Pictorial Surface Preparation Standards for Painting of Steel Surfaces
1981 Edition

IS 9954: Visual Standards for Steel Surface Preparation for Painting (1981)

Overview Highlights:

• Objective: To unify surface preparation procedures for painting ferrous metals in construction.
• Coverage: Addresses pretreatment techniques crucial for paint adhesion and durability.
• Terminology (Clause 2.0): Defines key terms related to surface treatment.
• Numerical Rounding Guidelines (Clause 2.6): Updated rules for rounding numeric data.
• 2010 Revision: Enhanced pictorial standards for surface preparation quality.

Key Specifications:

• Grades of Surface Preparation: Visual pictorial standards describing cleanliness (e.g., Rust and Surface Grades).
• Pretreatment Techniques: Includes cleaning, rust elimination, and surface profiling before coating.
• Rounding Consistency: Ensures uniform reporting of measurements.

Typical Surface Preparation Grades (summary):

flowchart LR
    A[Raw Steel Surface] --> B[Cleaning Process]
    B --> C[Rust Removal]
    C --> D[Surface Profiling]
    D --> E[Application of Paint]

This standard guarantees effective paint bonding and extended service life by setting clear preparation benchmarks.

Scope Summary of IS 9954

This standard primarily governs the preparation and painting of ferrous metal surfaces in building construction, emphasizing:

• Pretreatment processes for steel surfaces prior to painting.
• Ensuring the longevity and corrosion resistance of coatings.
• Standardizing surface cleaning and rust removal methods.

Essential Points from Scope (Clause 2.0 and related):

• Applicable to ferrous metal surfaces used structural in buildings.
• Establishes surface preparation criteria to promote paint adhesion.
• Utilizes visual pictorial standards to define cleanliness levels.
• Includes rules for rounding numerical data (Clause 2.6).

Common Surface Preparation Grades (from pictorial standards):

Paint Film Thickness Formula:

[ \text{Total Dry Film Thickness} = \sum \text{Thickness of Each Coat} ]

Recommended range: 50–100 microns based on exposure conditions.

flowchart LR
    A[Steel Surface] --> B[Surface Preparation]
    B --> C{Type of Cleaning}
    C --> D[Hand Tool Cleaning (St 2)]
    C --> E[Blast Cleaning (St 3)]
    D & E --> F[Paint Application]
    F --> G[Achieved Dry Film Thickness]

This ensures consistent surface readiness to achieve corrosion resistance.

IS 9954: Definitions and Numeric Rounding (Clauses 2.0 & 2.6)

• Clause 2.0: Provides terminology definitions to maintain clarity throughout the standard.
• Clause 2.6: Details rules for rounding off numerical values ensuring uniformity in calculations and documentation.

Principal Rounding Guidelines:

• Numbers ending with 5 are rounded to the nearest even digit (e.g., 2.5 rounds to 2; 3.5 rounds to 4).
• Values are rounded to the decimal places as specified in corresponding clauses.
• Intermediate calculations should retain additional decimal places to reduce cumulative rounding errors.

Sample Rounding Table:

Summary:

• Follow standard rounding rules as per Clause 2.6.
• Definitions ensure consistent understanding of terms.
• Observe specified decimal precision in calculations.

flowchart TD
    A[Input Number] --> B{Digit After Rounding Place < 5?}
    B -- Yes --> C[Round Down]
    B -- No --> D{Digit After Rounding Place = 5?}
    D -- Yes --> E{Is Previous Digit Even?}
    E -- Yes --> C
    E -- No --> F[Round Up]
    D -- No --> F
    C --> G[Final Rounded Number]
    F --> G

IS 9954: Categorization of Rust Grades on Steel Surfaces

Rust Grades (Clause 3.1)

Surface Preparation Grades (Clauses 1.1 & 4)

• Manual Cleaning:

  • St 2: Comprehensive scraping and wire brushing to eliminate loose rust and millscale.
  • St 3: Intensive scraping and wire brushing removing rust, millscale, and debris.

• Abrasive Blast Cleaning:

  • Sa 1: Light blast cleaning.
  • Sa 2: Thorough blast cleaning leaving no visible rust, millscale, or foreign substances.
  • Sa 2½: Very rigorous blast cleaning approaching near-white metal finish.
  • Sa 3: Blast cleaning to achieve visually clean white metal surface.

Summary

• Rust grades describe the initial surface condition from A to D.
• Preparation grades specify cleaning level and method (St 2/St 3 for manual; Sa 1 to Sa 3 for blast).
• Matching rust and preparation grades ensures proper coating adhesion and durability.

flowchart TD
    A[Rust Grade] --> B[Preparation Grades]
    B --> C[Manual Cleaning: St 2 / St 3]
    B --> D[Blast Cleaning: Sa 1 / Sa 2 / Sa 2½ / Sa 3]

This classification guides proper surface treatment before applying protective coatings.

IS 9954: Surface Preparation Grades and Cleaning Procedures – Key Information

• Surface Condition Terms:

  • Rust Grades: Initial state of steel surface before cleaning.
  • Preparation Grades: Level of cleanliness after treatment.

• Classification of Preparation Grades:

  • Six degrees of surface cleanliness (St and Sa grades) categorized by cleaning technique.
  • Four rust conditions defined initially.

• Reference for Cleaning Techniques:

  • Detailed methodologies are provided in IS 1477 (Part I)-1971.

• Process:

  • Visually compare the cleaned surface to full-scale color prints (Clause 1.1.1).
  • Continue surface cleaning until it matches the prescribed preparation grade print (Clause 5.1.3).

Typical Preparation Grades (per IS 9954 and IS 1477)

Visual Inspection Workflow

flowchart TD
    A[Initial Rust Condition] --> B[Choose Cleaning Method]
    B --> C[Execute Cleaning]
    C --> D[Compare with IS 9954 Reference Prints]
    D -->|If Match| E[Accept Surface]
    D -->|If No Match| B

Summary: Utilize IS 9954 pictorial prints for visual verification of surface cleanliness. Follow cleaning standards in IS 1477 to attain required preparation grades ensuring effective paint adhesion and corrosion resistance.

IS 9954: Use of Pictorial Prints for Assessing Steel Surface Preparation

Highlights on Pictorial Print Usage (Clause 5.1)

• Objective: To unify visual assessment of steel surface cleanliness prior to coating.
• Procedure (5.1.1 to 5.1.3):
  1. Visual Matching: Compare the prepared steel surface against pictorial prints depicting various cleanliness levels.
  2. Evaluation: Determine the closest match to identify surface condition (rust grade, millscale presence).
  3. Decision: Decide on acceptance or further preparation based on this comparison.

Specifications

• Surface Grades: Prints depict cleanliness from mill scale, rust grades (A-D), to near-white metal states.
• Visual Assessment: Enables quick, consistent evaluation without specialized instruments.

Practical Steps

Summary

IS 9954 offers pictorial print references as a practical tool for consistent surface condition assessment before painting.

flowchart TD
    A[Steel Surface] --> B{Visual Comparison}
    B -->|Print Match| C[Identify Cleanliness Grade]
    C --> D{Meets Specification?}
    D -->|Yes| E[Proceed to Paint Application]
    D -->|No| F[Continue Surface Preparation]

This approach simplifies quality control by employing standardized visual benchmarks.

IS 9954: Surface Preparation Designations – Key Details

• Initial Surface Condition (Rust Grade): Indicates the rust status before cleaning, e.g., Grade B.
• Preparation Grade: Level of cleaning achieved, expressed as a number from 1 to 6 based on cleaning technique.
• Cleaning Methods:
  • Manual cleaning (scraping/wire brushing) denoted by "St".
  • Abrasive blast cleaning denoted by "Sa".

Format of Designation:

[Initial Rust Grade] + [Cleaning Method] + [Preparation Grade]

Examples:

Summary of Preparation Grades (Indicative):

flowchart LR
    A[Initial Rust Grade] --> B[Cleaning Process]
    B --> C[Preparation Grade]
    C --> D[Surface Designation e.g. BSt 2 or B Sa 2]

The pictorial standards help visually define these grades for practical field use.

IS 9954: Basic Guidelines for Preparing Steel Surfaces

• Initial Rust Conditions: Four rust grades describe the initial steel surface state, from light to heavy rust.

• Preparation Grades: Six levels define the cleaning intensity based on methods such as hand tool, power tool, or blast cleaning.

• Reference Standards:

  • ISO 8501-1:2007 provides visual standards for rust and preparation grades.
  • IS 1477 (Part 1):2000 recommends cleaning techniques for various preparation grades.

• Important Notes:

  • The quality of surface preparation strongly influences the lifespan of anticorrosive coatings.
  • Until updated prints are available, use Swedish SIS 05 5900-1967 pictorial standards as visual guides.
  • Cleaning methods must correspond appropriately to the initial rust grade and desired preparation grade.

Conceptual Summary Table

Practical Recommendations

• Visual Inspection: Employ ISO 8501-1 pictorial standards for surface evaluation.
• Cleaning Selection: Follow IS 1477 guidance based on rust and preparation requirements.
• Surface Condition: Ensure absence of oils, grease, dirt, and loose rust prior to painting.

flowchart TD
    A[Initial Rust Grade] --> B{Choose Cleaning Method}
    B -->|Light Rust| C[Hand/Power Tool Cleaning]
    B -->|Moderate Rust| D[Power Tool/Blast Cleaning]
    B -->|Heavy Rust| E[Blast Cleaning]
    C --> F[Achieve Desired Preparation Grade]
    D --> F
    E --> F

IS 9954: Cross-References to Related Standards

IS 9954 mainly focuses on surface preparation standards for painting steel surfaces. Important related standards include:

• IS 9953: Code of practice for painting ferrous metals in buildings – Part I: Surface pretreatment.
• IS 9954: Pictorial standards for surface preparation.
• IS 5: Guidelines for rounding numerical values (latest revision).

Key Notes:

• Surface prep requirements align with IS 9953 for pretreatment procedures.
• Numerical rounding should conform to IS 5 rules.
• Visual pictorial standards offer guidance for assessing surface cleanliness and preparation.

Typical Surface Preparation Sequence (per IS 9953 & IS 9954):

• Remove rust, mill scale, and contaminants mechanically or chemically.
• Attain cleaning levels such as St 2 (hand tool) or St 3 (power tool).
• Employ abrasive blasting to achieve near-white metal condition (Sa 2½).

flowchart LR
    A[Raw Steel Surface] --> B[Remove Rust and Scale]
    B --> C[Mechanical Cleaning (St 2 / St 3)]
    C --> D[Abrasive Blasting (Sa 2½)]
    D --> E[Apply Primer and Paint]

For detailed visuals and procedures, consult the original IS 9954 and IS 9953 documentation.