessment Procedures (Clause 5.5, Appendix E)

Durability Testing

• Class A: Specimens exposed to natural weathering for 12 months, followed by tests from Appendices C, D, and E.
• If samples fail, retest on three fresh specimens; failure here results in consignment rejection.
• Classes B & C: Similar 12-month weathering and retesting protocols outlined in Appendix G.

Water Evaporation Measurement

• For Class A materials, evaporation rates through treated surfaces are measured to assess water repellency retention.

flowchart TD
    A[Initial Sample Testing] --> B[12 Months Weathering]
    B --> C[Repeat Tests (Appendices C, D, E)]
    C --> D{All Tests Passed?}
    D -- Yes --> E[Consignment Accepted]
    D -- No --> F[Retest on 3 New Samples]
    F --> G{Retests Passed?}
    G -- Yes --> E
    G -- No --> H[Consignment Rejected]

This process verifies long-term performance under environmental conditions.

Weathering Exposure Test Details (Clauses 1.2, 5.5.2, Appendix F)

1. Duration: Tests repeated after 12 months of outdoor exposure.
2. Scope: Tests from Appendices C, D, and E are conducted post exposure.
3. Classes B & C: Must comply with Clauses 5.2, 5.3, and 5.4 following weathering.
4. Failure Handling: Specimens failing Clause 5.3 are retested on three fresh samples; any failure causes batch rejection.
5. Reference: Durability table G-1.2 confirms the procedure.

Evaporation Test (Appendix E)

• Measures rate of water evaporation through treated surfaces to evaluate durability.
• Primarily applicable to Class A materials.

flowchart TD
    A[New Repellent Formulation] --> B[Initial Testing (Appendices C, D, E)]
    B --> C[12 Months Weather Exposure]
    C --> D[Repeat Testing]
    D --> E{Pass?}
    E -- Yes --> F[Batch Accepted]
    E -- No --> G[Retest 3 New Samples]
    G --> H{Pass Retest?}
    H -- Yes --> F
    H -- No --> I[Batch Rejected]

This ensures repellents maintain performance after weather exposure.

Long-Term Durability Testing Summary (Appendix G)

• Exposure: Samples undergo 12 months of outdoor weathering.
• Test Repetition: After exposure, tests from Appendices C, D, and E are repeated.
• Applicability:
  • Appendix F covers Class A repellents.
  • Appendix G focuses on Classes B and C.

Testing Overview

Notes

• Tests cover physical, chemical, water repellency, adhesion, and weather resistance properties.

Contact for Testing

• Central Laboratory: Plot No. 20/9, Site IV, Sahibabad Industrial Area, Sahibabad 201010.
• Regional testing offices available across India.

flowchart TD
    A[Apply Water Repellent] --> B[12 Months Weather Exposure]
    B --> C{Repellent Class}
    C -->|Class A| D[Durability Testing per Appendix F]
    C -->|Class B or C| E[Durability Testing per Appendix G]
    D & E --> F[Repeat Tests from Appendices C, D, E]
    F --> G[Evaluate Durability and Performance]

Refer to Appendices C through G for detailed test methodology.