Pictorial Surface Preparation Standards for Painting of Steel Surfaces

IS 9954: Pictorial Surface Preparation Standards for Painting of Steel Surfaces (1981)

Foreword Key Points:

• Purpose: Standardizes surface preparation for painting ferrous metals in buildings.
• Scope: Focuses on pretreatment methods ensuring paint adhesion and durability.
• Definitions (Clause 2.0): Clarifies terminology related to surface preparation.
• Rounding Rules (Clause 2.6): Revised rules for numerical value rounding in measurements.
• Amendment (2010): Updated pictorial standards for surface preparation quality.

Important Specifications:

• Surface Preparation Grades: Visual pictorial standards define cleanliness levels (e.g., Rust Grades, Surface Profiles).
• Pretreatment Methods: Includes cleaning, rust removal, and surface profiling before painting.
• Numerical Rounding: Ensures consistency in measurement reporting.

Typical Surface Preparation Grades (summary):

flowchart LR
    A[Steel Surface] --> B[Cleaning]
    B --> C[Rust Removal]
    C --> D[Surface Profiling]
    D --> E[Painting]

This standard ensures optimal paint adhesion and longevity by defining clear surface preparation criteria.

IS 9954: Scope Summary

IS 9954 primarily covers surface preparation and painting of ferrous metals in buildings, focusing on:

• Pretreatment of steel surfaces before painting.
• Ensuring durability and protection against corrosion.
• Standardizing surface preparation methods (e.g., cleaning, rust removal).

Key Points from Scope (Clause 2.0 & related):

• Applies to ferrous metal surfaces in building construction.
• Defines surface preparation standards to ensure paint adhesion.
• Includes pictorial standards for surface cleanliness levels.
• Covers rules for rounding off numerical values in measurements (Clause 2.6).

Typical Surface Preparation Grades (from pictorial standards):

General Formula for Paint Thickness:

[ \text{Total Dry Film Thickness (D.F.T)} = \sum \text{(Thickness of each coat)} ]

Recommended D.F.T: 50 to 100 microns depending on exposure.

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

This standard ensures uniform surface prep for effective painting and corrosion resistance.

IS 9954: Definitions & Rounding Rules (Clause 2.0 & 2.6)

• Clause 2.0: Defines terminology used throughout IS 9954 to ensure uniform understanding.
• Clause 2.6: Specifies rules for rounding off numerical values to maintain consistency in calculations and reporting.

Key Rounding Rules (Typical practice in IS codes):

• Values ending in 5 are rounded to the nearest even digit (e.g., 2.5 → 2, 3.5 → 4).
• Values are rounded off to the number of decimal places specified in the relevant clause.
• Intermediate calculations should retain extra decimals to minimize cumulative rounding errors.

Example Table for Rounding Off:

Summary:

• Use standard rounding rules as per Clause 2.6.
• Definitions ensure clarity and uniformity in terminology.
• Always check the specific decimal precision required in related clauses.

flowchart TD
    A[Start: Numerical Value] --> B{Is digit after rounding place <5?}
    B -- Yes --> C[Round down]
    B -- No --> D{Is 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 value]
    F --> G

IS 9954: Rust Grades of Steel Surfaces

Rust Grades (Clause 3.1)

Surface Preparation Grades (Clause 1.1 & 4)

• Scraping & Wire Brushing:

  • St 2: Thorough scraping and wire brushing to remove loose rust and millscale.
  • St 3: Thorough scraping and wire brushing to remove rust, millscale, and foreign matter.

• Blast Cleaning:

  • Sa 1: Light blast cleaning.
  • Sa 2: Thorough blast cleaning (visually free from all rust, millscale, and foreign matter).
  • Sa 2½: Very thorough blast cleaning (near white metal finish).
  • Sa 3: Blast cleaning to visually clean white metal.

Summary

• Rust grade determines initial surface condition (A to D).
• Preparation grade depends on cleaning method and desired cleanliness (St 2/St 3 for manual; Sa 1 to Sa 3 for blast cleaning).
• Proper matching of rust grade and preparation grade ensures optimal paint adhesion and durability.

flowchart TD
    A[Rust Grades] -->|Initial Surface| B[Preparation Grades]
    B --> C[St 2 / St 3 (Manual Cleaning)]
    B --> D[Sa 1 / Sa 2 / Sa 2½ / Sa 3 (Blast Cleaning)]

This classification guides surface treatment prior to painting for corrosion protection.

IS 9954: Preparation Grades and Cleaning Procedures - Key Points

• Surface Condition Terms:

  • Rust Grades: Initial condition of steel surface before cleaning.
  • Preparation Grades: Degree of cleaning achieved after surface treatment.

• Preparation Grades Classification:

  • Six degrees of cleaning (St and Sa grades) based on cleaning method.
  • Four initial rust conditions defined.

• Cleaning Techniques Reference:

  • Detailed cleaning methods for each grade are in IS 1477 (Part I)-1971.

• Procedure:

  • Compare cleaned surface visually with full-scale colour prints (per Clause 1.1.1).
  • Continue cleaning until the surface matches the required preparation grade print (Clause 5.1.3).

Typical Preparation Grades (per IS 9954 & IS 1477)

Visual Comparison Workflow

flowchart TD
    A[Initial Rust Grade] --> B[Select Cleaning Procedure]
    B --> C[Perform Cleaning]
    C --> D[Compare Surface with IS 9954 Prints]
    D -->|Match| E[Accept Surface]
    D -->|No Match| B

Summary:
Use IS 9954 prints for visual comparison of surface finish post-cleaning. Follow IS 1477 for cleaning methods to achieve the required preparation grade ensuring proper paint adhesion and corrosion resistance.

IS 9954: Pictorial Surface Preparation Standards for Painting of Steel Surfaces

Key Points on Use of Pictorial Prints (Clause 5.1)

• Purpose: To standardize visual assessment of steel surface cleanliness before painting.
• Procedure (5.1.1 to 5.1.3):
  1. Visual Comparison: Match the prepared steel surface with pictorial prints representing various cleanliness grades.
  2. Assessment: Identify the closest match to determine the surface condition (e.g., rust grade, mill scale removal).
  3. Decision: Use this assessment to decide if further surface preparation is required.

Specifications

• Surface Grades: Pictorial prints illustrate cleanliness levels from mill scale, rust grades (A, B, C, D), to near-white metal.
• Visual Assessment: Enables quick, reliable, and uniform evaluation without complex instruments.

Practical Use

Summary

IS 9954 provides pictorial prints as a practical tool for surface assessment, ensuring uniformity in steel surface preparation before painting.

flowchart TD
    A[Steel Surface] --> B{Visual Comparison}
    B -->|Match with Print| C[Identify Cleanliness Grade]
    C --> D{Meets Spec?}
    D -->|Yes| E[Proceed to Painting]
    D -->|No| F[Further Surface Preparation]

This method simplifies quality control in surface preparation by using standardized visual references.

IS 9954: Designation of Prepared Surfaces – Key Points

• Initial Condition (Rust Grade): Steel surface condition before cleaning, e.g., Rust Grade B.
• Preparation Grade: Degree of cleaning achieved, numbered 1 to 6 depending on cleaning method.
• Cleaning Procedure Types:
  • Scraping or brushing (denoted as "St")
  • Blast cleaning (denoted as "Sa")

Designation Format:

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

Examples:

Summary Table of Surface Preparation Grades (Indicative):

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

Note: IS 9954 uses pictorial standards to visually define these grades for clarity in field application.

IS 9954: General Guidelines for Surface Preparation of Steel Surfaces

• Initial Conditions (Rust Grades):
  Four rust grades define the initial surface condition before painting, ranging from lightly rusted to heavily rusted steel.

• Preparation Grades (Degree of Cleaning):
  Six preparation grades specify the thoroughness of cleaning required, depending on the cleaning method used (e.g., hand tool cleaning, power tool cleaning, blast cleaning).

• Reference Standards:

  • ISO 8501-1:2007 — Visual assessment of rust and preparation grades with pictorial standards.
  • IS 1477 (Part 1):2000 — Recommended cleaning procedures for different preparation grades.

• Key Points:

  • Surface preparation quality directly affects the anticorrosive paint life.
  • Use pictorial standards (e.g., Swedish SIS 05 5900-1967) for visual grading until IS 9954 prints are updated.
  • Cleaning methods must match required preparation grade for the initial rust grade.

Summary Table (Conceptual)

Practical Recommendations

• Visual Inspection: Use ISO 8501-1 pictorial grades for assessment.
• Cleaning Procedure: Select method per IS 1477 based on rust grade and desired preparation grade.
• Surface Quality: Ensure no visible oil, grease, dirt, or loose rust before painting.

flowchart TD
    A[Initial Rust Grade] --> B{Select 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 Preparation Grade P

IS 9954: References to Related Standards

IS 9954 primarily deals with surface preparation standards for painting steel surfaces. Key related standards referenced include:

• IS 9953: Code of practice for painting ferrous metals in buildings – Part I: Pretreatment.
• IS 9954 itself covers pictorial surface preparation standards.
• IS 5: Rules for rounding off numerical values (revised).

Key Points:

• Surface preparation standards align with IS 9953 for pretreatment.
• Numerical values in the code should be rounded as per IS 5.
• The code references pictorial standards for visual guidance on surface cleanliness and preparation.

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

• Remove rust, mill scale, and contaminants by mechanical or chemical means.
• Achieve cleanliness levels such as St 2 (hand tool cleaning) or St 3 (power tool cleaning).
• Use abrasive blasting for near-white metal finish (Sa 2½).

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

For detailed pictorial references, consult IS 9954 and IS 9953 documents directly.